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Metals, Volume 15, Issue 2 (February 2025) – 81 articles

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19 pages, 6018 KiB  
Article
Effect of Aging Temperature on the Impact Wear Properties and Wear Mechanism of Lightweight Wear-Resistant Steel
by Liwen Liang, Jianchang Sun, Ben Cheng, Suotao Wang, Mintao Chen and Qingfeng Wang
Metals 2025, 15(2), 178; https://doi.org/10.3390/met15020178 (registering DOI) - 10 Feb 2025
Abstract
In this study, the microstructure, mechanical properties, wear resistance, and wear-hardening mechanism of Fe-28Mn-8.5Al-1.0C lightweight wear-resistant steel after heat treatment at different aging temperatures were examined. The results show that the nano-scale κ-carbides precipitated in the grains after aging treatment increased the strength [...] Read more.
In this study, the microstructure, mechanical properties, wear resistance, and wear-hardening mechanism of Fe-28Mn-8.5Al-1.0C lightweight wear-resistant steel after heat treatment at different aging temperatures were examined. The results show that the nano-scale κ-carbides precipitated in the grains after aging treatment increased the strength and hardness of the material through the strengthening effect of the second phase. The yield strength of the material is 697 MPa, the tensile strength is 905 MPa, and the hardness is up to 294 HB after aging at 500 °C for 5 h. However, the large-sized κ-carbides precipitating continuously at the grain boundary are unfavorable to the plasticity and toughness of the material. Compared with the aging treatment at 300 °C for 5 h, the elongation and low-temperature impact energy decreased by 12.0% and 47.1%, respectively. Except for the dominant wear mechanism being plastic deformation after heat treatment at 500 °C for 5 h with a 4J impact energy, the predominant wear mechanisms for different impact energies under all other heat treatment conditions are micro-cutting. The increase in aging temperature increases the number and volume of κ-carbide precipitation, which leads to enhanced second-phase strengthening and dislocation strengthening, and the wear resistance of the material is improved. The hardening mechanism of the material after wear at different impact energy levels under aging treatment conditions is a cross-distributed dislocation wall and high-density dislocation entanglement. The increase in aging temperature reduces the spacing of the dislocation wall, increases the area and density of dislocation entanglement, and enhances the work-hardening effect. Full article
(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)
24 pages, 8491 KiB  
Article
Mechanical and Corrosion Properties of AA2024 Aluminum Alloy with Multimodal Gradient Structures
by Zhenwei Xie, Liexing Zhou, Jun Li, Yonghua Duan, Mingjun Peng, Hongbo Xiao, Xiong Du, Yuanjie Zhao and Mengnie Li
Metals 2025, 15(2), 177; https://doi.org/10.3390/met15020177 - 10 Feb 2025
Viewed by 96
Abstract
Enhancing the strength and toughness of aluminum alloys using microstructure optimization remains a key challenge. In this study, an AA2024 aluminum alloy with a double-layer multi-gradient structure was fabricated using 50% constrained deformation and single-stage peak aging at 150 °C. Microstructural and compositional [...] Read more.
Enhancing the strength and toughness of aluminum alloys using microstructure optimization remains a key challenge. In this study, an AA2024 aluminum alloy with a double-layer multi-gradient structure was fabricated using 50% constrained deformation and single-stage peak aging at 150 °C. Microstructural and compositional analysis was performed using SEM, XRD, and TEM to investigate grain structures, dislocation density, and the distribution of precipitated phases. The results revealed a heterogeneous microstructure with variations in grain size, dislocation gradient, and precipitation phases between the constrained and deformation layers. Mechanical testing demonstrated a 30.9% increase in yield strength, a 16.4% increase in tensile strength, and a 13.9% improvement in uniform elongation compared to the T6 temper. Corrosion tests showed enhanced resistance, with a shallower intergranular corrosion depth and higher self-corrosion potential. The improved mechanical properties were attributed to the dislocation gradient and heterogeneous precipitation phases, while the enhanced corrosion resistance resulted from the transformation of the S phase from a continuous grain boundary distribution to a discontinuous distribution along dislocations. This study provides a novel approach for optimizing the mechanical and corrosion properties of AA2024 aluminum alloy using microstructure design and precise thermal–mechanical treatment. Full article
(This article belongs to the Special Issue Light Alloy and Its Application (2nd Edition))
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15 pages, 10156 KiB  
Article
Deformation Behavior and Microstructure Evolution of High-Strength and -Toughness Ti55531 Titanium Alloy
by Yucheng Yang, Tongsheng Deng, Zhi Liu, Hai Liu, Yupeng Yuan and Wei Chen
Metals 2025, 15(2), 176; https://doi.org/10.3390/met15020176 - 10 Feb 2025
Viewed by 96
Abstract
In this paper, constant strain rate compression was carried out by means of an MMS-100 thermal/force simulation tester in a temperature range of 790~940 °C, with a strain rate of 0.01–1 s−1 and a compression volume of 60%. A linear regression method [...] Read more.
In this paper, constant strain rate compression was carried out by means of an MMS-100 thermal/force simulation tester in a temperature range of 790~940 °C, with a strain rate of 0.01–1 s−1 and a compression volume of 60%. A linear regression method was used to fit the relationship between strain stress, strain rate, and deformation temperature, and the Arrhenius-type constitutive equation of Ti55531 titanium alloy was established; the heat deformation activation energy of Ti55531 titanium alloy was obtained as 211,747.5 kJ·mol−1. A thermal processing map of Ti55531 alloy was established. EBSD results show that after hot compression, the recrystallization volume fraction greatly increased. The original sample recrystallization volume fraction was 23.2%. Under a deformation temperature of 850 degrees Celsius and deformation rate of 0.01, the recrystallization volume fraction rose to 38.5%; after the annealing process, the recrystallization volume fraction further increased to 72.6%. Under the deformation temperature of the thermal compression process, the higher the deformation rate, the larger its recrystallization volume fraction. After annealing, the recrystallization volume fraction further increased. This study can provide a reference and theoretical guidance for the development and optimization of the thermal processing process of Ti55531 titanium alloy. Full article
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13 pages, 4983 KiB  
Article
Effects of Mg Content and Pulsed Magnetic Field Treatment on Microstructure and Properties of As-Cast Biodegradable Zn-3Cu Alloy
by Lizhen Shi, Hui Liu, Houqing Liu, Cong Peng and Ling Ren
Metals 2025, 15(2), 175; https://doi.org/10.3390/met15020175 - 10 Feb 2025
Viewed by 135
Abstract
The microstructure, mechanical properties, corrosion behavior, cytocompatibility, and antibacterial properties of biodegradable Zn-3Cu-xMg (x = 0, 0.5, 1 wt.%) alloys with or without pulsed magnetic field treatment during casting were systematically investigated. Mg addition induced the formation of fine Mg2Zn11 [...] Read more.
The microstructure, mechanical properties, corrosion behavior, cytocompatibility, and antibacterial properties of biodegradable Zn-3Cu-xMg (x = 0, 0.5, 1 wt.%) alloys with or without pulsed magnetic field treatment during casting were systematically investigated. Mg addition induced the formation of fine Mg2Zn11 precipitated along the matrix grain boundaries. With the increase in Mg content, the precipitation of the Mg2Zn11 phase increased, and the grain size became finer. Pulsed magnetic field treatment exacerbated the occurrence of this phenomenon. Under the combined action of the Mg2Zn11 phase and refined grain size, Zn3Cu0.5Mg alloy with pulsed magnetic field treatment had the best strength–ductility match (σUTS = 181.46 ± 1.06 MPa, δ = 3.95 ± 0.07%), moderate corrosion rate (icorr = 5.69 ± 3.96 μA/cm2), positive cytocompatibility, and antibacterial properties. This study indicated that Zn3Cu0.5Mg alloy with pulsed magnetic field treatment had the greater potential to further improve its properties through subsequent conventional metal-forming processing and severe plastic deformation techniques to meet clinical requirements, compared to existing as-cast Zn alloys. Full article
(This article belongs to the Special Issue Feature Papers in Biobased and Biodegradable Metals)
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24 pages, 18017 KiB  
Article
Microstructure and Mechanical Behaviors of Fiber-Laser-Welded QP980-QP1180 Steels
by Hafize Çelik and Onur Saray
Metals 2025, 15(2), 174; https://doi.org/10.3390/met15020174 - 9 Feb 2025
Viewed by 395
Abstract
Advanced high-strength steels are considered the first choice when manufacturing lighter vehicles. Quench-partitioning (QP) steels are good candidates that fulfill manufacturing and performance requirements with their outstanding strength and formability. Laser welding offers a productive solution to the challenges of liquid metal embrittlement [...] Read more.
Advanced high-strength steels are considered the first choice when manufacturing lighter vehicles. Quench-partitioning (QP) steels are good candidates that fulfill manufacturing and performance requirements with their outstanding strength and formability. Laser welding offers a productive solution to the challenges of liquid metal embrittlement due to a low heat input and higher welding efficiency. This study investigated the microstructural evolution and mechanical performance of dissimilar laser-welded joints between QP980 and QP1180 steels. The microstructure of the joint mainly consisted of martensite phase in the fusion zone (FZ) and super-critical heat-affected zone (HAZ). In the mid and sub-critical HAZ, the microstructure consisted of tempered martensite along with ferrite and retained austenite on both sides. Due to these microstructural evolutions, FZ and HAZ are strengthened, and thus, laser welds can be achieved without the formation of a visible soft zone. Fracture of the joints occurred in softer base metal (BM) with ductile characteristics without any considerable strength loss. However, the ductility of the joints was lower than that of BMs because of deformation localization due to microstructure, yield strength, and thickness variations in the tensile and Erichsen test specimens. These results show that laser welding can be considered an effective alternative for joining QP steels. Full article
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15 pages, 6357 KiB  
Article
Numerical Simulation of the Hot Isostatic Pressing Densification Behavior of Ti6Al4V Powder for a Thin-Walled Tubular Component with Non-Axisymmetric Inner Ribs
by Yanqing Jiang, Lin Geng and Guofeng Zhang
Metals 2025, 15(2), 173; https://doi.org/10.3390/met15020173 - 8 Feb 2025
Viewed by 374
Abstract
Hot isostatic pressing (HIP) technology is an efficient near-net-shape forming method to prepare complex-shaped structural components. However, for non-axisymmetric components with a complex shape, the powder flow and densification behaviors during HIP are still not clear, leading to a need for lots of [...] Read more.
Hot isostatic pressing (HIP) technology is an efficient near-net-shape forming method to prepare complex-shaped structural components. However, for non-axisymmetric components with a complex shape, the powder flow and densification behaviors during HIP are still not clear, leading to a need for lots of experiments to optimize the process parameters. In the current work, a typical aerospace thin-walled tubular component with non-axisymmetric inner ribs was selected as the research object, and its instantaneous powder flow and relative density during the whole HIP process were investigated by a numerical simulation method, focusing on the influence of HIP process conditions on powder densification. The simulation results indicate that the upper end of the Ti6Al4V thin-walled tubular part is preferentially densified, and the lowest densification is observed at the inner rib of the cylinder wall. Moreover, the effect on densification of each HIP condition, including sintering temperature (900–970 °C), pressure (120–180 MPa), and holding time (3–4 h), was evaluated separately. The HIP sintering temperature contributes the most to the improvement of densification, followed by the pressure, while the holding time contributes the least. Investigating HIP densification behavior is beneficial to the structural and process optimization of metal near-net-shape forming applications. Full article
(This article belongs to the Special Issue Powder Metallurgy of Metallic Materials)
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28 pages, 5162 KiB  
Article
Post Neutron Irradiation Recovery and Recrystallization of ITER Grade Forged Tungsten Bar
by Dimitrios Papadakis, Efthimios Manios and Konstantina Mergia
Metals 2025, 15(2), 172; https://doi.org/10.3390/met15020172 - 8 Feb 2025
Viewed by 286
Abstract
Defect recovery and recrystallization studies of neutron-irradiated tungsten (W) addressing the microstructural evolution in relation to the mechanical properties, provide valuable insight into defect interactions and annihilation processes. Understanding these mechanisms can aid in the development of effective healing processes, potentially extending the [...] Read more.
Defect recovery and recrystallization studies of neutron-irradiated tungsten (W) addressing the microstructural evolution in relation to the mechanical properties, provide valuable insight into defect interactions and annihilation processes. Understanding these mechanisms can aid in the development of effective healing processes, potentially extending the lifespan of fusion reactor components. Additionally, this research helps to elucidate how neutron exposure alters the behaviour of materials used in fusion reactor components, contributing to improved design and durability. Within this framework, an ITER grade forged W bar was neutron irradiated to a damage of 0.21 displacements per atom at 600 °C and subsequently isochronally annealed from 700 up to 1550 °C in 50 °C steps. Irradiation causes the formation of dislocation loops and vacancy clusters as well as the formation of Re and Os transmutation products, leading to a 35% increase in hardness and a 23% increase in resistivity. The evolution of the microstructure after isochronal annealing is investigated through positron annihilation lifetime spectroscopy, X-ray diffraction, resistivity, and Vickers hardness measurements. The total dislocation line density as well as the number density and size of voids are determined as a function of annealing temperature. Specifically, the critical resolved stresses of dislocations and voids are correlated with their densities and distinct recovery stages are identified. The kinetics of defect annihilation are discussed in relation to the annealing temperature. Nearly complete dislocation annihilation occurs after annealing at 1300 °C, followed by complete void dissolution and recrystallization at 1450 °C. Full article
(This article belongs to the Special Issue Radiation Damage in Metallic Systems for Fusion Energy Applications)
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20 pages, 5609 KiB  
Article
New Process for Efficient Separation and Comprehensive Recovery of Valuable Metals from Jarosite Residues
by Qi Zhou, Jian Pan, Deqing Zhu, Congcong Yang, Zhengqi Guo, Siwei Li and Xianqing Xu
Metals 2025, 15(2), 171; https://doi.org/10.3390/met15020171 (registering DOI) - 8 Feb 2025
Viewed by 166
Abstract
Jarosite residue (JR), a hazardous solid waste generated in non-ferrous metallurgy, poses significant environmental challenges due to its large volume and poor storage stability. However, its high content of valuable metals (such as iron, zinc, gallium, indium, silver, …) makes its efficient recovery [...] Read more.
Jarosite residue (JR), a hazardous solid waste generated in non-ferrous metallurgy, poses significant environmental challenges due to its large volume and poor storage stability. However, its high content of valuable metals (such as iron, zinc, gallium, indium, silver, …) makes its efficient recovery and comprehensive utilization highly significant. This study investigates the “oxidative roasting–reductive smelting” process for JR treatment. The reduction thermodynamics of JR-R (roasted JR) were analyzed, and the effects of smelting temperature, time, and slag basicity on the reduction and smelting process were examined. The results indicate that increasing slag basicity and temperature generally decreases slag viscosity. Thermodynamic calculations demonstrate that reductive smelting effectively enriches valuable metals (>1039 °C). The optimal conditions for reductive smelting of JR were determined to be as follows: smelting temperature of 1550 °C, smelting time of 60 min, and slag basicity of 0.9. Under these conditions, the process achieved an Fe grade of 92.87% in pig iron with a recovery rate of 90.66%, a Ga grade of 377 g/t with a recovery rate of 94.91%, and Zn and In volatilization rates of 99.91% and 83.36%, respectively. This study provides a feasible approach for the comprehensive recovery of valuable metals such as Ga, Fe, Zn, and In from JR, offering promising economic and social benefits. Full article
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17 pages, 6456 KiB  
Article
Non-Uniform Thermal Transfer of Molten Steel and Its Effect on Inclusion Particles Removal Behavior in Continuous Casting Tundish
by Zhixiao Zhang, Tianpeng Qu, Deyong Wang, Xianglong Li, Lei Fan and Xingzhi Zhou
Metals 2025, 15(2), 170; https://doi.org/10.3390/met15020170 - 8 Feb 2025
Viewed by 244
Abstract
The temperature gradient inside a tundish leads to the uneven density distribution of molten steel, resulting in thermal buoyancy, which has a significant impact on the motion of inclusion particles. Based on practice data and necessary assumptions, a three-dimensional model of a tundish [...] Read more.
The temperature gradient inside a tundish leads to the uneven density distribution of molten steel, resulting in thermal buoyancy, which has a significant impact on the motion of inclusion particles. Based on practice data and necessary assumptions, a three-dimensional model of a tundish considering non-uniform thermal transfer was established. The flow and temperature distribution were studied, and the changes in inclusion removal rate were compared with different casting speeds and temperature reduction rates using computational fluid dynamics simulation. It was observed that, when the inlet temperature is higher, the molten steel floats up under the action of thermal buoyancy, which can form a horizontal stream behind the weir. While the inlet temperature is lower, the horizontal stream cannot be maintained, resulting in a decrease in the removal rate of inclusions. Increasing the casting speed will increase the velocity of the molten steel in the tundish, make it easier to shorten the temperature difference between the inlet and outlet, and reduce the removal rate of inclusions. When formulating production processes, the impact of thermal buoyancy on the flow field should be taken into account. Full article
(This article belongs to the Special Issue Purification Metallurgy in Steelmaking)
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16 pages, 6624 KiB  
Article
Experimental and Numerical Study of Behavior of Additively Manufactured 316L Steel Under Challenging Conditions
by Lenka Kunčická, Radim Kocich and Marek Pagáč
Metals 2025, 15(2), 169; https://doi.org/10.3390/met15020169 - 8 Feb 2025
Viewed by 263
Abstract
AISI 316L stainless steel, widely used in numerous industrial fields, can be fabricated by conventional methods, but also by additive manufacturing. As materials prepared by additive manufacturing typically feature various printing defects deteriorating their mechanical and utility properties, post-processing by plastic deformation is [...] Read more.
AISI 316L stainless steel, widely used in numerous industrial fields, can be fabricated by conventional methods, but also by additive manufacturing. As materials prepared by additive manufacturing typically feature various printing defects deteriorating their mechanical and utility properties, post-processing by plastic deformation is able to enhance their performance. The determination of optimized post-processing conditions can advantageously be performed by combining experimental work and numerical simulations using the finite element method. The presented research focuses on investigating the deformation behavior of AISI 316L stainless steel prepared by additive manufacturing under a variety of thermomechanical conditions (temperatures of 900–1250 °C, strain rates of 0.1–100 s−1). Together with the deformation behavior of the steel, the kinetics of the occurring softening processes is also discussed. The experimentally acquired data are further used for numerical simulations to predict the expected magnitudes of force and imposed strains during prospective post-processing. Observing the microstructures and mechanical properties reveals that the prospective post-processing of AISI 316L stainless steel, prepared by additive manufacturing, via plastic deformation is the most favorable when performed at the temperature of 900 °C and using high strain rates. The flow stress/microhardness generally increase at lower temperatures and higher strain rates, as a result of the development of a substructure. On the contrary, higher temperatures support the recrystallization of grains and their coarsening, which consequently decreases the mechanical properties. Full article
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17 pages, 6891 KiB  
Article
Weld Bead Shape and Formation Prediction for Robotic MIG Welding Process Using Numerical Calculation
by Ping Yao, Yunyi Huang, Riheng He, Junxi Huang, Meiyi Chen, Wenxiao Yu and Kang Zhou
Metals 2025, 15(2), 168; https://doi.org/10.3390/met15020168 - 8 Feb 2025
Viewed by 341
Abstract
To optimize the robotic MIG welding process for joining 316 L stainless steel sheets and to clearly understand the process, a new numerical model for a combined heat source, based on a Gaussian surface and Gaussian cylinder, was developed using ANSYS software. After [...] Read more.
To optimize the robotic MIG welding process for joining 316 L stainless steel sheets and to clearly understand the process, a new numerical model for a combined heat source, based on a Gaussian surface and Gaussian cylinder, was developed using ANSYS software. After confirming the proper welding parameter combination for producing a weld bead with a good appearance, the model could be developed using the parameter combination. The influence of four parameters—effective heat delivery radius, the depth and heat distribution coefficients of the Gaussian surface, and the Gaussian cylinder heat source effects on the bead width and penetration—was explored using the model, and then a general and convenient method was proposed to effectively and reasonably set the parameters of the combined heat source. Finally, the numerical calculation results for the shape of the fusion line of the weld bead section could be obtained under different input powers and different welding speeds. The numerical calculation results had small errors compared to the experiments results. Hence, this model could realize temperature field simulation and weld bead formation prediction. This work can be used to accurately and effectively predict the robotic MIG welding process in the academic research and supply references for actual production. Full article
(This article belongs to the Special Issue Modeling and Mechanism Analysis of Welding Process for Metals)
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17 pages, 18766 KiB  
Article
Development of Calvarial-Derived Osteogenic Cells on GDF-5 Coated Nanoporous Titanium Surfaces
by Renan B. L. Bueno, Lucas N. Teixeira, Felippe J. Pavinatto, William M. A. Maximiano, Leonardo R. Zuardi, Adalberto L. Rosa, Osvaldo N. Oliveira, Jr., Silvia Spriano and Paulo Tambasco de Oliveira
Metals 2025, 15(2), 167; https://doi.org/10.3390/met15020167 - 7 Feb 2025
Viewed by 369
Abstract
This study evaluated the impact of a single variation in the etching time of H2SO4/H2O2-treated titanium (Ti) surfaces on the adsorption of growth and differentiation factor-5 (GDF-5) and their effects on the acquisition of the [...] Read more.
This study evaluated the impact of a single variation in the etching time of H2SO4/H2O2-treated titanium (Ti) surfaces on the adsorption of growth and differentiation factor-5 (GDF-5) and their effects on the acquisition of the osteogenic phenotype in vitro. Rat primary calvarial osteogenic cells were grown for up to 14 days on the following Ti surfaces: (1) 30 min: nanotopography obtained with a 1:1 mixture of H2SO4/H2O2 for 30 min (control); (2) 30 min + GDF-5: a 30 min-etched Ti sample adsorbed with recombinant human (rh) GDF-5; (3) 4 h: nanotopography obtained with a 1:1 mixture of H2SO4/H2O2 for 4 h (control); (4) 4 h + GDF-5: a 4 h-etched Ti sample adsorbed with rhGDF-5. The GDF-5 adsorption procedure was carried out on the day before cell plating using 200 ng/mL rhGDF-5 overnight at 4 °C. The 30 min- and 4 h-etched Ti samples exhibited a high hydrophilic network of nanopits with a tendency towards larger nanopits for the 4 h group, which corresponded to an enhanced GDF-5 adsorption. For both etching times, coating with GDF-5 resulted in less hydrophilic surfaces that supported (1) a reduction in the proportion of spread cells and an enhanced extracellular osteopontin labeling at early time points of culture, and (2) increased alkaline phosphatase activity preceding an enhanced mineralized matrix formation compared with controls, with a tendency towards higher osteogenic activity for the 4 h + GDF-5 group. In conclusion, the osteogenic potential induced by the GDF-5 coating can be tailored by subtle changes in the nanotopographic characteristics of Ti surfaces. Full article
(This article belongs to the Section Biobased and Biodegradable Metals)
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14 pages, 5945 KiB  
Article
The Microstructure and Wear Resistance of Laser Cladding Ni60/60%WC Composite Coatings
by Junxiao Liu, Chen Liu, Xiaoyu Zhang, Xiuyuan Yin, Fanyu Meng and Changsheng Liu
Metals 2025, 15(2), 166; https://doi.org/10.3390/met15020166 - 7 Feb 2025
Viewed by 256
Abstract
In this study, Ni60/60%WC composite coatings were fabricated on 45 steel by laser cladding. The optimum process was selected through high throughput optimization experiments which had a laser power of 2400 W, scanning speed of 8 mm/s, and powder feeding rate of 20 [...] Read more.
In this study, Ni60/60%WC composite coatings were fabricated on 45 steel by laser cladding. The optimum process was selected through high throughput optimization experiments which had a laser power of 2400 W, scanning speed of 8 mm/s, and powder feeding rate of 20 g/min. The single-layer multilayer coatings were prepared without any cracks and pores, and the thickness of the coatings was 1.52 mm. The coating and the substrate were found to have an effective metallurgical connection. WC was distributed relatively uniformly throughout the coating, which involved the γ-(Fe, Ni), WC, W2C, Cr23C6, and Fe3.57W9.43C3.54 phases. The average microhardness of the coating was 1416.14 HV0.2, approximately 5.47 times that of the substrate, and the average coefficient of friction of the coating was 0.5144, which was 43.5% lower than that of the substrate. The wear rate was reduced by 79.13%. Full article
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10 pages, 2253 KiB  
Article
Highly Selective Precipitation of Platinum(IV) from HCl Solutions Using m-Phenylenediamine Utilizing Difference in Stability of Ionic Crystals
by Kazuya Matsumoto, Yuki Hata, Hiroshi Katagiri and Mitsutoshi Jikei
Metals 2025, 15(2), 165; https://doi.org/10.3390/met15020165 - 7 Feb 2025
Viewed by 285
Abstract
The development of a selective separation and recovery method for platinum-group metals (PGMs) is in high demand to establish efficient and practical recycling technologies for different secondary materials such as industrial automobile catalysts. In this study, the highly selective precipitation of Pt(IV) from [...] Read more.
The development of a selective separation and recovery method for platinum-group metals (PGMs) is in high demand to establish efficient and practical recycling technologies for different secondary materials such as industrial automobile catalysts. In this study, the highly selective precipitation of Pt(IV) from hydrochloric acid (HCl) solutions containing Pd(II), Pt(IV), and Rh(III) was successfully achieved using m-phenylenediamine dihydrochloride (MPDA) as a precipitant. Pt(IV) selectivity was observed at HCl concentrations higher than 7 M, whereas the co-precipitation of Rh(III) could not be suppressed using 3–7 M HCl solutions. Successful recovery of Pt(IV)-containing precipitates with high Pt yield (94.6%) and Pt purity (98.5%) was also achieved using an actual catalyst leaching solution with a complex composition containing PGMs, base metals, and rare metals. Structural analyses revealed that the Pt(IV)-containing precipitate forms ionic crystals composed of [PtCl6]2−/protonated m-phenylenediamine (MPDA-2H+) in a 1:1 ratio. The high stability and insolubility of the Pt(IV)-containing ionic crystals, owing to their highly packed structure, resulted in the highly selective precipitation of Pt(IV) at high HCl concentrations. Full article
(This article belongs to the Section Extractive Metallurgy)
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15 pages, 8669 KiB  
Article
Elucidating the Effects of Material Flow from Deposition Offset on AFSD Repair of AA7050
by Victor A. Rojas, Ismael Y. Hidalgo, Khaled Matalgah, Trevor J. Fleck, Luke N. Brewer, Gregory W. Kubacki, J. Brian Jordon and Paul G. Allison
Metals 2025, 15(2), 164; https://doi.org/10.3390/met15020164 - 7 Feb 2025
Viewed by 353
Abstract
In this work, the effects of tool bias as a processing parameter on an additive friction stir deposition repair of AA7050-T7451 plates were investigated. In this study, the asymmetrical material flow effect was assessed by subjecting a machined groove plate to different tool [...] Read more.
In this work, the effects of tool bias as a processing parameter on an additive friction stir deposition repair of AA7050-T7451 plates were investigated. In this study, the asymmetrical material flow effect was assessed by subjecting a machined groove plate to different tool biases during the AFSD process. The tool bias effectiveness on repairs was quantified through mechanical testing and destructive and non-destructive evaluation. Monotonic tensile tests conducted in parallel with a digital image correlation method captured the mechanical performance of the repairs and the local strain effects of the heat-affected zone. X-ray computed tomography images of the different tool bias repairs were analyzed for any voids or defects to measure the overall bonding effectiveness. The results suggest that the advancing side tool bias had adequate bonding with the substrate, which yielded improved mechanical performance compared to the centered and retreating side depositions. Full article
(This article belongs to the Section Additive Manufacturing)
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24 pages, 13575 KiB  
Article
Biodegradability and Cavitation Erosion Behavior of Some Zinc Alloys from the System ZnCuMg
by Brandusa Ghiban, Aurora Antoniac, Ilare Bordeasu, Iulian Antoniac, Gabriela Petre, Julietta V. Rau, Dorin Bordeasu and Lavinia Madalina Micu
Metals 2025, 15(2), 161; https://doi.org/10.3390/met15020161 - 7 Feb 2025
Viewed by 421
Abstract
This paper presents experimental results regarding the development of new alloys from the binary ZnCu and ternary ZnCuMg systems. The alloys had controlled chemical compositions and were annealed at 300 °C and 400 °C, with holding times of 5 h and 10 h, [...] Read more.
This paper presents experimental results regarding the development of new alloys from the binary ZnCu and ternary ZnCuMg systems. The alloys had controlled chemical compositions and were annealed at 300 °C and 400 °C, with holding times of 5 h and 10 h, followed by air cooling. Mechanical properties (tensile strength, yield strength, elongation, and elastic modulus) were determined. Structural analysis conducted after different heat treatments revealed that homogenization transforms the dendritic structure into a granular structure with intergranular eutectic presence. Biodegradation behavior showed that the ternary alloy exhibits higher degradation rates than the binary alloy. Applying the homogenization heat treatment has a good influence on the binary alloy only, not on the ternary alloy. Our research shows that that the complex alloying of zinc with copper and magnesium may improve cavitation behavior, doubling both the MDEmax parameter and cavitation resistance expressed by Rcav. Full article
(This article belongs to the Section Metal Casting, Forming and Heat Treatment)
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24 pages, 21001 KiB  
Article
Wear Resistance and Failure Mode of Coatings Based on the ZrN System with the Introduction of Ti, Nb, and Hf Deposited on a Titanium Alloy Substrate
by Sergey Grigoriev, Catherine Sotova, Alexander Metel, Valery Zhylinski, Filipp Milovich, Anton Seleznev, Yanpeng Xue and Alexey Vereschaka
Metals 2025, 15(2), 163; https://doi.org/10.3390/met15020163 - 6 Feb 2025
Viewed by 269
Abstract
The article presents the results of a comparison of the wear resistance of coatings with a two-layer architecture (adhesion layer–wear-resistant layer) of Zr-ZrN, Zr-(Zr,Ti)N, Zr,Hf-(Zr,Hf)N, Zr,Nb-(Zr,Nb)N, Zr,Hf-(Ti,Zr,Hf)N, and Zr,Nb-(Ti,Zr,Nb)N coatings, deposited on a titanium alloy substrate. The wear resistance was studied using two [...] Read more.
The article presents the results of a comparison of the wear resistance of coatings with a two-layer architecture (adhesion layer–wear-resistant layer) of Zr-ZrN, Zr-(Zr,Ti)N, Zr,Hf-(Zr,Hf)N, Zr,Nb-(Zr,Nb)N, Zr,Hf-(Ti,Zr,Hf)N, and Zr,Nb-(Ti,Zr,Nb)N coatings, deposited on a titanium alloy substrate. The wear resistance was studied using two different counterbodies: Al2O3 and steel. When in contact with the Al2O3 counterbodies, the best wear resistance was demonstrated by samples with Zr,Hf-(Zr,Hf)N and Zr,Nb-(Zr,Nb,Ti)N coatings. In tests conducted in contact with the steel counterbody, the best resistance was demonstrated by samples with Zr-ZrN and Zr,Hf-(Ti,Zr,Hf)N coatings. The wear resistance of samples with (Zr,Hf)N and (Zr,Nb,Ti)N coatings was 2.5–3.3 times higher than that of the uncoated sample. The Zr,Nb adhesion layer ensures better adhesion of the coating to the substrate. It was found that not only the adhesion strength of the adhesion layer to the substrate and coating is of significant importance but also the strength of the adhesion layer itself. The surface film of titanium oxide must be completely etched off to ensure maximum strength of the adhesive bond between the coating and the substrate. It has been established that the adhesion of the coating and the titanium substrate is also affected by the characteristics of the outer (wear-resistant) coating layer, which is the composition and structure of the wear-resistant coating layer. Delamination can occur both at the boundary of the adhesive layer with the substrate and at the boundary of the wear-resistant and adhesive layers of the coating depending on the strength of the adhesive bonds in the corresponding pair. It is necessary to ensure a good combination of properties both in the substrate–adhesion layer system and in the adhesion layer–wear-resistant layer system. Full article
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21 pages, 7102 KiB  
Article
Exploring the Interfacial Microstructure Evolution and Bonding Properties of Al/Steel Composite Plates Fabricated Through Semi-Solid Cast-Rolling
by Jin Qiu, Yuandong Li, Hongwei Zhou and Guangli Bi
Metals 2025, 15(2), 162; https://doi.org/10.3390/met15020162 - 6 Feb 2025
Viewed by 471
Abstract
This study prepared Al/steel composite plates with high shear strength using semi-solid cast-rolling (SSCR). The results indicate that the semi-solid diffusion effectively reduced the diffusion and reaction rate between Al and steel, thereby impeding the formation of the free FeAl3 phase and [...] Read more.
This study prepared Al/steel composite plates with high shear strength using semi-solid cast-rolling (SSCR). The results indicate that the semi-solid diffusion effectively reduced the diffusion and reaction rate between Al and steel, thereby impeding the formation of the free FeAl3 phase and mitigating the rapid growth of the Fe2Al5 phase, facilitating the regulation of the microstructure and bonding property. Notably, the morphology of the FeAl3 phase transformed from a loose sponge-like eutectic structure to a densely serrated-like configuration with the increase in the holding time, correlating with an enhancement in shear strength. At a holding time of 120 s, the shear strength of a 5.5 mm thick composite plate reached a notable 68.5 MPa. After a holding time of 120 s, the thickness of the FeAl3 phase stabilized at approximately 9.5 μm. However, the grain size and thickness of the Fe2Al5 phase continued to increase, leading to a subsequent decline in shear strength. Furthermore, shear strength increased substantially with the decreasing thickness of the composite plate. SSCR enabled the formation of dense intermetallic compounds (IMCs) with grain sizes below 3 μm at the Al/steel interface while retaining residual compressive stress within the matrix, yielding shear strength higher than that of composite casting and comparable to composite rolling. Full article
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3 pages, 122 KiB  
Editorial
Advances in Lightweight Metal Matrix Composites
by Pilar Rey and Gaspar González-Doncel
Metals 2025, 15(2), 160; https://doi.org/10.3390/met15020160 - 6 Feb 2025
Viewed by 327
Abstract
Metal matrix composites, MMCs, are materials that combine the attractive properties of metals and those of a reinforcing phase [...] Full article
(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)
15 pages, 5045 KiB  
Article
Effect of Pulse Energy on the Microstructure and Mechanical Properties of the Non-Optical Contact Femtosecond Laser Welding of Quartz Glass and the TC4 Alloy
by Xin Li, Runbo Zhang, Xian Tang, Ming Liu, Sijie Li, Gang Wang and Luyu Li
Metals 2025, 15(2), 159; https://doi.org/10.3390/met15020159 - 5 Feb 2025
Viewed by 350
Abstract
Currently, the quartz glass–TC4 dissimilar joint has been applied in fields such as radiation environment testing, reactor engineering, and other areas. However, the high brittleness of the quartz glass and thermal mismatch during the welding process limit require further development. Thus, a femtosecond [...] Read more.
Currently, the quartz glass–TC4 dissimilar joint has been applied in fields such as radiation environment testing, reactor engineering, and other areas. However, the high brittleness of the quartz glass and thermal mismatch during the welding process limit require further development. Thus, a femtosecond laser was employed to perform the direct joining of these materials under non-optical contact conditions, with the aid of a well-designed clamp and optimized process, and the effect of pulse energy on the microstructure and mechanical properties was analyzed. It was revealed that a lot of welding zones form at the interface through the diffusion of Si, O, and Ti and, thus, consist of a stable joint. Element distribution is related to pulse energy, which can affect the composition of secondary phases in the weld zones. The maximum shear strength of joints was 10.4 MPa with laser pulses of 0.3 mJ, while a further increase in the pulse energy led to more defects and stress unevenness. These findings provide valuable insights into enhancing the reliability of metal–glass welding joints and the promotion of femtosecond laser technology. Full article
(This article belongs to the Section Welding and Joining)
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20 pages, 3746 KiB  
Review
Additive Manufacturing: Prospects and Diverse Applications
by Zeyuan Li, Hulong Ruan, Minghao Li, Chenglong Yu, Qixing Jia, Junjun Wang and Lina Chen
Metals 2025, 15(2), 158; https://doi.org/10.3390/met15020158 - 5 Feb 2025
Viewed by 449
Abstract
Additive manufacturing (AM), also known as 3D printing, has emerged as a transformative technology in various industries, providing unprecedented design freedom and customized manufacturing solutions. This paper presents a detailed exploration of additive manufacturing applications in metallic materials, introducing the various types of [...] Read more.
Additive manufacturing (AM), also known as 3D printing, has emerged as a transformative technology in various industries, providing unprecedented design freedom and customized manufacturing solutions. This paper presents a detailed exploration of additive manufacturing applications in metallic materials, introducing the various types of additive manufacturing technologies, elucidating their fundamental principles, and summarizing current research endeavors. The manuscript offers insights into future directions and challenges in this rapidly evolving field, serving as a valuable resource for researchers and engineers aiming to harness the potential of additive manufacturing in advancing metallic materials. Full article
(This article belongs to the Section Additive Manufacturing)
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11 pages, 14409 KiB  
Article
Effects of Bi and In Addition on Microstructure and Properties of Sn-0.7Cu Solder
by Xiaochun Lv, Zhen Pan, Yang Liu, Chenghao Zhang, Zhiyuan Wang and Fenglian Sun
Metals 2025, 15(2), 157; https://doi.org/10.3390/met15020157 - 4 Feb 2025
Viewed by 570
Abstract
With the widespread application of lead-free solder, solder represented by the SAC series has been widely used. However, with the miniaturization and multifunctionalization of electronic devices, the distance between solder joints is becoming increasingly smaller, and the problem of electrochemical migration caused by [...] Read more.
With the widespread application of lead-free solder, solder represented by the SAC series has been widely used. However, with the miniaturization and multifunctionalization of electronic devices, the distance between solder joints is becoming increasingly smaller, and the problem of electrochemical migration caused by Ag in the SAC series is gradually emerging. Therefore, it becomes imperative to develop a solder that has a melting point, mechanical properties, and other properties similar to those of the SAC series but does not contain silver. In this study, 1–3% of Bi and 1–3% of In were added to the Sn-0.7Cu solder to investigate the effects of these elements on the melting characteristics, microstructure, mechanical properties, wettability, and electrical conductivity of the Sn-0.7Cu solder. Due to the addition of Bi and In elements, the melting point of the Sn-0.7Cu solder was lowered, the shear strength was improved, and the solderability was enhanced, but the electrical conductivity was reduced. This article obtained the mechanism of the influence of Bi and In elements on the properties of the Sn-0.7Cu solder through experiments and theoretical analysis, providing a certain degree of theoretical support for the development of silver-free solder. Full article
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12 pages, 1501 KiB  
Article
Experimental Study on Bismuth Removal from Lead with Auxiliary Calcium Magnesium
by Linxing Deng, Haocheng Qin, Weichen Yang and Xiangfeng Kong
Metals 2025, 15(2), 156; https://doi.org/10.3390/met15020156 - 4 Feb 2025
Viewed by 319
Abstract
The separation of lead from the impurity bismuth remains a significant challenge, with achieving effective separation being a critical bottleneck in the production of high-purity lead via the vacuum gasification method. This study focuses on lead as the primary subject of investigation, conducting [...] Read more.
The separation of lead from the impurity bismuth remains a significant challenge, with achieving effective separation being a critical bottleneck in the production of high-purity lead via the vacuum gasification method. This study focuses on lead as the primary subject of investigation, conducting both theoretical and experimental research on the auxiliary conversion of lead through vacuum gasification. The calculations of the Gibbs free energy indicate that, within the temperature range of 600 to 610 K, the impurity bismuth reacts completely with calcium and magnesium, resulting in the formation of the compound CaMg2Bi2. Under optimal experimental conditions, the bismuth compound CaMg2Bi2 is converted into BiCa2. Notably, BiCa2 is nonvolatile and remains in the crucible as a residue. The auxiliary calcium is entirely transformed into CaSe and CaTe, leading to a reduction in the calcium content of the volatile substances from 0.5% to 16 ppm. Similarly, the magnesium content in the volatiles decreases from 0.66% to 187 ppm. Ultimately, the bismuth content in the final product is reduced from 6 ppm to 1.4 ppm, achieving a removal rate of 76.6%, while the direct yield of metallic lead reaches 71%. This process effectively facilitates the separation of metallic lead from the bismuth impurities. Full article
(This article belongs to the Special Issue Green Technologies in Metal Recovery)
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22 pages, 2532 KiB  
Article
Magnetic Pulse Powder Compaction
by Viktors Mironovs, Jekaterina Nikitina, Matthias Kolbe, Irina Boiko and Yulia Usherenko
Metals 2025, 15(2), 155; https://doi.org/10.3390/met15020155 - 4 Feb 2025
Viewed by 304
Abstract
Powder metallurgy (PM) offers several advantages over conventional melt metallurgy, including improved homogeneity, fine grain size, and pseudo-alloying capabilities. Transitioning from conventional methods to PM can result in significant enhancements in material properties and production efficiency by eliminating unnecessary process steps. Dynamic compaction [...] Read more.
Powder metallurgy (PM) offers several advantages over conventional melt metallurgy, including improved homogeneity, fine grain size, and pseudo-alloying capabilities. Transitioning from conventional methods to PM can result in significant enhancements in material properties and production efficiency by eliminating unnecessary process steps. Dynamic compaction techniques, such as impulse and explosive compaction, aim to achieve higher powder density without requiring sintering, further improving PM efficiency. Among these techniques, magnetic pulse compaction (MPC) has gained notable interest due to its unique process mechanics and distinct advantages. MPC utilizes the rapid discharge of energy stored in capacitors to generate a pulsed electromagnetic field, which accelerates a tool to compress the powder. This high-speed process is particularly well-suited for compacting complex geometries and finds extensive application in industries such as powder metallurgy, welding, die forging, and advanced material manufacturing. This paper provides an overview of recent advancements and applications of MPC technology, highlighting its capabilities and potential for broader integration into modern manufacturing processes. Full article
(This article belongs to the Special Issue Powder Metallurgy of Metallic Materials)
18 pages, 35240 KiB  
Article
Selection of Trajectories to Improve Thermal Fields During the Electric Arc Welding Process Using Hybrid Model CFD-FNN
by Sixtos A. Arreola-Villa, Alma Rosa Méndez-Gordillo, Alejandro Pérez-Alvarado, Rumualdo Servín-Castañeda, Ismael Calderón-Ramos and Héctor Javier Vergara-Hernández
Metals 2025, 15(2), 154; https://doi.org/10.3390/met15020154 - 3 Feb 2025
Viewed by 504
Abstract
Effective thermal management is essential in welding processes to maintain structural integrity and material quality, especially in high-precision industrial applications. This study examines the thermal behavior of an AISI 1080 steel plate containing 100 blind holes filled using robotic electric arc welding. Temperature [...] Read more.
Effective thermal management is essential in welding processes to maintain structural integrity and material quality, especially in high-precision industrial applications. This study examines the thermal behavior of an AISI 1080 steel plate containing 100 blind holes filled using robotic electric arc welding. Temperature measurements, recorded with eight strategically positioned thermocouples, monitored the thermal evolution throughout the robotic welding process. The experimental results validated a computational heat transfer model developed with ANSYS Fluent software to simulate and predict temperature distribution achieving a mean absolute percentage error (MAPE) below 4.53%. A feedforward neural network was trained with simulation-generated data to optimize welding sequences. The optimization focuses on minimizing the area under the thermal history curves, reducing temperature gradients, and mitigating overheating risks. Integrating CFD simulations and neural networks introduces a hybrid methodology combining precise numerical modeling with advanced predictive capabilities. The hybrid CFD-FNN results reached a determination coefficient (R2) of 0.93 and an MAPE of 3.5% highlighting the potential of this approach to predict the thermal behavior in multipoint welding processes. This model generated optimized welding trajectories improving the uniformity of the temperature field, reducing thermal gradients and minimizing temperature peaks, thus aiding in preventing overheating. This framework represents a significant advancement in welding technologies, demonstrating the effective application of deep learning techniques in optimizing complex industrial processes. Full article
(This article belongs to the Special Issue Fusion Welding, 2nd Edition)
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2 pages, 109 KiB  
Editorial
Advanced Applications of Artificial Intelligence in Metallic Materials Processing
by Panorios Benardos
Metals 2025, 15(2), 153; https://doi.org/10.3390/met15020153 - 1 Feb 2025
Viewed by 377
Abstract
As the name of this Special Issue indicates, its aim was to highlight advanced applications of Artificial Intelligence (AI) in metallic materials processing, containing a final total of 12 published papers [...] Full article
29 pages, 5792 KiB  
Article
Probabilistic Modelling of Fatigue Behaviour of 51CrV4 Steel for Railway Parabolic Leaf Springs
by Vítor M. G. Gomes, Felipe K. Fiorentin, Rita Dantas, Filipe G. A. Silva, José A. F. O. Correia and Abílio M. P. de Jesus
Metals 2025, 15(2), 152; https://doi.org/10.3390/met15020152 - 1 Feb 2025
Viewed by 402
Abstract
The longevity of railway vehicles is an important factor in their mechanical and structural design. Fatigue is a major issue that affects the durability of railway components, and therefore, knowledge of the fatigue resistance characteristics of critical components, such as the leaf springs, [...] Read more.
The longevity of railway vehicles is an important factor in their mechanical and structural design. Fatigue is a major issue that affects the durability of railway components, and therefore, knowledge of the fatigue resistance characteristics of critical components, such as the leaf springs, must be extensively investigated. This research covers the fatigue resistance of chromium–vanadium alloy steel, usually designated as 51CrV4, from the high-cycle regime (HCF) (103104) up to very high-cycle fatigue (VHCF) (109) under the bending loading conditions typical of leaf springs and under uniaxial tension/compression loading, respectively, for a stress ratio, Rσ, of −1. Different test frequencies were considered (23, 150, and 20,000 Hz) despite the material not exhibiting a relatively significant frequency effect. In order to create a new fatigue prediction model, two prediction models, the Basquin SN linear regression model and the Castillo–Fernandez–Cantelli (CFC) model, were evaluated. According to the analysis carried out, the CFC model provided a better prediction of the fatigue failures than the SN model, especially when outlier failure data were considered. The investigation also examined the failure modes, observing multiple cracks for higher loads and single cracks that initiated on the surface or from internal inclusions at lower loading. The present investigation aims to provide a fatigue resistance prediction model encompassing the HCF and VHCF regions for the fatigue design of railway wagon leaf springs, or even for other components made of 51CrV4 with a tempered martensitic microstructure. Full article
(This article belongs to the Special Issue Fracture Mechanics of Metals (2nd Edition))
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19 pages, 14656 KiB  
Article
Research Progress on Development of PVP-Ag-Doped LaMnO3 Composites for Methyl Orange Degradation
by Adina Căta, Madalina-Gabriela Ivanovici, Paula Svera, Ioana Maria Carmen Ienașcu and Paula Sfirloaga
Metals 2025, 15(2), 151; https://doi.org/10.3390/met15020151 - 1 Feb 2025
Viewed by 497
Abstract
Water pollution caused by emerging contaminants is increasing due to rising urbanization, industrialization, and agriculture production; therefore, new materials with high efficiency for wastewater decontamination are needed. A perovskite material based on 1% Ag-doped LaMnO3 synthesized through a sol–gel technique was combined [...] Read more.
Water pollution caused by emerging contaminants is increasing due to rising urbanization, industrialization, and agriculture production; therefore, new materials with high efficiency for wastewater decontamination are needed. A perovskite material based on 1% Ag-doped LaMnO3 synthesized through a sol–gel technique was combined with PVP in a 1:10 (w/w) ratio and subjected to different temperature and microwave conditions at various time intervals. The composite materials were obtained as thin films (S1, S2) or powders (S3) and were analyzed by modern techniques. The SEM analysis showed strongly agglomerated, asymmetric formations for the S1, S2 materials; as for the S3 composite, irregularly shaped grains of perovskite were deposited on the polymer surface. Small, round formations across the surface, mainly organized as clusters with conic/square-shaped particles and observed asperity on top, were highlighted by AFM images. The XRD spectra confirmed the presence of both the perovskite and PVP phases, and the crystallite size of the materials was determined to be in the range of 33–43 nm. The structural analyses, FT-IR, and Raman spectroscopy proved the interactions between the perovskite and the polymer, which led to novel composite materials. The different methods used for the synthesis of the new materials influenced their features and behavior. Moreover, the composites were successfully tested for methyl orange (MO) elimination from an acidic aqueous solution in dark conditions, with fast and complete (>95%) MO degradation at pH = 2. Full article
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10 pages, 2840 KiB  
Article
The Effect of Final Cooling Temperature on Nano Cu Precipitation in a Cu-Bearing High-Strength Low-Alloy Steel
by Haitao Cui, Haicheng Liang, Xinglong Sun, Yonghua Li, Zhanjie Gao and Jinsong Liu
Metals 2025, 15(2), 150; https://doi.org/10.3390/met15020150 - 1 Feb 2025
Viewed by 377
Abstract
Nano Cu precipitation plays a crucial role in significantly improving the performance of the Cu-bearing high-strength low-alloy steel. The final cooling temperature effects the transformation products of austenite during the continuous cooling process, as well as the nano precipitations of steel. This study [...] Read more.
Nano Cu precipitation plays a crucial role in significantly improving the performance of the Cu-bearing high-strength low-alloy steel. The final cooling temperature effects the transformation products of austenite during the continuous cooling process, as well as the nano precipitations of steel. This study investigated the microstructure and hardness at different final cooling temperatures (750, 700, 650, 600, 550, and 500 °C) using the MMS-300 thermal simulation experimental machine (Northeastern University, Shenyang, China) and Vickers hardness tester. The changes in microstructure and the phase transformation law of austenite were determined during continuous cooling and then analyzed. The precipitation reaction of nano Cu precipitation during continuous cooling was studied using transmission electron microscopy (TEM), revealing the precipitation state under different final cooling temperature conditions. The results showed that the precipitations led to an increase and then a decrease in the microhardness, and the microhardness reaches its peak at 550 °C. The precipitations changed from spherical to elliptical, and the size gradually increased when the final cooling temperature increased. Full article
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16 pages, 15712 KiB  
Article
Anisotropic Hardening of HC420 Steel Sheet: Experiments and Analytical Modeling
by Thamer Sami Alhalaybeh, Hammad Akhtar, Ashiq Iqbal Chowdhury and Yanshan Lou
Metals 2025, 15(2), 149; https://doi.org/10.3390/met15020149 - 1 Feb 2025
Viewed by 422
Abstract
Choosing the appropriate yield function is essential to precisely predicting the anisotropic hardening behavior of steel metals considering general loading directions. This research investigates the anisotropic hardening behavior of HC420 steel sheet by combining experimental and analytical modeling. Experiments are conducted for uniaxial [...] Read more.
Choosing the appropriate yield function is essential to precisely predicting the anisotropic hardening behavior of steel metals considering general loading directions. This research investigates the anisotropic hardening behavior of HC420 steel sheet by combining experimental and analytical modeling. Experiments are conducted for uniaxial tensile tests according to the three different directions and bulging tests to obtain hardening data. The experimental findings show that the loading direction affects the anisotropic behavior of HC420 steel’s strength and plastic deformation. The Chen-coupled quadratic and non-quadratic (Chen-CQN) approach is used to ensure the convexity of the HC420 steel. By comparing the Chen-CQN approach with the Yld2000-2d and Stoughton-Yoon’2009 yield functions, the Chen-CQN approach shows superiority in predicting the hardening behavior of the HC420 sheet, exhibiting a more straightforward numerical implementation and enhanced accuracy in yield stress predictions under different loading directions. Results from experimental hardening tests reveal that the Chen-CQN function precisely and flexibly characterizes the yield surface of HC420 steel, with a constant variation of within 2% from its predictions. Full article
(This article belongs to the Special Issue Metal Plastic Deformation and Forming)
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