Metals

24 pages, 13332 KiB

Open AccessArticle

Corrosion Mechanism of Press-Hardened Steel with Aluminum-Silicon Coating in Controlled Atmospheric Conditions

by Nikola Macháčková, Darja Rudomilova, Tomáš Prošek, Thierry Sturel and Maxime Brossard

Metals 2025, 15(1), 97; https://doi.org/10.3390/met15010097 - 20 Jan 2025

Viewed by 461

The effect of various atmospheric parameters on the corrosion mechanism of press-hardened steel (PHS) coated with Al-Si (AS) was studied. Quantitative models of the composition of soluble and stable corrosion products were developed. A high chloride concentration led to a localized corrosion due [...] Read more.

The effect of various atmospheric parameters on the corrosion mechanism of press-hardened steel (PHS) coated with Al-Si (AS) was studied. Quantitative models of the composition of soluble and stable corrosion products were developed. A high chloride concentration led to a localized corrosion due to the presence of cracks in the coating. Increased corrosion resistance of silicon-rich Al₈Fe₂Si and AlFe at the expense of the Al₅Fe₂ phase with low silicon content was shown. Under low-chloride-deposition conditions, the coating exhibited good corrosion resistance and provided sufficient protection to the underlying steel. The formation of more local anodes and cathodes under conditions of lower relative humidity led to a reduction in the depth of corrosion pits in the steel substrate. Constant high relative humidity and sulphate deposits on the surface were critical for the acceleration of steel corrosion in coating cracks. Full article

(This article belongs to the Special Issue Metallurgy, Surface Engineering and Corrosion of Metals and Alloys)

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30 pages, 6469 KiB

Open AccessReview

Elemental Segregation and Solute Effects on Mechanical Properties and Processing of Vanadium Alloys: A Review

by Tianjiao Lei, Chongze Hu, Qiaofu Zhang and Xin Wang

Metals 2025, 15(1), 96; https://doi.org/10.3390/met15010096 - 20 Jan 2025

Viewed by 721

Abstract

Vanadium (V) alloys, such as V-Cr, V-Ti, and V-Cr-Ti alloys, are promising candidates for structural components in fusion energy systems because of their low activation, excellent radiation resistance, good compatibility with liquid lithium, and high ductility. Despite these advantages, the limited high-temperature strength [...] Read more.

Vanadium (V) alloys, such as V-Cr, V-Ti, and V-Cr-Ti alloys, are promising candidates for structural components in fusion energy systems because of their low activation, excellent radiation resistance, good compatibility with liquid lithium, and high ductility. Despite these advantages, the limited high-temperature strength and poor creep performances of V alloys have constrained their operating temperature range, challenging the application of these materials over the past few decades. The mechanical behavior is strongly dependent on microstructural features, including precipitates, intergranular and intragranular boundaries, dislocations, and point defects. At the same time, these features serve as preferable sites for solute or impurity atoms to segregate. The elemental segregation alters the local chemistry and stability of these defects, influencing microstructural evolutions and various materials properties that are essential for fusion energy applications. This review paper aims to provide a comprehensive overview of experimental and computational studies on elemental segregation and solute/impurity effects on the mechanical behaviors and microstructural evolution in V alloys. The conventional and advanced manufacturing processes of V alloys will be also discussed. Finally, this review will provide a concise perspective on the potential research directions of V alloys for future fusion reaction applications. Full article

(This article belongs to the Special Issue Mechanical Behaviors and Interfacial Segregation Phenomena in Metallic Materials: Simulation, Theory, and Characterization)

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14 pages, 23724 KiB

Open AccessArticle

Enhanced Cutting Performance of 50Cr15MoV Martensitic Stainless Steel Through Controlled Residual Austenite Stability

by Fujian Guo, Zhimin Peng, Guangyi Lu, Wenle Liu, Guoqing Li, Pan Zhang and Chengjia Shang

Metals 2025, 15(1), 95; https://doi.org/10.3390/met15010095 - 19 Jan 2025

Viewed by 555

Abstract

The relationship between the stability of tool materials and their cutting performance is a critical technical challenge for the manufacturing industry, which is essential for selecting appropriate treatment processes to achieve superior treatment tool performance. In this paper, a standard cutting tool experiment [...] Read more.

The relationship between the stability of tool materials and their cutting performance is a critical technical challenge for the manufacturing industry, which is essential for selecting appropriate treatment processes to achieve superior treatment tool performance. In this paper, a standard cutting tool experiment was used to study the sharpness of the knife with different residual austenite content. The cutting edges of the knife were characterized by an optical microscope (OM), scanning electron microscope (SEM), electron back scattering diffraction (EBSD), and transmission electron microscope (TEM), to analyze the relationship between tool edge hardness and microstructure. The microstructure stability of the material was analyzed by a separated Hopkinson pressure bar (SHPB) experiment. The results show that the hardness and cutting performance of the knives are affected by the joint action of carbide and residual austenite, with an initial increase followed by decreases as the heat treatment quenching temperature increases. After the knife material is treated by cryogenic process, the hardness of the knife is increased by 3.89 HRC, the initial sharpness by 15.3%, and the sharpness and durability by 18.8%. The residual austenite in the knives was found to be unstable and easy to transformation during high-rate deformation processes. This study elucidates the effect of residual austenite content on the sharpness of the knives, providing a foundation for the reasonable control of residual austenite content in the actual production settings. Full article

(This article belongs to the Special Issue Recent Insights into Mechanical Properties of Metallic Alloys)

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16 pages, 4824 KiB

Open AccessArticle

Atomistic Insight into the Effects of Collision Angle on the Characteristics of Cu-Ta Joining by Explosive Welding

by Van-Thuc Nguyen, Nguyen Quang Hien, Pham Minh Duc, Tran Duy Nam, Van Huong Hoang and Van Thanh Tien Nguyen

Metals 2025, 15(1), 94; https://doi.org/10.3390/met15010094 - 19 Jan 2025

Viewed by 414

Abstract

This study aims to examine how the collision angle affects the Cu-Ta weld generated by the explosive welding method using molecular dynamics modeling. When two blocks collide, the metallic substrates melt rapidly. Subsequently, when heat energy dissipates to the surrounding areas, the weld [...] Read more.

This study aims to examine how the collision angle affects the Cu-Ta weld generated by the explosive welding method using molecular dynamics modeling. When two blocks collide, the metallic substrates melt rapidly. Subsequently, when heat energy dissipates to the surrounding areas, the weld interface begins rapidly cooling. Eventually, the weld joint’s surface shape and temperature stabilize. A meta-solid solution state between Cu and Ta could develop under extreme collision conditions of explosive welding through a dynamic diffusion mechanism. Furthermore, the plastic deformation process of the face-centered cubic (FCC) matrix after the explosive collision causes twin boundary scattering in the Cu substrate. The stress evolution experiences three stages: quick increasing, spreading out, and stabling. The stress mainly concentrates on the weld joint. Due to its dynamic recrystallization mechanism, the Cu substrate has a lower residual stress level than the Ta substrate. The atomic strain of the Cu-Ta weld joint improves dramatically as the impact angle increases. The high-strain zone extends toward the lower Ta block between 5° and 15°. Furthermore, the atomic strain and amorphous structure rates increase when the impact angles increase from 5° to 15°. After further improvement up to 20°, they then suffer a decrease. The Cu-Ta weld achieves a tensile strength ranging from 6.37 to 8.94 GPa. The Cu/Cu-Ta/Cu welding joint’s interface is coherent, transforming from an amorphous to a body-centered cubic (BCC) structure. Because of the dynamic diffusion mechanism at the interface, which creates an almost identical atomic rate between Cu and Ta atoms, combined with the dynamic recrystallization phenomenon, explosive welding provides the advantage of combining two low-solubility solid-solution metals. Full article

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9 pages, 3135 KiB

Open AccessArticle

Hybrid Solder Joints: Viscosity Studies of the Nanocomposite Flux with Fe Nanoparticle Additions

by Andriy Yakymovych, Irina Wodak and Golta Khatibi

Metals 2025, 15(1), 93; https://doi.org/10.3390/met15010093 - 18 Jan 2025

Viewed by 492

Abstract

Viscosity is one of the most important physical characteristics of choosing a flux for solder paste. However, not in all cases do the producers give information about the viscosity of commercial flux. A recent promising trend is to mix various kinds of nanoparticles [...] Read more.

Viscosity is one of the most important physical characteristics of choosing a flux for solder paste. However, not in all cases do the producers give information about the viscosity of commercial flux. A recent promising trend is to mix various kinds of nanoparticles with solder paste or flux and investigate the produced solder joints. However, the impact of nanosized inclusions on the viscosity of the flux has practically not been investigated. In this study, the temperature and shear rate dependencies of the viscosity of the nanocomposite flux were measured. For this purpose, the commercial flux has been mixed with Fe nanoparticles up to 2.0 wt.% of inclusions. It has been shown that viscosity increases with the addition of Fe nanoparticles. However, it is valid only for first heating up to circa 340 K. The viscosity values of the flux with and without nanosized inclusions are practically similar by further heating to 360 K as well as by subsequent cooling. Additionally, the performed differential thermal analysis has shown the heat effects, which are in good agreement with viscosity behavior. Full article

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18 pages, 12290 KiB

Open AccessArticle

Investigation of the Heat Treatment Regimes on the Structure and Microhardness of Laser Direct Energy Deposition Aluminum Alloy AlSi10Mg

by Darya Volosevich, Zhanna Shabunina, Nikita Yurchenko, Ruslan Mendagaliev, Edem Slatenko, Georgii Klimov, Olga Klimova-Korsmik and Aleksey Eremeev

Metals 2025, 15(1), 92; https://doi.org/10.3390/met15010092 - 18 Jan 2025

Viewed by 505

Abstract

This study investigates the influence of various heat treatment regimes on the structure and microhardness of the aluminum alloy AlSi10Mg processed by the L-DED method. The study considers heat treatment regimes for solid solution in the temperature range of 500−540 °C with holding [...] Read more.

This study investigates the influence of various heat treatment regimes on the structure and microhardness of the aluminum alloy AlSi10Mg processed by the L-DED method. The study considers heat treatment regimes for solid solution in the temperature range of 500−540 °C with holding times of 30–120 min, as well as artificial aging regimes in the temperature range of 160−190 °C with holding times of 4–8 h. As a result of studying the structure and mechanical properties of the heat-treated samples, it became clear that the optimal regime can be considered the regime of 500 °C for 30 min followed by 190 °C for 6 h. This regime leads to the formation of a uniform structure with the breakage of the eutectic network into separate spherical silicon inclusions. The microhardness in this case is 90 HV, which is 55% higher than the initial state. Using TEM, it was established that the reason for the increase in hardness is the formation of nanoscale inclusions β″ (Mg₅Si₆). Full article

(This article belongs to the Section Additive Manufacturing)

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17 pages, 13183 KiB

Open AccessArticle

Development of a Finite Element Model for the HAZ Temperature Field in Longitudinal Welding of Pipeline Steel

by Zhixing Wang, Chengjia Shang and Xuelin Wang

Metals 2025, 15(1), 91; https://doi.org/10.3390/met15010091 - 18 Jan 2025

Viewed by 543

Abstract

In this study, a novel hybrid heat source model was developed to simulate the welding temperature field in the heat-affected zone (HAZ) of X80 pipeline steel. This model replicates welding conditions with high accuracy and allows flexible three-dimensional adjustments to suit various scenarios. [...] Read more.

In this study, a novel hybrid heat source model was developed to simulate the welding temperature field in the heat-affected zone (HAZ) of X80 pipeline steel. This model replicates welding conditions with high accuracy and allows flexible three-dimensional adjustments to suit various scenarios. Its development involved the innovative integration of microstructural crystallography information with a multi-scale calibration and validation methodology. The methodology focused on three critical aspects: the weld interface morphology, the location of the Ac₁ temperature, and the size of prior austenite grains (PAG). The morphology of the weld interface was calibrated to align closely with experimental observations. The model’s prediction of the Ac₁ location in actual welded joints exhibited a deviation of less than ±0.3 mm. Furthermore, comparisons of reconstructed PAG sizes between thermal simulation samples and actual HAZ samples revealed minimal discrepancies (5 μm). Validation results confirmed that the calibrated model accurately describes the welding temperature field, with reconstructed PAG size differences between simulation and experimental results being less than 9 μm. These findings validate the accuracy of the calibrated model in predicting welding temperature fields. This research introduces a novel framework for the development of heat source models, offering a robust foundation for improving welding performance and controlling microstructure in different regions during the welding process of high-strength low-alloy (HSLA) steel. Full article

(This article belongs to the Special Issue High-Strength Low-Alloy (HSLA) Steel: Welding Performance and Microstructure Analysis)

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23 pages, 10467 KiB

Open AccessArticle

A Study on the Effect of Ladle Structures and Stirrer Positions on the Internal Flow Field in the Hot Metal Desulfurization Process

by Lifei Wang, Qingchun Yu, Shubiao Yin, Guozhi Wang and Songlai Zhang

Metals 2025, 15(1), 90; https://doi.org/10.3390/met15010090 - 18 Jan 2025

Viewed by 391

Abstract

The geometry of the ladle bottom and the position of stirring paddles during hot metal stirring significantly influence hydrodynamic characteristics, thereby affecting desulfurization efficiency. Water model experiments and hydrodynamic simulations were conducted to investigate the effects of ladle structures and stirrer positions on [...] Read more.

The geometry of the ladle bottom and the position of stirring paddles during hot metal stirring significantly influence hydrodynamic characteristics, thereby affecting desulfurization efficiency. Water model experiments and hydrodynamic simulations were conducted to investigate the effects of ladle structures and stirrer positions on the flow field and mixing characteristics in hot metal desulfurization. The results indicate that ladles with a spherical-bottom structure effectively reduced the “dead zone” volume in the hot metal flow. In the water model tests, the mixing time for the spherical-bottom ladle was reduced by 22.5% and 20% at different stirring paddle speeds compared to the flat-bottom ladle, facilitating the better dispersion of the desulfurization agents. The hot metal flow velocities in all directions were also superior in spherical-bottom ladles. Under identical conditions, eccentric stirring generated shallower and broader vortices, with the vortex center offset from the stirring shaft axis, thereby minimizing the risk of “air entrainment” associated with high-speed central stirring. During eccentric stirring, the flow-field distribution was uneven, and the polarization of the stirrer was observed in the water model, whereas central stirring revealed a more uniform and stable flow field, reducing the risk of paddle wear and ladle wall erosion. Central stirring exhibits distinct advantages in the desulfurization process, whereas eccentric stirring is exclusively applicable to metallurgical modes requiring a rapid enhancement of bottom flow and localized rapid dispersion of desulfurizing agents. Full article

(This article belongs to the Special Issue Metallurgy Investigation in Nonferrous Metal Smelting)

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35 pages, 18653 KiB

Open AccessArticle

Phase Transitions and Structural Evolution of Manganese Ores During High-Temperature Treatment

by Ruslan Z. Safarov, Yerlan A. Baikenov, Assemgul K. Zhandildenova, Eldar E. Kopishev, Ruslan M. Kamatov, Jumat B. Kargin, H. Sanchez Cornejo, Crispin H. W. Barnes and Luis De Los Santos Valladares

Metals 2025, 15(1), 89; https://doi.org/10.3390/met15010089 - 18 Jan 2025

Viewed by 804

Abstract

The aim of this research is to investigate the phase composition and structural peculiarities of complex metamorphic manganese ores from Central Kazakhstan before and after sintering in the temperature range of 600–1200 °C in an air atmosphere. X-ray diffraction, X-ray fluorescence, scanning electron [...] Read more.

The aim of this research is to investigate the phase composition and structural peculiarities of complex metamorphic manganese ores from Central Kazakhstan before and after sintering in the temperature range of 600–1200 °C in an air atmosphere. X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and optical microscopy were used to analyze changes in elemental and phase composition. In their initial state, according to XRF analysis, the Bogach ore was manganese-rich, with a manganese content of 60.77 wt.%, while the Zhaksy ore contained manganese (44.88 wt.%), silicon (20.85 wt.%), and iron (6.14 wt.%) as its main components. In the Bogach ore samples, manganese content increased from 60.77% to 65.7% as the sintering temperature rose to 1100 °C, while the hausmannite phase (Mn₃O₄) emerged as the dominant phase, comprising 95.77% of the crystalline component at 1200 °C. Conversely, the Zhaksy ore samples displayed a sharp increase in braunite-phase (Mn₇O₁₂Si) content, reaching 83.81% at 1100 °C, alongside significant quartz amorphization. The degree of crystallinity in Bogach ore peaked at 56.2% at 900 °C but declined at higher temperatures due to amorphous phase formation. A surface morphology analysis revealed the transformation of dense, non-uniform particles into porous, granular structures with pronounced recrystallization as the temperature increased. In the Bogach samples, sintering at 900 °C resulted in elongated, needle-like crystalline formations, while at 1200 °C, tetragonal crystals of hausmannite dominated, indicating significant grain growth and recrystallization. For Zhaksy samples, sintering at 1100 °C led to a porous morphology with interconnected grains and microvoids, reflecting enhanced braunite crystallization and quartz amorphization. These findings provide quantitative insights into optimizing manganese oxide phases for industrial applications, such as catalysts and pigments, and emphasize the impact of thermal treatment on phase stability and structural properties. This research contributes to the development of efficient processing technologies for medium-grade manganese ores, aligning with Kazakhstan’s strategic goals in sustainable resource utilization. Full article

(This article belongs to the Special Issue Recent Progress in Metal Extraction and Recycling)

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16 pages, 7374 KiB

Open AccessArticle

Effect of Roundness and Surface Roughness of Foundry Sand on the Temperature Change of Sand Cores for Aluminum Casting

by Taekyu Ha, Jongmin Kim, Youngki Lee, Byungil Kang and Youngjig Kim

Metals 2025, 15(1), 88; https://doi.org/10.3390/met15010088 - 18 Jan 2025

Viewed by 424

Abstract

Organic binder in sand cores, such as phenol-formaldehyde binder, rapidly decomposes above 550 K, releasing gases including volatile organic compounds (VOCs) and hydrocarbon gases. A rapid temperature rise in the core increases gas evolution during the casting process. The roundness and surface roughness [...] Read more.

Organic binder in sand cores, such as phenol-formaldehyde binder, rapidly decomposes above 550 K, releasing gases including volatile organic compounds (VOCs) and hydrocarbon gases. A rapid temperature rise in the core increases gas evolution during the casting process. The roundness and surface roughness of foundry sand particles influence temperature changes in sand cores. This study investigates how these factors affect temperature change in packed sand beds and cores and the gas porosity at the interface between the core and the A356 Al castings. Temperature changes were measured using three types of sand: angular artificial sand (AAS), natural sand (NS) with different roundness and surface roughness, and polished AAS with a smooth surface. Additionally, the temperature rise in cores was measured with varying proportions of AAS. Packed sand beds and cores with low roundness and rough surface morphology form macro and micro-gaps due to high porosity and surface roughness. These gaps, filled with interstitial gas of low thermal conductivity, hinder heat conduction. Delaying the temperature rise of the core could reduce weight loss from binder decomposition, thereby decreasing gas porosity at the interface between the A356 Al castings and the core. These findings on the effects of roundness and surface roughness on temperature changes in packed sand beds and cores provide methods for reducing gas emission during the casting process. Full article

(This article belongs to the Special Issue Structure and Properties of Aluminium Alloys 2024)

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6 pages, 162 KiB

Open AccessEditorial

Solidification and Casting of Metals and Alloys

by Wenchao Yang

Metals 2025, 15(1), 87; https://doi.org/10.3390/met15010087 - 18 Jan 2025

Viewed by 479

Abstract

Establishing control of the cast structure is the underlying object of solidification metallurgy [...] Full article

(This article belongs to the Special Issue Solidification and Casting of Metals and Alloys)

4 pages, 124 KiB

Open AccessEditorial

Laser Welding Technology

by Xiangdong Gao

Metals 2025, 15(1), 86; https://doi.org/10.3390/met15010086 - 18 Jan 2025

Viewed by 493

Abstract

Laser welding technology, recognized for its advantages such as its fast welding speed, high productivity, and energy concentration, is widely used in the industrial manufacturing field [...] Full article

(This article belongs to the Special Issue Laser Welding Technology)

23 pages, 11972 KiB

Open AccessArticle

Effect of Trace Rare Earth Elements (Ce) on the Corrosion Resistance of High-Strength Weathering Bridge Steels

by Jiquan Chen, Ruifeng Dong, Yuansu Lei, Peiying Zhou, Xiong Yang and Lifeng Fan

Metals 2025, 15(1), 85; https://doi.org/10.3390/met15010085 - 17 Jan 2025

Viewed by 410

Abstract

In this study, Q370qENH high-strength weathering bridge steel was used as the base material. The corrosion experiment in a marine atmosphere was simulated by the salt spray test, and the outdoor atmospheric exposure corrosion experiment and electrochemical method test were carried out. The [...] Read more.

In this study, Q370qENH high-strength weathering bridge steel was used as the base material. The corrosion experiment in a marine atmosphere was simulated by the salt spray test, and the outdoor atmospheric exposure corrosion experiment and electrochemical method test were carried out. The corrosion behavior of Q370qENH high-strength weathering bridge steel in a marine atmosphere was studied using electron probe microanalysis (EPMA), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and other surface testing techniques. The results show that the corrosion rate of the steel gradually decreases with the increase in the content of trace rare earth elements. Ce played a role in the modification of inclusions so that MnS was modified into rare earth composite inclusions, which slowed down the occurrence of corrosion. The enrichment of Cu alloy elements in the inner rust layer of the rare earth experimental steel improves the compactness of the rust layer, and the thickness of the inner rust layer is increased by 42%, which enhances the stability of the rust layer. With the increase in cerium, the protection coefficient α/γ* of the rust layer of experimental steel increases, indicating that the corrosion resistance of the material is improved. In addition, the electrochemical results show that the addition of rare earth elements in Q370qENH steel will lead to a positive shift in the electrochemical self-corrosion potential, a larger impedance radius of the steel rust layer, and a stronger protective effect. Due to the addition of trace cerium, the seawater corrosion resistance of the test steel is improved. Full article

(This article belongs to the Special Issue Recent Advances in Microstructure and Mechanical Properties of High-Strength Steels)

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14 pages, 12626 KiB

Open AccessArticle

Study of the Intrinsic Factors Determining the Near-Threshold Fatigue Crack Propagation Behavior of a High-Strength Titanium Alloy

by Huan Wang, Yongqing Zhao, Ping Guo, Fei Qiang, Lei Zhang, Zhongli Qiao and Shewei Xin

Metals 2025, 15(1), 84; https://doi.org/10.3390/met15010084 - 17 Jan 2025

Viewed by 460

Abstract

The resistance to near-threshold fatigue crack growth and its correlation with the microstructure of the Ti-5Al-3Mo-3V-2Zr-2Cr-1Nb-1Fe alloy were investigated. K-decreasing fatigue crack propagation rate tests were conducted on compact tension samples (ASTM standard) with a stress ratio R of 0.1 and a [...] Read more.

The resistance to near-threshold fatigue crack growth and its correlation with the microstructure of the Ti-5Al-3Mo-3V-2Zr-2Cr-1Nb-1Fe alloy were investigated. K-decreasing fatigue crack propagation rate tests were conducted on compact tension samples (ASTM standard) with a stress ratio R of 0.1 and a frequency of 15 HZ in a laboratory atmosphere. At a similar strength level of 1200 MPa, the sample with a fine basket-weave microstructure (F-BW) displayed the slowest near-threshold fatigue crack propagation rate compared with the samples with equiaxed (EM) and basket-weave (BW) microstructures. The fatigue threshold value (ΔK_th) was 4.4 MPa·m^1/2 for F-BW, 3.6 for BW, and 3.2 for EM. The fracture surfaces and crack profiles were observed by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) to elucidate the mechanism of fatigue crack propagation in the near-threshold regime. The results revealed that the near-threshold crack growth in the three samples was primarily transgranular. The crack always propagated parallel to the crystal plane, with a high Schmid factor. In addition, the near-threshold fatigue crack growth behavior was synergistically affected by the crack tip plastic zone and crack bifurcation. The increased fatigue crack propagation resistance in F-BW was attributed to the better stress/strain compatibility and greater number of interface obstacles in the crack tip plastic zone. Full article

(This article belongs to the Special Issue Structure and Mechanical Properties of Titanium Alloys)

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19 pages, 10739 KiB

Open AccessArticle

Unveiling Temperature Distribution and Residual Stress Evolution of Additively Manufactured Ti6Al4V Alloy: A Thermomechanical Finite Element Simulation

by Qihong Fang, Pei Zhao, Jia Li, Hong Wu and Jing Peng

Metals 2025, 15(1), 83; https://doi.org/10.3390/met15010083 - 17 Jan 2025

Viewed by 377

Abstract

The performance of the selective electron beam melting (SEBM) products depends on the SEBM-induced temperature and stress. Here, the thermomechanical finite element simulations are conducted to investigate the dynamic evolution of temperature and the thermal stress of melt pool during the SEBM process [...] Read more.

The performance of the selective electron beam melting (SEBM) products depends on the SEBM-induced temperature and stress. Here, the thermomechanical finite element simulations are conducted to investigate the dynamic evolution of temperature and the thermal stress of melt pool during the SEBM process of Ti6Al4V alloys under various processing parameters and scanning strategies. The results show that the melt pool undergoes three stages of preheating, melting, and remelting under the influence of adjacent scanning tracks. This complex thermal history drives significant changes in thermal stress within the melt pool. After adjusting the processing parameters, it is found that a low scanning speed and high electron beam energy result in a high temperature gradient and stress in the molten pool. Compared to the electron beam energy, the scanning speed has a more significant impact on temperature and residual stress. For the dual-electron-beam scanning strategy, the coupling thermal effect between electron beams can reduce the temperature gradient of the melt pool, thereby suppressing the formation of columnar crystals. The electron beam energy of 300 W and the scanning speed of 1.5 m/s can be selected under various scanning strategies, which are expected to suppress the formation of coarse and columnar β grains and achieve relatively low residual stress. These results contribute to providing a theoretical basis for selecting optimized process parameters and scanning strategies. Full article

(This article belongs to the Special Issue Additive Manufacturing and Processing of Metallic Alloys and Composites)

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13 pages, 2667 KiB

Open AccessArticle

Sustainable Leaching of Cu, Ni, and Au from Waste Printed Circuit Boards Using Choline Chloride-Based Deep Eutectic Solvents

by Sara Saffaj, Diego Mantovani and Georgios Kolliopoulos

Metals 2025, 15(1), 82; https://doi.org/10.3390/met15010082 - 17 Jan 2025

Viewed by 701

Abstract

Electronic waste (e-waste) is becoming a serious problem that impacts the environment due to its fast-growing volume. This rise is linked to high electronic and electrical equipment production to meet the increasing demand for high-end electronic devices. Conventional e-waste recycling approaches, including hydrometallurgy [...] Read more.

Electronic waste (e-waste) is becoming a serious problem that impacts the environment due to its fast-growing volume. This rise is linked to high electronic and electrical equipment production to meet the increasing demand for high-end electronic devices. Conventional e-waste recycling approaches, including hydrometallurgy and pyrometallurgy, often involve substantial water and energy consumption and the generation of by-products, such as the emission of toxic gases or hazardous effluents. Within this context, solvometallurgy has emerged as a compelling alternative, whereby green non-toxic non-aqueous solvents, namely deep eutectic solvents (DESs), are used to extract and recover the metals with minimal water and harsh acid/base chemical use. The current study presents the solvo-leaching results of critical and strategic metals, i.e., copper (Cu) and nickel (Ni), and precious metals, i.e., gold (Au), from waste printed circuit boards (PCBs). Five different DESs were tested at mild conditions, namely at a temperature of 65 °C, a stirring speed of 300 rpm, a solid/liquid ratio of 10 g/L, and in the presence of iodine (I₂) for 96 h. Among the different solvents tested, the one consisting of choline chloride (ChCl), acetic acid (AA), and I₂ emerged as the optimal solvent, leading to the selective extraction of 99% of Cu, 92% of Ni, and 90% of Au from the PCB powder. Full article

(This article belongs to the Special Issue Trends and Advances in Leaching, Extraction and Flotation for Sustainable Metal Recovery)

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18 pages, 6401 KiB

Open AccessArticle

Finite Element and Machine Learning-Based Prediction of Buckling Strength in Additively Manufactured Lattice Stiffened Panels

by Saiaf Bin Rayhan, Md Mazedur Rahman, Jakiya Sultana, Szabolcs Szávai and Gyula Varga

Metals 2025, 15(1), 81; https://doi.org/10.3390/met15010081 - 17 Jan 2025

Viewed by 564

Abstract

The current research aimed to investigate the critical buckling load of a simply supported aerospace-grade stiffened panel made of additively manufactured cubic lattice unit cell arrays, namely simple cubic, face-centered cubic (FCC) and body-centered cubic (BCC) structures. Ansys Design Modeler was chosen to [...] Read more.

The current research aimed to investigate the critical buckling load of a simply supported aerospace-grade stiffened panel made of additively manufactured cubic lattice unit cell arrays, namely simple cubic, face-centered cubic (FCC) and body-centered cubic (BCC) structures. Ansys Design Modeler was chosen to design and analyze the critical buckling load of the panel, while a popular material, Ti-6Al-4V, was used as the build material. Numerical validation on both the stiffened panel and a lattice beam structure was established from multiple resources from the literature. Finally, the panels were tested against increments of a strut diameter ranging from 0.5 mm to 2 mm, which corresponds to a relative density of 6% to 78%. It was found that considering the relative density and fixed relative density, the simple cubic lattice cell outperformed the buckling results of the FCC and BCC panels. Moreover, the relationship of the parameters was found to be non-linear. Finally, the data samples collected from numerical outcomes were utilized to train four different machine learning models, namely multi-variable linear regression, polynomial regression, the random forest regressor and the K-nearest neighbor regressor. The evaluation metrics suggest that polynomial regression provides the highest accuracy among all the tested models, with the lowest mean squared error (MSE) value of 0.0001 and a perfect

R^{2}

score. The current research opens up the discussion of using cubic lattice cells as potential structures for future stiffened panels. Full article

(This article belongs to the Special Issue Research Progress of Crystal in Metallic Materials)

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32 pages, 6334 KiB

Open AccessReview

Recent Developments in Heavy Metals Detection: Modified Electrodes, Pretreatment Methods, Prediction Models and Algorithms

by Yujie Shi, Shijie Zhang, Hang Zhou, Yue Dong, Gang Liu, Wenshuai Ye, Renjie He and Guo Zhao

Metals 2025, 15(1), 80; https://doi.org/10.3390/met15010080 - 17 Jan 2025

Viewed by 642

Abstract

Heavy metal pollution has become an increasingly serious environmental issue, making the detection of heavy metals essential for safeguarding public health and the environment. This review aims to highlight the commonly used methods for detecting heavy metals (such as atomic absorption spectroscopy (AAS), [...] Read more.

Heavy metal pollution has become an increasingly serious environmental issue, making the detection of heavy metals essential for safeguarding public health and the environment. This review aims to highlight the commonly used methods for detecting heavy metals (such as atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), inductively coupled plasma–mass spectrometry (ICP-MS), square-wave anodic stripping voltammetry (SWASV), etc.), with a particular focus on electrochemical detection and electrode modification materials. Metal nanomaterials (such as titanium dioxide (TiO₂), copper oxide (CuO), ZIF-8, MXene, etc.) are emphasized as promising candidates for enhancing the performance of sensors due to their high surface area and excellent catalytic properties. However, challenges such as interference from non-target heavy metal ions and the formation of organometallic complexes with organic compounds can complicate the detection process. To address these issues, two potential solutions have been proposed: the development of advanced algorithms (such as machine learning (ML), back-propagation neural network (BPNN), support vector machines (SVM), random forests (RF), etc.) for signal processing and the use of pretreatment methods (such as Fenton oxidation (FO), ozone oxidation, and photochemical oxidation) to suppress such interferences. This paper aims to review commonly used methods for detecting heavy metals, with a particular emphasis on electrochemical techniques. It will also highlight the challenges faced in these methods, such as interference and sensitivity limitations, and propose innovative solutions, including the use of metal nanomaterials for improved sensor performance and the integration of advanced algorithms and pretreatment techniques to address interference and enhance detection accuracy. Full article

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16 pages, 7149 KiB

Open AccessArticle

Corrosion Behavior and Microhardness of a New B₄C Ceramic Doped with 3% Volume High-Entropy Alloy in an Aggressive Environment

by Alberto Daniel Rico-Cano, Julia Claudia Mirza-Rosca, Burak Cagri Ocak and Gultekin Goller

Metals 2025, 15(1), 79; https://doi.org/10.3390/met15010079 - 17 Jan 2025

Viewed by 522

Abstract

The aim of this paper is to study both the mechanical and chemical properties of a new material composed of B₄C doped with 3% volume of CoCrFeNiMo HEA by the spark plasma sintering technique. Scanning electron microscopy and microhardness were used [...] Read more.

The aim of this paper is to study both the mechanical and chemical properties of a new material composed of B₄C doped with 3% volume of CoCrFeNiMo HEA by the spark plasma sintering technique. Scanning electron microscopy and microhardness were used to characterize the composite microstructure and hardness. Corrosion behavior was studied by corrosion potential, corrosion rate and electrochemical impedance spectroscopy, where the equivalent circuit was obtained, characterized by the presence of the Warburg element. The addition of HEA resulted in a more compact microstructure, filling pores and inhibiting ceramic grain growth. A microhardness statistical analysis revealed that the sample followed a normal distribution, which suggests that the sample has a homogeneous structure. The doped material exhibits excellent corrosion resistance in artificial seawater, where its chemical interaction occurs in two steps, with an important diffusional component. This study highlights the potential for use in environments where both corrosion resistance and mechanical strength are critical factors. Full article

(This article belongs to the Special Issue Advances in High-Entropy Alloys’ Microstructure, Properties and Preparation)

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18 pages, 40226 KiB

Open AccessArticle

The Effect of Post-Deposition Heat Treatment on the Microstructure, Texture, and Mechanical Properties of Inconel 718 Produced by Hybrid Wire-Arc Additive Manufacturing with Inter-Pass Forging

by Dmitrii Panov, Gleb Permyakov, Stanislav Naumov, Vladimir Mirontsov, Egor Kudryavtsev, Liying Sun, Alexander Aksenov, Nikita Stepanov, Dmitriy Trushnikov and Gennady Salishchev

Metals 2025, 15(1), 78; https://doi.org/10.3390/met15010078 - 17 Jan 2025

Viewed by 624

Abstract

The microstructure, texture, and mechanical properties of Inconel 718 fabricated via hybrid wire-arc additive manufacturing (WAAM) with inter-pass forging, and the subsequent modified post-deposition heat treatment (PDHT), were investigated. The modified PDHT included homogenization at 1185 °C and double ageing at 720 °C, [...] Read more.

The microstructure, texture, and mechanical properties of Inconel 718 fabricated via hybrid wire-arc additive manufacturing (WAAM) with inter-pass forging, and the subsequent modified post-deposition heat treatment (PDHT), were investigated. The modified PDHT included homogenization at 1185 °C and double ageing at 720 °C, with furnace-cooling to 620 °C; this process was first used for Inconel 718 obtained via WAAM and inter-pass forging. In the as-printed material, two characteristic zones were distinguished, as follows: (i) columnar grains with a preferable <100> orientation and (ii) fine grains with a random crystallographic orientation. The development of static recrystallization induced via inter-pass forging and further heating during the deposition of the next (upper) layer provoked the formation of the fine-grained zone. In the as-printed material, particles of (Nb,Ti)C and TiN, and precipitates of a Nb-rich Laves phase that caused premature cracking and failure during mechanical testing, were detected. In the PDHT material, two zones were found, as follows: (i) a zone with coarse uniaxial grains and (ii) a zone with a gradient grain size distribution. PDHT resulted in the precipitation of γ″ nanoparticles in the γ-Ni matrix and the dissolution of the brittle Laves phase. Therefore, significant hardening and strengthening, as well as increases in ductility and impact toughness, occurred. Full article

(This article belongs to the Section Additive Manufacturing)

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22 pages, 7887 KiB

Open AccessArticle

Effect of Feature Size on Defects, Microstructure, and Mechanical Properties of Selective Laser Melted AlSi10Mg Lattice Structure

by Chengkuan Peng, Junfeng Qi, Sheng Zhou, Sanqiang Yang, Ran Tao, Heng Shao and Weining Li

Metals 2025, 15(1), 77; https://doi.org/10.3390/met15010077 - 16 Jan 2025

Viewed by 382

Abstract

Selective laser melting lightweight lattice structures have broad application prospects in the aerospace field. Understanding the dependence of mechanical performance on feature size is crucial for structure design. This work optimized the process parameters based on large-size metal blocks (20 mm) and then [...] Read more.

Selective laser melting lightweight lattice structures have broad application prospects in the aerospace field. Understanding the dependence of mechanical performance on feature size is crucial for structure design. This work optimized the process parameters based on large-size metal blocks (20 mm) and then fabricated submillimeter features with a size of 0.4~1.0 mm. The influence of feature size on the defects, microstructures, and mechanical properties was investigated. The results showed that the dimensional errors for all size features were above 15%. When matched with appropriate border offset, these features could be printed precisely. The densification of submillimeter features was more than 99%, demonstrating the applicability of the optimized process parameters for the fine features. The porosity and relative roughness decreased and tended to stabilize with increasing feature size. Due to having less defects, the thicker features exhibited better mechanical properties in terms of ultimate strength and elongation. After being processed with polishing treatment, the roughness was reduced below 1 μm and the tensile strength increased above 320 MPa. The elastic modulus, yield strength, and elongation were also significantly improved. Full article

(This article belongs to the Special Issue Recent Developments in Laser Additive Manufacturing of Metallic Materials)

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20 pages, 20531 KiB

Open AccessArticle

Numerical Simulation of the Influence Mechanism of Melt Rate Variation on the Macrosegregation of 8Cr4Mo4V-Bearing Steel During Vacuum Arc Remelting

by Tao Pan, Hongchun Zhu, Zhouhua Jiang, Huabing Li, Zhiyu He, Zhuowen Ni, Fubin Liu, Hao Feng and Shucai Zhang

Metals 2025, 15(1), 76; https://doi.org/10.3390/met15010076 - 16 Jan 2025

Viewed by 369

Abstract

In this study, 8Cr4Mo4V steel was selected as the research material to develop a numerical model of the macrosegregation phenomenon during vacuum arc remelting (VAR). The accuracy of the model was validated by comparing it with the literature and experimental results. According to [...] Read more.

In this study, 8Cr4Mo4V steel was selected as the research material to develop a numerical model of the macrosegregation phenomenon during vacuum arc remelting (VAR). The accuracy of the model was validated by comparing it with the literature and experimental results. According to the simulation results, molten steel flows down along the solidification front, resulting in positive segregation at the center and negative segregation close to the edge of the ingot. Solute enrichment reduces the undercooling of the alloy system, which in turn decreases the local solidification rate and causes a slight increase in steady-state molten pool depth. Notably, as the molten pool depth increases, the temperature gradient decreases, while the local cooling rate remains nearly constant, which leads to an increase in the local solidification rate again. Consequently, the positive segregation degree at the ingot’s center is gradually alleviated, and the depth of the molten pool gradually decreases. Furthermore, macrosegregation in VAR ingots becomes pronounced with an increase in melt rate. The main reason for this is due to the increased molten pool depth when the melt rate is increasing, which strengthens fluid flow and accelerates the migration of solute elements to the center. Additionally, due to the increase in the extent of solute enrichment when the melt rate is increasing, the degree of fluctuation in both the steady-state molten pool depth and positive segregation increases. Full article

(This article belongs to the Section Computation and Simulation on Metals)

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17 pages, 7431 KiB

Open AccessArticle

Study on the Electromigration Organization and Mechanical Properties of Sn2.5Ag0.7Cu0.1RE/Cu Solder Joints

by Yuming Wang, Keke Zhang, Chao Zhang, Fupeng Huo and Yijie Gao

Metals 2025, 15(1), 75; https://doi.org/10.3390/met15010075 - 16 Jan 2025

Viewed by 358

Abstract

In this study, we designed and manufactured an ideal electromigration testing device for soldering joints to solve the reliability problems caused by temperature and current density changes in the electromigration processes of micro solder joints. We analyzed the effects of temperature and current [...] Read more.

In this study, we designed and manufactured an ideal electromigration testing device for soldering joints to solve the reliability problems caused by temperature and current density changes in the electromigration processes of micro solder joints. We analyzed the effects of temperature and current density on the electromigration β-Sn (single-crystal β-Sn grain) of Sn2.5Ag0.7Cu0.1RE/Cu solder joints, the relationship between the grain orientation and interfacial IMC (intermetallic compound) growth of Sn2.5Ag0.7Cu0.1RE/Cu solder joints, and the mechanical properties of solder joints. The results showed that the angle θ between the c-axis of the β-Sn grain and the current direction for the Sn2.5Ag0.7Cu0.1RE/Cu solder joint gradually decreased to 8.2° when the temperature increased to 150 °C, which accelerated the diffusion of Cu atoms and Cu substrate dissolution. The recrystallization and grain growth of Cu₆Sn₅ (An intermetallic compound formed by the fusion of copper and tin in a ratio of six to five) grains in the anode region promoted electromigration polarity. Compared with the initial state, the shear strength decreased to 11 MPa, a decrease of 61.3%, the fracture position shifted from the top of the IMC at the cathode interface to the root of the IMC at the cathode interface, and the fracture mode changed from ductile fracture to brittle fracture. With an increase in the current density to 1.1 × 10⁴ A/cm², θ decreased to 3.2°. In addition, we observed the recrystallization of Cu₆Sn₅ grains in the anode region and an increase in the grain length and diameter to 6.8–31.9 μm, which further promoted electromigration polarity. Compared with the initial state, the shear strength decreased by 72.5% to 7.8 MPa, and the fracture position shifted from the top of the IMC at the cathode interface to the root of the IMC at the cathode interface. Additionally, the fracture mode changed from ductile to brittle fracture. Full article

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19 pages, 2503 KiB

Open AccessArticle

Optimizing Recycling Processes for Mixed LFP/NMC Lithium-Ion Batteries: A Comparative Study of Acid-Excess and Acid-Deficient Leaching

by Pierric Hubert, Angelina Noclain, Safi Jradi and Alexandre Chagnes

Metals 2025, 15(1), 74; https://doi.org/10.3390/met15010074 - 16 Jan 2025

Viewed by 513

Abstract

This study explores the optimization of hydrometallurgical processes for recycling lithium-ion batteries (LIBs) containing a mixture of lithium iron phosphate (LFP) and nickel–manganese–cobalt (NMC) cathodes. Two approaches were investigated: acid-excess leaching and acid-deficient leaching with residue recirculation. A design of experiments (DoE) framework [...] Read more.

This study explores the optimization of hydrometallurgical processes for recycling lithium-ion batteries (LIBs) containing a mixture of lithium iron phosphate (LFP) and nickel–manganese–cobalt (NMC) cathodes. Two approaches were investigated: acid-excess leaching and acid-deficient leaching with residue recirculation. A design of experiments (DoE) framework was applied to assess the impact of key parameters, including sulfuric acid and hydrogen peroxide concentrations, as well as solid-to-liquid (S/L) ratios, on the dissolution yields of target metals (Ni, Mn, Co, and Li). Acid-excess leaching achieved nearly complete dissolution of target metals but required additional purification steps to remove impurities. Acid-deficient leaching with a 60% recirculation of leaching residue improved dissolution yields by up to 12.5%, reduced reagent consumption, and minimized operational complexity. The study also evaluated separation strategies for manganese and cobalt through solvent extraction. Results indicate that while acid-excess leaching offers higher yields, acid-deficient leaching with residue recirculation is more cost-effective and environmentally friendly. These findings provide valuable insights for developing sustainable LIB recycling technologies. Full article

(This article belongs to the Special Issue Metal Extraction/Refining and Product Development)

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14 pages, 13519 KiB

Open AccessArticle

Study on the Coarsening Behavior of Interphase Precipitates and Random Precipitates in Steel Under the High-Temperature Environment of Fire

by Jinghua Cong, Yongzhe Yang, Haibin Zhu, Xueliang Shang, Hongyu Wu, Zhendong Song, Xuemin Wang and Xiangyu Xu

Metals 2025, 15(1), 73; https://doi.org/10.3390/met15010073 - 16 Jan 2025

Viewed by 376

Abstract

In the domain of fire-resistant steels, the characteristics of precipitates significantly influence material properties. This study developed a novel heat treatment protocol to concurrently achieve both interphase precipitation and random precipitation. Samples were subjected to isothermal treatments at various temperatures and durations, while [...] Read more.

In the domain of fire-resistant steels, the characteristics of precipitates significantly influence material properties. This study developed a novel heat treatment protocol to concurrently achieve both interphase precipitation and random precipitation. Samples were subjected to isothermal treatments at various temperatures and durations, while techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to thoroughly analyze the coarsening behavior of the two types of precipitate and reveal their thermal stability differences. The results show that the growth and coarsening rates of interphase precipitates are substantially lower than random precipitates. Coarsening kinetics analysis reveals that the radius of random precipitates follows a 1/3 power law with time at 600 °C and 650 °C, whereas the radius of interphase precipitates adheres to a 1/6 power law at 600 °C and a 1/5 power law at 650 °C. Furthermore, interphase precipitation demonstrates excellent size uniformity, which hinders the formation of a concentration gradient, thereby reducing the coarsening rate and enhancing thermal stability. After prolonged tempering treatment, interphase precipitation maintains a higher strengthening contribution than random precipitation. This study provides novel insights and theoretical foundations for the design and development of fire-resistant steels. Full article

(This article belongs to the Special Issue Design, Preparation and Properties of High Performance Steels)

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17 pages, 3785 KiB

Open AccessArticle

The Defect Structure Evolution in MgH₂-EEWNi Composites in Hydrogen Sorption–Desorption Processes

by Viktor N. Kudiiarov, Alan Kenzhiyev, Roman R. Elman, Nikita Kurdyumov, Ivan A. Ushakov, Andrei V. Tereshchenko, Roman S. Laptev, Mark A. Kruglyakov and Parvizi I. Khomidzoda

Metals 2025, 15(1), 72; https://doi.org/10.3390/met15010072 - 16 Jan 2025

Viewed by 493

Abstract

This paper presents the results of the study of the composite based on magnesium hydride with the addition of nanosized nickel powder, obtained by the method of an electric explosion of wires. The obtained MgH₂-EEWNi (20 wt.%) composite with the core-shell [...] Read more.

This paper presents the results of the study of the composite based on magnesium hydride with the addition of nanosized nickel powder, obtained by the method of an electric explosion of wires. The obtained MgH₂-EEWNi (20 wt.%) composite with the core-shell configuration demonstrated the development of a defect structure, which makes it possible to significantly reduce the hydrogen desorption temperature from 418 °C for pure magnesium hydride to 229 °C for hydride with the addition of nickel powder. In situ studies of the evolution of the defect structure using positron annihilation methods and diffraction methods made it possible to draw conclusions about the influence of the Mg₂NiH_0.3 and Mg₂NiH₄ phases on the sorption and desorption properties of the composite. The results obtained in this work can be used in the field of hydrogen energy in mobile or stationary hydrogen storage systems. Full article

(This article belongs to the Special Issue Deposition of Metals and Their Application in Catalytic Processes of Energy Interest (2nd Edition))

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15 pages, 5027 KiB

Open AccessArticle

Hybridization in Metal Wire Additive Manufacturing: A Case Study of an Impeller

by Shahu R. Karade, Siddhartha Siddhartha, Neel Kamal Gupta, Ganesan G, K. P. Karunakaran and Henning Zeidler

Metals 2025, 15(1), 71; https://doi.org/10.3390/met15010071 - 15 Jan 2025

Viewed by 594

Abstract

Additive manufacturing (AM) has evolved to enable the direct production of functional components through the hybridization of additive and subtractive processes. In metal wire AM, hybridization is key, encompassing process integration (addition/subtraction), energy source combinations (arc/laser), kinematic options (3/4/5 axis), and slicing techniques [...] Read more.

Additive manufacturing (AM) has evolved to enable the direct production of functional components through the hybridization of additive and subtractive processes. In metal wire AM, hybridization is key, encompassing process integration (addition/subtraction), energy source combinations (arc/laser), kinematic options (3/4/5 axis), and slicing techniques (planar/conformal). This paper focuses on these hybridization methods, with a unified system designed for single-machine setups, improving efficiency and accuracy. This study presents a detailed exploration of these hybridization levels through the fabrication of a complex 5-axis geometry—an impeller. The impeller was manufactured with hybridization using various levels and subsequently compared with manufacturing processes like additive manufacturing with interlayer machining and traditional machining methods. The hybrid approach significantly reduced the manufacturing time for the selected impeller geometry from 3536 min to 792 min (saving 77.6% manufacturing time) and minimized material waste to 9.3%, compared with 74.07% in traditional machining. This demonstrates a more efficient, precise, and cost-effective method to optimize metal wire AM for producing complex metal components, advancing capabilities and applications. Full article

(This article belongs to the Special Issue Additive Manufacturing of Metallic Materials)

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21 pages, 11873 KiB

Open AccessArticle

The Effect of Corrosion Inhibitors on the Corrosion Behavior of Ductile Cast Iron

by Jing Liu, Bingqin Wang, Tianqi Chen, Lianjun Hao, Jun Wu and Chao Liu

Metals 2025, 15(1), 70; https://doi.org/10.3390/met15010070 - 15 Jan 2025

Viewed by 483

Abstract

Based on actual service environment parameters, this experiment investigated the change in the corrosion rate of nodular cast iron (DCI) in an environment containing organic (triethanolamine phosphate, PTEA) and inorganic (hexametaphosphate, SHMP) inhibitors, and analyzed the effects of both inhibitors and the pH [...] Read more.

Based on actual service environment parameters, this experiment investigated the change in the corrosion rate of nodular cast iron (DCI) in an environment containing organic (triethanolamine phosphate, PTEA) and inorganic (hexametaphosphate, SHMP) inhibitors, and analyzed the effects of both inhibitors and the pH value of the solution on the corrosion behavior of DCI. Additionally, a variable flow rate device was used to conduct immersion tests, enabling the accurate evaluation of the materials’ corrosion resistance in an actual service environment. After a certain period, the corrosion of the DCI surface was observed, and the weight loss corrosion rate of the materials was calculated to analyze the differences in corrosion resistance under varying environmental parameters. It was found that the inhibitory effect of both inhibitors on DCI increased with the immersion time, and the inhibitory effect of the SHMP inhibitor was more pronounced under alkaline conditions. Based on the electrochemical and flow rate immersion test results, it can be concluded that, in the solution environment used in this experiment, the inhibitory effect of the SHMP inhibitor on DCI is stronger than that of the PTEA inhibitor. Full article

(This article belongs to the Special Issue Corrosion of Metals: Behaviors and Mechanisms)

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16 pages, 4414 KiB

Open AccessArticle

Effect of Alternating Magnetic Field Treatment on the Friction/Wear Resistance of 20Cr2Ni4A Under Lubricated Conditions

by Sufyan Akram, Mose Bevilacqua, Anatolii Babutskyi and Andreas Chrysanthou

Metals 2025, 15(1), 69; https://doi.org/10.3390/met15010069 - 14 Jan 2025

Viewed by 386

Abstract

High-strength nickel–chromium steel (20Cr2Ni4A) is typically used in bearing applications. Alternating magnetic field treatment, which is based on the use of a magnetiser, and which is fast and cost-effective in comparison to conventional processes, was applied to the material to improve its wear [...] Read more.

High-strength nickel–chromium steel (20Cr2Ni4A) is typically used in bearing applications. Alternating magnetic field treatment, which is based on the use of a magnetiser, and which is fast and cost-effective in comparison to conventional processes, was applied to the material to improve its wear resistance. The results of pin-on-disc wear testing using a AISI 52100 alloy counter pin revealed a decrease in the specific wear rate of the treated samples by 58% and a reduction in the value of the coefficient of friction by 28%. X-ray diffraction analysis showed a small increase in the amount of martensite and higher surface compressive residual stresses by 28% leading to improved hardness. The observed changes were not induced thermally. The volume expansion by the formation of martensite was achieved at near room temperature and led to a further increase in compressive residual stresses. The significance of this study is that the improvement in the properties was achieved at a current density value that was two orders of magnitude higher than the threshold for phase transformation and dislocation movement. The reasons for the effect of the alternating magnetic field treatment on the friction and wear properties are discussed in terms of the contribution of the magnetic field to the austenite-to-martensite phase transformation and the interaction between the magnetic domain walls and dislocations. Full article

(This article belongs to the Special Issue Advances in Electromagnetic Processing of Metallic Materials)

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29 pages, 20537 KiB

Open AccessArticle

Formability Assessment Based on Q-Value for Optimizing the Deep Drawing Process of Automotive Parts Made from Aluminum Alloys Sheet

by Jidapa Leelaseat, Aekkapon Sunanta and Surasak Suranuntchai

Metals 2025, 15(1), 68; https://doi.org/10.3390/met15010068 - 14 Jan 2025

Viewed by 521

Abstract

This paper presents a novel Q-value-based formability assessment for optimizing deep drawing processes. The Q-value, derived from thinning limit diagrams (TLDs), uses offset thinning and wrinkling limit curves to define severity levels. It is calculated by summing the product of Pascal’s triangle weighting [...] Read more.

This paper presents a novel Q-value-based formability assessment for optimizing deep drawing processes. The Q-value, derived from thinning limit diagrams (TLDs), uses offset thinning and wrinkling limit curves to define severity levels. It is calculated by summing the product of Pascal’s triangle weighting factors and normalized element counts within each severity level. The effectiveness of this Q-value assessment was demonstrated using experimentally validated finite element analysis (FEA) to optimize blank size, tool geometry, and drawbead design (male bead height and contra-bead radius) for a deep-drawn AA5754-O automotive fuel tank. Validation of FEA results with experimental thickness measurements showed that the Barlat and Lian 1989 yield criterion provided higher accuracy than Hill’s 1948 model. An optimal condition, determined using the Q-value, consists of a 430 mm × 525 mm blank formed by a redesigned tool cooperated with optimized semi-circular drawbead geometries, achieving experimental significant formability improvements by minimizing wrinkling and thinning. During optimization, this study revealed a significant interaction between blank width and length, which influenced formability. Side-wall wrinkles were attributed to insufficient tool support for the blank during forming and were relieved through tool redesign. Furthermore, increasing the male drawbead height effectively reduced wrinkling but led to increased thinning, whereas increasing the contra-bead radius had the opposite effect. Full article

(This article belongs to the Special Issue Modeling, Simulation and Experimental Studies in Metal Forming)

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Metals, Volume 15, Issue 1 (January 2025) – 97 articles

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