Advanced Forming Technology of Metallic Materials

Topic Information

Dear Colleagues,

Metallic materials have extensive applications in diverse areas, including aerospace, construction, automobile, machinery, electronics, medical devices, and many other things that are commonly found in our daily lives. The forming of metallic materials is the final stage of metallurgical manufacturing for the fabrication of metalware that is used in the national economy as the finished products or as the billets for further processing. The forming operation helps to give raw metallic materials the required shape and size by subjecting them to plastic deformation through the application of tensile force, compressive force, bending or shear force, or a combination of these forces. The variety of forming technologies of metallic materials permits the fabrication of a wide range of metal products with high productivity, exact dimensions, and required mechanical properties. Especially with the increasing demand for high-quality products and the rapid development of science and technology, advanced forming technologies of metallic materials have been successfully developed in recent years.

This Topic provides an excellent opportunity for those who are studying and working with the advanced forming technology of metallic materials. Research papers, review articles, and communications relating to the theory, simulation, and practice of sheet, bulk, and powder forming and the related forming processes and equipment of metallic materials are all invited to this Topic.

Prof. Dr. Jingwei Zhao
Prof. Dr. Zhengyi Jiang
Prof. Dr. Leszek Adam Dobrzański
Prof. Dr. Chong Soo Lee
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Alloys alloys	-	-	2022	22.5 Days	CHF 1000
Applied Sciences applsci	2.5	5.3	2011	18.4 Days	CHF 2400
Materials materials	3.1	5.8	2008	13.9 Days	CHF 2600
Metals metals	2.6	4.9	2011	17.8 Days	CHF 2600
Inventions inventions	2.1	4.8	2016	18.5 Days	CHF 1800

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13 pages, 8782 KiB  

Open AccessArticle

Study of Copper/Aluminum Bimetallic Tube Rotary Ring Spinning Composite Forming Characteristics

by Chen Wang, Binkai Zhang, Dongfang Yao, Zhuangzhuang Tian and Chunjiang Zhao

Appl. Sci. 2023, 13(8), 4727; https://doi.org/10.3390/app13084727 - 9 Apr 2023

Cited by 3 | Viewed by 2227

Abstract

As a plastic forming process developed based on rotary wheel spinning technology, the rotary ring spinning process has the excellent characteristics of high forming accuracy and high material utilization rate, and has been gradually applied to the manufacture of bimetallic composite pipes. In [...] Read more.

As a plastic forming process developed based on rotary wheel spinning technology, the rotary ring spinning process has the excellent characteristics of high forming accuracy and high material utilization rate, and has been gradually applied to the manufacture of bimetallic composite pipes. In this paper, the forming law of a bimetallic tube in the process of rotary ring spinning was analyzed by numerical simulation and experimentation. The results show that the deformation coordination of the basic and cover tubes increased with the increasing press amount, and the feed ratio had less of an effect on the thickness variation. In addition, the three-way strain of the basic and cover tubes and the degree of influence of the process parameters on the equivalent strain of the tubes were also studied. The results show that the radial strain on both tubes was the largest, followed by the axial strain, and the tangential strain was the smallest; the press amount had the largest effect on the equivalent strain of the tubes, followed by the angle of attack and the feed ratio. These results provide some guidance for the manufacture of high-performance bimetallic composite tubes by rotary ring spinning. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 10797 KiB  

Open AccessArticle

Application of Mean Modulus in Three-Point Bending and Roll Forming

by Menglong Xing, Haijun Wang, Jiyan Liu, Yutao Fu and Fengshan Du

Materials 2023, 16(7), 2571; https://doi.org/10.3390/ma16072571 - 23 Mar 2023

Cited by 3 | Viewed by 2048

Abstract

Nonlinear unloading plays an important role in predicting springback during plastic forming process. To improve the accuracy of springback prediction which could provide a guide for precision forming, uniaxial tensile tests and uniaxial loading–unloading–loading tensile tests on SUS304 stainless steel were carried out. [...] Read more.

Nonlinear unloading plays an important role in predicting springback during plastic forming process. To improve the accuracy of springback prediction which could provide a guide for precision forming, uniaxial tensile tests and uniaxial loading–unloading–loading tensile tests on SUS304 stainless steel were carried out. The flow stress mathematical model and chord modulus mathematical model were calibrated according to the test results. A constant elastic modulus three-point bending finite element model ($E_{0}FEMB$) and a constant elastic modulus roll forming finite element model ($E_{0}FEMR$) were established in MSC.MARC. The chord modulus was output by the PLOTV subroutine to determine the mean modulus of different regions, and the mean modulus three-point bending finite element model (${\overline{E}}_{c}FEMB$) and the mean modulus roll forming finite element model (${\overline{E}}_{c}FEMR$) were defined. The constant modulus finite element model ($E_{0}FEM$) simulation results and the mean modulus finite element model (${\overline{E}}_{c}FEM$) simulation results were compared with the three-point bending tests and roll forming tests test results. The difference between the simulation results and the test results was small, indicating that the mean modulus was feasible to predict the springback, which verified the suitability of the ${\overline{E}}_{c}FEM$. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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18 pages, 7222 KiB  

Open AccessArticle

Research on Microstructure and Mechanical Properties of Laser Welding of BR1500HS Joints

by Yongwang Kang, Xi Xia, Chundong Zhu and Raofu Wu

Appl. Sci. 2023, 13(6), 3490; https://doi.org/10.3390/app13063490 - 9 Mar 2023

Cited by 2 | Viewed by 1591

Abstract

In this research, BR1500HS high strength steel was laser welded under various process parameters. The welded samples were heated in a furnace for 5 min with a temperature of 900 °C and then water-quenched. The effects of process parameters and quenching process on [...] Read more.

In this research, BR1500HS high strength steel was laser welded under various process parameters. The welded samples were heated in a furnace for 5 min with a temperature of 900 °C and then water-quenched. The effects of process parameters and quenching process on mechanical properties and microstructure of the joints were investigated. The results show that when the heat input is 1440 J/cm, the best mechanical properties of the welded joint can be obtained. When the welding speed increases, the minimum hardness increases, and the width of the softened area decreases; while the laser power increases, the width of the softened area increases, and the minimum hardness does not change significantly. As the welding speed increases, the front-bead width A, back-bead width B, and the height of smooth segment H all decrease; while the laser power increases, the back-bead width B increases, the front-bead width A and the height of the smooth segment H increase first and then decrease. The front-bead width A reaches the maximum when the laser power is 3000 W and the height of the smooth segment H does not change much. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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13 pages, 8614 KiB  

Open AccessArticle

Process Optimization of the Hot Stamping of AZ31 Magnesium Alloy Sheets Based on Response Surface Methodology

by Pengjing Zhao, Qi Wu, Yo-Lun Yang and Zhanghua Chen

Materials 2023, 16(5), 1867; https://doi.org/10.3390/ma16051867 - 24 Feb 2023

Cited by 5 | Viewed by 2230

Abstract

Hot stamping is an important manufacturing process for sheet metal parts. However, it is easy to produce defects such as thinning and cracking in the drawing area during the stamping process. In this paper, the finite element solver ABAQUS/Explicit was used to establish [...] Read more.

Hot stamping is an important manufacturing process for sheet metal parts. However, it is easy to produce defects such as thinning and cracking in the drawing area during the stamping process. In this paper, the finite element solver ABAQUS/Explicit was used to establish the numerical model of the magnesium alloy hot-stamping process. The stamping speed (2~10 mm/s), the blank-holder force (3~7 kN), and the friction coefficient (0.12~0.18) were selected as the influencing factors. Taking the maximum thinning rate obtained through simulation as the optimization objective, the response surface methodology (RSM) was applied to optimize the influencing factors in sheet hot stamping at a forming temperature of 200 °C. The results showed that the maximum thinning rate of sheet metal was most influenced by the blank-holder force, and the interaction between the stamping speed and the blank-holder force/friction coefficient had a great influence on the maximum thinning rate. The optimal value of the maximum thinning rate of the hot-stamped sheet was 7.37%. Through the experimental verification for the hot-stamping process scheme, the maximum relative error between the simulation and the experimental results was 8.72%. This proves the accuracy of the established finite element model and the response surface model. This research provides a feasible optimization scheme for the analysis of the hot-stamping process of magnesium alloys. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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19 pages, 6329 KiB  

Open AccessArticle

Mechanical Properties of B1500HS/AA5052 Joints by Self-Piercing Riveting

by Yong-Chao Zhang, Zhi-Chao Huang, Yu-Qiang Jiang and Ying-Lian Jia

Metals 2023, 13(2), 328; https://doi.org/10.3390/met13020328 - 6 Feb 2023

Cited by 9 | Viewed by 2219

Abstract

Self-piercing riveting (SPR) is a suitable technology to join various materials and has attracted more attention in the automotive industry. In this work, the effects of forming parameters on the forming qualities and mechanical properties of B1500HS steel/AA5052 aluminum alloy SPR joints were [...] Read more.

Self-piercing riveting (SPR) is a suitable technology to join various materials and has attracted more attention in the automotive industry. In this work, the effects of forming parameters on the forming qualities and mechanical properties of B1500HS steel/AA5052 aluminum alloy SPR joints were analyzed. The results show that the sheet stack sequence has little influence on the peak tensile load and rigidity of SPR joints. When the steel sheet is placed on the aluminum sheet, the failure displacement, energy absorption, and ductility factor are, respectively, 2.77, 2.13, and 2.28 times larger than those of the joints with the aluminum sheet placed on the steel sheet. The SPR joints with steel sheets placed on aluminum sheets have better mechanical stability. Meanwhile, when the steel sheet is placed on the aluminum sheet, the fatigue life of the joint can be increased by about 98.4%, 88.3%, and 118.1%, respectively, under high, medium, and low fatigue loads. A joint with opposite riveting direction has the optimal fatigue performance and the fatigue life is 1.64 and 2.14 times those of the other two-rivet joints. Generally, the fatigue fractures of aluminum alloy sheets in SPR joints occurred in fatigue tests. The fatigue fracture of a joint with a steel sheet stacked on an aluminum sheet extends uni-directionally to the edge of the sheet from the riveting point, while a symmetric fatigue crack of aluminum occurs for joints with the opposite sequence. The distribution of fatigue cracks is related to fatigue load, and fatigue cracks mainly originate in the fretting wear area of the contact interface between the rivet leg, upper sheet, and lower sheet. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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23 pages, 30086 KiB  

Open AccessArticle

Finite Element Analysis of Split Sleeve Cold Expansion Process on Multiple Hole Aluminum Alloy

by Yuan Lv, Meng’en Dong, Teng Zhang, Changkai Wang, Bo Hou and Changfan Li

Materials 2023, 16(3), 1109; https://doi.org/10.3390/ma16031109 - 27 Jan 2023

Cited by 12 | Viewed by 2317

Abstract

Multiple cold expansion holes are widely used in connection areas of aircraft structures, in order to achieve uniform load transfer of the skin or connection parts. Split sleeve cold expansion (SSCE) is widely used to enhance the fatigue life of fastener holes by [...] Read more.

Multiple cold expansion holes are widely used in connection areas of aircraft structures, in order to achieve uniform load transfer of the skin or connection parts. Split sleeve cold expansion (SSCE) is widely used to enhance the fatigue life of fastener holes by applying compressive residual stresses around the holes. In this study, the finite element method (FEM) was used to research the distribution and variation of residual stresses along the hole edges of 7075AA single-hole and multi-hole cold expansion (CE) specimens. Full-field strain measurements of single-hole and multi-hole specimens were performed using two-dimensional digital image correlation (DIC), and the residual stress and strain at the hole edge of the specimens measured by FEM and DIC were compared. FEM results shows that the maximum circumferential and radial residual stresses of three-hole specimens with three-hole spacing are increased by 5.37% and 31.53% compared with single-hole specimens. The maximum circumferential residual stress of three-hole specimens with four-hole spacing increases by 7.25% compared with a single hole, but the radial residual stress decreases by 12.98%. In addition, for three-hole specimens with hole spacing three times the hole diameter, the strengthening effect of SSCE in the order of middle hole, then left hole, and, finally, right hole is better than that of SSCE in the order of left to right hole. FEM and DIC full-field strain results are basically consistent. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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21 pages, 7520 KiB  

Open AccessArticle

Research on the Curvature Prediction Method of Profile Roll Bending Based on Machine Learning

by Hongqiang Cao, Gaochao Yu, Tong Liu, Pengcheng Fu, Guoyan Huang and Jun Zhao

Metals 2023, 13(1), 143; https://doi.org/10.3390/met13010143 - 10 Jan 2023

Cited by 7 | Viewed by 2532

Abstract

Roll-bending technology has a high degree of flexibility and does not require special molds. However, based on the existing plastic mechanics theory and finite element simulation, it is difficult to accurately analyze the complex spatial relationship of profile roll forming. Therefore, a fixed-curvature [...] Read more.

Roll-bending technology has a high degree of flexibility and does not require special molds. However, based on the existing plastic mechanics theory and finite element simulation, it is difficult to accurately analyze the complex spatial relationship of profile roll forming. Therefore, a fixed-curvature prediction model is constructed based on XGBoost (extreme gradient boosting), and the coupling effect of the process parameters and material performance parameters on the roll-forming process is explored. Combined with a Bayesian optimization algorithm, the hyperparameters of the fixed-curvature prediction model are optimized. In addition, based on the prediction result of the fixed curvature, a variable-curvature prediction model is established using the conditional random field (CRF). To further improve the prediction accuracy, an error compensation network is added after the result of the CRF in order to map the discrete sequence to the continuous sequence. The experimental results show that the mean square error (MSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) predicted by the models above are much smaller than other methods, which verifies the superiority of the prediction models. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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8 pages, 1992 KiB  

Open AccessFeature PaperArticle

Identifying Optimal Hot Forming Conditions for AA6010 Alloy by Means of Elevated Temperature Tensile Testing

by Scott Taylor, Sisir Dhara, Carl Slater and Hiren Kotadia

Metals 2023, 13(1), 76; https://doi.org/10.3390/met13010076 - 28 Dec 2022

Cited by 1 | Viewed by 1958

Abstract

AA6010 in the F temper was investigated using a Gleeble 3800 test rig across a range of temperatures (350–550 °C) and strain rates (1 × 10⁻¹ s⁻¹ 1 × 10¹ s⁻¹) to identify optimal forming conditions. Post-forming electron [...] Read more.

AA6010 in the F temper was investigated using a Gleeble 3800 test rig across a range of temperatures (350–550 °C) and strain rates (1 × 10⁻¹ s⁻¹ 1 × 10¹ s⁻¹) to identify optimal forming conditions. Post-forming electron back-scattered diffraction analysis was conducted to identify the mechanisms responsible for the material formability. Optimal forming conditions were observed to be 500 °C and a strain rate of 1 × 10⁻¹ s⁻¹, with clear evidence of dynamic recrystallisation observed, this being the dominant mechanism responsible for the increased formability. Peak yield strength of 335 MPa was achieved using a rapid aging treatment of 205 °C for one hour. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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17 pages, 14115 KiB  

Open AccessFeature PaperArticle

Prediction and Optimization of Wear Depth on Rectangular Tube Surface in Roll Forming

by Menglong Xing, Jiyan Liu, Yuhao Wang, Zhanrui Wang, Yutao Fu and Fengshan Du

Metals 2023, 13(1), 68; https://doi.org/10.3390/met13010068 - 26 Dec 2022

Cited by 1 | Viewed by 1928

Abstract

The outer surface of the tube is worn under the interaction between the velocity difference and rolling pressure, in the process of rolling the circular tube into a rectangular tube. In order to predict the wear depth, according to the characteristics of roll [...] Read more.

The outer surface of the tube is worn under the interaction between the velocity difference and rolling pressure, in the process of rolling the circular tube into a rectangular tube. In order to predict the wear depth, according to the characteristics of roll forming, the causes of wear in the forming process are analyzed. The finite element model of rolling forming was established based on Archard theory, and the 40 mm × 27.5 mm × 3 mm SUS304 stainless steel rectangular tube was simulated. The simulated results were compared with a test rolling of the steel tubes of the same size material, and the wear areas were found to be highly consistent, which verified the accuracy of the finite element model. The effects of the friction coefficient and the flat roller angular velocity on the simulation results which wear depth were analyzed, and the regression model of wear depth was established by response surface method. The results showed that the flat roller angular velocity had the greatest effect on wear depth; moreover, the flat roller friction coefficient was the second, and the vertical roller friction coefficient was the lowest. The minimum value of the regression model was optimized, the simulation value of the optimization scheme was compared with the optimized value, and the error of the two values was less than 5%, which verified the correctness of the regression model. The wear depth of the rectangular tube after optimization was reduced by 64.69% compared with that before optimization, which verified the effectiveness of the optimization results. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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8 pages, 3013 KiB  

Open AccessArticle

Electron Beam-Induced Reduction of Cuprite

by Anna Siudzinska, Sandeep M. Gorantla, Jaroslaw Serafinczuk, Robert Kudrawiec, Detlef Hommel and Alicja Bachmatiuk

Metals 2022, 12(12), 2151; https://doi.org/10.3390/met12122151 - 15 Dec 2022

Cited by 3 | Viewed by 1770

Abstract

Cu-based materials are used in various industries, such as electronics, power generation, and catalysis. In particular, monolayered cuprous oxide (Cu₂O) has potential applications in solar cells owing to its favorable electronic and magnetic properties. Atomically thin Cu₂O samples derived [...] Read more.

Cu-based materials are used in various industries, such as electronics, power generation, and catalysis. In particular, monolayered cuprous oxide (Cu₂O) has potential applications in solar cells owing to its favorable electronic and magnetic properties. Atomically thin Cu₂O samples derived from bulk cuprite were characterized by high-resolution transmission electron microscopy (HRTEM). Two voltages, 80 kV and 300 kV, were explored for in situ observations of the samples. The optimum electron beam parameters (300 kV, low-current beam) were used to prevent beam damage. The growth of novel crystal structures, identified as Cu, was observed in the samples exposed to isopropanol (IPA) and high temperatures. It is proposed that the exposure of the copper (I) oxide samples to IPA and temperature causes material nucleation, whereas the consequent exposure via e-beams generated from the electron beam promotes the growth of the nanosized Cu crystals. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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17 pages, 4275 KiB  

Open AccessArticle

Numerical and Experimental Studies on the Load Characteristics of Geometric Interference of Steel-Aluminum Knurled Interference Fit

by Chi-Peng Chen, Marlon Ho, Tomi-T. Li and Yiin-Kuen Fuh

Metals 2022, 12(12), 2078; https://doi.org/10.3390/met12122078 - 3 Dec 2022

Viewed by 2255

Abstract

This research studied the knurled interference fits (KIF) jointing process, which involves connection via a shaft and hub. KIF are widely used in many industries and products, but the related research is limited, especially in the case of auto parts. To confirm the [...] Read more.

This research studied the knurled interference fits (KIF) jointing process, which involves connection via a shaft and hub. KIF are widely used in many industries and products, but the related research is limited, especially in the case of auto parts. To confirm the optimal parameters for KIF joining, two different simulations in the finite element method (FEM), two hub thicknesses, three geometry versions, and four coefficients of friction (COF) were adopted to simulate the KIF forming process in this study. All the parameters were investigated in detail and accurately referred to experimental examination outcomes. The simulations and the experimental results offered explicit explanations of the relationship between jointing force and geometry dimensions. The hub-forming shape and the simulation of hoop deformation were analyzed, and the analysis results provide useful suggestions for other related industrial research as well. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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18 pages, 7242 KiB  

Open AccessArticle

A Comparison and Analysis of Three Methods of Aluminum Crown Forgings in Processing Optimization

by Chi-Peng Chen, Hui-Zhen Su, Jyun-Kai Shih, Cheng-Fu Huang, Hao-Yun Ku, Chien-Wei Chan, Tomi-T. Li and Yiin-Kuen Fuh

Materials 2022, 15(23), 8400; https://doi.org/10.3390/ma15238400 - 25 Nov 2022

Cited by 3 | Viewed by 1985

Abstract

In this study, three parameter optimization methods and two designs of experiments (DOE) were used for the optimization of three major design parameters ((bill diameter (D), billet length (L), and barrier wall design (BWD)) in crown forging to improve the formability of aluminum [...] Read more.

In this study, three parameter optimization methods and two designs of experiments (DOE) were used for the optimization of three major design parameters ((bill diameter (D), billet length (L), and barrier wall design (BWD)) in crown forging to improve the formability of aluminum workpiece for shock absorbers. The first optimization method is the response surface method (RSM) combined with Box–Behnken’s experimental design to establish fifteen (15) sets of parameter combinations for research. The second one is the main effects plot method (MEP). The third one is the multiobjective optimization method combined with Taguchi’s experimental design method, which designed nine (9) parameter combinations and conducted research and analysis through grey relational analysis (GRA). Initially, a new type of forging die and billet in the controlled deformation zone (CDZ) was established by CAD (computer-aided design) modeling and the finite element method (FEM) for model simulation. Then, this investigation showed that the optimal parameter conditions obtained by these three optimization approaches (RSM, MEP, and multiobjective optimization) are consistent, with the same results. The best optimization parameters are the dimension of the billet ((D: 40 mm, the length of the billet (L): 205 mm, and the design of the barrier wall (BWD): 22 mm)). The results indicate that the optimization methods used in this research all have a high degree of accuracy. According to the research results of grey relational analysis (GRA), the size of the barrier wall design (BWD) in the controllable deformation zone (CDZ) has the greatest influence on the improvement of the preforming die, indicating that it is an important factor to increase the filling rate of aluminum crown forgings. At the end, the optimized parameters are verified by FEM simulation analysis and actual production validation as well as grain streamline distribution, processing map, and microstructure analysis on crown forgings. The novelty of this work is that it provides a novel preforming die through the mutual verification of different optimization methods to solve a typical problem such as material underfill. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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10 pages, 3389 KiB  

Open AccessArticle

Effects of Laser Forming on the Mechanical Properties and Microstructure of DP980 Steel

by Wenbin Dong, Le Bao, Wenqi Li, Kyoosik Shin and Changsoo Han

Materials 2022, 15(21), 7581; https://doi.org/10.3390/ma15217581 - 28 Oct 2022

Cited by 3 | Viewed by 1664

Abstract

Due to its high strength and good plasticity, dual-phase (DP) steel is widely used for manufacturing the structural and reinforcement components of automobiles. Therefore, it is urgent to investigate the mechanical properties and microstructure variation in DP steel after deformation, especially those subjected [...] Read more.

Due to its high strength and good plasticity, dual-phase (DP) steel is widely used for manufacturing the structural and reinforcement components of automobiles. Therefore, it is urgent to investigate the mechanical properties and microstructure variation in DP steel after deformation, especially those subjected to hot-forming processes. In this study, the mechanical properties and microstructure of laser-formed DP980 steel plates under different laser parameters were investigated by means of monotonic tensile tests, microhardness tests, and metallographic tests. The results showed that both yield strength and tensile strength increased with increasing laser line energy in the range of 5~19 J/mm due to the increasing volume content of martensite laths. Elongation was slightly improved after the laser-forming process due to the existence of residual austenite. The average microhardness of the heat-affected zone also increased with an increase in laser line energy and reached a maximum of 412.8 HV_0.2—an improvement of 23.5% compared to that of the parent material. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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18 pages, 9276 KiB  

Open AccessArticle

The Rollers’ Offset Position Influence on the Counter-Roller Flow-Forming Process

by Chengcheng Zhu, Fan Li, Yuanzhe Dong, Shengdun Zhao, Jingxiang Lv and Dean Meng

Metals 2022, 12(9), 1471; https://doi.org/10.3390/met12091471 - 2 Sep 2022

Cited by 6 | Viewed by 1960

Abstract

Background: The general counter-roller flow-forming (CRFF) process rarely considers the roller’s offset position for the symmetric rollers. However, the rollers’ offset position can regulate the tube shape, force, and other features. Studying the novel asymmetric CRFF process, which is the CRFF process with [...] Read more.

Background: The general counter-roller flow-forming (CRFF) process rarely considers the roller’s offset position for the symmetric rollers. However, the rollers’ offset position can regulate the tube shape, force, and other features. Studying the novel asymmetric CRFF process, which is the CRFF process with the rollers’ offset position, is essential. Methods: The influence of the rollers’ offset position, the tube blank thickness, thickness reduction on the material deformation, flow-forming force, final tube middle radius, and thickness in the CRFF process are studied using AA5052 aluminum tube experiments and numerical simulation. Result: The final tubes with three tube blank thicknesses, four thickness reduction, and four rollers’ offset positions were obtained by the symmetric and asymmetric CRFF processes. Conclusions: AA5052 aluminum alloy tube can be made by the novel asymmetric CRFF process using a small rollers’ offset position (−17.5–0%). Different rollers’ positions could change the tube’s middle radius. With negative rollers’ offset position, the outer roller force is larger than the inner roller force. The force differences increase with the increase of tube blank thickness, the increase of thickness reduction, and the decrease of rollers’ offset position. The asymmetric CRFF process helps design and construct large tube flow-forming equipment. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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14 pages, 2188 KiB  

Open AccessArticle

Research on Conventional and High-Speed Machining Cutting Force of 7075-T6 Aluminum Alloy Based on Finite Element Modeling and Simulation

by Zhijie Wang, Yan Cao, Sergey Gorbachev, Victor Kuzin, Weiliang He and Junde Guo

Metals 2022, 12(8), 1395; https://doi.org/10.3390/met12081395 - 22 Aug 2022

Cited by 10 | Viewed by 2991

Abstract

In current industrial practice, the finite element modeling of the metal cutting process is essential. In this paper, finite element analysis of conventional and high-speed cutting of 7075-T6 aluminum alloy is carried out. A finite element model of the 7075-T6 aluminum alloy was [...] Read more.

In current industrial practice, the finite element modeling of the metal cutting process is essential. In this paper, finite element analysis of conventional and high-speed cutting of 7075-T6 aluminum alloy is carried out. A finite element model of the 7075-T6 aluminum alloy was developed using the Johnson Cook instant on equation to investigate the milling behavior of the alloy under conventional and high-speed conditions. The cutting forces in the X-direction, Y-direction, and Z-direction were predicted analytically for five groups of different Johnson Cook models with different material constants, and the predicted results were compared with the experimentally determined cutting forces to investigate the influence of the Johnson Cook constitutive model parameters on the simulation of the cutting forces of the 7075-T6 aluminum alloy. The results showed that the constitutive model parameters are inconsistent for conventional and higher speed cutting conditions. Under conventional cutting conditions, the JC4 model predicts the material factor cutting forces in good agreement with the experimental results, while under high-speed cutting conditions, the JC5 model predicts the material factor cutting forces in good agreement with the experimental results, but that the finite element model has good applicability in predicting machining performance. Only the experimental data obtained by covering the real strain, strain rate and temperature range to determine the material constant of the Johnson Cook constitutive equation can accurately predict the cutting force in all directions. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 9129 KiB  

Open AccessArticle

Enhancement of Domain Wall Pinning in High-Temperature Resistant Sm₂Co₁₇ Type Magnets by Addition of Y₂O₃

by Zhuang Liu, Chaoyue Zhang, Haichen Wu, Renjie Chen and Aru Yan

Materials 2022, 15(15), 5160; https://doi.org/10.3390/ma15155160 - 25 Jul 2022

Cited by 5 | Viewed by 1726

Abstract

In this study, the effects of Y₂O₃ addition on the magnetic properties, microstructure and magnetization reversal behavior of Sm(Co_0.79Fe_0.09Cu_0.09Zr_0.03)_7.68 magnet were investigated. By addition of Y₂O₃, the [...] Read more.

In this study, the effects of Y₂O₃ addition on the magnetic properties, microstructure and magnetization reversal behavior of Sm(Co_0.79Fe_0.09Cu_0.09Zr_0.03)_7.68 magnet were investigated. By addition of Y₂O₃, the coercivity was increased from 21.34 kOe to 27.42 kOe at 300 K and from 5.14 kOe to 6.27 kOe at 823 K. A magnet with a maximum magnetic energy product of 9.86 MGOe at 823 K was obtained. With the interdiffusion of Y and Sm after appropriate addition, the Cu content within the cell boundary phase close to the oxide was detected to be nearly twice as high as that away from the oxide. We report for the first time that a collection of lamellar phases were formed on both sides of the inserted oxide, providing a strong pinning field against magnetic domain wall motion based on in-situ Lorentz TEM observation. Furthermore, the ordering process of the original magnet was delayed after Y₂O₃ addition, resulting in the refinement of cellular structure, which can also enhance the domain wall pinning ability of cellular structures based on micromagnetic simulation. However, excessive addition of Y₂O₃ led to large Cu-rich phase and Zr-rich impurity phase precipitated at the edge of the oxide, resulting in the destruction of cellular structures and a significant reduction in coercivity. This study provides a new technical approach to regulate the microstructure of Sm₂Co₁₇ type magnets. Addition of Y₂O₃ is expected to play a significant role in improvement of high temperature magnetic properties. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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14 pages, 36249 KiB  

Open AccessArticle

Numerical Investigation on Comparison of Electromagnetic Forming and Drawing for Electromagnetic Forming Characterization

by Mirae Lim, Hanbi Byun, Yunjun Song, Jungsoo Park and Jeong Kim

Metals 2022, 12(8), 1248; https://doi.org/10.3390/met12081248 - 25 Jul 2022

Cited by 4 | Viewed by 1830

Abstract

Due to environmental regulations, vehicle weight reduction technology has recently emerged as a key factor influencing market competitiveness in the automobile industry. Although the demand for aluminum alloy for vehicle weight reduction is increasing, its application in the automobile industry is limited due [...] Read more.

Due to environmental regulations, vehicle weight reduction technology has recently emerged as a key factor influencing market competitiveness in the automobile industry. Although the demand for aluminum alloy for vehicle weight reduction is increasing, its application in the automobile industry is limited due to its low formability. Electromagnetic forming (EMF) technology has been proposed as a method to improve the low formability of aluminum alloys. EMF is a technology of forming a metal workpiece at high speed without physical contact by applying a strong electromagnetic field to the workpiece to be formed. In this study, we performed an analytical study on the characteristics of electromagnetic forming. Finite element analysis was performed with the same model as in the general drawing process, and the results of the forming process, formability, and finite element analysis were compared. Through the results of finite element analysis, it was confirmed that the EMF process showed significant deformation at the die shoulder and center. Furthermore, EMF has an advantage in formability due to having a smaller amount of sheet inflow than the drawing process; however, its forming accuracy is low. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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17 pages, 6008 KiB  

Open AccessArticle

Combination of Scanning Strategies and Optimization Experiments for Laser Beam Powder Bed Fusion of Ti-6Al-4V Titanium Alloys

by Wentian Shi, Jihang Li, Yanlong Jing, Yude Liu, Yuxiang Lin and Yufan Han

Appl. Sci. 2022, 12(13), 6653; https://doi.org/10.3390/app12136653 - 30 Jun 2022

Cited by 15 | Viewed by 2960

Abstract

This paper studies the effects of different combinations of scanning strategies between layers on the surface quality, tensile properties, and microstructure of samples in a laser beam powder bed fusion (L-PBF) formation experiment of Ti-6Al-4V titanium alloy. The purpose of this experiment was [...] Read more.

This paper studies the effects of different combinations of scanning strategies between layers on the surface quality, tensile properties, and microstructure of samples in a laser beam powder bed fusion (L-PBF) formation experiment of Ti-6Al-4V titanium alloy. The purpose of this experiment was to improve the comprehensive performance of the piece by selecting the optimal combination of scanning strategies. The results show that the surface roughness of the L-PBF specimen was the lowest under the combination of the CHESS scanning strategy, reaching 14 μm. The surface hardness of the samples was generally higher with the LINE scanning strategy and the angle offset of 90°, reaching 409 HV. The overall density of the samples was higher under the combination of CHESS scanning strategies, reaching 99.88%. Among them, the CHESS&45° sample had the best comprehensive properties, with a density of 99.85%, a tensile strength of up to 1125 MPa, a yield strength of 912 MPa, and an elongation of 8.2%. The fractured form was a ductile fracture, with many dimple structures. Compared with the CHESS scanning strategy, the tensile properties of the CHESS&45° samples were improved by 12.8%. The microstructure of the L-PBF sample was mainly composed of the primary β phase and α’ martensite phase. The upper surface of the CHESS scanning strategy combination sample had a clear melt channel, and the distribution of each phase was uniform. A certain number of columnar β crystals were distributed in the longitudinal section of the sample, which was paralleled to the build direction. The columnar β crystals of CHESS&45° were relatively coarse, which enhanced the tensile properties of the sample. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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11 pages, 13905 KiB  

Open AccessArticle

Texture-Less Shiny Objects Grasping in a Single RGB Image Using Synthetic Training Data

by Chen Chen, Xin Jiang, Shu Miao, Weiguo Zhou and Yunhui Liu

Appl. Sci. 2022, 12(12), 6188; https://doi.org/10.3390/app12126188 - 17 Jun 2022

Cited by 4 | Viewed by 2434

Abstract

In the industrial domain, estimating the pose of texture-less shiny parts is challenging but worthwhile. In this study, it is impractical to utilize texture information to obtain the pose because the features are likely to be affected by the surrounding objects. In addition, [...] Read more.

In the industrial domain, estimating the pose of texture-less shiny parts is challenging but worthwhile. In this study, it is impractical to utilize texture information to obtain the pose because the features are likely to be affected by the surrounding objects. In addition, the colors of the metal parts are similar, making object segmentation challenging. This study proposes dividing the entire process into three steps: object detection, feature extraction, and pose estimation. We use the Mask-RCNN to detect objects and HRNet to extract the corresponding features. For metal parts of different shapes, different keypoints were chosen accordingly. Conventional contour-based methods are inapplicable to parts containing planar surfaces because the objects occlude each other in clustered environments. In this case, we used dense discrete points along the edges as semantic keypoints for metal parts containing planar elements. We chose skeleton points as semantic keypoints for parts containing cylindrical components. Subsequently, we combined the localization of semantic keypoints and the corresponding CAD model information to estimate the 6D pose of an individual object in sight. The implementation of deep learning approaches requires massive training datasets and intensive labeling. Thus, we propose a method to generate training datasets and automatically label them. Experiments show that the algorithm based on synthetic data performs well in a natural environment, despite not utilizing real scenario images for training. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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15 pages, 11197 KiB  

Open AccessArticle

Comparison of Constitutive Models and Microstructure Evolution of GW103K Magnesium Alloy during Hot Deformation

by Lan Yin and Yunxin Wu

Materials 2022, 15(12), 4116; https://doi.org/10.3390/ma15124116 - 9 Jun 2022

Cited by 11 | Viewed by 1924

Abstract

The characteristics of constitutive behavior and microstructure evolution of GW103K magnesium alloy were investigated via hot compression tests at a strain rate of 0.001–1 s⁻¹ and a temperature of 623–773 K. The rheological stress of GW103K alloy decreased with increasing temperature or [...] Read more.

The characteristics of constitutive behavior and microstructure evolution of GW103K magnesium alloy were investigated via hot compression tests at a strain rate of 0.001–1 s⁻¹ and a temperature of 623–773 K. The rheological stress of GW103K alloy decreased with increasing temperature or decreasing strain rate during hot deformation. Three models including the Johnson Cook (JC) model, the strain-compensated Arrhenius (SCA) model and back-propagation neural networks (BPNN) were applied to describe the constitutive relationships. Subsequently, the predictability and precision of the models were compared by evaluating the correlation coefficient (R), root mean square errors (RMSE), and relative errors (RE). Compared with the JC and SCA models, the BPNN model was more efficient and had higher prediction accuracy in describing flow stress behavior. Furthermore, EBSD maps confirmed that magnesium alloy easily causes dynamic recrystallization (DRX) during hot deformation. The volume fraction and size of DRX grains increased with decreasing strain rate and/or increasing temperature. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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21 pages, 4506 KiB  

Open AccessArticle

Mechanical Modeling of Tube Bending Considering Elastoplastic Evolution of Tube Cross-Section

by Zongcai Zhang, Jianjun Wu, Xinliang Xu, Zekun Yang, Wei Wu and Long Liu

Materials 2022, 15(11), 3997; https://doi.org/10.3390/ma15113997 - 3 Jun 2022

Cited by 10 | Viewed by 3109

Abstract

Aluminum alloy tubes are widely used in various industries because of their excellent performance. Up to now, when the tube is bent, the elastoplastic deformation evolution mechanism of the cross-section has not been clear, and no direct analytical proof has been found. In [...] Read more.

Aluminum alloy tubes are widely used in various industries because of their excellent performance. Up to now, when the tube is bent, the elastoplastic deformation evolution mechanism of the cross-section has not been clear, and no direct analytical proof has been found. In this paper, based on the bilinear material model assumption, a new mechanical model of tube plane bending deformation is constructed. The analytical model can describe in detail the evolution mechanism of elastic–plastic deformation on the cross-section of the tube after bending deformation, the position of the elastic–plastic boundary, the position of the radius of the strain neutral layer, and the relationship between the bending moment over the section and the bending radius. According to this model, the deformation law of the tube cross-section during bending is elucidated. The results are as follows: (1) the deformation evolution of the cross-section of the bending deformed tube calculated by the analytical model is in good agreement with the finite element model (FEM) of pure bending. (2) By comparing the results of the analytical model with FEM results, and the processing test of the self-designed four-axis free bending forming tube bender, the bending moments are in good agreement. (3) Compared with the bending moments calculated by several other analytical models of tube bending, this model has a relatively small deviation value. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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16 pages, 7808 KiB  

Open AccessArticle

Optimization of Si Content to Inhibit Inhomogeneous Deformation in Al-Mg-Si Alloy Fabricated via Twin-Roll Casting

by Bowen Wei, Shiju Li, Tao Jiang, Youyun Zhang, Guangming Xu, Yong Li and Zhaodong Wang

Metals 2022, 12(6), 941; https://doi.org/10.3390/met12060941 - 30 May 2022

Cited by 3 | Viewed by 1870

Abstract

Herein, the effects of Si content on the microstructure evolution of Al-Mg-Si alloys during twin-roll casting (TRC) and subsequent heat treatment were characterized using scanning electron microscopy, emission electron probe micro analysis, electron backscatter diffraction, and transmission electron microscopy. The effects of insoluble [...] Read more.

Herein, the effects of Si content on the microstructure evolution of Al-Mg-Si alloys during twin-roll casting (TRC) and subsequent heat treatment were characterized using scanning electron microscopy, emission electron probe micro analysis, electron backscatter diffraction, and transmission electron microscopy. The effects of insoluble Si particles, solute gradient, and recrystallization on the mechanical properties of the alloy in the T4P state were analyzed. An inhomogeneous deformation in the thickness direction of the TRC strip was observed during the pre-strain test. A premature local deformation at the element barren region (EBR) in the middle of the strip was considered to be the origin of the limited mechanical properties. By increasing the Si from 0.7 wt% to 1.1 wt%, the content and uniformity of the solute in the EBR can be effectively improved. The stronger work-hardening ability weakens the inhomogeneous deformation. Si addition significantly increased the number of insoluble Si particles during the heat treatment. The structure with a hard shell and soft core in the TRC strip significantly reduced the negative effect of insoluble Si particles on the mechanical properties. The tensile strength and uniform elongation of the strip increased from 159.44 MPa and 18.36% to 209.96 MPa and 29.791%, respectively. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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18 pages, 10699 KiB  

Open AccessArticle

The Microstructure Evolution of Mg-RE Alloy Produced by Reciprocating Upsetting Extrusion during Hot Compression

by Ziwei Zhang, Jianmin Yu, Zeru Wu, Hongbing Hu, Zhimin Zhang, Mo Meng, Yong Xue and Xubin Li

Metals 2022, 12(5), 888; https://doi.org/10.3390/met12050888 - 23 May 2022

Viewed by 2140

Abstract

Mg-13Gd-4Y-2Zn-0.4Zr (wt. %) alloy bar produced by three passes reciprocating upsetting extrusion (named as RUE-ed bar) exhibited fine grain with the average grain size of 3.02 μm. Hot compression tests of the RUE-ed bar were carried out on Gleeble-3800 compression unit at different [...] Read more.

Mg-13Gd-4Y-2Zn-0.4Zr (wt. %) alloy bar produced by three passes reciprocating upsetting extrusion (named as RUE-ed bar) exhibited fine grain with the average grain size of 3.02 μm. Hot compression tests of the RUE-ed bar were carried out on Gleeble-3800 compression unit at different deformation temperatures (653, 683, 713, and 743 K) and strain rates (0.001–1 s, 0.01–1 s, 0.1–1 s, and 0.5–1 s). This alloy showed work hardening and softening stages in hot compression, the thermal activation energy of the RUE-ed bar was 150 ± 1 kJ/mol and the constitutive equation was: $\dot{\epsilon }=1.80\times {10}^9{\left[\mathit{sinh}\left(0.0174\sigma \right)\right]}^{2.47}exp\left[-\frac{150\times {10}^3}{8.314\times T}\right]$. Numerous Mg₅ (Gd, Y, Zn) phase re-dissolved in α-Mg matrix appeared in the RUE-ed samples during hot compression deformation. The movement of the dislocation stimulated the re-dissolution of the Mg₅ (Gd, Y, Zn) phase. The re-dissolution of Mg₅ (Gd, Y, Zn) phase promoted texture strengthening and DRX grains growth in this experiment. In addition, the transformation and kinking of LPSO phase played an important coordinating role in the process of hot compression; 18R-LPSO was changed to 14H-LPSO phase at low strain rate while the LPSO phase kinked dominant to coordinated deformation at high strain rate. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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9 pages, 2923 KiB  

Open AccessArticle

Enhanced Mechanical Performance of a Biodegradable Fe–Mn Alloy Manufactured by Metal Injection Molding and Minor Carbon Addition

by Ye Zhang, Song Li, Dongyang Li, Yimin Li, Hao He and Chang Shu

Metals 2022, 12(5), 884; https://doi.org/10.3390/met12050884 - 23 May 2022

Cited by 2 | Viewed by 2345

Abstract

At present, FeMn-based degradable alloys prepared by direct sintering generally face the problems of Mn volatilization, difficult densification, and poor mechanical properties. In this work, a Fe-35Mn-0.5C alloy with low Mn volatility, high density, and favorable mechanical properties is fabricated by the metal [...] Read more.

At present, FeMn-based degradable alloys prepared by direct sintering generally face the problems of Mn volatilization, difficult densification, and poor mechanical properties. In this work, a Fe-35Mn-0.5C alloy with low Mn volatility, high density, and favorable mechanical properties is fabricated by the metal injection molding (MIM) process. The effects of sintering pressure and minor carbon addition on microstructure and mechanical properties were studied. The corresponding mechanical deformation mechanism was discussed. The results show that a significant reduction in the proportion of Mn volatilization to less than 0.5% and higher relative density of 97 ± 0.30% are achieved in the MIM-treated Fe-35Mn-0.5C alloy by pressurized sintering at 5 atm and 0.5 wt.% carbon addition. The optimized tensile properties are attained, with an ultimate tensile strength of 772 MPa, yield strength of 290 MPa, and elongation of 35% at room temperature, which meets the mechanical needs of metallic materials for biologically implantable medical devices. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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14 pages, 3753 KiB  

Open AccessArticle

Electrochemical Corrosion Behavior of MIG-Welded 7N01-T4 Aluminum Alloy by ER5356 and ER5087 Welding Wires

by Ping Wei, Mingfang Wu, Dashuang Liu, Ziqiang Zhao, Yun Liang and Zhihui Dong

Materials 2022, 15(10), 3737; https://doi.org/10.3390/ma15103737 - 23 May 2022

Cited by 4 | Viewed by 2367

Abstract

7N01-T4 aluminum alloy plates were welded by the metal inert gas (MIG) welding method, with ER5087 and ER5356 welding wires, respectively. The electrochemical corrosion behavior of the weld zones in the two kinds of welded joints using 3.5 wt.% and 5 wt.% NaCl [...] Read more.

7N01-T4 aluminum alloy plates were welded by the metal inert gas (MIG) welding method, with ER5087 and ER5356 welding wires, respectively. The electrochemical corrosion behavior of the weld zones in the two kinds of welded joints using 3.5 wt.% and 5 wt.% NaCl solutions were investigated by polarization curve, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and laser confocal scanning microscope (LCSM). The results indicated the better corrosion resistance of the weld zone in the ER5356 welded joint than that in the ER5087 welded joint, which was related to the different contents of Mn and Zn elements and the distribution of precipitates for the weld zones in the two kinds of welded joints. Based on the LSCM of the weld zones, the maximum depth (d_max) of corrosion pits for the weld zone in the ER5356 welded joint was lower than that in the ER5087 welded joint when immersed in the same NaCl concentrations. The d_max of the corrosion pit of the weld zone in the ER5356 welded joint using the 5 wt.% NaCl solution was 78.5 ± 0.96 μm, which was much bigger than that using the 3.5 wt.% NaCl solution. For the weld zone in the ER5087 welded joint with 5 wt.% NaCl solution, more Cl^- was adsorbed onto the active surface of weld zones, which accelerated the corrosion, resulting in the corrosion mechanism from pitting to intergranular corrosion. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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15 pages, 8388 KiB  

Open AccessArticle

Recrystallization Mechanism and Processing Map of 18CrNiMo7-6 Alloy Steel during Hot Deformation

by Yikui Xie, Qicheng Wang, Zikun Chen, Xiaodong Wu, Hui Liu and Zhongying Wang

Metals 2022, 12(5), 838; https://doi.org/10.3390/met12050838 - 13 May 2022

Cited by 9 | Viewed by 2583

Abstract

In this study, isothermal single-pass forming doformation of forged 18CrNiMo7-6 alloy steel was carried out by Gleeble-3500 thermal simulation testing machine. The constitutive equations and processing maps with parameters of deformation temperature and strain rate were established. The results show that the optimum [...] Read more.

In this study, isothermal single-pass forming doformation of forged 18CrNiMo7-6 alloy steel was carried out by Gleeble-3500 thermal simulation testing machine. The constitutive equations and processing maps with parameters of deformation temperature and strain rate were established. The results show that the optimum hot deformation parameters are temperature 1050 °C, strain rate 0.1 s^–1 with the peak power efficiency being 0.432. The mechanism of grain refinement during hot compression was also characterized by electron backscatter diffraction (EBSD). The results show that continuous dynamic recrystallization (CDRX), discontinuous dynamic recrystallization (DDRX) and grain growth are the main microstructure evolution mechanisms during hot working. The rotation of sub-grains under CDRX mechanism is the main factor for the formation of new grains. In addition, the DDRX mechanism is formed by the bulging of HAGBs at the grain boundary triple junction of the original grains, and the CDRX mechanism forms finer grains. The study also found that temperature affected the organization evolution mechanism, the DDRX mechanism plays a leading role when the temperature is low. With the increase of deformation temperature, CDRX begins to play a leading role and forms finer grains. When the deformation temperature rises to 1150 °C, the grains continue to grow at a higher temperature. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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21 pages, 5418 KiB  

Open AccessArticle

Research and Progress on Truing and Sharpening Process of Diamond Abrasive Grinding Tools

by Song Cai, Wenhao Liu, Jinchao Song, Kai Deng and Yinghong Tang

Appl. Sci. 2022, 12(9), 4683; https://doi.org/10.3390/app12094683 - 6 May 2022

Cited by 4 | Viewed by 3721

Abstract

With respect to the truing and sharpening of diamond abrasive grinding tools, traditional machining methods are briefly described, and new dressing methods, such as the laser dressing method, are described in detail. It is pointed out that laser dressing of diamond abrasive tools [...] Read more.

With respect to the truing and sharpening of diamond abrasive grinding tools, traditional machining methods are briefly described, and new dressing methods, such as the laser dressing method, are described in detail. It is pointed out that laser dressing of diamond abrasive tools is a green processing method with high efficiency and no environmental pollution. Numerical simulation research on pulse laser dressing of a bronze diamond abrasive grinding wheel was carried out, and a cumulative heat transfer model of laser dressing energy was developed. The temperature evolution law of the bronze bond and diamond abrasive grains dressed by pulsed fiber laser was determined by numerical analysis of the model. An experiment on the laser dressing grinding wheel was carried out; it was found that when the laser power density was 2.52 × 10⁸ W/cm²∼3.36 × 10⁸ W/cm², the bronze bond materials could be properly removed, and the diamond abrasive grains could be better sharpened. The laser dressing method can achieve the combination of diamond abrasive grinding tool sharpening and truing. The experiment not only demonstrated the correctness and feasibility of the theoretical model but also provided process optimization for research into pulse laser dressing of diamond abrasive grinding tools. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 3992 KiB  

Open AccessArticle

Effect of High-Temperature Heat Treatment on Strengthening Mechanism of AlCoCrFeNi Component Fabricated by LMD

by Zheng Pang, Jin Yang, Sunusi Marwana Manladan, Yangchuan Cai and Jian Han

Metals 2022, 12(5), 767; https://doi.org/10.3390/met12050767 - 29 Apr 2022

Cited by 8 | Viewed by 2349

Abstract

In the present study; an AlCoCrFeNi high-entropy alloy (HEA) component was produced by laser melting deposition (LMD) technique. Then; a heat-treatment process based on the detection results of Differential Scanning Calorimeter (DSC) was used. The effects of heat treatment on the phase transition; [...] Read more.

In the present study; an AlCoCrFeNi high-entropy alloy (HEA) component was produced by laser melting deposition (LMD) technique. Then; a heat-treatment process based on the detection results of Differential Scanning Calorimeter (DSC) was used. The effects of heat treatment on the phase transition; microstructure and mechanical properties of the AlCoCrFeNi component were systematically studied. The results showed that low-temperature heat treatment (600 °C) had little effect on the microstructure and mechanical properties of component. The 800 °C heat treatment precipitated σ and face-center cubic (FCC) phases near grain boundaries in the component. The high dislocation capacity of FCC phase and precipitation strengthening of σ phase improved the strength and plasticity of this component. However; hard and brittle σ phase was not conducive to uniform distribution of microhardness. High-temperature heat treatment (1000 °C) caused the σ phase to remelt and increased FCC phase content at grain boundaries; resulting in a significant increase in strength and plasticity. Although the microhardness of the AlCoCrFeNi component after this heat treatment was reduced; the good strength and plasticity will facilitate its application in the structural field. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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22 pages, 1374 KiB  

Open AccessArticle

Research and Optimization of Process Parameters for Internal Thread Forming Based on Numerical Simulation and Experimental Analysis

by Qiang He, Yuxiang Jiang, Xuwen Jing, Yonggang Jiang, Honggen Zhou and Bofeng Fu

Materials 2022, 15(9), 3160; https://doi.org/10.3390/ma15093160 - 27 Apr 2022

Cited by 13 | Viewed by 2658

Abstract

In order to improve the forming quality of extruded thread, finite element analysis and experimental research are combined to reduce the two keys that affect thread quality in the machining process—extrusion torque and extrusion temperature. The effects of different processing parameters on the [...] Read more.

In order to improve the forming quality of extruded thread, finite element analysis and experimental research are combined to reduce the two keys that affect thread quality in the machining process—extrusion torque and extrusion temperature. The effects of different processing parameters on the extrusion torque and temperature are obtained by numerical simulation, including the bottom hole diameter of the workpiece, the machine tool speed, and the lubrication medium. For the purpose of reducing extrusion torque and temperature, the process parameters for internal thread forming are further optimized by orthogonal design. It is determined that when machining the M22 × 2 internal thread on the connecting rod of the marine diesel engine made of 42CrMo4 steel, the bottom hole diameter of the workpiece should be 21.20 mm, the speed of the machine tool should be 40 RPM, and the lubricating medium should be PDMS polydimethylsiloxane coolant. Compared to before optimization, the maximum extrusion torque and the maximum extrusion temperature are reduced by 19.27% and 15.07%, respectively. On the premise of ensuring the thread connection strength, the height of the thread tooth is reduced by 0.052 mm, and the surface condition of the thread is improved. The surface microhardness at the root, top, and side of the thread increases by about 5 HV_0.2, and the depth of the hardened layer increases by 0.05 mm. The results show that the quality of the optimized thread is higher. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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22 pages, 11099 KiB  

Open AccessArticle

Hardening and Softening Behavior of Caliber-Rolled Wire

by Joong-Ki Hwang

Materials 2022, 15(8), 2939; https://doi.org/10.3390/ma15082939 - 18 Apr 2022

Cited by 3 | Viewed by 3103

Abstract

The different behaviors of the mechanical properties of drawn and caliber-rolled wires with applied strain were investigated to determine the appropriate process between wire drawing and caliber rolling with consideration of materials and process conditions. Ferritic, pearlitic, and TWIP steels were drawn and [...] Read more.

The different behaviors of the mechanical properties of drawn and caliber-rolled wires with applied strain were investigated to determine the appropriate process between wire drawing and caliber rolling with consideration of materials and process conditions. Ferritic, pearlitic, and TWIP steels were drawn and caliber-rolled under the same process conditions. Caliber-rolled wires exhibited a hardening behavior in the early deformation stage and softening behavior in the later deformation stage compared with the drawn wires, regardless of the steel. The hardening behavior of the caliber-rolled wires was explained by the higher strain induced by caliber rolling compared with wire drawing, especially the higher amount of redundant work in caliber-rolled wire. The caliber-rolled wire had approximately 36% higher strain than the drawn wire and approximately 85% higher strain than nominal strain. The softening behavior of the caliber-rolled wire in later deformation stages was related to the Bauschinger effect or low-cycle fatigue effect caused by the roll geometries and loading conditions during caliber rolling. The different intersection points of the tensile strength between drawn and caliber-rolled wires with the steels were attributed to the different strain hardening rates of each steel. Between the options of the caliber rolling and wire drawing processes, the appropriate process should be selected according to the strain hardening rate of the material and the amount of plastic deformation. For instance, when the wires need to deform at high levels, wire drawing is the better process because of the appearance of the Bauschinger effect in caliber-rolled wire. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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14 pages, 8276 KiB  

Open AccessArticle

Intermediate Model Design in the Progressive Stamping Process of a Truss Core Lightweight Panel

by Zhilei Tian, Chenghai Kong, Wei Zhao, Jingchao Guan and Xilu Zhao

Appl. Sci. 2022, 12(8), 4002; https://doi.org/10.3390/app12084002 - 15 Apr 2022

Cited by 1 | Viewed by 2123

Abstract

The truss core panel has been verified to be effective for structural weight reduction in former research studies. However, it is difficult to manufacture using the sheet metal pressing method because the forming height of the truss core panel is limited by the [...] Read more.

The truss core panel has been verified to be effective for structural weight reduction in former research studies. However, it is difficult to manufacture using the sheet metal pressing method because the forming height of the truss core panel is limited by the physical properties of the material. Although progressive stamping has been used to solve this problem, it is still difficult to practically use the truss core panel. In this study, the author proposed a manufacturing method and a hexagonal frustum intermediate structure to improve the forming quality of truss core panels using a progressive stamping method and verified its effectiveness through numerical analysis and prototype experiments. Compared to the conventional hemispherical intermediate model, the manufacturing process of the truss core panel using the proposed method was significantly improved. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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13 pages, 3561 KiB  

Open AccessArticle

Experimental Investigations of Expansion Strength of Hydraulic Expansion Joints Interconnecting Tube and Fins Heat Exchanger

by Haimei Han, Lianfa Yang, Jingyu Jiang and Jianping Ma

Metals 2022, 12(4), 641; https://doi.org/10.3390/met12040641 - 10 Apr 2022

Cited by 3 | Viewed by 2735

Abstract

As a high expansion strength corresponds to a high heat transfer efficiency, this study investigated the expansion strength of an air-conditioning heat exchanger jointed by hydraulic expansion. A device that would be reliable and adaptable to different types of tubes and fins was [...] Read more.

As a high expansion strength corresponds to a high heat transfer efficiency, this study investigated the expansion strength of an air-conditioning heat exchanger jointed by hydraulic expansion. A device that would be reliable and adaptable to different types of tubes and fins was designed and developed for testing hydraulic expansion. The device was used to perform a non-pulsating hydraulic expansion experiment on samples comprising tubes and fins to determine the hydraulic pressure range. The expansion strength was tested by performing tensile tests to evaluate the pull-out force at different bulging zones of the same sample with the selected hydraulic pressure. A series of pulsating hydraulic expansion experiments were performed on the joints of tubes and fins with different pulsating amplitudes and frequencies. Tensile tests were performed on the pulsating hydraulic expansion samples to study the influence of the pulsation parameters on the pull-out force. When the amplitude was fixed, an increase in frequency led to uniform expansion in the exchanger. This indicates that joint expansion in tubes and fins results in a more reliable heat exchanger performance. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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7 pages, 1949 KiB  

Open AccessCommunication

Intrinsic Effect of Pulsed Current on the Recrystallization of Deformed AZ31 Alloy

by Jie Wu and Xiaobo Wang

Materials 2022, 15(7), 2698; https://doi.org/10.3390/ma15072698 - 6 Apr 2022

Cited by 2 | Viewed by 1739

Abstract

Two ensemble configurations were designed to investigate the intrinsic effect of a pulsed current on the recrystallization of rolled AZ31 alloy. The samples with a total reduction of about 60% were crystallized at 473K for 5 min when treated with the pulsed current. [...] Read more.

Two ensemble configurations were designed to investigate the intrinsic effect of a pulsed current on the recrystallization of rolled AZ31 alloy. The samples with a total reduction of about 60% were crystallized at 473K for 5 min when treated with the pulsed current. By forcing the pulsed current flow only through the graphite die, and the sample was heated by Joule effect, a microstructure with a grain size of ~5 μm was formed and the recrystallized fraction achieved 60% reduction. Moreover, a fully recrystallized microstructure with a grain size of ~9 μm was obtained when heated with Joule and athermal effects by forcing the pulsed current flow through the sample only. Based on the experimental results, the recrystallization behavior of deformed AZ31 under a pulsed current should be governed by the high Joule heating effect, which could generate transient high stress in the sample due to the nonsynchronous change in temperature and thermal expansion. The athermal effect of the pulsed current could enhance the dislocation mobility and thus accelerate coarsening of the recrystallization grains, but it should not be the key factor governing the recrystallization behavior of rolled AZ31B. This led to the p erroneous conclusion that the athermal effect of pulsed current played a crucial role in the recrystallization of deformed alloys. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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11 pages, 7535 KiB  

Open AccessArticle

Microstructure and Mechanical Properties of TiB₂/AlSi7Mg0.6 Composites Fabricated by Wire and Arc Additive Manufacturing Based on Cold Metal Transfer (WAAM-CMT)

by Qingfeng Yang, Cunjuan Xia, Haowei Wang, Mingyang Zhou, Shixin Gao, Bingjin Li and Shichao Liu

Materials 2022, 15(7), 2440; https://doi.org/10.3390/ma15072440 - 25 Mar 2022

Cited by 5 | Viewed by 2511

Abstract

Wire and arc additive manufacturing based on cold metal transfer (WAAM-CMT), as a kind of clean and advanced technology, has been widely researched recently. It was analyzed in detail for the microstructure and mechanical properties of WAAM-CMT printed TiB₂/AlSi7Mg0.6 samples fore-and-aft [...] Read more.

Wire and arc additive manufacturing based on cold metal transfer (WAAM-CMT), as a kind of clean and advanced technology, has been widely researched recently. It was analyzed in detail for the microstructure and mechanical properties of WAAM-CMT printed TiB₂/AlSi7Mg0.6 samples fore-and-aft heat treatment in this study. Compared with the grain size of casted AlSi7Mg0.6 samples (252 μm), the grain size of WAAM-CMT printed AlSi7Mg0.6 samples (53.4 μm) was refined, showing that WAAM-CMT process could result in significant grain refinement. Besides, the grain size of WAAM-CMT printed TiB₂/AlSi7Mg0.6 samples was about 35 μm, revealing that the addition of TiB₂ particles played a role in grain refinement. Nevertheless, the grain size distribution was not uniform, showing a mixture of fine grain and coarse grain, and the mechanical properties were anisotropic of the as-printed samples. This study shows that T6 heat treatment is an efficient way to improve the nonuniform microstructure and eliminate the anisotropy in mechanical properties. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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13 pages, 4308 KiB  

Open AccessArticle

Springback Reduction of Ultra-High-Strength Martensitic Steel Sheet by Electrically Single-Pulsed Current

by Minki Kim, Gihyun Bae, Namsu Park and Jung Han Song

Materials 2022, 15(7), 2373; https://doi.org/10.3390/ma15072373 - 23 Mar 2022

Cited by 3 | Viewed by 2539

Abstract

This paper investigates the reduction of springback by an electrically single-pulsed current for an ultra-high-strength martensitic steel sheet, MART1470 1.2t. In order to evaluate the springback reduction by the electric current, V-bending tests were performed with various parameter-sets (current density and pulse duration). [...] Read more.

This paper investigates the reduction of springback by an electrically single-pulsed current for an ultra-high-strength martensitic steel sheet, MART1470 1.2t. In order to evaluate the springback reduction by the electric current, V-bending tests were performed with various parameter-sets (current density and pulse duration). The amount of springback reduction was then calculated from the measured bent-angle of tested specimens. Experimental results show the springback is reduced with the increase in the current density, the pulse duration, and the electric energy density. In order to clarify thermal and athermal portions in the effect of electric current on the springback reduction, two ratios of force and isothermal flow stress were calculated based on bending theory. From the comparison of the ratios, it is noted that the athermal portion mainly contributes to the force relaxation, so the springback amount decreases. The athermal portion significantly increases as the electric energy density increases. Microstructures and micro-Vickers hardness were observed to confirm the applicability of the single-pulsed current to forming processes in practice. The springback reduction can be achieved up to 37.5% without severe changes in material properties when the electric energy density increases up to 281.3 mJ/mm³. Achievable reduction is 85.4% for the electric energy density of 500 mJ/mm³, but properties remarkably change. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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17 pages, 3872 KiB  

Open AccessReview

Review of Thermoplastic Drawing with Bulk Metallic Glasses

by Shweta Jagdale, Akib Jabed, Sumanth Theeda, Chandra Sekhar Meduri, Zhonglue Hu, Molla Hasan and Golden Kumar

Metals 2022, 12(3), 518; https://doi.org/10.3390/met12030518 - 18 Mar 2022

Cited by 15 | Viewed by 3586

Abstract

This study summarizes the recent progress in thermoplastic drawing of bulk metallic glasses. The integration of drawing with templated embossing enables the fabrication of arrays of high-aspect-ratio nanostructures whereas the earlier drawing methodologies are limited to a single fiber. The two-step drawing can [...] Read more.

This study summarizes the recent progress in thermoplastic drawing of bulk metallic glasses. The integration of drawing with templated embossing enables the fabrication of arrays of high-aspect-ratio nanostructures whereas the earlier drawing methodologies are limited to a single fiber. The two-step drawing can produce metallic glass structures such as, vertically aligned nanowires on substrates, nanoscale tensile specimens, hollow microneedles, helical shafts, and micro-yarns, which are challenging to fabricate with other thermoplastic forming operations. These geometries will open new applications for bulk metallic glasses in the areas of sensors, optical absorption, transdermal drug-delivery, and high-throughput characterization of size-effects. In this article, we review the emergence of template-based thermoplastic drawing in bulk metallic glasses. The review focuses on the development of experimental set-up, the quantitative description of drawing process, and the versatility of drawing methodology. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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13 pages, 3739 KiB  

Open AccessArticle

Multipoint Forming Using Hole-Type Rubber Punch

by Abror Tolipov, Hany Hassanin, Mahmoud Ahmed El-Sayed, Hossam Mohamed Eldessouky, Naser A. Alsaleh, Adel Khalid Alfozan, Khamis Essa and Mahmoud Ahmadein

Metals 2022, 12(3), 491; https://doi.org/10.3390/met12030491 - 14 Mar 2022

Cited by 1 | Viewed by 3431

Abstract

Reconfigurable multipoint forming is a flexible sheet forming technique aimed at customised sheet metal products. However, one drawback of multipoint forming is the cost and time needed to set up and align the upper and lower pin matrices. This study introduces an optimisation [...] Read more.

Reconfigurable multipoint forming is a flexible sheet forming technique aimed at customised sheet metal products. However, one drawback of multipoint forming is the cost and time needed to set up and align the upper and lower pin matrices. This study introduces an optimisation study of a novel hole-type rubber punch replacing the top pin matrix of multipoint incremental forming, aiming to reduce pins setting up and alignment complexity and time. Finite element modelling and design of experiments were used to investigate the effect of hole-type rubber punch configuration such as hole size, hole type, and the compression ratio on the wrinkling, thickness variation, and shape deviation. This research shows that the most significant process parameter in all responses was the hole size. The compression ratio of the material was found to be insignificant in wrinkling and shape deviation. The hole-type rubber punch parameters were found to be a hole size of 9 mm, circular hole type, and a compression ratio of 75%. This experimentally resulted in an improved parts wrinkling of 80%, when compared to using solid rubber punch, with the added benefits of reduction of the cost and time needed to set up and align the pin matrices. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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14 pages, 3569 KiB  

Open AccessArticle

Construction of Al-Mg-Zn Interatomic Potential and the Prediction of Favored Glass Formation Compositions and Associated Driving Forces

by Bei Cai, Jiahao Li, Wensheng Lai, Jianbo Liu and Baixin Liu

Materials 2022, 15(6), 2062; https://doi.org/10.3390/ma15062062 - 11 Mar 2022

Cited by 3 | Viewed by 2405

Abstract

An interatomic potential is constructed for the ternary Al-Mg-Zn system under a proposed modified tight-binding scheme, and it is verified to be realistic. Applying this ternary potential, atomistic simulations predict an intrinsic glass formation region in the composition triangle, within which the glassy [...] Read more.

An interatomic potential is constructed for the ternary Al-Mg-Zn system under a proposed modified tight-binding scheme, and it is verified to be realistic. Applying this ternary potential, atomistic simulations predict an intrinsic glass formation region in the composition triangle, within which the glassy alloys are more energetically favored in comparison with their solid solution counterparts. Kinetically, the amorphization driving force of each disordered state is derived to correlate the readiness of its glass-forming ability in practice; thus, an optimal stoichiometry region is pinpointed around Al₃₅Mg₃₅Zn₃₀. Furthermore, by monitoring the structural evolution for various (Al₅₀Mg₅₀)_1−xZn_x (x = 30, 50, and 70 at.%) compositions, the optimized-glass-former Al₃₅Mg₃₅Zn₃₀ is characterized by both the highest degree of icosahedral ordering and the highest phase stability among the investigated compositions. In addition, the icosahedral network in Al₃₅Mg₃₅Zn₃₀ exhibits a much higher cross-linking degree than that in Al₂₅Mg₂₅Zn₅₀. This suggests that there is a certain correlation between the icosahedral ordering and the larger glass-forming ability of Al₃₅Mg₃₅Zn₃₀. Our results have significant implications in clarifying glass formation and hierarchical atomic structures, and in designing new ternary Al-Mg-Zn glassy alloys with high GFA. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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15 pages, 5799 KiB  

Open AccessArticle

The Influence of the Deformation Method on the Microstructure and Properties of Magnesium Alloy Mg-Y-RE-Zr

by Iwona Bednarczyk and Dariusz Kuc

Materials 2022, 15(6), 2017; https://doi.org/10.3390/ma15062017 - 9 Mar 2022

Cited by 3 | Viewed by 2387

Abstract

This article presents the influence of the applied extrusion method on the microstructure and mechanical properties of the WE43 magnesium alloy. The materials for tests were ingots made from magnesium alloy, with dimensions of 40 × 90 mm, marked with the symbol WE43. [...] Read more.

This article presents the influence of the applied extrusion method on the microstructure and mechanical properties of the WE43 magnesium alloy. The materials for tests were ingots made from magnesium alloy, with dimensions of 40 × 90 mm, marked with the symbol WE43. Two extrusion methods were used: the classic one—concurrent extrusion, and the complex one—concurrent extrusion with a reversible die (KoBo). As a result of the application of deformation processes, rods were obtained. The implemented deformation methods made it possible to determine the influence of the deformation process parameters on changes in the structure and properties of the WE43 alloy. In addition, compression tests were performed to determine the values of the yield stress and to analyze changes in the microstructure after plastic deformation. The hot plastic deformation activation energy and the process parameters, for which the course of plastic flow is affected by the presence of twins in the microstructure, were determined for the WE43 alloy. The effects of superplastic flow at 350 °C (250% elongation) and microstructure refinement (d = 1 µm) were demonstrated after applying the KoBo method. The results will be useful in the development of forming technology of selected construction elements, which serve as light substitutes for currently used materials. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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20 pages, 33031 KiB  

Open AccessArticle

A Novel Force Variation Fine-Blanking Process for the High-Strength and Low-Plasticity Material

by Huajie Mao, Han Chen, Yanxiong Liu and Kaisheng Ji

Metals 2022, 12(3), 458; https://doi.org/10.3390/met12030458 - 8 Mar 2022

Cited by 6 | Viewed by 3816

Abstract

High forming force is often needed when high-strength and low-plasticity materials are processed by fine blanking. Too high forming force increases the load of the die and greatly increases the risk of die failure. If the forming force is reduced, the material will [...] Read more.

High forming force is often needed when high-strength and low-plasticity materials are processed by fine blanking. Too high forming force increases the load of the die and greatly increases the risk of die failure. If the forming force is reduced, the material will fracture prematurely, which will lead to poor quality parts. Aiming at this problem, a new force variation load fine-blanking technology is proposed in this paper. During the loading process, the forming force does not remain constant but changes with the blanking stroke. A 2D finite element fine-blanking model was established for the TC4 material. The mechanism of force variation fine blanking is also revealed. This paper proposes a method to design the loading route of the forming force with variable load. This method combines finite element simulation with neural network and a multi-objective genetic algorithm. Finally, the application of variable load fine blanking production and the application of traditional fine blanking production parts are verified by the experimental method. The same results are obtained from both simulation and experiment. It is found that the variable load fine blanking process can greatly reduce the load of the die on the premise of ensuring the quality of fine-blanking parts. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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16 pages, 8579 KiB  

Open AccessArticle

Hydrogen Assisted Magnesiothermic Reduction of Y-Doped, Nanocrystalline TiO₂

by Hank Lloyd, Ying Xu and Peng Cao

Metals 2022, 12(3), 448; https://doi.org/10.3390/met12030448 - 4 Mar 2022

Viewed by 2445

Abstract

The direct reduction of TiO₂ to low-oxygen titanium metal is achievable via Hydrogen Assisted Magnesiothermic Reduction (HAMR). To investigate and leverage the oxygen-scavenging properties of rare-earth dopant species on the HAMR process, Y-doped and undoped TiO₂ powders were synthesized and characterized. [...] Read more.

The direct reduction of TiO₂ to low-oxygen titanium metal is achievable via Hydrogen Assisted Magnesiothermic Reduction (HAMR). To investigate and leverage the oxygen-scavenging properties of rare-earth dopant species on the HAMR process, Y-doped and undoped TiO₂ powders were synthesized and characterized. HAMR blends incorporating the synthesized TiO₂ were reduced under forming gas atmospheres. X-ray powder diffraction (XRD) and scanning electron microscope (SEM) characterization was performed prior to and following reduction. The TiO₂ powders were observed to be dense and nanocrystalline. Following reduction, more extensive development of intermediate HAMR phases was observed as a result of Y-doping. The microstructure/phase evolution of the HAMR reduction phases was observed to deviate from the expected for dense TiO₂ particles. Rapid restructuring of the TiO₂ particle interiors was attributed to increased bulk diffusion rates of nanocrystalline materials. Doped nanocrystalline TiO₂ powders were identified as potential alternative feedstocks for HAMR experiments. The byproduct MgO phase was observed to grow as a particle agglomerating network that is dense when formed at 750 °C and porous when formed at 900 °C. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 6686 KiB  

Open AccessArticle

Microstructure and Thermal Deformation Behavior of Hot-Pressing Sintered Zr-6Al-0.1B Alloy

by Huajun Yan, Wei Wang, Shuangjie Zhang, Shibo Ma, Jianhui Li and Bo Wang

Materials 2022, 15(5), 1816; https://doi.org/10.3390/ma15051816 - 28 Feb 2022

Cited by 1 | Viewed by 1938

Abstract

Zr-6Al-0.1B alloy rich in Zr₃Al phase is prepared by hot-pressing sintering. The thermal deformation behavior of sintered Zr-6Al-0.1B is analyzed by isothermal compression tests at deformation temperatures of 950, 1050, and 1150 °C with strain rates of 0.01, 0.1, and 1 [...] Read more.

Zr-6Al-0.1B alloy rich in Zr₃Al phase is prepared by hot-pressing sintering. The thermal deformation behavior of sintered Zr-6Al-0.1B is analyzed by isothermal compression tests at deformation temperatures of 950, 1050, and 1150 °C with strain rates of 0.01, 0.1, and 1 s⁻¹. The results indicate that at the early stage of thermal deformation, the stress increases rapidly with the increase of strain and then reaches the peak value. Subsequently, the stress decreases with the increase of strain under the softening effect. On the whole, the true stress-strain curve shifts to the high stress area with the increase of strain rate or the decrease of deformation temperature, so the sintered Zr-6Al-0.1B alloy belongs to the temperature and strain rate sensitive material. For the microstructure evolution of sintered Zr-6Al-0.1B during the isothermal compression, the high strain rate can improve the grain refinement. However, because sintered Zr-6Al-0.1B is a low plastic material, too high strain rate will exceed the deformation capacity of the material, resulting in an increase in defects. The increase of deformation temperature also contributes to grain refinement, but when the temperature is too high, due to the decomposition of Zr₃Al phase, the deformation coordination of the material decreases, leading to the increase of the probability of the occurrence of defects. This study verified the feasibility of hot-pressing sintering to prepare Zr-6Al-0.1B alloy rich in Zr₃Al phase and laid the foundation of “hot-pressing sintering + canning hot-extrusion” process of Zr-6Al-0.1B alloy components. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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18 pages, 25562 KiB  

Open AccessArticle

Hot Deformation Behavior, Processing Maps and Microstructural Evolution of the Mg-2.5Nd-0.5Zn-0.5Zr Alloy

by Junfei Ma, Songhui Wang, Jianlei Yang, Wencong Zhang, Wenzhen Chen, Guorong Cui and Guannan Chu

Materials 2022, 15(5), 1745; https://doi.org/10.3390/ma15051745 - 25 Feb 2022

Cited by 5 | Viewed by 1798

Abstract

Isothermal hot compression experiments were conducted on Mg-2.5Nd-0.5Zn-0.5Zr alloy to investigate hot deformation behavior at the temperature range of 573–773 K and the strain rate range of 0.001 s⁻¹–10 s⁻¹ using a Gleeble-3500D thermomechanical simulator. The results showed that the [...] Read more.

Isothermal hot compression experiments were conducted on Mg-2.5Nd-0.5Zn-0.5Zr alloy to investigate hot deformation behavior at the temperature range of 573–773 K and the strain rate range of 0.001 s⁻¹–10 s⁻¹ using a Gleeble-3500D thermomechanical simulator. The results showed that the rheological curve showed a typical work hardening stage, and there were three different stages: work hardening, transition and steady state. A strain compensation constitutive model was established to predict the flow stress of the Mg-2.5Nd-0.5Zn-0.5Zr alloy, and the results proved that it had high predictability. The main deformation mechanism of the Mg-2.5Nd-0.5Zn-0.5Zr alloy was dislocation climbing. The processing maps were established to distinguish the unstable region from the working region. The maps showed that the instability generally occurred at high strain rates and low temperatures, and the common forms of instability were cracking and flow localization. The optimum machining range of the alloy was determined to be 592–773 K and 0.001–0.217 s⁻¹. With the increase in deformation temperature, the grain size of the alloy grew slowly at the 573–673 K temperature range and rapidly at the 673–773 K temperature range. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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14 pages, 6620 KiB  

Open AccessArticle

Microstructure and Pitting Corrosion Resistance of AISI 430 Ferritic Stainless Steel Joints Fabricated by Ultrasonic Vibration Assisted Cold Metal Transfer Technique

by Naiqiang Xu, Junqi Shen, Jie Zhou and Shengsun Hu

Metals 2022, 12(3), 382; https://doi.org/10.3390/met12030382 - 23 Feb 2022

Cited by 3 | Viewed by 2696

Abstract

The influences of ultrasonic vibration during cold metal transfer welding process on the microstructure, element distribution and pitting resistance of AISI 430 ferritic stainless steel joints with ER 308L as filler metal were investigated. The combined effects of mechanical vibration, acoustic streaming and [...] Read more.

The influences of ultrasonic vibration during cold metal transfer welding process on the microstructure, element distribution and pitting resistance of AISI 430 ferritic stainless steel joints with ER 308L as filler metal were investigated. The combined effects of mechanical vibration, acoustic streaming and cavitation of ultrasonic vibration significantly refined the primary ferrite grain in the weld metal and then impacted the subsequent solid-phase transition process, leading to the ~45% reduction of ferrite content in the weld metal. Moreover, these effects also resulted in the homogenization of alloying elements in the weld metal. The pitting corrosion resistance of the welded joints with ultrasonic vibration was increased compared with that of without ultrasonic vibration, but lower than the base metal. The pitting resistance of the weld metal with ultrasonic vibration was higher than that of the weld metal without ultrasonic vibration and base metal, while that of the one without ultrasonic vibration was lower than the base metal. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 34483 KiB  

Open AccessArticle

Effect of Initial Fe Content on Microstructure and Mechanical Properties of Recycled Al-7.0Si-Fe-Mn Alloys with Constant Mn/Fe Ratio

by Dongfu Song, Yiwang Jia, Qing Li, Yuliang Zhao and Weiwen Zhang

Materials 2022, 15(4), 1618; https://doi.org/10.3390/ma15041618 - 21 Feb 2022

Cited by 17 | Viewed by 3471

Abstract

The effect of initial Fe content on the iron removal efficiency, morphology evolution of the Fe-rich phase and the mechanical properties of the recycled Al-7Si-xFe-1.2xMn alloy during melt holding was studied using an optical microscope (OM), scanning electron microscope [...] Read more.

The effect of initial Fe content on the iron removal efficiency, morphology evolution of the Fe-rich phase and the mechanical properties of the recycled Al-7Si-xFe-1.2xMn alloy during melt holding was studied using an optical microscope (OM), scanning electron microscope (SEM) and tensile testing. The results show that with the increase of the initial Fe content, the residual Fe concentration of the alloys gradually increased, and the corresponding removal efficiency of Fe gradually was increased to 77.67%. The type of Fe-rich phase in the alloys changes from α-Al₁₅(FeMn)₃Si₂ to a mixture of α-Al₁₅(FeMn)₃Si₂ and β-Al₅FeSi, and its morphological evolution is as follows: coarse Chinese-script + polygon → dense Chinese-script + polygon → polygonal + dense Chinese-script + plate-like. Furthermore, the morphology of the Fe-rich phase in the slag changes from a polygonal shape to an irregular shape with a two-layer structure. The formation and increase of the inner layer with high Mn-content in the irregular-shape phase is the main reason for the increasing residual Fe content. The plasticity of the alloy increases obviously with the increase of the initial Fe content, but the formation of the β-Al₅FeSi with plate-like morphology in higher Fe-containing alloy may hinder further improvement of the plasticity. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 6616 KiB  

Open AccessArticle

Effect of Electromagnetic Field on Wear Resistance of Fe901/Al₂O₃ Metal Matrix Composite Coating Prepared by Laser Cladding

by Yaobang Chen, Jianzhong Zhou, Pengfei Li, Kun Huo and Xiankai Meng

Materials 2022, 15(4), 1531; https://doi.org/10.3390/ma15041531 - 18 Feb 2022

Cited by 11 | Viewed by 2180

Abstract

Fe901/Al₂O₃ metal matrix composite (MMC) coatings were deposited on the surface of 45 steel via electromagnetic field (EF)-assisted laser cladding technology. The influences of EF on the microstructure, phase composition, microhardness, and wear resistance of the Fe901/Al₂O₃ [...] Read more.

Fe901/Al₂O₃ metal matrix composite (MMC) coatings were deposited on the surface of 45 steel via electromagnetic field (EF)-assisted laser cladding technology. The influences of EF on the microstructure, phase composition, microhardness, and wear resistance of the Fe901/Al₂O₃ MMC coating were investigated. The generated Lorentz force (F_L) and Joule heating due to the application of EF had a positive effect on wear resistance. The results showed that F_L broke up the columnar dendrites. Joule heating produced more nuclei, resulting in the formation of fine columnar dendrites, equiaxed dendrites, and cells. The EF affected the content of hard phase in the coatings while it did not change the phase composition of the coating, because the coatings with and without EF assistance contained (Fe, Cr), (Fe, Cr)₇C₃, Fe₃Al, and (Al, Fe)₄Cr phases. The microhardness under 20 mT increased by 84.5 HV_0.2 compared to the coating without EF due to the refinement of grains and the increased content of hard phase. Additionally, the main wear mechanism switched from adhesive wear to abrasive wear. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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25 pages, 96857 KiB  

Open AccessArticle

Effects of Low-Frequency Vibrations on Single Point Incremental Sheet Forming

by Xiao Xiao, Se-Hyeon Oh, Sang-Hoon Kim and Young-Suk Kim

Metals 2022, 12(2), 346; https://doi.org/10.3390/met12020346 - 16 Feb 2022

Cited by 7 | Viewed by 3114

Abstract

This study investigated the effects of longitudinal low-frequency vibrations on the performance of the single point incremental forming process of an aluminum alloy 1050 (AA1050) sheet. Low-frequency vibrations were added to the forming tool’s axial movement. A finite element model of low-frequency vibration [...] Read more.

This study investigated the effects of longitudinal low-frequency vibrations on the performance of the single point incremental forming process of an aluminum alloy 1050 (AA1050) sheet. Low-frequency vibrations were added to the forming tool’s axial movement. A finite element model of low-frequency vibration single point incremental forming was established. Numerical simulation analyzed the effect of low-frequency vibrations on the entire forming process. Then, the simulation results were verified through actual experiments. The results showed that low-frequency vibrations could significantly reduce the forming force and improve the formed product’s geometric accuracy. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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12 pages, 5982 KiB  

Open AccessArticle

Effect on Microstructure and Mechanical Properties of Microwave-Assisted Sintered H13 Steel Powder with Different Vanadium Contents

by Xuebin Chen, Lei Zhao, Min Wei, Danqi Huang, Liwu Jiang and Haizhou Wang

Materials 2022, 15(4), 1273; https://doi.org/10.3390/ma15041273 - 9 Feb 2022

Viewed by 2088

Abstract

The present work demonstrated the first-ever preparation of block specimens by the microwave sintering of H13 alloy powder. Varying proportions of vanadium powder (1.5%, 2.5%, 3.5%, 4.5%, and 5.5% on a mass basis) were added to H13 mold steel and these mixtures were [...] Read more.

The present work demonstrated the first-ever preparation of block specimens by the microwave sintering of H13 alloy powder. Varying proportions of vanadium powder (1.5%, 2.5%, 3.5%, 4.5%, and 5.5% on a mass basis) were added to H13 mold steel and these mixtures were sintered using microwaves. X-ray fluorescence spectroscopy was employed to determine the compositions of the resulting specimens and vanadium percentages of 1.56%, 2.04%, 3.10%, 4.06%, and 4.20% were determined. These results demonstrate a clear trend, with significantly lower vanadium amounts than expected based on the nominal values at higher vanadium loadings. Different samples were also found to exhibit different degrees of ablation, and this effect was related to the presence of voids in the materials. The surface compositions of these specimens were examined by laser-induced breakdown spectroscopy and were found to be relatively uniform. The microstructures as well as the hardness properties of the materials were assessed. Microwave sintering of 100 g specimens at 1300 °C for 10-min generated samples with hardness values ranging from 205 HV (at the lowest vanadium content) to 175.2 HV (at the highest vanadium content). The wear behavior of samples prepared by microwave sintering H13 die steel with different vanadium contents at room temperature has been studied. The results showed that 1.5% vanadium content is the best mass ratio. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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15 pages, 2986 KiB  

Open AccessArticle

A Novel Algorithm for Thickness Prediction in Incremental Sheet Metal Forming

by Yuhuai Wang, Lidong Wang, Huixi Zhang, Yong Gu and Yaokun Ye

Materials 2022, 15(3), 1201; https://doi.org/10.3390/ma15031201 - 4 Feb 2022

Cited by 9 | Viewed by 2119

Abstract

Incremental sheet metal forming characterized as increased flexibility and local plastic deformation is well suitable for low-production-run manufacturing and a new sample trial production of complex shapes. Thickness thinning is still an obstacle to the application of incremental forming. In this study, a [...] Read more.

Incremental sheet metal forming characterized as increased flexibility and local plastic deformation is well suitable for low-production-run manufacturing and a new sample trial production of complex shapes. Thickness thinning is still an obstacle to the application of incremental forming. In this study, a novel mathematical algorithm based on a non-uniform rational B-spline (NURBS) surface was proposed and implemented which focuses on predicting and calculating the final thickness for arbitrary parts in incremental forming. In order to evaluate the validity of the proposed model, the finite element simulation and forming experiments of three kinds of parts, such as truncated cones, truncated pyramids and ellipsoid parts, were conducted. The thickness of theoretical prediction was compared with that of finite element simulation and experiment, and good agreements were obtained. The results show that the proposed model and the method are effective and robust for predicting the thickness of the formed parts in incremental sheet metal forming. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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17 pages, 7618 KiB  

Open AccessArticle

Effect of Ultrasonic-Assisted Casting on the Hydrogen and Lithium Content of Al-Li Alloy

by Yuqi Hu, Ripeng Jiang, Xiaoqian Li and Renjun Hu

Materials 2022, 15(3), 1081; https://doi.org/10.3390/ma15031081 - 30 Jan 2022

Cited by 9 | Viewed by 2495

Abstract

Dehydrogenation of the 2195 Al–Li alloy was accomplished using argon degassing, ultrasonic degassing, and vacuum degassing. The concentration of hydrogen, its microstructure, and its mechanical characteristics were all investigated. The hydrogen content in the 2195 Al–Li alloy is high. The degassing process significantly [...] Read more.

Dehydrogenation of the 2195 Al–Li alloy was accomplished using argon degassing, ultrasonic degassing, and vacuum degassing. The concentration of hydrogen, its microstructure, and its mechanical characteristics were all investigated. The hydrogen content in the 2195 Al–Li alloy is high. The degassing process significantly improved the mechanical properties of the cast alloy, owing the removal of hydrogen. Among the three degassing techniques, ultrasonic argon treatment was an efficient dehydrogenation approach and an effective procedure for enhancing the microstructure while minimizing lithium loss in the Al–Li alloy. On the one hand, ultrasonic waves can dissolve purged argon bubbles, allowing them to degas more efficiently. On the other hand, ultrasonic waves may cause a large number of cavitation bubbles to form in the melt, which should be the cause of the microstructure refinement. The dynamics of rising argon bubbles and ultrasonic effects are involved in ultrasonic argon treatments such as cavitation and flow. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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20 pages, 26578 KiB  

Open AccessArticle

The Deformation Characteristics and Effect of Processing Parameters on the Microstructure of 7075 Al Shell Part Manufactured by Rotating Backward Extrusion

by Ning Guo, Shuchang Li, Fafa Yan, Zhen Wang, Kemin Xue, Rou Wang and Wenfang Xing

Metals 2022, 12(2), 227; https://doi.org/10.3390/met12020227 - 26 Jan 2022

Cited by 3 | Viewed by 2832

Abstract

Rotating backward extrusion (RBE) is known as a new severe plastic deformation technology that effectively combines the features of conventional backward extrusion (CBE) and torsion deformation. In this study, 7075 Al alloy shell parts were successfully prepared by CBE and RBE with a [...] Read more.

Rotating backward extrusion (RBE) is known as a new severe plastic deformation technology that effectively combines the features of conventional backward extrusion (CBE) and torsion deformation. In this study, 7075 Al alloy shell parts were successfully prepared by CBE and RBE with a different number of revolutions (N = 5, 10, 15, 25, 50) at 410 °C. The effects of the RBE process on the grain refinement, precipitates and properties of extruded parts were revealed, and the deformation characteristics were compared with CBE. The results showed that the RBE process could greatly eliminate the dead deformation zone at the bottom of the CBE section and significantly improved the comprehensive strain level of the material due to the addition of severe torsional deformation via an open punch. The grain refinement feature of RBE parts showed a gradient distribution that continuously weakened from the inner wall to the outer wall with decreasing compressive and torsional stress. Increasing the number of revolutions significantly promoted the level of grain refinement, the grain refinement range, and effectively broke down and refined the coarse insoluble Fe-rich phases of the extruded parts. It was revealed that the finest grain size of approximately 1.3 μm could be obtained in the inner wall region when N was increased to 25, which was linked to the comprehensive effects of continuous dynamic recrystallization and geometric dynamic recrystallization. RBE greatly promoted an improvement in properties of the extruded parts. After T6 treatment, the microhardness of the fine-grained region of the RBE (25 N) part increased to ~192–197 HV, compared with ~180 HV in the initial T6-extruded state. Full article

(This article belongs to the Topic Advanced Forming Technology of Metallic Materials)

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