-
Temperature-Based Magnetic Viscosity Parameter for Evaluating Long-Term Magnetization Stability of Permanent Magnets -
The Influence of Geometry and Orientation on the Cellular Substructure and Local Mechanical Properties of Additively Manufactured AISI 316L -
Enhanced Pressureless Sinter-Bonding of Ag Nanoparticle Paste Through In Situ Ag Complex Reduction -
Numerical Study of Steel Ball Rolling Using Spiral Discs
Journal Description
Metals
Metals
is an international, peer-reviewed, open access journal published monthly online by MDPI. The Spanish Materials Society (SOCIEMAT) is affiliated with Metals and their members receive discounts 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, Ei Compendex, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Metallurgy and Metallurgical Engineering) / CiteScore - Q1 (Metals and Alloys)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15.3 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the first half of 2026).
- Recognition of Reviewers: Reviewers whose reports are timely and of high quality receive an APC discount voucher for a future publication in an MDPI journal. Become a reviewer.
- Companion journals for Metals include: Compounds, Alloys and Iron.
- Journal Cluster of Metallurgy and Corrosion Science: Metals, Coatings, Crystals, Corrosion and Materials Degradation, Alloys, Iron and Welding.
Impact Factor:
3.1 (2025);
5-Year Impact Factor:
3.2 (2025)
Latest Articles
Influence of Process Parameters on Chromium Metallization During Chromite Pellet Pre-Reduction
Metals 2026, 16(10), 1056; https://doi.org/10.3390/met16101056 - 22 Sep 2026
Abstract
The present study compares the effects of temperature, holding time, and nominal carbon excess on the pre-reduction of Donskoy chromite pellets with semi-coke. FactSage equilibrium calculations were interpreted alongside three laboratory series with different baselines. At 180 min with activated bentonite and 25%
[...] Read more.
The present study compares the effects of temperature, holding time, and nominal carbon excess on the pre-reduction of Donskoy chromite pellets with semi-coke. FactSage equilibrium calculations were interpreted alongside three laboratory series with different baselines. At 180 min with activated bentonite and 25% carbon excess, chromium metallization increased from 58.5% at 1350 °C to 87.0% at 1500 °C. At 1400 °C with attapulgite and 10% excess, extending holding time from 195 to 210 min increased chromium metallization from 70.6% to 82.8%, while residual carbon decreased from 4.96 to 4.00 wt.%. At 1500 °C and 180 min with activated bentonite, increasing excess from 15% to 25% increased chromium metallization from 68.9% to 87.0% and residual carbon from 2.30 to 4.74 wt.%. These condition-specific endpoints do not establish factor interactions, an optimum regime, or a kinetic mechanism. Unavailable uncertainty estimates limit quantitative interpretation. Equilibrium predictions and elemental maps do not independently verify the experimental phase sequence. Any industrial benefits, including chromium recovery, energy consumption, and continuous-process performance, require further validation.
Full article
(This article belongs to the Section Extractive Metallurgy)
Open AccessArticle
Effect of Heat Treatment on Tribological Behavior of Cr12Mo1V1Co Steel
by
Jue Wang, Yikai Guo, Hui Guo, Yuting Zhang and Bin Feng
Metals 2026, 16(10), 1055; https://doi.org/10.3390/met16101055 - 22 Sep 2026
Abstract
Relationships among processing, microstructure, and properties of Cr12Mo1V1Co steel under various quenching and tempering conditions were systematically investigated, with particular emphasis on tribological behavior. The microstructural evolution during heat treatment was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, and thermodynamic calculations.
[...] Read more.
Relationships among processing, microstructure, and properties of Cr12Mo1V1Co steel under various quenching and tempering conditions were systematically investigated, with particular emphasis on tribological behavior. The microstructural evolution during heat treatment was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, and thermodynamic calculations. Reciprocating wear tests were performed with wear-scar morphologies analyzed using a three-dimensional optical profiler. The results reveal that the dominant wear mechanisms of Cr12Mo1V1Co steel are abrasive wear, oxidative wear, and fatigue wear under the present experimental conditions. Hardness represents the primary factor controlling the wear rate. High-hardness specimens deliver superior resistance to plastic deformation, which provides sufficient mechanical support for the oxide layer. This minimizes deformation within both the oxide film and the matrix during reciprocating friction, suppresses oxide spallation and mitigates abrasive, oxidative, and fatigue wear. The fracture and pull-out of large irregular M7C3 carbides constitute another important wear mechanism, and the associated carbide-originated wear can be alleviated via carbide edge dissolution triggered by elevated quenching temperatures. Considering both critical factors, specimens after 1100 °C quenching + 480 °C tempering and 1120 °C quenching + 500 °C tempering achieve optimal wear resistance among the investigated heat treatments under the present testing conditions.
Full article
(This article belongs to the Section Metal Casting, Forming and Heat Treatment)
►▼
Show Figures

Figure 1
Open AccessReview
Analysis and Prospects of Cyanide-Free Methods for In Situ Borehole Leaching of Precious Metals
by
Bagdaulet Kenzhaliyev, Tatiana Surkova, Dinara Yessimova and Zhazira Baltabekova
Metals 2026, 16(10), 1054; https://doi.org/10.3390/met16101054 - 22 Sep 2026
Abstract
The declining quality of primary mineral resources necessitates the development of new approaches to the recovery of precious metals. One promising approach is in situ borehole leaching (ISL), which has been successfully applied to the recovery of uranium and copper. However, the use
[...] Read more.
The declining quality of primary mineral resources necessitates the development of new approaches to the recovery of precious metals. One promising approach is in situ borehole leaching (ISL), which has been successfully applied to the recovery of uranium and copper. However, the use of toxic cyanide for precious-metal leaching under ISL conditions is impractical, primarily due to environmental concerns. In this context, halogen-, thiourea-, and thiosulfate-based reagent systems are among the most promising alternatives. This review examines various leaching systems based on these reagents, with particular emphasis on their advantages and limitations. The most promising approaches for the application of ISL to gold recovery are highlighted, and potential directions for further research and development in this field are discussed.
Full article
(This article belongs to the Section Extractive Metallurgy)
►▼
Show Figures

Figure 1
Open AccessArticle
Effects of Wire Manufacturing Processes on Microstructures and Mechanical Properties of TIG Hardfaced Specimens Deposited by CoCrMo-Based Alloy Wires
by
Guohui Zhang, Biao Zhou, Shuai Huang, Tianyuan Wang, Jian Miao, Renyao Qin and Bingqing Chen
Metals 2026, 16(9), 1053; https://doi.org/10.3390/met16091053 - 21 Sep 2026
Abstract
CoCrMo-based alloy wires manufactured by powder metallurgy and casting processes for wear-resistant coatings of aerospace turbine blades are taken as the research objects in this study, and TIG hardfacing experiments are carried out. Microstructure characteristics of the two wires are systematically compared. Furthermore,
[...] Read more.
CoCrMo-based alloy wires manufactured by powder metallurgy and casting processes for wear-resistant coatings of aerospace turbine blades are taken as the research objects in this study, and TIG hardfacing experiments are carried out. Microstructure characteristics of the two wires are systematically compared. Furthermore, microstructure differences among the hardfaced layer, transition zone and base metal are analyzed. High-temperature hardness, tensile strength, and stress rupture resistance, as well as friction and wear properties, are measured. The results indicate that favorable weldability is possessed by both wires, whereas obvious discrepancies are found in the morphology of the Laves phase. Better comprehensive mechanical properties are exhibited by hardfaced specimens deposited with powder metallurgy wire. Slightly superior friction and wear properties are shown by hardfaced specimens from cast wire. The intrinsic relationships among wire manufacturing processes, hardfaced specimen microstructures and mechanical properties are elucidated in this study. Theoretical guidance and experimental support are provided for the structural design and engineering application of CoCrMo-based alloy wires.
Full article
(This article belongs to the Section Welding and Joining)
►▼
Show Figures

Figure 1
Open AccessArticle
Variation in Fatigue Property and Life Prediction for Curved Component of AA 7075-T651 Aluminum Alloy During Damage-Healing Process by Laser Shock Peening
by
Xiao-Dong Liu, Yi-Ming Wang, Zhou Ding and Yin Yuan
Metals 2026, 16(9), 1052; https://doi.org/10.3390/met16091052 - 21 Sep 2026
Abstract
A healing method for fatigue damage was investigated by laser shock treatment with a Nd:YAG nanosecond laser shock device for AA 7075-T651 aluminum alloy. It was found that a stable residual compressive stress field was generated by the improved laser parameters, and this
[...] Read more.
A healing method for fatigue damage was investigated by laser shock treatment with a Nd:YAG nanosecond laser shock device for AA 7075-T651 aluminum alloy. It was found that a stable residual compressive stress field was generated by the improved laser parameters, and this stable residual compressive stress field could be responsible for the improvement in the total fatigue life of the damaged curved structural specimen due to the improved laser treatment. Further analysis is gained from the fracture morphology, and it is concluded that the fatigue crack initiation and early propagation at the notch root may be effectively delayed for the damaged curved specimen by the improved laser treatment. Based on a proposed equivalent stress concentration factor , a total fatigue life prediction method is established during the damage-healing process for the curved structural specimen manufactured from AA 7075-T651 aluminum alloy. The predicted lives by the proposed method agree well with the experimental results.
Full article
(This article belongs to the Special Issue Mechanical Structure Damage of Metallic Materials)
►▼
Show Figures

Figure 1
Open AccessArticle
Molecular Dynamics Insights into Microstructure, Viscosity and Surface Tension of Steelmaking Slag
by
Ruyi Zhao, Guibin Jia and Wei Yan
Metals 2026, 16(9), 1051; https://doi.org/10.3390/met16091051 - 21 Sep 2026
Abstract
The microstructure, ionic transport, diffusivity-based viscosity estimates, and surface tension of CaO–SiO2–FeO–MgO(–Al2O3) steelmaking slags were investigated in the homogeneous liquid state by molecular dynamics simulation. The effects of basicity and Al2O3 were examined separately;
[...] Read more.
The microstructure, ionic transport, diffusivity-based viscosity estimates, and surface tension of CaO–SiO2–FeO–MgO(–Al2O3) steelmaking slags were investigated in the homogeneous liquid state by molecular dynamics simulation. The effects of basicity and Al2O3 were examined separately; basicity was varied from 1.4 to 2.6 in the Al2O3-free series, whereas Al2O3 content was varied from 0 to 10 wt.% at a fixed basicity of . Increasing basicity depolymerizes the silicate network, as indicated by the decrease in bridging oxygen and degree of structural complexity and the shift of species toward lower-order units. At , increasing Al2O3 promotes the formation of a more interconnected Si–O–Al network, accompanied by an increase in bridging oxygen. These structural variations are associated with corresponding changes in ionic diffusion and diffusivity-based viscosity estimates. Increasing basicity enhances ionic mobility and lowers the viscosity estimate, whereas increasing Al2O3 at reduces ionic mobility and increases the estimate. The calculated surface tension shows an overall increasing trend with both basicity and Al2O3 content, qualitatively consistent with the comparison models. The results provide a unified atomic-scale assessment of composition-dependent structure, transport behavior, and surface-tension trends in FeO-bearing steelmaking slags.
Full article
(This article belongs to the Special Issue Smelting Process of Metals)
►▼
Show Figures

Figure 1
Open AccessArticle
Effects of Cr, Al, and Mo on the Mechanical Properties and CO2 Corrosion Resistance of Cr-Al Alloyed Oil Well Tubular Steel
by
Yameng Qi, Zhenguo Hou and Zan Yao
Metals 2026, 16(9), 1050; https://doi.org/10.3390/met16091050 - 21 Sep 2026
Abstract
CO2 corrosion is one of the major failure mechanisms affecting oil well tubular steels during oil and gas extraction. Although high-Cr stainless steels exhibit excellent corrosion resistance, their high cost limits practical applications. Therefore, developing economical low-Cr steels with balanced mechanical properties
[...] Read more.
CO2 corrosion is one of the major failure mechanisms affecting oil well tubular steels during oil and gas extraction. Although high-Cr stainless steels exhibit excellent corrosion resistance, their high cost limits practical applications. Therefore, developing economical low-Cr steels with balanced mechanical properties and CO2 corrosion resistance is of great significance. In this study, Cr-Al alloyed steels were designed for oil well tubular applications, and the effects of alloy composition on microstructure, mechanical properties, and CO2 corrosion behavior were systematically investigated through microstructural characterization, mechanical testing, corrosion simulation, and electrochemical measurements. The results demonstrate that alloy composition strongly regulates microstructural evolution and mechanical properties. Increasing Al content promotes prior austenite grain and martensite packet coarsening, while excessive Cr addition without Mo addition accelerates carbide coarsening and aggregation, resulting in reduced strength. Ti addition results in two types of Ti-containing precipitates, including micrometer-scale TiN particles formed during steelmaking and nanoscale TiC precipitates formed during subsequent solid-state transformation, which contribute to microstructural stabilization. Cr-Al alloying significantly improves CO2 corrosion resistance by modifying the composition and structure of corrosion product films. For the 6.5Cr0.6Al and 6.5Cr0.6Al0Mo alloys, the corrosion rates decrease to 0.114 and 0.143 mm·a−1, respectively, approximately 7–9% of that of N80 steel. The improved corrosion resistance is associated with the formation of Cr- and Al-enriched corrosion product films containing FeCO3, Ca-containing carbonate/aluminate phases, and Al/Cr-containing hydroxide-related species. This study provides insights into the development of Cr-Al-alloyed oil well tubular steels through optimized alloying strategies, reduced reliance on costly alloying elements, and improved mechanical properties and CO2 corrosion resistance.
Full article
(This article belongs to the Section Corrosion and Protection)
►▼
Show Figures

Figure 1
Open AccessArticle
An Industrial Composition Prediction Methodology Based on a Stage-Dependent Thermodynamic–Kinetic Prediction Framework for Aluminum Volatilization During Electron Beam Cold Hearth Melting of TA18 Titanium Alloy
by
Bobo Li, Jiangkun Fan, Peng Lin, Bingyao Yan, Zhe Wang, Zhenghong Liu, Xiaobo Hao, Teng Pei, Huifa Tao, Yang Li, Peng Jiang and Jinshan Li
Metals 2026, 16(9), 1049; https://doi.org/10.3390/met16091049 - 21 Sep 2026
Abstract
Aluminum volatilization during electron beam cold hearth melting (EBCHM) makes precise composition control of titanium alloys difficult. In this study, a thermodynamic–kinetic framework was established to describe Al evaporation, and a Global Prediction Model (GPM) and Stage-Dependent Prediction Model (SPM) were developed for
[...] Read more.
Aluminum volatilization during electron beam cold hearth melting (EBCHM) makes precise composition control of titanium alloys difficult. In this study, a thermodynamic–kinetic framework was established to describe Al evaporation, and a Global Prediction Model (GPM) and Stage-Dependent Prediction Model (SPM) were developed for composition prediction and process analysis. Under the reported comparison basis, the GPM predicted final Al content with a mean absolute percentage error (MAPE) of 4.51% and a maximum error of 8.47%; a first-order normalization of the 4.5 wt.% theoretical predictions to the 4.4 wt.% industrial charging basis reduced the concentration MAPE to approximately 2.10%, showing that part of the original offset arose from the charge-basis mismatch. The SPM showed a MAPE of 8.33% for final Al concentration. Both models systematically underestimated the measured Al loss, indicating a directional bias that remains to be resolved. The SPM predicted that the refining and melting hearths contributed approximately 44.4% and 32.5%, respectively, or 76.9% in total; these percentages are model-derived stage attributions and were not independently validated by stage-resolved measurements. The GPM is therefore most suitable for rapid overall composition prediction, whereas the SPM provides physically interpretable, stage-specific guidance for identifying candidate critical volatilization regions and optimizing EBCHM operating conditions.
Full article
(This article belongs to the Special Issue Advanced Smelting and Casting Technologies for Metallic Materials)
►▼
Show Figures

Figure 1
Open AccessArticle
Effects of Cr Addition on Microstructure and Mechanical Properties of Heat-Resistant Al-Cu-Mg Alloys
by
Shun He, Yu Xiong, Tingting Zhang, Kaiyan Zhang, Chunting Zhang, Jinjin Li and Liwen Pan
Metals 2026, 16(9), 1048; https://doi.org/10.3390/met16091048 - 20 Sep 2026
Abstract
Al-7Cu-0.3Mg alloys with different Cr contents were prepared by melting and casting. The microstructure and tensile mechanical properties of the as-cast and T6 heat-treated alloys were investigated at room temperature and 350 °C. The results show that Cr addition not only significantly refines
[...] Read more.
Al-7Cu-0.3Mg alloys with different Cr contents were prepared by melting and casting. The microstructure and tensile mechanical properties of the as-cast and T6 heat-treated alloys were investigated at room temperature and 350 °C. The results show that Cr addition not only significantly refines the primary α-Al grains and the α-Al + θ-Al2Cu eutectic structure in the as-cast alloy, but also promotes the precipitation and refinement of the θ′-Al2Cu phase in the matrix after T6 heat treatment. However, the refinement effect does not increase monotonically with increasing Cr content; both the as-cast and heat-treated alloys exhibit optimal refinement at a Cr content of 0.36 wt.%. After heat treatment, the average size of the θ′-Al2Cu precipitates in the alloy with optimal refinement is approximately 185 nm, which is 24.8% smaller than that in the base alloy without Cr. Mechanical testing indicates that Cr significantly enhances the tensile strength of both the as-cast and heat-treated alloys at both room and elevated temperatures, and the relationship between Cr content and strength exhibits a Gaussian-type trend, with the maximum tensile strength achieved at a Cr content of 0.36 wt.%. After heat treatment, the highest high-temperature tensile strength reaches 173.43 MPa, representing a 47.2% improvement over the base alloy without Cr. Thermal exposure tests at 350 °C demonstrate that the addition of Cr significantly improves the coarsening resistance of the θ′-Al2Cu phase. Therefore, the enhanced high-temperature tensile strength of the Cr-containing alloy is attributed to an increased number density, refined size, and improved thermal stability of the θ′-Al2Cu precipitates.
Full article
(This article belongs to the Section Metal Casting, Forming and Heat Treatment)
►▼
Show Figures

Figure 1
Open AccessArticle
Microstructure-Informed Prediction of Transformation Products in C-Mn and C-Mn-Nb Steels for Data-Driven Process-Window Design
by
Marie Stiefel, Björn-Ivo Bachmann, Martin Müller, Dominik Britz, Miriam Weikert-Müller, Thorsten Staudt and Frank Mücklich
Metals 2026, 16(9), 1047; https://doi.org/10.3390/met16091047 - 20 Sep 2026
Abstract
Controlling the final microstructure of C-Mn and microalloyed C-Mn-Nb steels requires understanding how the prior austenite state and cooling path determine the transformation products, morphology, and mechanical response. In this work, a microstructure-informed prediction framework was developed to evaluate which transformation products can
[...] Read more.
Controlling the final microstructure of C-Mn and microalloyed C-Mn-Nb steels requires understanding how the prior austenite state and cooling path determine the transformation products, morphology, and mechanical response. In this work, a microstructure-informed prediction framework was developed to evaluate which transformation products can be predicted from experimentally quantified austenite descriptors within a defined industrial processing domain. A thermomechanical matrix of 80 specimens was combined with correlative light optical, scanning electron, and electron backscatter diffraction microscopy to quantify the prior austenite grain size, axial ratio, dislocation density, and cooling rate as the inputs, and the phase fractions, morphology descriptors, and hardness as the targets. The target-specific regression models from linear, kernel-based, tree-based, and gradient-boosting families were evaluated against a dummy regressor baseline using cross-validation. Reliable quantitative predictions were obtained for ferrite, pearlite, pearlite mean free path length, final size descriptor, and hardness, while the predictions for martensite, Widmanstätten ferrite, and individual bainitic subclasses remained limited by sparse occurrence and overlapping transformation windows. The framework is therefore proposed as a microstructure-informed process-window screening and experiment prioritization tool rather than a universal transformation model, with a closed-data transparency strategy enabling critical evaluation under industrial confidentiality constraints.
Full article
(This article belongs to the Special Issue Characterization and Modeling of Microstructure Evolution During Metallic Material Processing)
►▼
Show Figures

Figure 1
Open AccessArticle
From Microstructure to Mechanical Performance: Characterization of Similar and Dissimilar Welds in Cast, Wrought, and LPBF Aluminum Alloys
by
Omar Bologna, Silvia Cecchel, Riccardo Ferraresi and Giovanna Cornacchia
Metals 2026, 16(9), 1046; https://doi.org/10.3390/met16091046 - 20 Sep 2026
Abstract
Hybrid lightweight structures increasingly combine cast, wrought, and additively manufactured aluminum alloys, but the mechanical response of their welded joints remains strongly material-dependent. In this study, cast EN AC-42100-T6, wrought EN AW-6082-T6, and laser powder bed fusion (LPBF) AlSi10Mg stress-relieved plates were welded
[...] Read more.
Hybrid lightweight structures increasingly combine cast, wrought, and additively manufactured aluminum alloys, but the mechanical response of their welded joints remains strongly material-dependent. In this study, cast EN AC-42100-T6, wrought EN AW-6082-T6, and laser powder bed fusion (LPBF) AlSi10Mg stress-relieved plates were welded in 4 and 8 mm configurations using cold metal transfer and pulsed multi-control processes over two campaigns. Weld defects, microstructure, hardness profiles, and tensile properties were analyzed using a framework combining a hardness derived local yield-stress descriptor (σy,loc), a cumulative hardness deficit (IDHV), and a porosity increment metric (ΔP). The second campaign eliminated fusion and penetration related defects, but did not mitigate fusion zone porosity in LPBF-related joints, which reached 13.7% in the 8 mm LPBF–Cast joint. Hardness analysis showed the widest hardness-affected region in the wrought alloy, an intermediate response in the cast alloy, and localized alteration in LPBF. Tensile results identified three degradation modes: strength loss associated with heat-affected zone (HAZ) softening in wrought-containing joints, ductility limitation associated with the initial cast condition, and porosity-associated ductility loss in LPBF-related joints. The lower yield strength reduction in LPBF-related joints does not imply improved performance, as fracture remains strongly influenced by fusion zone porosity. The results support material specific mitigation and design strategies for hybrid welded aluminum structures.
Full article
(This article belongs to the Special Issue Light Metals for Automotive Applications)
►▼
Show Figures

Figure 1
Open AccessArticle
Rate Constants of the Initial Reduction of a Single Iron Ore Pellet by CO-H2 Gas Mixture
by
Jieon Lee, Hong-Jae Yoo, Hyuk Kim and Youngjo Kang
Metals 2026, 16(9), 1045; https://doi.org/10.3390/met16091045 - 20 Sep 2026
Abstract
As the global community moves toward carbon neutrality by 2050, the iron and steel industries are facing significant pressure to reduce CO2 emissions. Direct reduction processes using hydrogen-rich gases are emerging as a critical alternative to traditional blast furnace methods. This study
[...] Read more.
As the global community moves toward carbon neutrality by 2050, the iron and steel industries are facing significant pressure to reduce CO2 emissions. Direct reduction processes using hydrogen-rich gases are emerging as a critical alternative to traditional blast furnace methods. This study investigates the reduction behavior of single hematite pellets using varying H2-CO gas mixtures. Thermogravimetric analysis (TGA) was employed to measure reduction rates, while exhaust gas analysis helped elucidate the reaction mechanism. The results indicate that while higher temperatures and H2 concentrations accelerate reduction, carbon deposition presents a significant challenge for real-time TGA measurements at lower temperatures. By focusing on the initial stage of reduction, this study effectively excluded the influence of carbon formation on the weight change. Under these controlled conditions, a topochemical receding interface model was found to be the most appropriate for determining rate constants and activation energies under different gas mixing ratios. The derived kinetic parameters and the understanding of H2-CO reduction behavior provide essential fundamental data for optimizing the operating conditions of gas-based direct reduction processes.
Full article
(This article belongs to the Section Extractive Metallurgy)
►▼
Show Figures

Figure 1
Open AccessArticle
Sequential Structural and Casting Simulation Approach for the Fabrication of Ni–Al–Bronze Submarine Mast Cover
by
Chul Kyu Jin
Metals 2026, 16(9), 1044; https://doi.org/10.3390/met16091044 - 20 Sep 2026
Abstract
Submarine mast covers are critical cantilever appendages subjected to extreme hydrostatic pressure during submerged transit. To ensure structural reliability and control internal defects inherent in heavy-section casting, an integrated design-to-manufacturing framework sequentially linking structural finite element analysis (FEA), fluid volume method (FVM)-based casting
[...] Read more.
Submarine mast covers are critical cantilever appendages subjected to extreme hydrostatic pressure during submerged transit. To ensure structural reliability and control internal defects inherent in heavy-section casting, an integrated design-to-manufacturing framework sequentially linking structural finite element analysis (FEA), fluid volume method (FVM)-based casting simulation, and full-scale experimental sand casting was established. FEA under a 600 m submergence depth (7.0 MPa hydrostatic pressure) identified stress concentrations on the inner surface along the major-axis section. Introducing an optimized fillet radius at a sharp step reduced peak equivalent stress from 216.0 MPa to below 194.0 MPa, securing a safety factor exceeding 2.0 against the yield strength of nickel–aluminum–bronze (390 MPa). MAGMA5 casting simulations verified an unpressurized bottom-gating system (S:R:G = 1.00:2.88:4.80), achieving smooth laminar filling with gate velocities under 1.25 m/s without cold shuts. To mitigate predicted shrinkage porosity, process modifications enlarging riser diameters from Ø30 mm to Ø60 mm and placing chills were implemented in the actual casting trial, while top porosity was removed via machining allowances. Specimens harvested from the full-scale prototype yielded 757.8 MPa UTS, 392.5 MPa yield strength, 17.9% elongation, and 197 HB hardness.
Full article
(This article belongs to the Special Issue Applications of Computational Methods in Metallic Materials Manufacturing Processes)
►▼
Show Figures

Figure 1
Open AccessArticle
A Framework for Knowledge Reuse in Sheet Metal Forming Tooling Design: From Tacit Expertise to Data-Driven Decision
by
Aju Sukumaran Menon, Roland Stolt, Fredrik Elgh and Karl-Johan Jonsson
Metals 2026, 16(9), 1043; https://doi.org/10.3390/met16091043 - 19 Sep 2026
Abstract
Despite advances in digital engineering tools, early-stage sheet metal forming tooling design remains strongly dependent on the tacit knowledge of experienced engineers, making systematic knowledge reuse difficult. This study addresses the need for a structured method to capture, organize, retrieve, and reuse historical
[...] Read more.
Despite advances in digital engineering tools, early-stage sheet metal forming tooling design remains strongly dependent on the tacit knowledge of experienced engineers, making systematic knowledge reuse difficult. This study addresses the need for a structured method to capture, organize, retrieve, and reuse historical tooling knowledge during early design decision-making. A data-driven decision-support framework is proposed, in which previous tooling projects are represented as structured knowledge cases containing CAD-derived features and performance-related data. The framework is developed within a Case-Based Reasoning paradigm and consists of three modules: a Difficulty Assessment Module for estimating manufacturing difficulty, a Similarity Retrieval Module for identifying comparable historical cases, and a Performance Module for linking design decisions with maintenance and operational outcomes. A prototype implementation was developed, tested, and evaluated through expert validation workshops with industrial tooling partners. The results indicate that the proposed framework has the potential to support more interpretable and systematic early-stage tooling decisions by formalizing design knowledge and enabling the retrieval of relevant past cases. The study concludes that data-driven knowledge reuse can reduce reliance on individual experience, may potentially reduce the design lead time, and support early design stages.
Full article
(This article belongs to the Special Issue Innovations and Insights in Sheet Metal Forming)
►▼
Show Figures

Figure 1
Open AccessArticle
Hot Deformation Behaviour of Q690 High-Strength Steel
by
Haiwen Liu, Yang Yuan, Lifeng Fan and Erbin Yue
Metals 2026, 16(9), 1042; https://doi.org/10.3390/met16091042 - 19 Sep 2026
Abstract
This study systematically investigated the thermal deformation characteristics of industrial-grade Q690 HSLA steel under different temperatures and strain rates through isothermal compression tests conducted on the Gleeble-3500 simulator. The flow stress of Q690 steel exhibits significant sensitivity to deformation parameters (850–1150 °C and
[...] Read more.
This study systematically investigated the thermal deformation characteristics of industrial-grade Q690 HSLA steel under different temperatures and strain rates through isothermal compression tests conducted on the Gleeble-3500 simulator. The flow stress of Q690 steel exhibits significant sensitivity to deformation parameters (850–1150 °C and 0.001–10 s−1), characterized by a pronounced thermal softening effect at higher temperatures and strain-rate hardening as the strain rate increases. Through the construction of processing maps, we identified an optimal processing window within the temperature range of 1000–1100 °C and strain rates of 0.01–0.1 s−1, where the power dissipation efficiency (η) reaches a peak of 0.34, indicating superior hot workability. Conversely, flow instability zones were predominantly observed at lower temperatures and higher strain rates, with these regions expanding as strain increased. By integrating flow curve analysis, instability criteria, and microstructural characterization, we determined that complete dynamic recrystallization (DRX) is achieved at 1050 °C and 0.1 s−1. Under these conditions, the material exhibits a refined, homogeneous equiaxed grain structure with uniform martensitic laths and an average prior austenite grain size of approximately 9.88 µm.
Full article
(This article belongs to the Special Issue Advanced High-Performance Steels: From Fundamental to Applications)
►▼
Show Figures

Figure 1
Open AccessArticle
Tin-Smelting Parameter Optimization via an RBFN-Assisted Dynamic Multiobjective Approach
by
Zhaojun Ma, Jubo Peng, Xiaojun Zhou, Zerui Wang and Hua Zhong
Metals 2026, 16(9), 1041; https://doi.org/10.3390/met16091041 - 18 Sep 2026
Abstract
Tin smelting in a top-blowing furnace is a key non-ferrous metallurgical process in which tin recovery, energy consumption, and the service life of the magnesia–chrome refractory lining are affected by strongly coupled operating variables. The degradation of the magnesia–chrome lining is associated with
[...] Read more.
Tin smelting in a top-blowing furnace is a key non-ferrous metallurgical process in which tin recovery, energy consumption, and the service life of the magnesia–chrome refractory lining are affected by strongly coupled operating variables. The degradation of the magnesia–chrome lining is associated with the combined effects of thermal shock, chemical attack by molten slag and metal, and mechanical wear caused by high-temperature, turbulent, and particle-laden flow during blowing, charging, and tapping operations. First-principles modeling is difficult under extreme thermochemical conditions, whereas experience-based adjustment lacks reproducibility and scalability. Existing surrogate-assisted evolutionary methods also suffer from approximation errors, unreliable constraint handling, and limited interpretability in dynamic, data-scarce industrial settings. To address these issues, this study proposes RAMOSTA, an RBFN-assisted dynamic multiobjective state transition algorithm for tin-smelting parameter optimization. The proposed method integrates radial basis function neural-network surrogate models for tin recovery, energy consumption, and refractory-lining degradation; an uncertainty-aware adaptive offset penalty strategy for conservative constraint handling; a Pareto-based dynamic state-transition optimizer for searching time-varying trade-offs with a limited number of real evaluations; and a hybrid-weight TOPSIS decision layer. The latter combines expert preferences derived using the fuzzy analytic hierarchy process (FAHP), which accounts for the relative importance and uncertainty of decision criteria, with objective weights calculated from Shapley values, which quantify the marginal contribution of each objective to the overall decision. Experiments on an industrial tin-smelting dataset compare RAMOSTA with NSGA-II, NSGA-III, MOEA/D, and C-TAEA using Pareto-front quality, constraint satisfaction, hypervolume, and inverted generational distance.
Full article
(This article belongs to the Section Computation and Simulation on Metals)
►▼
Show Figures

Figure 1
Open AccessArticle
Integrated Pyrometallurgical Recovery of High-Purity Fe from Spent LiFePO4 Batteries Through Selective Cu Removal and Oxidative Dephosphorization
by
A-Jin Im and Jei-Pil Wang
Metals 2026, 16(9), 1040; https://doi.org/10.3390/met16091040 - 18 Sep 2026
Abstract
Spent lithium iron phosphate (LiFePO4, LFP) batteries contain considerable amounts of Fe; however, most conventional recycling processes primarily target Li recovery, while Fe is often discarded or utilized as a low-value residue. In this study, an integrated pyrometallurgical refining process was
[...] Read more.
Spent lithium iron phosphate (LiFePO4, LFP) batteries contain considerable amounts of Fe; however, most conventional recycling processes primarily target Li recovery, while Fe is often discarded or utilized as a low-value residue. In this study, an integrated pyrometallurgical refining process was developed to recover and purify Fe from spent LFP battery-derived materials through sequential Cu and P removal. Following decarbonization and oxidative smelting, an FeO-rich slag was subjected to carbothermic reduction to produce an Fe–Cu–P alloy. Cu was subsequently removed by FeS-assisted sulfidation and slag refining, and the remaining P was removed by oxidative dephosphorization using Fe2O3 and a CaO–SiO2-based slag. The effects of reaction temperature, Cu molar ratio, and slag basicity were systematically investigated. The optimum Cu-removal condition was obtained at 1400 °C with a Cu molar ratio of 2:1, under which the Cu content decreased from 6.44 to 1.47 wt.%, corresponding to an estimated Cu-removal efficiency of 77.45%. Subsequent dephosphorization was strongly influenced by slag basicity. Increasing the CaO/SiO2 ratio from 2.0 to 3.0 decreased the residual P content from 1.33 to 0.042 wt.% and increased the phosphorus distribution ratio from 3.36 to 138.57. At a basicity of 3.0, the P removal efficiency reached 99.44%. Under the optimum conditions, the final metallic product exhibited a calculated Fe purity of 98.55% with an Fe recovery of 93.27%. The results demonstrate that sequential sulfidation and oxidative dephosphorization can effectively remove Cu and P while minimizing Fe loss, providing a feasible pyrometallurgical route for upgrading Fe recovered from spent LFP batteries into a reusable metallic resource.
Full article
(This article belongs to the Special Issue Separation, Purification and Extraction of Metals from Primary and Secondary Resources)
►▼
Show Figures

Graphical abstract
Open AccessArticle
Microbiologically Influenced Corrosion on Turbine Blades in a Hydroelectric Power Plant
by
Jaka Burja, Borut Žužek, Tjaša Danevčič, David Stopar, Damjan Požun and Barbara Šetina Batič
Metals 2026, 16(9), 1039; https://doi.org/10.3390/met16091039 - 18 Sep 2026
Abstract
This study investigated the root cause of severe corrosion damage observed on G-X4CrNi13-4 martensitic stainless steel turbine blades at the Brežice hydroelectric power plant on the Sava River in Slovenia. The investigation employed a comprehensive analytical approach, including on-site visual inspections, non-destructive testing
[...] Read more.
This study investigated the root cause of severe corrosion damage observed on G-X4CrNi13-4 martensitic stainless steel turbine blades at the Brežice hydroelectric power plant on the Sava River in Slovenia. The investigation employed a comprehensive analytical approach, including on-site visual inspections, non-destructive testing with a portable microscope (Struers, Ballerup, Denmark), X-ray fluorescence spectroscopy (Thermo Fisher Scientific, Waltham, MA, USA), and 3D topographical mapping (Bruker Alicona, Graz, Austria). Laboratory analyses utilized scanning electron microscopy (ZEISS, Oberkochen, Germany) and energy-dispersive X-ray spectroscopy (EDAX, Pleasanton, CA, USA) to examine surface deposits, biofilms, and corrosion products, complemented by physical and chemical water quality assessments. A visual inspection revealed a dense layer of biological deposits, approximately 0.3 mm thick, with stochastic pitting damage located beneath the biofilm. The analytical results confirmed that the blade material met the specifications; however, EDS analysis (EDAX, Pleasanton, CA, USA) revealed significant localized manganese enrichment within the pits (~1.4 wt%) and in the biofilm (>10 wt%). Although water analysis showed relatively low manganese concentrations (7–18 µg/L), these values may be sufficient to support the metabolic activity of manganese-oxidizing microorganisms. Historical hydrological data suggest that extreme drought conditions in 2022, stagnant water, and elevated temperatures facilitated the attachment of microorganisms and the formation of a corrosive biofilm. These findings highlight the impact of changing environmental conditions and low-flow periods on the integrity of stainless steel components in hydroelectric facilities.
Full article
(This article belongs to the Section Metal Failure Analysis)
►▼
Show Figures

Figure 1
Open AccessCommunication
Influence of Boron Content on the Tensile Properties and Deformation Behavior of GH3230 Nickel-Based Superalloy
by
Bin Zan, Wenxin Xu, Shichong Yuan and Zhanglong Zhao
Metals 2026, 16(9), 1038; https://doi.org/10.3390/met16091038 - 18 Sep 2026
Abstract
Minor alloying elements play critical roles in the microstructural evolution and mechanical properties of wrought superalloys. The wrought GH3230 Ni-based superalloys with boron (B) contents ranging from 0.0018 to 0.0088 wt.% were prepared by a casting–forging process to investigate the effects of B
[...] Read more.
Minor alloying elements play critical roles in the microstructural evolution and mechanical properties of wrought superalloys. The wrought GH3230 Ni-based superalloys with boron (B) contents ranging from 0.0018 to 0.0088 wt.% were prepared by a casting–forging process to investigate the effects of B on microstructure and tensile deformation behavior. The results showed that while the B content had a limited influence on ultimate tensile strength, it significantly improved macroscopic ductility by promoting deformation homogeneity through the modification of carbide morphology and distribution. The carbides exhibited blocky aggregation at low B contents (0.0018–0.0052 wt.%), whereas the formation of uniformly dispersed granular carbides was promoted at higher B contents (0.0066–0.0088 wt.%). Digital image correlation and EBSD analyses revealed that aggregated carbides induced localized deformation and high dislocation density regions, while dispersed granular carbides facilitated homogeneous strain distribution. These findings demonstrate that the B-induced carbide evolution plays a critical role in regulating tensile deformation behavior of GH3230 alloys.
Full article
(This article belongs to the Special Issue Advanced Manufacturing and Processing Technology for Metallic Materials)
►▼
Show Figures

Figure 1
Open AccessArticle
Efficient Recovery of High-Purity Li2CO3 from Spent Li-SOCl2 Primary Batteries Through Thermal Treatment and Selective Hydrometallurgical Processing
by
Lorena Alcaraz, Olga Rodríguez-Largo and Félix A. López
Metals 2026, 16(9), 1037; https://doi.org/10.3390/met16091037 - 18 Sep 2026
Abstract
►▼
Show Figures
Lithium-thionyl chloride (Li-SOCl2) primary batteries contain a large amount of lithium and are increasingly being produced as hazardous waste, but little work has been done on recycling these batteries. This study reports an efficient process for the recycling of Li from
[...] Read more.
Lithium-thionyl chloride (Li-SOCl2) primary batteries contain a large amount of lithium and are increasingly being produced as hazardous waste, but little work has been done on recycling these batteries. This study reports an efficient process for the recycling of Li from used Li-SOCl2 batteries using thermal treatment, water leaching and selective precipitation. The recovered black mass obtained after manual dismantling of the batteries contained 6.734 wt.% Li, which was thermally treated under different conditions to minimize lithium loss. Thermal treatment at 500 °C for 2 h limited Li volatilization to about 7%, but loss was significant at higher temperatures. Water leaching selectively recovered lithium into solution, leaving most of the impurities in the solid residue. Different precipitation strategies were assessed for the recovery of lithium as Li2CO3. Although ammonium carbonate yielded a recovery efficiency at 68%, sodium carbonate provided higher overall precipitation yields. Thus, the optimal conditions involved solution preconcentration, pH adjustment to above 11, and the use of ethanol as an antisolvent using sodium carbonate as a precipitating agent. These results reveal an efficient recycling pathway to recover lithium from spent Li-SOCl2 batteries, contributing to the sustainable management of this under-explored battery waste stream.
Full article

Graphical abstract
Journal Menu
► ▼ Journal Menu-
- Metals Home
- Aims & Scope
- Editorial Board
- Reviewer Board
- Topical Advisory Panel
- Early Career Editorial Board
- Instructions for Authors
- Special Issues
- Topics
- Sections
- Article Processing Charge
- Indexing & Archiving
- Editor’s Choice Articles
- Most Cited & Viewed
- Journal Statistics
- Journal History
- Journal Awards
- Society Collaborations
- Conferences
- Editorial Office
Journal Browser
► ▼ Journal BrowserHighly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Topic in
Alloys, Materials, Metals
Development of Light Alloys with Excellent Mechanical Properties
Topic Editors: Zhirou Zhang, Isaac ChangDeadline: 10 October 2026
Topic in
Materials, Crystals, Metals, Coatings, Alloys
Microstructure and Properties in Metals and Alloys, 4th Edition
Topic Editors: Andrea Di Schino, Claudio Testani, Robert BidulskýDeadline: 31 October 2026
Topic in
Alloys, JETA, Materials, Metals, Sci, Applied Mechanics, Buildings
Advanced Failure Analysis of Materials
Topic Editors: Franco Concli, Isaac J. HongDeadline: 31 December 2026
Topic in
Ceramics, Materials, Metals, Polymers, Coatings
Advances in Coatings Technology and Their Multidisciplinary Applications
Topic Editors: Kamalan Kirubaharan Amirtharaj Mosas, Doni DanielDeadline: 31 January 2027
Conferences
Special Issues
Special Issue in
Metals
Thermodynamic Assessments and Phase Equilibria Studies of Sustainable Alloy Systems
Guest Editor: Erwin Povoden-KaradenizDeadline: 25 September 2026
Special Issue in
Metals
Nondestructive Testing Methods for Metallic Material
Guest Editor: Dazhao ChiDeadline: 25 September 2026
Special Issue in
Metals
Metals Machining—Analysis of Metal Cutting Processes
Guest Editor: Zhenyu ShiDeadline: 25 September 2026
Special Issue in
Metals
Diversified Development of Steel Structures: Cross-Disciplinary Applications and Enhancement of Safety and Resilience
Guest Editors: Zhihua Chen, Hai Zhang, Hongbo Liu, Zhanzhong YinDeadline: 25 September 2026




