Metals

22 pages, 13327 KiB

Open AccessArticle

Efficient Representative Volume Element of a Matrix–Precipitate Microstructure—Application on AlSi10Mg Alloy

by Chantal Bouffioux, Luc Papeleux, Mathieu Calvat, Hoang-Son Tran, Fan Chen, Jean-Philippe Ponthot, Laurent Duchêne and Anne Marie Habraken

Metals 2024, 14(11), 1244; https://doi.org/10.3390/met14111244 (registering DOI) - 1 Nov 2024

Abstract

In finite element models (FEMs), two- or three-dimensional Representative Volume Elements (RVEs) based on a statistical distribution of particles in a matrix can predict mechanical material properties. This article studies an alternative to 3D RVEs with a 2.5D RVE approach defined by a [...] Read more.

In finite element models (FEMs), two- or three-dimensional Representative Volume Elements (RVEs) based on a statistical distribution of particles in a matrix can predict mechanical material properties. This article studies an alternative to 3D RVEs with a 2.5D RVE approach defined by a one-plane layer of 3D elements to model the material behavior. This 2.5D RVE relies on springs applied in the out-of-plane direction to constrain the two lateral deformations to be compatible, with the goal of achieving the isotropy of the studied material. The method is experimentally validated by the prediction of the tensile stress–strain curve of a bi-phasic microstructure of the AlSi10Mg alloy. Produced by additive manufacturing, the sample material becomes isotropic after friction stir processing post treatment. If a classical plane strain 2D RVE simulation is clearly too stiff compared to the experiment, the predictions of the stress–strain curves based on 2.5D RVE, 2D RVE with no transversal constraint (called 2D free RVE), and 3D RVE simulations are close to the experiments. The local stress fields within a 2.5D RVE present an interesting similarity with 3D RVE local fields, but differences with the 2D free RVE local results. Since a 2.5D RVE simplifies one spatial dimension, the simulations with this model are faster than the 3D RVE (factor 2580 in CPU or taking into account an optimal parallel computation, a factor 417 in real time). Such a discrepancy can affect the FEM² multi-scale simulations or the time required to train a neural network, enhancing the interest in a 2.5D RVE model. Full article

(This article belongs to the Special Issue Feature Papers in Crystallography and Applications of Metallic Materials (2nd Edition))

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12 pages, 7574 KiB

Open AccessArticle

The Effect of Process Parameters on the Pore Structure of Lotus-Type Porous Copper Fabricated via Continuous Casting

by Byung-Sue Shin and Soong-Keun Hyun

Metals 2024, 14(11), 1243; https://doi.org/10.3390/met14111243 - 31 Oct 2024

Abstract

The pores in lotus-type porous copper are formed due to the difference in hydrogen solubility between the liquid and solid phases of copper. In a pressurized hydrogen atmosphere, hydrogen gas is released at the gas release and crystallization temperature, which is the melting [...] Read more.

The pores in lotus-type porous copper are formed due to the difference in hydrogen solubility between the liquid and solid phases of copper. In a pressurized hydrogen atmosphere, hydrogen gas is released at the gas release and crystallization temperature, which is the melting point of copper. This study systematically analyzes the effects of process parameters, including hydrogen ratio, total pressure, and continuous casting speed, on the pore structure of lotus-type porous copper, with the aim of identifying the most critical process parameters for controlling pore diameter and density. Within the hydrogen ratio up to 50%, it was observed that as the hydrogen ratio increases, the pores tend to increase in porosity, and the pore diameter increases. As the hydrogen ratio increased from 25% to 50%, the pore diameter increased from 300 μm to 400 μm, while the pore density decreased from 3.3 N·mm⁻² to 2.8 N·mm⁻². As the total pressure increased, the pore diameter tended to decrease, and the pore density increased. Specifically, when the total pressure increased from 0.2 MPa to 0.4 MPa, the pore diameter decreased from 1100 μm to 400 μm, while the pore density increased significantly from 0.5 N·mm⁻² to 2.8 N·mm⁻². In addition, as the continuous casting speed increased, 30 to 90 mm·min⁻¹, the pore diameter decreased from 850 μm to 400 μm, and the pore density increased from 0.7 N·mm⁻² to 2.8. N·mm⁻². Specifically, the increase in total pressure led to a decrease in Gibbs free energy and a reduction in the critical pore nucleation radius, which promoted pore formation and resulted in the creation of more, smaller pores. These results suggest that total pressure is the primary factor influencing both pore diameter and density in lotus-type porous copper. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Metal Casting, Forming and Heat Treatment)

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17 pages, 6507 KiB

Open AccessArticle

Microstructure Evolution and Mechanical Properties of Pure Ti Alloy Sheet Fabricated by Double-Side Corrugated Rolling

by Zhihao Du, Wei Zhang and Jianchao Han

Metals 2024, 14(11), 1242; https://doi.org/10.3390/met14111242 (registering DOI) - 31 Oct 2024

Abstract

In this study, pure Ti alloy sheets were fabricated by double corrugated roll + flat roll rolling (DCFR) and flat roll + flat roll rolling (FFR) at 700 °C and 400 °C, respectively. The microstructure, texture, and mechanical properties were investigated systematically. The [...] Read more.

In this study, pure Ti alloy sheets were fabricated by double corrugated roll + flat roll rolling (DCFR) and flat roll + flat roll rolling (FFR) at 700 °C and 400 °C, respectively. The microstructure, texture, and mechanical properties were investigated systematically. The results showed that the recrystallization fraction was small and there were a large number of substructures and deformation structures in the two rolling processes. The textures of the sheet rolled at 700 °C and 400 °C were the basal bimodal TD texture and mainly consisted of B and E types with Euler angles (15°, 25°, 0°) and (15°, 30°, 30°). Compared with the FFR sheet, the texture was weakened at the center of the DCFR sheet rolled at 700 °C, while the texture weakening of the sheet rolled at 400 °C is insignificant. The tensile strength of the sheet rolled by DCFR at 400 °C was about 90 MPa higher than that of the sheet rolled by DCFR at 700 °C. The elongation in the rolling direction is almost 15%, and that in the transverse direction varies from 10% to 23% for the sheet rolled at different temperatures and rolling processes. The tensile test indicates that the alloy rolled by DCFR at 400 °C exhibits superior isotropy. Through the analysis of texture types, it is discovered that although the texture intensity of the alloy is higher than that of the FFR alloy, its more abundant texture types weaken its anisotropy. After annealing at 650 °C for 1 h, the grains recrystallized from the deformed and elongated state into equiaxed crystals, the texture intensity decreased, and the grain orientation became more diversified. Full article

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22 pages, 28555 KiB

Open AccessArticle

Ultrasound-Enhanced Friction Stir Welding of Aluminum Alloy 6082: Advancements in Mechanical Properties and Microstructural Refinement

by Marat Rebrin, Andreas Gester, Dmitrii Ozherelkov, Christiane Wächtler, Toni Sprigode, Martin Mädlow and Guntram Wagner

Metals 2024, 14(11), 1241; https://doi.org/10.3390/met14111241 - 31 Oct 2024

Abstract

This study examines the effects of ultrasound-enhanced friction stir welding (USE-FSW) on the mechanical properties and microstructural characteristics of aluminum alloy AA6082-T6, commonly used in automotive, aerospace, and construction industries. The investigation included tensile and bending tests, as well as detailed microstructural evaluations [...] Read more.

This study examines the effects of ultrasound-enhanced friction stir welding (USE-FSW) on the mechanical properties and microstructural characteristics of aluminum alloy AA6082-T6, commonly used in automotive, aerospace, and construction industries. The investigation included tensile and bending tests, as well as detailed microstructural evaluations using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDS). The results indicate that USE-FSW led to an approximately 26% increase in tensile strength compared to similar samples produced by conventional friction stir welding (CFSW). Additionally, the elongation at break improved by around 52%, indicating better ductility. Flexural strength also showed a notable improvement of over 70%. Microstructural analysis revealed a finer grain structure in the stir zone, contributing to these mechanical enhancements. However, the changes in texture and grain orientation were relatively modest, as shown by EBSD and Kernel Average Misorientation (KAM) analyses. Overall, USE-FSW offers incremental improvements in weld quality and mechanical performance, making it a promising technique for producing joints with slightly enhanced strength and ductility. Full article

(This article belongs to the Special Issue New Welding Materials and Green Joint Technology—2nd Edition)

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22 pages, 3903 KiB

Open AccessReview

Comprehensive Study of CoCrCuNi High-Entropy Alloys: Effects of Preparation, Heat Treatment, Computational Simulation, and Alloying Elements

by Fachang Zhao, Xingming Zhao, Tianzhi Jiang, Rongda Zhao and Fufa Wu

Metals 2024, 14(11), 1240; https://doi.org/10.3390/met14111240 - 30 Oct 2024

Abstract

High-entropy alloys have attracted widespread attention from researchers worldwide due to their unique microstructure and outstanding mechanical properties, making them a prominent focus in the field of metallurgy. Among the various high-entropy alloys, the CoCrCuNi system was among the first alloys discovered, and [...] Read more.

High-entropy alloys have attracted widespread attention from researchers worldwide due to their unique microstructure and outstanding mechanical properties, making them a prominent focus in the field of metallurgy. Among the various high-entropy alloys, the CoCrCuNi system was among the first alloys discovered, and it has shown significant progress in development. By employing different preparation and heat treatment processes, researchers have obtained alloys with diverse performances. The addition of various alloying elements or other components can lead to pronounced variations in the properties of CoCrCuNi high-entropy alloys. This work provides a comprehensive review of recent research progress on CoCrCuNi high-entropy alloys. It covers the preparation methods, thermodynamic and kinetic simulation calculations, as well as discussions on heat treatment processes and the influence of alloying elements on the microstructure and mechanical properties of CoCrCuNi high-entropy alloys. Finally, the review concludes with a prospective analysis and predictions for the potential applications and future directions in developing novel high-entropy alloys. Full article

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16 pages, 11277 KiB

Open AccessArticle

Microstructural and Oxidation Effects of Nb Additions to U₃Si₂

by Geronimo Robles, Joshua T. White, Scarlett Widgeon Paisner and Elizabeth S. Sooby

Metals 2024, 14(11), 1239; https://doi.org/10.3390/met14111239 - 30 Oct 2024

Abstract

U₃Si₂ is a long term, accident-tolerant nuclear fuel candidate for light-water reactors because of its superior thermal conductivity and increased uranium density when compared to traditional uranium dioxide (UO₂). While reducing internal thermal stresses and increasing efficiency, U [...] Read more.

U₃Si₂ is a long term, accident-tolerant nuclear fuel candidate for light-water reactors because of its superior thermal conductivity and increased uranium density when compared to traditional uranium dioxide (UO₂). While reducing internal thermal stresses and increasing efficiency, U₃Si₂ exhibits energetic oxidation during certain off-normal and accident scenarios, which include coolant or steam exposure. To mitigate this, Nb is investigated as an alloy constituent to enhance corrosion resistance and increase mechanical strength. The work presented investigates the response of Nb-alloyed U₃Si₂ to steam atmospheres. A thermogravimetric analysis is conducted in flowing steam to T > 1000 °C to assess oxidation resistance. The phase characterization of as-melted, thermally annealed and post-oxidation compositions with up to 12 vol% Nb by powder X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy is reported. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Metal Casting, Forming and Heat Treatment)

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18 pages, 17246 KiB

Open AccessArticle

Comparative Study of High-Cycle Fatigue and Failure Mechanisms in Ultrahigh-Strength CrNiMoWMnV Low-Alloy Steels

by Atef Hamada, Mohammed Ali, Sumit Ghosh, Matias Jaskari, Tarek Allam, Ruth Schwaiger, Mamdouh Eissa and Taha Mattar

Metals 2024, 14(11), 1238; https://doi.org/10.3390/met14111238 - 29 Oct 2024

Abstract

This study provides a thorough analysis of the fatigue resistance of two low-alloy ultrahigh-strength steels (UHSSs): Steel A (fully martensitic) and Steel B (martensitic–bainitic). The investigation focused on the fatigue behaviour, damage mechanisms, and failure modes across different microstructures. Fatigue strength was determined [...] Read more.

This study provides a thorough analysis of the fatigue resistance of two low-alloy ultrahigh-strength steels (UHSSs): Steel A (fully martensitic) and Steel B (martensitic–bainitic). The investigation focused on the fatigue behaviour, damage mechanisms, and failure modes across different microstructures. Fatigue strength was determined through fully reversed tension–compression stress-controlled fatigue tests. Microstructural evolution, fracture surface characteristics, and crack-initiation mechanisms were investigated using laser scanning confocal microscopy and scanning electron microscopy. Microindentation hardness (H_IT) tests were conducted to examine the cyclic hardening and softening of the steels. The experimental results revealed that Steel A exhibited superior fatigue resistance compared to Steel B, with fatigue limits of 550 and 500 MPa, respectively. Fracture surface analysis identified non-metallic inclusions (NMIs) comprising the complex MnO-SiO₂ as critical sites for crack initiation during cyclic loading in both steels. The H_IT results after fatigue indicated significant cyclic softening for Steel A, with H_IT values decreasing from 7.7 ± 0.36 to 5.66 ± 0.26 GPa. In contrast, Steel B exhibited slight cyclic hardening, with H_IT values increasing from 5.24 ± 0.23 to 5.41 ± 0.31 GPa. Furthermore, the martensitic steel demonstrated superior yield and tensile strengths of 1145 and 1870 MPa, respectively. Analysis of the fatigue behaviour revealed the superior fatigue resistance of martensitic steel. The complex morphology and shape of the NMIs, examined using the 3D microstructure characterisation technique, demonstrated their role as stress concentrators, leading to localised plastic deformation and crack initiation. Full article

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

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4 pages, 252 KiB

Open AccessEditorial

Advances in Nanostructured Metallic Materials—A Pathway to Future Innovations

by Marek Wojnicki, Marc Escribà-Gelonch and Volker Hessel

Metals 2024, 14(11), 1237; https://doi.org/10.3390/met14111237 - 29 Oct 2024

Abstract

The development of civilization has always been deeply intertwined with advancements in metallurgy [...] Full article

(This article belongs to the Special Issue Advances in Nanostructured Metallic Materials)

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5 pages, 179 KiB

Open AccessEditorial

Editorial for Special Issue “Casting Alloy Design and Characterization”

by Eleani Maria da Costa and Carlos Alexandre dos Santos

Metals 2024, 14(11), 1236; https://doi.org/10.3390/met14111236 - 29 Oct 2024

Abstract

Solidification, the genesis of metallic materials, is a complex phenomenon encompassing fluid flow, heat transfer, phase transformation, liquid–solid interface, solute redistribution, gas trapping, and others [...] Full article

(This article belongs to the Special Issue Casting Alloy Design and Characterization)

13 pages, 5763 KiB

Open AccessArticle

Variation of Surface Tension of Liquid Metal with Fluorides in Tungsten Inert Gas Welding

by Jinchang Guo, Jianxiao Bian, Jianrui Zhang and Chunkai Li

Metals 2024, 14(11), 1235; https://doi.org/10.3390/met14111235 - 29 Oct 2024

Abstract

Real-time measuring and obtaining surface tension of liquid metal during the arc welding process is critical for studying the behavior of the weld pool, such as Marangoni flow and flow velocity. The dynamic variation of surface tension of weld pool during tungsten inert [...] Read more.

Real-time measuring and obtaining surface tension of liquid metal during the arc welding process is critical for studying the behavior of the weld pool, such as Marangoni flow and flow velocity. The dynamic variation of surface tension of weld pool during tungsten inert gas welding process with and without fluoride flux was measured by weld pool oscillation sensing system, and the effect of fluoride flux on surface tension and pool behavior was analyzed. The results show that the surface tension gradient of liquid metal can convert from a negative to a positive value in a critical arc time. The flow velocity of liquid metal and critical arc time significantly increased and decreased, respectively, with fluoride flux. The variation of surface tension, flow velocity, and critical arc time with fluoride flux was induced by arc temperature increasing. Full article

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13 pages, 5579 KiB

Open AccessArticle

Small Punch Test to Estimate the Threshold Stress in Aggressive Environments by Incremental Step Loading

by Borja Arroyo, Laura Andrea, José A. Álvarez, Sergio Cicero, Federico Gutiérrez-Solana and Luis Abarca

Metals 2024, 14(11), 1234; https://doi.org/10.3390/met14111234 - 29 Oct 2024

Abstract

The present work is a relevant advance in the validation of the incremental step loading technique (ASTM F1624 standard) when applied to Small Punch tests (SPT) for the threshold load determination of medium- and high-strength steels in aggressive environments, as a novel alternative [...] Read more.

The present work is a relevant advance in the validation of the incremental step loading technique (ASTM F1624 standard) when applied to Small Punch tests (SPT) for the threshold load determination of medium- and high-strength steels in aggressive environments, as a novel alternative to conventional time-consuming tests under constant load. It completes previous works by the authors on this topic, extending a methodology to estimate the threshold stress from SPT tests in aggressive environments, covering the whole range of hardness marked by ASTM F1624 as the main goal. This is achieved by calibrating a model of the material’s hardness by the use of a coefficient in function of it. For this purpose, four medium- and high-strength steels of 33, 35, 50 and 60 HRC (Hardness Rockwell C) are exposed to three different cathodic polarization hydrogen embrittlement environments of 1, 5 and 10 mA/cm² in 1N H₂SO₄ acid electrolyte connected to a platinum anode. Threshold stresses in these circumstances are obtained by uniaxial specimens following ASTM F1624 and compared to their homologous threshold loads obtained by Small Punch tests according to the authors’ original methodology proposal. Finally, the aforementioned model, consisting of a correlation based on composing an elastic and a plastic part, is calibrated for a hardness ranging 33–60 HRC, this being the main original contribution of this work; the elastic part is dependent just on the elastic-to-plastic transition SPT load, while the plastic part is ruled by a material hardness-dependent coefficient. This technique supposes an advance in engineering tools, due to its applicability in situations of material shortage, such as in-service components, welded joints, local areas, complex geometries, small thicknesses, etc., often present in aerospace, automotive or oil–gas, among others. Full article

(This article belongs to the Special Issue Fatigue, Creep Behavior and Fracture Mechanics of Metals)

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10 pages, 2131 KiB

Open AccessArticle

Cu Evaporation from Liquid Iron Alloy in Stream

by Galiia Khalimova, Mykyta Levchenko, Hans-Peter Markus, Dariusz Sosin, Thilo Kreschel and Olena Volkova

Metals 2024, 14(11), 1233; https://doi.org/10.3390/met14111233 - 29 Oct 2024

Abstract

The accumulation of copper in steel scrap is becoming an increasingly problematic issue in the steelmaking industry. Accordingly, the present study was undertaken to investigate the removal of copper from a liquid Fe–Cu alloy via tapping under vacuum. Furthermore, the impact of surface-active [...] Read more.

The accumulation of copper in steel scrap is becoming an increasingly problematic issue in the steelmaking industry. Accordingly, the present study was undertaken to investigate the removal of copper from a liquid Fe–Cu alloy via tapping under vacuum. Furthermore, the impact of surface-active components sulfur and oxygen was examined. For this purpose, four Fe–0.5 wt% Cu alloys with varying oxygen and sulfur contents were melted and subsequently poured at a pressure of 100 Pa. The findings indicate that alloys with low oxygen and sulfur content exhibited enhanced copper evaporation. Additionally, the evaporation of other tramp metals, including manganese, phosphorus, and tin, was observed, and the influence of sulfur and oxygen on this process was discussed. Furthermore, the vacuum treatment conditions for copper evaporation in industrial settings were explored. Full article

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18 pages, 9114 KiB

Open AccessArticle

Two-Dimensional X-Ray Diffraction (2D-XRD) and Micro-Computed Tomography (Micro-CT) Characterization of Additively Manufactured 316L Stainless Steel

by Puskar Pathak, Goran Majkic, Timmons Erickson, Tian Chen and Venkat Selvamanickam

Metals 2024, 14(11), 1232; https://doi.org/10.3390/met14111232 - 29 Oct 2024

Abstract

In-depth quality assessment of 3D-printed parts is vital in determining their overall characteristics. This study focuses on the use of 2D X-Ray diffraction (2D-XRD) and X-Ray micro-computed tomography (micro-CT) techniques to evaluate the crystallography and internal defects of 316L SS parts fabricated by [...] Read more.

In-depth quality assessment of 3D-printed parts is vital in determining their overall characteristics. This study focuses on the use of 2D X-Ray diffraction (2D-XRD) and X-Ray micro-computed tomography (micro-CT) techniques to evaluate the crystallography and internal defects of 316L SS parts fabricated by the powder-based direct energy deposition (DED) technique. The test samples were printed in a controlled argon environment with variable laser power and print speeds, using a customized deposition pattern to achieve a high-density print (>99%). Multiple features, including hardness, elastic modulus, porosity, crystallographic orientation, and grain morphology and size were evaluated as a function of print parameters. Micro-CT was used for in-depth internal defect analysis, revealing lack-of-fusion and gas-induced (keyhole) pores and no observable micro-cracks or inclusions in most of the printed body. Some porosity was found mostly concentrated in the initial layers of print and decreased along the build direction. 2D-XRD was used for phase analysis and grain size determination. The phase analysis revealed single phase γ-austenitic FCC phase without any detectable presence of the δ-ferrite phase. A close correlation was found between Electron Backscatter Diffraction (EBSD) and 2D-XRD results on the average size distribution and the crystallographic orientation of grains in the sample. This work demonstrates the fast and reliable as-printed crystallography analysis using 2D-XRD compared to the EBSD technique, with potential for in-line integration. Full article

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17 pages, 9241 KiB

Open AccessArticle

Precipitation–Flotation Process for Molybdenum and Uranium Separation from Wastewater

by Yanfang Huang, Sa Yue, Aohua Li, Hu Sun, Yizhuang Wang, Qunzhen Bu, Bingbing Liu and Guihong Han

Metals 2024, 14(11), 1231; https://doi.org/10.3390/met14111231 - 28 Oct 2024

Abstract

The mining of molybdenum and uranium ores inevitably results in the generation of large volumes of wastewater containing low concentrations of metals, which poses significant threats to the environment. This study presents a novel precipitation–flotation process for the simultaneous separation of molybdenum and [...] Read more.

The mining of molybdenum and uranium ores inevitably results in the generation of large volumes of wastewater containing low concentrations of metals, which poses significant threats to the environment. This study presents a novel precipitation–flotation process for the simultaneous separation of molybdenum and uranium from wastewater. A systematic investigation was conducted on the impacts of the type of precipitant, flotation reagent type, and flotation parameters on the experimental results. Ferric salt served better as a precipitant than aluminum salt and humic acid did, and sodium dodecyl sulfate (SDS) was more suitable than sodium dodecyl benzene sulfonate for acting as a surfactant and foaming agent. Under specific conditions, including a pH of 6.6, an Fe³⁺ dosage of 0.6 mmol·L⁻¹, an SDS dosage of 40 mg·L⁻¹, an air flow rate of 25 mL·min⁻¹, and a flotation time of 10 min, the removal efficiencies of molybdenum and uranium reached 96.6% and 93.6%, respectively. After flotation, the molybdenum concentration, uranium concentration, chemical oxygen demand, and turbidity of the treated water all meet the emission standards. Furthermore, the metal removal mechanisms, including the particle size distribution, functional group structure, surface element composition, microstructure, and element distribution, were elucidated on the basis of characterization of the precipitation–flotation products. Full article

(This article belongs to the Special Issue Separation and Purification of Critical Metals)

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33 pages, 7753 KiB

Open AccessReview

State-of-the-Art Review of the Simulation of Dynamic Recrystallization

by Xin Liu, Jiachen Zhu, Yuying He, Hongbin Jia, Binzhou Li and Gang Fang

Metals 2024, 14(11), 1230; https://doi.org/10.3390/met14111230 - 28 Oct 2024

Abstract

The evolution of microstructures during the hot working of metallic materials determines their workability and properties. Recrystallization is an important softening mechanism in material forming that has been extensively researched in recent decades. This paper comprehensively reviews the basic methods and their applications [...] Read more.

The evolution of microstructures during the hot working of metallic materials determines their workability and properties. Recrystallization is an important softening mechanism in material forming that has been extensively researched in recent decades. This paper comprehensively reviews the basic methods and their applications in numerical simulations of dynamic recrystallization (DRX). The advantages and shortcomings of simulation methods are evaluated. Mean field models are used to implicitly describe the DRX process and are embedded into a finite element (FE) program for forming. These models provide recrystallization volume fraction and average grain size in the FE results without requiring extra computational resources. However, they do not accurately describe the microphysical mechanism, leading to a lower simulation accuracy. On the other hand, full field methods explicitly predict grain topology on a mesoscopic scale, fully considering the microscopic physical mechanism. This enhances the simulation accuracy but requires a significant amount of computational resources. Recently, the coupling of full field methods with polycrystal plasticity models and precipitation models has rapidly developed, considering more influencing factors of recrystallization on a microscale. Furthermore, integration with evolving machine learning methods has the potential to significantly improve the accuracy and efficiency of recrystallization simulation. Full article

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

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20 pages, 14745 KiB

Open AccessArticle

High-Temperature Steam Oxidation and Surface Microstructure Evolution of Fe13Cr6Al(1–4)Mo0.15Y Alloys

by Wen Qi, Yingjie Qiao, Wangwei Ru, Xiaodong Wang, Xiaohong Zhang, Ting Zheng, Shiyu Du, Peng Wang and Kun Yang

Metals 2024, 14(11), 1229; https://doi.org/10.3390/met14111229 - 28 Oct 2024

Abstract

The current study investigated the microstructure evolution and anti-corrosion behavior of low Y doping alloys of Fe13Cr6Al(1–4)Mo0.15Y subjected to high-temperature steam (800 °C to 1300 °C). The results indicate that steam oxidation induces the growth of high-quality oxidation film that is thermodynamically driven, [...] Read more.

The current study investigated the microstructure evolution and anti-corrosion behavior of low Y doping alloys of Fe13Cr6Al(1–4)Mo0.15Y subjected to high-temperature steam (800 °C to 1300 °C). The results indicate that steam oxidation induces the growth of high-quality oxidation film that is thermodynamically driven, with rapid increases in the thickness from 800 °C to 1300 °C without film convolution and spallation. The film convolution and spallation were successfully suppressed through on-site formation of the high-temperature stable ternary crystalline phase (Y₂Mo₃O₁₂) and decreasing of the thickness of α-Al₂O₃ oxidation film during the fabrication and oxidation scenario. The on-site steam oxidation rate has been significantly suppressed, with lower weight gain and less oxidizing film convolution than monolithic FeCrAlMo alloy, through the addition of a low concentration of Y. Full article

(This article belongs to the Special Issue Manufacture, Properties and Applications of Advanced Nuclear Alloys)

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17 pages, 6228 KiB

Open AccessArticle

A Transition State Theory-Based Continuum Plasticity Model Accounting for the Local Stress Fluctuation

by Yongjia Zheng, Hongwei Wang, Xiangyu Zhou, Ding Tang, Huamiao Wang, Guoliang Wang, Peidong Wu, Yinghong Peng and Yaodong Jiang

Metals 2024, 14(11), 1228; https://doi.org/10.3390/met14111228 - 27 Oct 2024

Abstract

Based on the transition state theory, a continuum plasticity theory is developed for metallic materials. Moreover, the nature of local stress fluctuation within a material point is considered by incorporating the probability distribution of the stresses. The model is applied to investigate the [...] Read more.

Based on the transition state theory, a continuum plasticity theory is developed for metallic materials. Moreover, the nature of local stress fluctuation within a material point is considered by incorporating the probability distribution of the stresses. The model is applied to investigate the mechanical behaviors of 316 L stainless steel under various loading cases. The simulated results closely match the results obtained by the polycrystal plasticity model and experiments. The mechanical behaviors associated with strain rate sensitivity, temperature dependence, stress relaxation, and strain creep are correctly captured by the model. Furthermore, the proposed model successfully characterizes the Bauschinger effect, which is challenging to capture with a conventional continuum model without additional assumptions. The proposed model could be further employed in the design, manufacturing, and service of engineering components. Full article

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

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20 pages, 6687 KiB

Open AccessArticle

Ajuga orientalis L. Extract as a Green Corrosion Inhibitor of Aluminum in an Acidic Solution: An Experimental and DFT Study

by Faten M. Abu Orabi, Sultan T. Abu-Orabi, Omaima A. Fodeh, Faisal K. Algethami, Abdel Monem M. Rawashdeh, Tareq T. Bataineh, Ghassab M. Al-Mazaideh and Mahmoud A. Al-Qudah

Metals 2024, 14(11), 1227; https://doi.org/10.3390/met14111227 - 27 Oct 2024

Abstract

The inhibitory effect of A. orientalis L. extract (AO) on aluminum corrosion in a 1.0 M HCl solution was investigated utilizing weight loss, electrochemical polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The results show that AO is a potent inhibitor [...] Read more.

The inhibitory effect of A. orientalis L. extract (AO) on aluminum corrosion in a 1.0 M HCl solution was investigated utilizing weight loss, electrochemical polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The results show that AO is a potent inhibitor in an acidic environment, and that the inhibition potency increases with concentration. Temperature investigations showed that, in an acidic medium, the efficiency decreased, increased, and then decreased as the temperature rose. Adsorption isotherms from Freundlich, Temkin, El Awady, and Redlich–Peterson (R-P) approximated the inhibitor’s adsorption properties. For the inhibitory behavior, a physical and chemical adsorption mechanism is proposed. The adsorption process’s thermodynamic parameters (Ea, ΔH*, and ΔS*) were determined and explained. The inhibitor, AO, was identified as a mixed-type (anodic and cathodic) inhibitor based on polarization studies. According to the SEM findings, the inhibitor partially covers the metal surface, providing it with a respectable level of protection. The weight loss, electrochemical polarization, EIS, scanning electron microscopy (SEM), and quantum chemical calculations show a strong agreement, indicating that the AO extract is a highly effective inhibitor of aluminum in an acidic solution. Full article

(This article belongs to the Special Issue Advances in Corrosion and Protection of Materials (Second Edition))

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16 pages, 9293 KiB

Open AccessArticle

Microstructure and Properties of 7050-T74 Aluminum Alloys with Different Zn/Mg Ratios

by Daihong Xiao, Zongzheng He and Lanping Huang

Metals 2024, 14(11), 1226; https://doi.org/10.3390/met14111226 - 27 Oct 2024

Abstract

Aluminum alloy 7050-T74 with varying zinc-to-magnesium (Zn/Mg) mass fractions was synthesized using melt casting and hot extrusion techniques. This study investigated the influence of different Zn/Mg ratios on the microstructure, mechanical properties, and corrosion resistance of the alloy. Light microscopy, scanning electron microscopy [...] Read more.

Aluminum alloy 7050-T74 with varying zinc-to-magnesium (Zn/Mg) mass fractions was synthesized using melt casting and hot extrusion techniques. This study investigated the influence of different Zn/Mg ratios on the microstructure, mechanical properties, and corrosion resistance of the alloy. Light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile testing, and corrosion testing were employed as analytical methods. The findings indicate that as the Zn/Mg ratio increases from 2.36 to 3.84, the proportion of low-angle boundaries (LABs) within the alloys initially rises and then decreases, achieving a balance between high strength and favorable elongation. Specifically, at a Zn/Mg ratio of 2.72, the alloy exhibits a tensile strength of 641 MPa, a yield strength of 609 MPa, and an elongation of 10.1%. Additionally, increasing the Zn/Mg ratio to 2.90 slightly reduces intergranular corrosion resistance while enhancing exfoliation corrosion resistance. Full article

(This article belongs to the Section Metal Casting, Forming and Heat Treatment)

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