Journal Description
Metals
Metals
is an international, peer-reviewed, open access journal published monthly online by MDPI. The Portuguese Society of Materials (SPM), and the Spanish Materials Society (SOCIEMAT) are affiliated with Metals and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Metallurgy & Metallurgical Engineering) / CiteScore - Q1 (Metals and Alloys)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journals for Metals include: Compounds and Alloys.
Impact Factor:
2.9 (2022);
5-Year Impact Factor:
2.9 (2022)
Latest Articles
The Influence of Multi-Pass Friction Stir Processing on the Microstructure Evolution and Mechanical Properties of IS2062 Steel
Metals 2024, 14(6), 685; https://doi.org/10.3390/met14060685 (registering DOI) - 9 Jun 2024
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The motive of present work is to explore the variation in the material characteristics of steel upon multi-pass friction stir processing. Steel plates (IS2062) that were 3 mm thick, were subjected to friction stir processing in a multi-pass manner. The selected transverse speed
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The motive of present work is to explore the variation in the material characteristics of steel upon multi-pass friction stir processing. Steel plates (IS2062) that were 3 mm thick, were subjected to friction stir processing in a multi-pass manner. The selected transverse speed was 150 mm/min, along with a tool rotation of 800 RPM when using a tungsten carbide tool (shoulder diameter—10 mm). Steel plates were processed using the single-pass, double-pass, and triple-pass travel of the rotating tool to observe the impact of multi-pass processing on the properties of steel plates. Multi-pass friction stir processing resulted in a higher micro-hardness of 175 VHN after the second pass, in comparison to the unprocessed metal, which had a micro-hardness of 130 VHN, owing to the collective effect of the plastic flow of the material due to the rotation of the tool and frictional heat, which also leads to grain refinement. The second pass evidenced an average grain size of 22 microns, whereas the unprocessed material had an average grain size of 57 microns. The results of EBSD and SEM characterization showed reasonably improved material properties of the processed work materials.
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Open AccessArticle
A Study on the Effects of Welding Deformation According to Weld Sequence in Overlay-Welded Structures
by
Hong-Lae Jang, Hyunsu Ryu and Sungwook Kang
Metals 2024, 14(6), 684; https://doi.org/10.3390/met14060684 (registering DOI) - 9 Jun 2024
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In this study, thermal elasto-plastic finite element analysis was conducted to derive the optimal welding sequence to minimize overlay welding deformation on the water wall panels of an SRF (solid refuse fuel) boiler. The water wall panels of an SRF boiler are exposed
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In this study, thermal elasto-plastic finite element analysis was conducted to derive the optimal welding sequence to minimize overlay welding deformation on the water wall panels of an SRF (solid refuse fuel) boiler. The water wall panels of an SRF boiler are exposed to high temperatures and corrosive environments, making overlay welding essential. However, because the length of the water wall panels and tubes exceeds 7 m, significant deformation occurs after overlay welding. Additionally, due to the large size of the water wall panels, full-size thermal elasto-plastic analysis requires huge computational costs. Therefore, in this study, the effects of welding sequence on overlay welding deformation were first investigated for a reduced model to derive the optimal welding sequence. Subsequently, an analysis model for the full-size pipe panels was established to compare and analyze the conventional welding sequence with the optimal welding sequence, thereby verifying the validity of the study. According to the welding sequence derived from the reduced model, welding deformation in the full-size model was significantly reduced compared to the conventional sequence. This reduction in deformation was discussed by analyzing the deformation behavior of the structure at each stage of the overlay welding process.
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Open AccessArticle
Interaction of Mechanical Characteristics in Workpiece Subsurface Layers with Drilling Process Energy Characteristics
by
Michael Storchak, Larysa Hlembotska, Oleksandr Melnyk and Nataliia Baranivska
Metals 2024, 14(6), 683; https://doi.org/10.3390/met14060683 (registering DOI) - 9 Jun 2024
Abstract
The performance properties of various types of parts are predominantly determined by the subsurface layer forming methods of these parts. In this regard, cutting processes, which are the final stage in the manufacturing process of these parts and, of course, their subsurface layers,
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The performance properties of various types of parts are predominantly determined by the subsurface layer forming methods of these parts. In this regard, cutting processes, which are the final stage in the manufacturing process of these parts and, of course, their subsurface layers, play a critical role in the formation of the performance properties of these parts. Such cutting processes undoubtedly include the drilling process, the effect of which on the mechanical characteristics of the drill holes subsurface layers is evaluated in this study. This effect was evaluated by analyzing the coincidence of the energy characteristics of the short hole drilling process with the mechanical characteristics of the drilled holes’ subsurface layers. The energy characteristics of the short-hole drilling process were the total drilling power and the cutting work in the tertiary cutting zone, which is predominantly responsible for the generation of mechanical characteristics in the subsurface layers. As mechanical characteristics of the drill holes’ subsurface layers were used, the microhardness of machined surfaces and total indenter penetration work determined by the instrumented nanoindentation method, as well as maximal indenter penetration depth, were determined by the sclerometry method. Through an analysis of the coincidence between the energy characteristics of the drilling process and the mechanical characteristics of the subsurface layers, patterns of the effect of drilling process modes, drill feed, and cutting speed, which essentially determine these energy characteristics, on the studied mechanical characteristics have been established. At the same time, the increase in the energy characteristics of the short-hole drilling process leads to a decrease in the total indenter penetration work and the maximum indenter penetration depth simultaneously with an increase in the microhardness of the drilled holes’ subsurface layers.
Full article
(This article belongs to the Special Issue Simulation and Optimization Methods in Machining and Structure/Material Design)
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Optimization of the Laser Drilling Processing Parameters for Carbon Steel Based on Multi-Physics Simulation
by
Shanqing Liang, Fengxian Li, Yichun Liu, Jianhong Yi and Jürgen Eckert
Metals 2024, 14(6), 682; https://doi.org/10.3390/met14060682 (registering DOI) - 8 Jun 2024
Abstract
The laser drilling of carbon steel is always suffered from the formation of slag, the presence of cutting burrs, the generation of a significant quantity of spatter, and the incomplete penetration of the substrate. In order to avoid these defects formed during the
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The laser drilling of carbon steel is always suffered from the formation of slag, the presence of cutting burrs, the generation of a significant quantity of spatter, and the incomplete penetration of the substrate. In order to avoid these defects formed during the laser drilling of carbon steel, the COMSOL multi-physics simulation method was used to model and optimize the laser drilling process. Considering the splash evolution of the material during the complex drilling process, the transient evolution of the temperature field, the flow of the molten fluid, the geometrical changes, and the absorption of the laser energy during the laser drilling process were investigated. The simulated borehole dimensions are consistent with the experimental results. The process parameters have a great influence on the fluid flow pattern and material slag splashing. The laser power has a significant effect on the laser processing compared with the process parameters. With the increase in laser power and the decrease in laser heat source radius, the time required for perforation is reduced, the flow of melt is accelerated, the perforation efficiency is increased, and the hole wall is smoother, but the degree of spattering is greater. The optimized process parameters were obtained: laser heat source radius of 0.3 mm, laser power of 3000 W. These findings can help reduce the machining defects in carbon steel with excellent mechanical properties by optimizing the laser drilling processing parameters.
Full article
(This article belongs to the Special Issue Metal-Based Composite Materials: Properties, Synthesis, Prospects and Challenges)
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Open AccessReview
Clinching of Carbon Fiber-Reinforced Composite and Aluminum Alloy
by
Daxin Han and Chengliang Hu
Metals 2024, 14(6), 681; https://doi.org/10.3390/met14060681 (registering DOI) - 8 Jun 2024
Abstract
The extensive use of carbon fiber-reinforced composites and aluminum alloys represents the highest level of automotive body-in-white lightweighting. The effective and secure joining of these heterogeneous materials remains a prominent and actively researched topic within the scientific community. Among various joining techniques, clinching
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The extensive use of carbon fiber-reinforced composites and aluminum alloys represents the highest level of automotive body-in-white lightweighting. The effective and secure joining of these heterogeneous materials remains a prominent and actively researched topic within the scientific community. Among various joining techniques, clinching has emerged as a particularly cost-effective solution, experiencing significant advancements. However, the application of clinching is severely limited by the properties of the joining materials. In this work, various clinching processes for the joining of composites and aluminum alloys reported in recent research are described in detail according to three broad categories based on the principle of technological improvement. By scrutinizing current clinching technologies, a forward-looking perspective is presented for the future evolution of clinching technology in terms of composite–aluminum joints, encompassing aspects of tool design, process analysis, and the enhancement of joint quality. This work provides an overview of current research on clinching of CFRP and aluminum and serves as a reference for the further development of clinching processes.
Full article
(This article belongs to the Special Issue Advanced Welding and Joining Processes for Automotive Applications)
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Open AccessArticle
Plasma Electrolytic Oxidation of Al-Zn-Mg-Ni-Fe “Nikalin” Alloys
by
Nikolay V. Letyagin, Torgom K. Akopyan, Alexander A. Sokorev, Ivan V. Shkaley, Stanislav O. Cherkasov, Vitali V. Doroshenko, Tatiana A. Sviridova and Alexander Yu. Churyumov
Metals 2024, 14(6), 680; https://doi.org/10.3390/met14060680 - 7 Jun 2024
Abstract
Ceramic coatings were formed on the surface of as-cast Al5.2Zn1.7Mg0.4Ni0.3Fe and heat-treated Al7.0Zn2.7Mg0.5Ni0.4Fe “nikalin” aluminum alloys by using the plasma electrolytic oxidation (PEO) technique in a silicate–alkaline electrolyte. Uniform coatings containing a minimum number of defects and consisting predominantly of a γ-Al2
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Ceramic coatings were formed on the surface of as-cast Al5.2Zn1.7Mg0.4Ni0.3Fe and heat-treated Al7.0Zn2.7Mg0.5Ni0.4Fe “nikalin” aluminum alloys by using the plasma electrolytic oxidation (PEO) technique in a silicate–alkaline electrolyte. Uniform coatings containing a minimum number of defects and consisting predominantly of a γ-Al2O3 phase were synthesized on the surface of both Al-Zn-Mg-Ni-Fe alloys. The coatings had a microhardness of 660–1200 HV, which is 3.5–11 times higher than that of the “bare” as-cast and heat-treated alloy. The coating on the Al5.2Zn1.65Mg0.4Ni0.3Fe alloy had the highest peak hardness, which is probably caused by the lower residual alloying elements Zn and Mg in the coating bulk. As a consequence, the PEO coating with the highest hardness synthesized on the as-cast alloy exhibited a lower wear rate as compared to the heat-treated alloy. The polarization curves in 3.5% NaCl show that the PEO coatings in all cases reduced the corrosion current density and shifted the corrosion potential toward positive values, thus indicating protective properties of the coatings. The corrosion rate of the as-cast and heat-treated Al-Zn-Mg-Ni-Fe alloys increased noticeably by about 3.7–5.7 times after PEO treatment. A relationship between the residual alloying elements Zn and Mg in the bulk of the PEO coatings and corrosion resistance was established.
Full article
(This article belongs to the Special Issue Advances in Casting, Thermomechanical and Heat Treatment of Aluminum Alloys: Second Edition)
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Open AccessArticle
Influence of the Machining Process on the Wear Properties of Self-Mated Structural Steel in Dry Sliding Conditions
by
Gian Luca Garagnani, Enrico Baroni, Annalisa Fortini, Luciano D’Angelo and Mattia Merlin
Metals 2024, 14(6), 679; https://doi.org/10.3390/met14060679 - 7 Jun 2024
Abstract
This work investigates the tribological behavior of a machined S355JR structural steel in dry sliding conditions for the development of an innovative seismic dissipation system. Flat-ended pins and disks were made of the same structural steel to simulate the conformal contact of different
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This work investigates the tribological behavior of a machined S355JR structural steel in dry sliding conditions for the development of an innovative seismic dissipation system. Flat-ended pins and disks were made of the same structural steel to simulate the conformal contact of different device parts. Pins were machined by turning, while disks were milled and turned to obtain a nominal average surface Ra roughness ranging from 0.8 µm to 6.3 µm. The influence of the surface roughness on the coefficient of friction (COF), specific wear rate (SWR), and time to steady-state (TSS) was investigated. Tribological tests were conducted reciprocating motion in dry sliding conditions to simulate the operating conditions of the device, with 1 Hz and 2 Hz reciprocating frequencies and an applied normal load of 50 N. The Rsk and Rku roughness parameters helped to better understand the tribological response of milled and turned disks, having an influence on the TSS and SWR.
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Open AccessArticle
Effect of Ag Doping on Mechanical Properties of Cu6Sn5 Intermetallic Compounds
by
Biao Wang, Junxi Lu, Lingyan Zhao, Junjie Liao and Jikang Yan
Metals 2024, 14(6), 678; https://doi.org/10.3390/met14060678 - 7 Jun 2024
Abstract
Cu6Sn5-xAg alloys (x = 0, 3, 6; %, mass fraction) were synthesized using Ag as a dopant through a high-temperature melting technique. The microstructure of the alloy was analyzed using X-ray diffraction (XRD), scanning electron microscopy
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Cu6Sn5-xAg alloys (x = 0, 3, 6; %, mass fraction) were synthesized using Ag as a dopant through a high-temperature melting technique. The microstructure of the alloy was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and other equipment, while the hardness of the alloy was measured to investigate the impact of Ag addition on the structure and microstructure of the Cu6Sn5 intermetallic compound. This study explored the influence of varying Ag contents on the properties of Cu6Sn5 intermetallic compounds, with calculations based on first principles revealing the mechanical properties and density of states of η′-Cu6Sn5 and its Ag-doped systems. The results indicated that Cu6Sn5-xAg alloys predominantly existed in three distinct forms, all exhibiting large masses without any impurities or precipitates. First-principle calculations demonstrated that Ag substitution in certain sites suppressed the anisotropy of the Young’s modulus of Cu6Sn5, particularly in the Cu1, Cu3, Sn1, and Sn3 positions, while the effect was less significant at the Cu2, Cu4, and Sn2 sites. The introduction of Ag through doping enhanced the covalent bonding within the η′-Cu6Sn5 structure, promoting the formation of a stable (Cu, Ag)6Sn5 structure.
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(This article belongs to the Special Issue Application of First Principle Calculation in Metallic Materials)
Open AccessReview
Optimization of Mechanical Properties of High-Manganese Steel for LNG Storage Tanks: A Comprehensive Review of Alloying Element Effects
by
Yuchen Li, Jiguang Li, Dazheng Zhang and Qihang Pang
Metals 2024, 14(6), 677; https://doi.org/10.3390/met14060677 - 7 Jun 2024
Abstract
High-manganese austenitic steel represents an innovative variety of low-temperature steel used in the construction of liquefied natural gas (LNG) storage tanks. This steel boasts remarkable characteristics such as exceptional plasticity, superior toughness at cryogenic temperatures, and robust fatigue resistance, all while providing significant
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High-manganese austenitic steel represents an innovative variety of low-temperature steel used in the construction of liquefied natural gas (LNG) storage tanks. This steel boasts remarkable characteristics such as exceptional plasticity, superior toughness at cryogenic temperatures, and robust fatigue resistance, all while providing significant cost benefits. By utilizing high-manganese steel, the material manufacturing costs can be considerably lowered, simultaneously ensuring the long-term stability and safety of LNG storage tanks. The alloying design is pivotal in attaining superior performance in high-manganese steel. Choosing the right chemical components to control the stacked fault energy (SFE) of high-manganese steel and fine-tuning its structure can further improve the balance between strength and plasticity. Summarizing the advancements in alloying design for high-manganese steel is of great importance, as it offers a foundational dataset for correlating the chemical composition with the performance. Therefore, this paper outlines the deformation mechanisms and the principles of low-temperature brittleness in high-manganese austenitic steel, and from this foundation, it explicates the precise functions of alloying elements within it. This aims to provide a reference for future alloying designs and the industrial deployment of high-manganese steel in LNG storage tanks.
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Open AccessArticle
Corrosion of Carbon Steel in a Tropical Marine Environment Enhanced by H2S from Sargassum Seaweed Decomposition
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Mahado Said Ahmed, Benoit Lescop, Julien Pellé, Stéphane Rioual, Christophe Roos and Mounim Lebrini
Metals 2024, 14(6), 676; https://doi.org/10.3390/met14060676 - 7 Jun 2024
Abstract
This article aims to investigate the atmospheric corrosion of carbon steel in a marine environment abundant in hydrogen sulfide (H2S) resulting from the decomposition of Sargassum seaweed. To accomplish this, four sites with varying degrees of impact were chosen along the
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This article aims to investigate the atmospheric corrosion of carbon steel in a marine environment abundant in hydrogen sulfide (H2S) resulting from the decomposition of Sargassum seaweed. To accomplish this, four sites with varying degrees of impact were chosen along the coast of Martinique. The corrosion rates of steel were evaluated through mass loss measurements. After one year of exposure, the corrosion rates were notably high, particularly in atmospheres rich in Cl− ions and H2S, ranging from 107 µm to 983 µm. Complementing these findings, surface and product morphologies were characterized using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). These analyses revealed a significant degradation of the corrosion surface in the most affected atmospheres compared to those unaffected by Sargassum seaweed strandings. Lepidocrocite (γFeOOH) was identified as the predominant product regardless of the exposure atmosphere. However, goethite (αFeOOH) was found to be present in atmospheres most impacted by H2S.
Full article
(This article belongs to the Special Issue Corrosion Behavior of Carbon Steels in Natural and Industrial Environments—2nd Edition)
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Open AccessArticle
Effect of Si Content on Microstructure and Properties of Low-Carbon Medium-Manganese Steel after Intercritical Heat Treatment
by
Zihan Hu and Hanguang Fu
Metals 2024, 14(6), 675; https://doi.org/10.3390/met14060675 - 6 Jun 2024
Abstract
The microstructure and mechanical properties of three kinds of low-carbon medium-manganese steels with different Si contents under an intercritical heat treatment process were studied. The results show that the microstructure of the test forged steel is mainly composed of ferrite and pearlite. After
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The microstructure and mechanical properties of three kinds of low-carbon medium-manganese steels with different Si contents under an intercritical heat treatment process were studied. The results show that the microstructure of the test forged steel is mainly composed of ferrite and pearlite. After 900 °C complete austenitizing quenching + 720 °C intercritical quenching, the microstructure of the test steel is mainly composed of ferrite and martensite. With the increase in Si content, the microstructure becomes finer and more uniform. The microstructure of the test steel after 900 °C complete austenitizing quenching + 720 °C intercritical quenching + 680 °C intercritical tempering is dominated by ferrite and tempered martensite, with a small amount of retained austenite and cementite. As the Si content increases, the boundaries between ferrite and tempered martensite become more clear. The tensile strength and hardness of the test steel increase with the increase in Si content, while the elongation first increases and then decreases; the comprehensive performance of the test steel is the best when the Si content is 0.685 wt. %, with a tensile strength of 726 MPa, a yield ratio of only 0.65, the highest elongation of 30.5%, and the highest strong plastic product of 22,143 MPa.%.
Full article
(This article belongs to the Special Issue Design, Preparation and Properties of High Performance Steels)
Open AccessArticle
Research on Atmospheric Corrosion of 45# Steel in Low-Latitude Coastal Areas of China
by
Lihong Liu, Bo Zhang, Guoqiang Liu, Liyan Wang, Jiao Li, Peng Yuan, Zi Yang and Zhiyuan Feng
Metals 2024, 14(6), 674; https://doi.org/10.3390/met14060674 - 6 Jun 2024
Abstract
Urgent action is required to mitigate the severe corrosion of carbon steel in low-latitude regions. The combination of high humidity, temperature, and salinity in these areas significantly accelerates steel corrosion, posing a substantial threat to the service safety of offshore engineering equipment. This
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Urgent action is required to mitigate the severe corrosion of carbon steel in low-latitude regions. The combination of high humidity, temperature, and salinity in these areas significantly accelerates steel corrosion, posing a substantial threat to the service safety of offshore engineering equipment. This study aims to elucidate the atmospheric corrosion mechanisms of 45# steel in low-latitude coastal areas. Samples of 45# steel were exposed to atmospheric conditions over various durations in the following three geographically distinct regions: Guangzhou, Wanning, and the South China Sea. The corrosion rates were calculated using weight loss tracking and potentiodynamic polarization measurements, while surface corrosion products were examined using X-ray diffraction (XRD) tests. The findings indicate a clear correlation between the corrosion rate of 45# steel and the latitude and specific location of the test area, with the highest to lowest rates observed in the South China Sea, Wanning, and Guangzhou, respectively. Similarly, the extent of corrosion rust penetration in defective coatings followed the same order. Moreover, the protection ability index (PAI) calculations revealed that none of the tested samples formed a protective corrosion film.
Full article
(This article belongs to the Special Issue Corrosion of Metals: Behaviors and Mechanisms)
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Open AccessArticle
Numerical Study on Heat Transfer Characteristic of Hot Metal Transportation before EAF Steelmaking Process
by
Weizhen Chen, Hang Hu, Shuai Wang, Feng Chen, Yufeng Guo and Lingzhi Yang
Metals 2024, 14(6), 673; https://doi.org/10.3390/met14060673 - 6 Jun 2024
Abstract
The temperature of hot metal (HM) is crucial for the energy input and smelting in the electric arc furnace (EAF) steelmaking process with HM and scrap as the charge structure. However, due to the influence of many factors in the heat dissipation in
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The temperature of hot metal (HM) is crucial for the energy input and smelting in the electric arc furnace (EAF) steelmaking process with HM and scrap as the charge structure. However, due to the influence of many factors in the heat dissipation in HM transportation before the EAF steelmaking process, the temperature drop of HM before charged is usually fluctuating and uncertain. This situation is not conducive to the input energy control and energy optimization of the EAF steelmaking process. In this paper, a three-dimensional numerical model of a 90-ton hot metal ladle is established to simulate the heat transfer characteristic of HM transportation through ANSYS Fluent 2023 and verified by on-the-spot testing and sample analysis. The effects of ambient temperature, air velocity, slag thickness and furnace cover thickness on the temperature drop of HM are investigated and quantitatively analyzed in 30 numerical schemes. The results indicate that slag thickness is the most influential factor, followed by furnace cover thickness, air velocity and ambient temperature. In the case of 50 min transport time, the temperature drop of HM is 55.2, 15.06, 12.08, 10.38, 10.29 and 10.26 °C when the slag thickness is 0, 50, 100, 150, 200 and 250 mm, respectively. While HM is not covered by slag, the furnace cover can also greatly reduce the temperature drop. Based on the simulated data, a prediction model of HM temperature drop is obtained through the multi-factor coupling analysis and mathematical fitting. This study can help develop targeted insulation measures and determine the temperature of HM, which is expected to control the input energy for deep energy-saving optimization in the EAF steelmaking process.
Full article
(This article belongs to the Special Issue Advances in Ironmaking and Steelmaking Processes (Volume II))
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Open AccessArticle
High-Pressure Torsion: A Path to Refractory High-Entropy Alloys from Elemental Powders
by
Andrey Mazilkin, Mahmoud R. G. Ferdowsi, Evgeniy Boltynjuk, Roman Kulagin and Rimma Lapovok
Metals 2024, 14(6), 672; https://doi.org/10.3390/met14060672 - 6 Jun 2024
Abstract
For the first time, the refractory high-entropy alloys with equiatomic compositions, HfNbTaTiZr and HfNbTiZr, were synthesized directly from a blend of elemental powders through ten revolutions of high-pressure torsion (HPT) at room temperature. This method has demonstrated its effectiveness and simplicity not only
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For the first time, the refractory high-entropy alloys with equiatomic compositions, HfNbTaTiZr and HfNbTiZr, were synthesized directly from a blend of elemental powders through ten revolutions of high-pressure torsion (HPT) at room temperature. This method has demonstrated its effectiveness and simplicity not only in producing solid bulk materials but also in manufacturing refractory high-entropy alloys (RHEAs). Unlike the melting route, which typically results in predominantly single BCC phase alloys, both systems formed new three-phase alloys. These phases were defined as the Zr-based hcp1 phase, the α-Ti-based hcp2 phase, and the Nb-based bcc phase. The volume fraction of the phases was dependent on the accumulated plastic strain. The thermal stability of the phases was studied by annealing samples at 500 °C for one hour, which resulted in the formation of a mixed structure consisting of the new two hexagonal and cubic phases.
Full article
(This article belongs to the Special Issue Physical Metallurgy of Refractory Alloys (2nd Edition))
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On the Problem of the Distillation Separation of Secondary Alloys of Magnesium with Zinc and Magnesium with Cadmium
by
Valeriy Volodin, Bagdaulet Kenzhaliyev, Sergey Trebukhov, Alina Nitsenko, Xeniya Linnik and Alexey Trebukhov
Metals 2024, 14(6), 671; https://doi.org/10.3390/met14060671 - 5 Jun 2024
Abstract
An alternative to the existing method of processing secondary magnesium raw materials by remelting in a salt furnace can be distillation separation into volatile metals (Mg, Zn and Cd), low-volatile metals (Al, Mn and Zr) and rare earth elements. The separation of metals
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An alternative to the existing method of processing secondary magnesium raw materials by remelting in a salt furnace can be distillation separation into volatile metals (Mg, Zn and Cd), low-volatile metals (Al, Mn and Zr) and rare earth elements. The separation of metals may be tracked based on phase diagrams where the field boundaries of the vapor–liquid equilibrium are plotted. Due to the fact that Mg, Zn and Cd have comparable saturated vapor pressures, the possibility of the distillation separation of Mg–Zn and Mg–Cd systems using full state diagrams including the melt–vapor phase transition boundaries were determined in this work. The boundaries of these systems were calculated based on the partial values of saturated vapor, determined by the boiling point method, and presented in the form of temperature–concentration dependencies with the indicated boundaries. The field boundaries were calculated (L + V) at atmospheric pressure (101.33 kPa) and in vacuum (1.33 kPa and 0.7 kPa,) supposing the implementation of the process. The possibility of the separate extraction of zinc and cadmium from magnesium was considered using complete phase diagrams including the boundaries of the melt–steam phase transition. When considering the boundaries of the vapor–liquid equilibrium in the binary systems Mg–Zn and Mg–Cd, it was established that it is impossible to separate metals in one “evaporation–condensation” cycle in a vacuum of 1.33 and 0.7 kPa. The problem is caused by the small size of the fields (L + V) at the temperature, which suggests processes of the re-evaporation of the condensate from the previous distillation stage. The separation of zinc and cadmium from liquid alloys with magnesium under equilibrium conditions requires several repetitions of the condensate distillation process. In non-equilibrium conditions, the real processes will require a larger number of conversions. This implies the expediency of the joint evaporation of magnesium with zinc and cadmium and the use of condensate for additional charging to liquid magnesium, and the remainder of the distillation, where volatile metals such as Al, Mn, Zr and rare earth elements will be concentrated, should be directed to the preparation of ligatures for special magnesium-based alloys.
Full article
(This article belongs to the Special Issue Separation and Purification of Metals (Second Edition))
Open AccessArticle
Surface Growth of Boronize Coatings Studied with Mathematical Models of Diffusion
by
Martín Ortiz-Domínguez, Ángel Jesús Morales-Robles, Oscar Armando Gómez-Vargas and Georgina Moreno-González
Metals 2024, 14(6), 670; https://doi.org/10.3390/met14060670 - 5 Jun 2024
Abstract
The following investigation focused on examining the kinetics of Fe2B coating formation on the surface of ASTM A681 steel during the powder-pack boronizing process. The study measured Fe2B coating thicknesses at various temperatures and exposure times to confirm the
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The following investigation focused on examining the kinetics of Fe2B coating formation on the surface of ASTM A681 steel during the powder-pack boronizing process. The study measured Fe2B coating thicknesses at various temperatures and exposure times to confirm the diffusion-controlled growth mechanism during boronizing. Five distinct mathematical models were devised to determine the boron diffusion coefficients in Fe2B coatings. Understanding the growth kinetics of boronize coatings is imperative as it facilitates the optimization and automation of industrial processes. This ensures the efficient and consistent production of boronize coatings on cutting tools, such as drills and milling cutters, due to their high hardness and wear resistance. The value of the activation energy estimated with five mathematical diffusion models for the Fe2B coating was 209.8 kJ∙mol−1. The X-ray diffraction technique was used to identify the presence of the iron boronize phase. Tribological studies were also performed to evaluate the coefficient of friction (COF) of the boronized (0.256) and untreated (0.781) samples, having a 300% positive effect of the boronize coating on wear resistance. Finally, the models were empirically validated for two supplementary treatment conditions for 1223 K for 3 h and 1273 K for 1.5 h, where the percentage error for both conditions was estimated to be approximately 2.5%.
Full article
Open AccessReview
Review of In Situ Detection and Ex Situ Characterization of Porosity in Laser Powder Bed Fusion Metal Additive Manufacturing
by
Beytullah Aydogan and Kevin Chou
Metals 2024, 14(6), 669; https://doi.org/10.3390/met14060669 - 5 Jun 2024
Abstract
Over the past decade, significant research has focused on detecting abnormalities in metal laser powder bed fusion (L-PBF) additive manufacturing. Effective online monitoring systems are crucial for enhancing process stability, repeatability, and the quality of final components. Therefore, the development of in situ
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Over the past decade, significant research has focused on detecting abnormalities in metal laser powder bed fusion (L-PBF) additive manufacturing. Effective online monitoring systems are crucial for enhancing process stability, repeatability, and the quality of final components. Therefore, the development of in situ detection mechanisms has become essential for metal L-PBF systems, making efficient closed-loop control strategies to adjust process parameters in real time vital. This paper presents an overview of current in situ monitoring systems used in metal L-PBF, complemented by ex situ characterizations. It discusses in situ techniques employed in L-PBF and evaluates the applicability of commercial systems. The review covers optical, thermal, acoustic, and X-ray in situ methods, along with destructive and non-destructive ex situ methods like optical, Archimedes, and X-ray characterization techniques. Each technique is analyzed based on the sensor used for defect detection and the type or size of defects. Optical in situ monitoring primarily identifies large defects from powder bed abnormalities, while thermal methods detect defects as small as 100 µm and keyholes. Thermal in situ detection techniques are notable for their applicability to commercial devices and efficacy in detecting subsurface defects. Computed tomography scanning excels in locating porosity in 3D space with high accuracy. This study also explores the advantages of multi-sensor in situ techniques, such as combining optical and thermal sensors, and concludes by addressing current research needs and potential applications of multi-sensor systems.
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(This article belongs to the Special Issue Advances in Additive Manufacturing Technology of Metals and Alloys)
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Open AccessArticle
Electrochemical Behaviour of an Au-Ge Alloy in an Artificial Saliva and Sweat Solution
by
Gyöngyi Vastag, Peter Majerič, Vojkan Lazić and Rebeka Rudolf
Metals 2024, 14(6), 668; https://doi.org/10.3390/met14060668 - 5 Jun 2024
Abstract
In modern times, more and more different materials (including alloys) are in direct contact with human electrolytes (sweat, saliva, lymph, blood, etc.). One of the most important properties for the use of these materials is therefore their chemical inertness or resistance to corrosion
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In modern times, more and more different materials (including alloys) are in direct contact with human electrolytes (sweat, saliva, lymph, blood, etc.). One of the most important properties for the use of these materials is therefore their chemical inertness or resistance to corrosion when they are in contact with human electrolytes. Consequently, during the development of such new materials, it is necessary to study and understand their basic electrochemical behaviour in a given environment. The purpose of this research was to monitor the electrochemical behaviour of the new Au-Ge alloy in artificial sweat and artificial saliva solutions, depending on the electrolyte composition and exposure time. This new alloy represents a potential material for use in dentistry or for jewellery. The obtained results of the study show that the immersion time and the pH value have a significantly greater influence on the corrosion resistance of the new Au-Ge alloy than the composition of the electrolyte solution. The results of the SEM/EDX analysis additionally confirm the main results of the electrochemical measurements.
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(This article belongs to the Special Issue Feature Papers in Extractive Metallurgy)
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Open AccessReview
Deep Rolling Techniques: A Comprehensive Review of Process Parameters and Impacts on the Material Properties of Commercial Steels
by
Dilifa Jossley Noronha, Sathyashankara Sharma, Raghavendra Prabhu Parkala, Gowri Shankar, Nitesh Kumar and Srinivas Doddapaneni
Metals 2024, 14(6), 667; https://doi.org/10.3390/met14060667 - 4 Jun 2024
Abstract
The proposed review demonstrates the effect of the surface modification process, specifically, deep rolling, on the material surface/near-surface properties of commercial steels. The present research examines the various process parameters involved in deep rolling and their effects on the material properties of AISI
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The proposed review demonstrates the effect of the surface modification process, specifically, deep rolling, on the material surface/near-surface properties of commercial steels. The present research examines the various process parameters involved in deep rolling and their effects on the material properties of AISI 1040 steel. Key parameters such as the rolling force, feed rate, number of passes, and roller geometry are analyzed in detail, considering their influence on residual stress distribution, surface hardness, and microstructural alterations. Additionally, the impact of deep rolling on the fatigue life, wear resistance, and corrosion behavior of AISI 1040 steel is discussed. Engineering components manufactured by AISI 1040 steel can perform better and last longer when deep rolling treatments are optimized with an understanding of how process variables and material responses interact. This review provides critical insights for researchers and practitioners interested in harnessing deep rolling techniques to enhance the mechanical strength and durability of steel components across diverse industrial settings. In summary, the valuable insights provided by this review pave the way for continued advancements in deep rolling techniques, ultimately contributing to the development of more durable, reliable, and high-performance steel components in diverse industrial applications. The establishment of generalized standardizations for the deep rolling process proves unfeasible because of the multitude of controlling parameters and their intricate interactions. Thus, specific optimization studies tailored to the material of interest are imperative for process standardization. The published literature on the characterization of surface and subsurface properties of deep-rolled AISI 1040 steel, as well as process parameter optimization, remains limited. Additionally, numerical, analytical, and statistical studies and the role of ANN are limited compared with experimental work on the deep rolling process.
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(This article belongs to the Special Issue Advances in Metal Rolling Processes)
Open AccessArticle
Study on Fracture Behavior and Toughening Mechanisms of Ultra-High-Strength Pipeline Steel
by
Ba Li, Xiaoshun Zhou, Shujun Jia, Xiaoping Chen, Song Fu, Dongliang Zhao, Haonan Zhang and Jie Guo
Metals 2024, 14(6), 666; https://doi.org/10.3390/met14060666 - 4 Jun 2024
Abstract
In this paper, a series of low-temperature CVN (Charpy V-notch impact test) and DWTT (drop-weight tear test) experiments were carried out to deal with the intensifying contradiction of strength and toughness of ultra-high-strength pipeline steel. The fracture behavior and toughening mechanisms of ultra-high-strength
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In this paper, a series of low-temperature CVN (Charpy V-notch impact test) and DWTT (drop-weight tear test) experiments were carried out to deal with the intensifying contradiction of strength and toughness of ultra-high-strength pipeline steel. The fracture behavior and toughening mechanisms of ultra-high-strength pipeline steel were investigated using scanning electron microscopy, transmission electron microscopy and backscattered electron diffraction systems. The results show that DWTT fractures in ultra-high-strength pipeline steel had a variety of unconventional morphological features compared to CVN fractures, including ridge protrusion in ductile fracture conditions and a large-size fracture platform in brittle fracture conditions. Therefore, DWTT fractures contained more information about the material fracturing process, and could better reflect the actual process of material fracturing. In ultra-high-strength pipeline steel, fine-grained granular bainite caused cracks to undergo large deflections or frequent small transitions, which consumed additional energy and improved toughness. In contrast, large-sized granular bainite, which consisted of low-angle grain boundaries, did not effectively prevent crack propagation when it encountered cracks, which was not conducive to improved toughness. Moreover, the M/A constituents in large-sized granular bainite aggregated, cracked, or fell off, which could easily lead to the formation of microcracks and was also detrimental to toughening.
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(This article belongs to the Special Issue Design, Preparation and Properties of High Performance Steels)
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