Nathalia Sartori da Silva, Aila Cossovan Alves, Jaine Aparecida da Silva Pereira, Leandro Antonio de Oliveira, Mara Cristina Lopes de Oliveira, Renato Altobelli Antunes
In the present work, the corrosion properties and the surface chemistry of a graphene oxide-coated AZ91D alloy were investigated. The coatings were deposited on the substrate specimens by immersion in solutions with GO concentrations of 0.05% and 0.1% (m/v). An intermediate silane layer was firstly obtained to improve adhesion between the GO films and the AZ91D substrate. The electrochemical behavior of the coated specimens was assessed using electrochemical impedance spectroscopy and potentiodynamic polarization curves in 3.5 wt.% NaCl solution. The surface chemistry was assessed using X-ray photoelectron spectroscopy (XPS). The GO films consisted of a mixture of carbon-based bonds (C-C, C-OH, C=O, and O-C=O). The surface morphology of the coated specimens was examined using scanning electron microscopy. The results revealed that the compactness of the GO films was dependent on the deposition conditions. The corrosion resistance was affected by the surface morphology.
本研究调查了氧化石墨烯涂层 AZ91D 合金的腐蚀性能和表面化学性质。涂层通过浸泡在浓度为 0.05% 和 0.1% （m/v）的 GO 溶液中沉积在基体试样上。为了提高 GO 薄膜与 AZ91D 基材之间的附着力，首先获得了中间硅烷层。在 3.5 wt.% 的 NaCl 溶液中，使用电化学阻抗光谱和电位极化曲线对涂覆试样的电化学行为进行了评估。利用 X 射线光电子能谱（XPS）对表面化学性质进行了评估。GO 薄膜由碳键（C-C、C-OH、C=O 和 O-C=O）混合物组成。使用扫描电子显微镜检查了涂覆试样的表面形态。结果表明，GO 薄膜的致密性取决于沉积条件。耐腐蚀性受表面形态的影响。
{"title":"Corrosion Properties and Surface Chemistry of Graphene Oxide-Coated AZ91D Magnesium Alloy in Sodium Chloride Solution","authors":"Nathalia Sartori da Silva, Aila Cossovan Alves, Jaine Aparecida da Silva Pereira, Leandro Antonio de Oliveira, Mara Cristina Lopes de Oliveira, Renato Altobelli Antunes","doi":"10.3390/met14091019","DOIUrl":"https://doi.org/10.3390/met14091019","url":null,"abstract":"In the present work, the corrosion properties and the surface chemistry of a graphene oxide-coated AZ91D alloy were investigated. The coatings were deposited on the substrate specimens by immersion in solutions with GO concentrations of 0.05% and 0.1% (m/v). An intermediate silane layer was firstly obtained to improve adhesion between the GO films and the AZ91D substrate. The electrochemical behavior of the coated specimens was assessed using electrochemical impedance spectroscopy and potentiodynamic polarization curves in 3.5 wt.% NaCl solution. The surface chemistry was assessed using X-ray photoelectron spectroscopy (XPS). The GO films consisted of a mixture of carbon-based bonds (C-C, C-OH, C=O, and O-C=O). The surface morphology of the coated specimens was examined using scanning electron microscopy. The results revealed that the compactness of the GO films was dependent on the deposition conditions. The corrosion resistance was affected by the surface morphology.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ningning Li, Zhenjie Hao, Lei Xu, Mingqi Tang, Leyu Wei, Lifei Wang
Ti-Al-based alloys, particularly two-phase TiAl and Ti3Al alloys, have garnered significant attention as potential replacements for various high-temperature structural materials due to their exceptional properties, including low density, oxidation resistance, and high strength at elevated temperatures. Despite these advantages, experimental studies on the microstructure evolution of Ti-Al-based alloys under complex conditions remain challenging to observe and characterize. This review article examines the current research on molecular dynamics (MD) simulations of Ti-Al-based alloys, focusing on two-phase Ti-Al alloys, Ti-Al amorphous alloys, Ti-Al composite materials, and the welding and multi-layer/film applications of Ti-Al alloys. This review highlights the unique capabilities of MD simulations in predicting the behavior of Ti-Al-based alloys and addresses existing scientific challenges. Furthermore, this article discusses future research directions and development prospects in this field.
{"title":"A Review of Molecular Dynamics Simulation of Different Ti-Al-Based Alloys","authors":"Ningning Li, Zhenjie Hao, Lei Xu, Mingqi Tang, Leyu Wei, Lifei Wang","doi":"10.3390/met14091018","DOIUrl":"https://doi.org/10.3390/met14091018","url":null,"abstract":"Ti-Al-based alloys, particularly two-phase TiAl and Ti3Al alloys, have garnered significant attention as potential replacements for various high-temperature structural materials due to their exceptional properties, including low density, oxidation resistance, and high strength at elevated temperatures. Despite these advantages, experimental studies on the microstructure evolution of Ti-Al-based alloys under complex conditions remain challenging to observe and characterize. This review article examines the current research on molecular dynamics (MD) simulations of Ti-Al-based alloys, focusing on two-phase Ti-Al alloys, Ti-Al amorphous alloys, Ti-Al composite materials, and the welding and multi-layer/film applications of Ti-Al alloys. This review highlights the unique capabilities of MD simulations in predicting the behavior of Ti-Al-based alloys and addresses existing scientific challenges. Furthermore, this article discusses future research directions and development prospects in this field.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lianqian Liu, Peng Chen, Ming Liu, Guodong Wang, Hongliang Yi
Maraging steels hardened by Cu + NiAl precipitation have recently garnered attention owing to their relatively low cost and exceptionally high strength. However, the high alloy content can cause issues such as solidification cracking, particularly in mass production. In this study, solidification cracking was observed in a Cu + NiAl-hardened maraging steel manufactured via an electroslag remelting process, and an improvement strategy was adopted to solve this problem. Increasing the aluminum content from 1.0 wt.% to 1.2 wt.% can adjust the δ ferrite, which affects the thermal expansion coefficient and density of the system, thereby reducing the rate of cooling shrinkage. The extra addition of 0.2 wt.% aluminum had a negligible effect on the final microstructure and mechanical properties, with both steels demonstrating excellent tensile properties. The reduction in internal stress from the increased aluminum content was also confirmed using X-ray diffraction (XRD) measurement and the finite element method (FEM). This strategy provides valuable insights for the manufacturing of such high-alloy steels on a mass production scale.
通过 Cu + NiAl 沉淀硬化的马氏体时效钢因其相对较低的成本和极高的强度最近备受关注。然而，高合金含量可能会导致凝固开裂等问题，尤其是在大规模生产中。在本研究中，通过电渣重熔工艺制造的 Cu + NiAl 硬化马氏体时效钢出现了凝固开裂现象，并采用了改进策略来解决这一问题。将铝含量从 1.0 wt.% 提高到 1.2 wt.%，可调整 δ 铁素体，从而影响体系的热膨胀系数和密度，降低冷却收缩率。额外添加 0.2 wt.%的铝对最终微观结构和机械性能的影响微乎其微，两种钢材都表现出优异的拉伸性能。通过 X 射线衍射 (XRD) 测量和有限元法 (FEM) 也证实了铝含量的增加会降低内应力。这一策略为大规模生产此类高合金钢提供了宝贵的启示。
{"title":"Solving the Solidification Cracking in Maraging Steel during Mass Production by Adjusting High-Temperature Delta Ferrite","authors":"Lianqian Liu, Peng Chen, Ming Liu, Guodong Wang, Hongliang Yi","doi":"10.3390/met14091020","DOIUrl":"https://doi.org/10.3390/met14091020","url":null,"abstract":"Maraging steels hardened by Cu + NiAl precipitation have recently garnered attention owing to their relatively low cost and exceptionally high strength. However, the high alloy content can cause issues such as solidification cracking, particularly in mass production. In this study, solidification cracking was observed in a Cu + NiAl-hardened maraging steel manufactured via an electroslag remelting process, and an improvement strategy was adopted to solve this problem. Increasing the aluminum content from 1.0 wt.% to 1.2 wt.% can adjust the δ ferrite, which affects the thermal expansion coefficient and density of the system, thereby reducing the rate of cooling shrinkage. The extra addition of 0.2 wt.% aluminum had a negligible effect on the final microstructure and mechanical properties, with both steels demonstrating excellent tensile properties. The reduction in internal stress from the increased aluminum content was also confirmed using X-ray diffraction (XRD) measurement and the finite element method (FEM). This strategy provides valuable insights for the manufacturing of such high-alloy steels on a mass production scale.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jae-Ook Jeon, Ye-Sol Yun, Moo-Keun Song, Pyeong-Soo Kim, Jong-Do Kim
This study aims to investigate the effect of the laser beam overlap rate on the mechanical properties of Al3003 aluminum alloy arc weldment with laser peening. To determine the optimal laser beam overlap rate for laser peening of the weldment, peening experiments were conducted on bead-welded and butt-welded specimens with varying overlap rates, and the effect of the beam overlap rate was analyzed. As the overlap rate increased, the residual stress changed from tensile to compressive, with the highest level of compressive residual stress at the overlap rate of 75%. Laser peening was performed on the aluminum weldment of the prototype, applying the optimal peening conditions identified earlier. As a result of comparing the residual stress, hardness, and tensile strength of the weld before and after laser peening, it was found that the tensile residual stress in the weldment was improved to a compressive residual stress of about −50 MPa or more. The hardness and tensile strength of the weld increased after peening, and the mechanical properties were also improved.
{"title":"Effect of Laser Beam Overlap Rate on Mechanical Properties of Aluminum Alloy Arc Welding with Laser Peening","authors":"Jae-Ook Jeon, Ye-Sol Yun, Moo-Keun Song, Pyeong-Soo Kim, Jong-Do Kim","doi":"10.3390/met14091021","DOIUrl":"https://doi.org/10.3390/met14091021","url":null,"abstract":"This study aims to investigate the effect of the laser beam overlap rate on the mechanical properties of Al3003 aluminum alloy arc weldment with laser peening. To determine the optimal laser beam overlap rate for laser peening of the weldment, peening experiments were conducted on bead-welded and butt-welded specimens with varying overlap rates, and the effect of the beam overlap rate was analyzed. As the overlap rate increased, the residual stress changed from tensile to compressive, with the highest level of compressive residual stress at the overlap rate of 75%. Laser peening was performed on the aluminum weldment of the prototype, applying the optimal peening conditions identified earlier. As a result of comparing the residual stress, hardness, and tensile strength of the weld before and after laser peening, it was found that the tensile residual stress in the weldment was improved to a compressive residual stress of about −50 MPa or more. The hardness and tensile strength of the weld increased after peening, and the mechanical properties were also improved.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interface dislocation networks have a great influence on the mechanical properties of the new Ni-based single-crystal alloy (NSC) containing Re, but it is difficult to find out the structural evolution behaviors at the micro-level. Thus, molecular dynamics (MD) simulation is used to analyze the atomic potential energy change and dislocation evolution mechanism, and non-linear characteristic parameters are used to analyze the microstructure evolution of NSC. First, a new model of Ni-Al-Re that is closer to the real properties of the material is established using the MD method according to the optimal volume ratio of matrix phase to precipitate phase. Then, the MD models of NSC with different contents of Re are calculated and analyzed under compressive and tensile loads. The results show that with an increase in Re atoms, the atomic potential energy at the interface dislocation networks is reduced; thus, the stability of the system is enhanced, and the hindrance of the interface dislocation networks to the dislocation movement of the matrix phase is strengthened. At the same time, the number of HCP structures and OISs formed by the destruction of the intact FCC structures also decreases. In the non-linear ultrasonic experiment, with the increase in Re atoms, the non-linear enhancement of the microstructure of the NSC leads to an increase in the corresponding non-linear characteristic parameters. Accordingly, the microstructural evolution behaviors of the phase interface of the new NSC can be effectively explored using the combination of MD simulation and non-linear ultrasonic experimentation. The results of this study lay a foundation for the subsequent research of the microscopic defects of NSCs by using ultrasonic phased-array technology.
界面位错网络对含有 Re 的新型镍基单晶合金（NSC）的力学性能有很大影响，但很难在微观层面上发现其结构演变行为。因此，采用分子动力学（MD）模拟分析原子势能变化和位错演化机理，并利用非线性特征参数分析 NSC 的微观结构演化。首先，根据基体相与析出相的最佳体积比，利用 MD 方法建立了更接近材料真实属性的 Ni-Al-Re 新模型。然后，计算并分析了不同 Re 含量的 NSC 在压缩和拉伸载荷下的 MD 模型。结果表明，随着 Re 原子含量的增加，界面位错网络的原子势能降低，从而提高了体系的稳定性，加强了界面位错网络对基体相位错运动的阻碍作用。同时，由完整的 FCC 结构破坏而形成的 HCP 结构和 OIS 的数量也会减少。在非线性超声实验中，随着 Re 原子的增加，NSC 微观结构的非线性增强导致相应的非线性特征参数增加。因此，结合 MD 模拟和非线性超声实验，可以有效地探索新型 NSC 相界面的微结构演化行为。该研究结果为后续利用超声相控阵技术研究 NSC 的微观缺陷奠定了基础。
{"title":"Research on Microstructural Evolution Behavior of Ni-Based Single-Crystal Alloy with Re Based on Non-Linear Ultrasonic Lamb Wave and Molecular Dynamics Method","authors":"Ben Li, Yilin Zhang, Hongyan Zhou, Xuewu Li","doi":"10.3390/met14091016","DOIUrl":"https://doi.org/10.3390/met14091016","url":null,"abstract":"Interface dislocation networks have a great influence on the mechanical properties of the new Ni-based single-crystal alloy (NSC) containing Re, but it is difficult to find out the structural evolution behaviors at the micro-level. Thus, molecular dynamics (MD) simulation is used to analyze the atomic potential energy change and dislocation evolution mechanism, and non-linear characteristic parameters are used to analyze the microstructure evolution of NSC. First, a new model of Ni-Al-Re that is closer to the real properties of the material is established using the MD method according to the optimal volume ratio of matrix phase to precipitate phase. Then, the MD models of NSC with different contents of Re are calculated and analyzed under compressive and tensile loads. The results show that with an increase in Re atoms, the atomic potential energy at the interface dislocation networks is reduced; thus, the stability of the system is enhanced, and the hindrance of the interface dislocation networks to the dislocation movement of the matrix phase is strengthened. At the same time, the number of HCP structures and OISs formed by the destruction of the intact FCC structures also decreases. In the non-linear ultrasonic experiment, with the increase in Re atoms, the non-linear enhancement of the microstructure of the NSC leads to an increase in the corresponding non-linear characteristic parameters. Accordingly, the microstructural evolution behaviors of the phase interface of the new NSC can be effectively explored using the combination of MD simulation and non-linear ultrasonic experimentation. The results of this study lay a foundation for the subsequent research of the microscopic defects of NSCs by using ultrasonic phased-array technology.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhongxue He, Jianying Wang, Mengzhen Zhu, Tao Wen, Feipeng Yang, Shouxun Ji, Jianming Zheng, Ling Shan, Hailin Yang
In the present study, the densification behavior, microstructural evolution, mechanical properties, and friction behavior of a TiB2/Al8SiCu composite and Al8SiCu alloy manufactured by laser powder-bed fusion (PBF-LB) were systematically investigated. The results confirm that the addition of in situ TiB2 particles into Al8SiCu alloys reduce the volumetric energy density required for a high-density TiB2/Al8SiCu composite. The TiB2 particles promoted a transformation of columnar to equiaxed crystals and the formation of high-angle grain boundaries. The grains on the vertical direction of the PBF-LBed TiB2/Al8SiCu composite were much finer than those of the PBF-LBed Al8SiCu alloy. The addition of TiB2 promoted the grain refinement of the Al8SiCu alloy, of which the average grain size decreased from 15.31 μm to 7.34 μm. The yield strength (YS), ultimate tensile strength (UTS), and elongation (El) of the PBF-LBed Al8SiCu alloy were 296 ± 6 MPa, 517 ± 6 MPa, and 11.7 ± 1.0%, respectively. The PBF-LBed TiB2/Al8SiCu composite achieved a balance between strength and ductility with a yield strength of 328 ± 8 MPa, an ultimate tensile strength of 541 ± 3 MPa, and an elongation of 9.1 ± 0.7%. The increase in strength mainly resulted from grain boundary strengthening, dislocation strengthening, load-bearing strengthening, solid-solution strengthening, and Orowan strengthening, of which the dislocation strengthening and Orowan strengthening were critical. The enhanced hardness associated with the grain refinement and the formation of the in situ TiB2 particles also led to an enhanced tribological performance, of which reductions in the average friction coefficient from 0.655 to 0.580 and wear rate from 1.76 × 10−3 mm3/Nm to 1.38 × 10−3 mm3/Nm were found.
{"title":"Effects of In Situ TiB2 on the Microstructural Evolution, Mechanical Properties, and Friction Behavior of the Al-Si-Cu Alloys Processed by Laser Powder-Bed Fusion","authors":"Zhongxue He, Jianying Wang, Mengzhen Zhu, Tao Wen, Feipeng Yang, Shouxun Ji, Jianming Zheng, Ling Shan, Hailin Yang","doi":"10.3390/met14091015","DOIUrl":"https://doi.org/10.3390/met14091015","url":null,"abstract":"In the present study, the densification behavior, microstructural evolution, mechanical properties, and friction behavior of a TiB2/Al8SiCu composite and Al8SiCu alloy manufactured by laser powder-bed fusion (PBF-LB) were systematically investigated. The results confirm that the addition of in situ TiB2 particles into Al8SiCu alloys reduce the volumetric energy density required for a high-density TiB2/Al8SiCu composite. The TiB2 particles promoted a transformation of columnar to equiaxed crystals and the formation of high-angle grain boundaries. The grains on the vertical direction of the PBF-LBed TiB2/Al8SiCu composite were much finer than those of the PBF-LBed Al8SiCu alloy. The addition of TiB2 promoted the grain refinement of the Al8SiCu alloy, of which the average grain size decreased from 15.31 μm to 7.34 μm. The yield strength (YS), ultimate tensile strength (UTS), and elongation (El) of the PBF-LBed Al8SiCu alloy were 296 ± 6 MPa, 517 ± 6 MPa, and 11.7 ± 1.0%, respectively. The PBF-LBed TiB2/Al8SiCu composite achieved a balance between strength and ductility with a yield strength of 328 ± 8 MPa, an ultimate tensile strength of 541 ± 3 MPa, and an elongation of 9.1 ± 0.7%. The increase in strength mainly resulted from grain boundary strengthening, dislocation strengthening, load-bearing strengthening, solid-solution strengthening, and Orowan strengthening, of which the dislocation strengthening and Orowan strengthening were critical. The enhanced hardness associated with the grain refinement and the formation of the in situ TiB2 particles also led to an enhanced tribological performance, of which reductions in the average friction coefficient from 0.655 to 0.580 and wear rate from 1.76 × 10−3 mm3/Nm to 1.38 × 10−3 mm3/Nm were found.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study explores the effects of Zn addition through micro-alloying on the microstructure and discharge performance of Mg-Al-Mn-Ca alloy anodes for magnesium-air batteries. The results show that the second-phase particles (d > 1 μm) in a Mg-Al-Mn-Ca alloy promote dynamic recrystallization (DRX) via particle-stimulated nucleation (PSN), resulting in a uniform equiaxed grain structure and fiber texture. In contrast, Zn and Ca co-segregation in a Mg-Al-Mn-Ca-Zn alloy facilitates continuous dynamic recrystallization (CDRX) and, combined with the PSN mechanism, forms a unique structure where three types of grains with different grain boundary densities coexist. The addition of Zn and Ca effectively reduces the c/a axis ratio, promoting texture homogenization. The Mg-Al-Mn-Ca alloy exhibits rough discharge surfaces due to simultaneous discharge at numerous grain boundaries and severe hydrogen evolution corrosion from micro-galvanic effects, inducing the chunk effect (CE). Conversely, the structure where three types of grains with different grain boundary densities coexist in the Mg-Al-Mn-Ca-Zn alloy promotes discharge product detachment through stress cracking, achieving uniform discharge and significantly enhancing discharge performance. The uniform texture reduces hydrogen evolution corrosion, improving anode utilization. This study demonstrates that controlling the microstructure, particularly grain boundary density and grain texture, enables the development of high-performance Mg-Al-Mn-Ca-Zn alloy anodes, especially at higher current densities, offering a new strategy for designing efficient magnesium alloy anode materials.
{"title":"Effect of Zn Addition on the Microstructure and Discharge Performance of Mg-Al-Mn-Ca Alloys for Magnesium-Air Batteries","authors":"Yiwei Gong, Kezheng Wei, Wenlong Jiang, Chongchen Xiang, Hanlin Ding, Zijian Wang","doi":"10.3390/met14091014","DOIUrl":"https://doi.org/10.3390/met14091014","url":null,"abstract":"This study explores the effects of Zn addition through micro-alloying on the microstructure and discharge performance of Mg-Al-Mn-Ca alloy anodes for magnesium-air batteries. The results show that the second-phase particles (d > 1 μm) in a Mg-Al-Mn-Ca alloy promote dynamic recrystallization (DRX) via particle-stimulated nucleation (PSN), resulting in a uniform equiaxed grain structure and fiber texture. In contrast, Zn and Ca co-segregation in a Mg-Al-Mn-Ca-Zn alloy facilitates continuous dynamic recrystallization (CDRX) and, combined with the PSN mechanism, forms a unique structure where three types of grains with different grain boundary densities coexist. The addition of Zn and Ca effectively reduces the c/a axis ratio, promoting texture homogenization. The Mg-Al-Mn-Ca alloy exhibits rough discharge surfaces due to simultaneous discharge at numerous grain boundaries and severe hydrogen evolution corrosion from micro-galvanic effects, inducing the chunk effect (CE). Conversely, the structure where three types of grains with different grain boundary densities coexist in the Mg-Al-Mn-Ca-Zn alloy promotes discharge product detachment through stress cracking, achieving uniform discharge and significantly enhancing discharge performance. The uniform texture reduces hydrogen evolution corrosion, improving anode utilization. This study demonstrates that controlling the microstructure, particularly grain boundary density and grain texture, enables the development of high-performance Mg-Al-Mn-Ca-Zn alloy anodes, especially at higher current densities, offering a new strategy for designing efficient magnesium alloy anode materials.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Palladium (Pd) and its alloys, renowned for their good corrosion resistance, catalytic efficiency, and hydrogen affinity, find extensive use in various industrial applications. However, the susceptibility of pure Pd to hydrogen embrittlement necessitates alloying strategies such as Pd-Ag systems. This study investigates the impact of the ordering on the phase stability and elastic properties of Pd-Ag alloys through first-principles calculations. We explore a series of ordered phase structures alongside random solid solutions using Special Quasirandom Structures (SQSs), evaluating their thermodynamic stability and elastic properties. Our findings indicate the possible existence of stable ordered L12 Pd3Ag and PdAg3 and L11 PdAg phases, which are thought to exist only in Cu-Pt alloys. An analysis of the elastic constants and anisotropy indices underscores some pronounced directional dependencies in the mechanical responses between the random solid-solution and ordered phases. This suggests that the ordered phases not only are thermodynamically and mechanically more stable than solid-solution phases, but also display a decrease in anisotropy indices. The results provide a deeper understanding of the atomic behavior of Pd-Ag alloys, and shed light on the design of multiphase Pd-Ag alloys to improve their mechanical properties.
{"title":"Effect of Atomic Ordering on Phase Stability and Elastic Properties of Pd-Ag Alloys","authors":"Xiaoli Chen, Guangxiong Luo, Yuxuan Cao, Chaoping Liang","doi":"10.3390/met14091017","DOIUrl":"https://doi.org/10.3390/met14091017","url":null,"abstract":"Palladium (Pd) and its alloys, renowned for their good corrosion resistance, catalytic efficiency, and hydrogen affinity, find extensive use in various industrial applications. However, the susceptibility of pure Pd to hydrogen embrittlement necessitates alloying strategies such as Pd-Ag systems. This study investigates the impact of the ordering on the phase stability and elastic properties of Pd-Ag alloys through first-principles calculations. We explore a series of ordered phase structures alongside random solid solutions using Special Quasirandom Structures (SQSs), evaluating their thermodynamic stability and elastic properties. Our findings indicate the possible existence of stable ordered L12 Pd3Ag and PdAg3 and L11 PdAg phases, which are thought to exist only in Cu-Pt alloys. An analysis of the elastic constants and anisotropy indices underscores some pronounced directional dependencies in the mechanical responses between the random solid-solution and ordered phases. This suggests that the ordered phases not only are thermodynamically and mechanically more stable than solid-solution phases, but also display a decrease in anisotropy indices. The results provide a deeper understanding of the atomic behavior of Pd-Ag alloys, and shed light on the design of multiphase Pd-Ag alloys to improve their mechanical properties.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Standard AA5083 (ZSE000), AA5083 modified with 0.3 wt.% Zr and 0.3wt.% Sc (ZSE330) and AA5083 modified with 0.3 wt.% Zr, 0.2wt.% Sc and 0.1wt.%Er(ZSE321) sheets were fabricated through a short process (including a simulated twin-belt continuous casting, subsequent direct rolling, intermediate annealing, cold rolling and stress-relief annealing) to systematically investigate the influence of partially substituting Er for Sc on the microstructure, mechanical properties and corrosion resistance of short-processed Al-4.7Mg-0.6Mn-0.3Zr-0.3Sc sheets. The results show that ZSE321 presents the optimal tensile properties (UTS: 541 MPa; 0.2%PS: 469 MPa and EF:7.7%) among the three experimental sheets. This is attributed to significant grain refinement, the inhibition of the recrystallization and promotion on the precipitation of Al3(Sc, Zr, Er) nanoparticles. Furthermore, the corrosion properties of the experimental sheets were also explored in this study, and the short-processed ZSE321 sheet presents the optimum corrosion resistance.
{"title":"Influence of Partial Er Substitution for Sc on the Microstructure, Mechanical Properties and Corrosion Resistance of Short-Processed Al-4.7Mg-0.6Mn-0.3Zr-0.3Sc Sheets","authors":"Guangxi Lu, Yabo Liang, Cong Xu, Wenfei Rao, Yaodong Xue, Longfei Li, Li Zhang, Shaokang Guan","doi":"10.3390/met14091013","DOIUrl":"https://doi.org/10.3390/met14091013","url":null,"abstract":"Standard AA5083 (ZSE000), AA5083 modified with 0.3 wt.% Zr and 0.3wt.% Sc (ZSE330) and AA5083 modified with 0.3 wt.% Zr, 0.2wt.% Sc and 0.1wt.%Er(ZSE321) sheets were fabricated through a short process (including a simulated twin-belt continuous casting, subsequent direct rolling, intermediate annealing, cold rolling and stress-relief annealing) to systematically investigate the influence of partially substituting Er for Sc on the microstructure, mechanical properties and corrosion resistance of short-processed Al-4.7Mg-0.6Mn-0.3Zr-0.3Sc sheets. The results show that ZSE321 presents the optimal tensile properties (UTS: 541 MPa; 0.2%PS: 469 MPa and EF:7.7%) among the three experimental sheets. This is attributed to significant grain refinement, the inhibition of the recrystallization and promotion on the precipitation of Al3(Sc, Zr, Er) nanoparticles. Furthermore, the corrosion properties of the experimental sheets were also explored in this study, and the short-processed ZSE321 sheet presents the optimum corrosion resistance.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The solidification structure characteristics are decisive for the production of extra-thick slabs. This study developed a solidification heat transfer model and a cellular automaton–finite element coupled model to investigate the solidification behavior and structure characteristics of a 475 mm extra-thick slab. The models were applied under various continuous casting process parameters and different alloy element content. The simulation results reveal that casting speed has the most significant effect on the solidification behavior of extra-thick slabs, surpassing the impact of specific water flow and superheat. The solidification structure characteristics of the 475 mm extra-thick slabs were investigated under various conditions. The findings indicate that at higher casting speeds and superheats, the average grain size increases and the grain number decreases. The average grain size initially decreases and then increases with the rise in specific water flow, reaching its minimum at approximately 0.17 L·kg−1. Additionally, the average grain radius first decreases and then slightly increases with an increase in carbon content, achieving the minimum value of about 0.17% carbon. Compared with carbon and manganese, silicon has a greater impact on the solidification structure of ultra-thick slabs, and a moderate increase in silicon content can effectively refine the grain size. This study provides a theoretical foundation for understanding the changes in solidification structure characteristics and optimizing continuous casting process parameters for 475 mm extra-thick slabs.
{"title":"Investigation on the Solidification Structure of Q355 in 475 mm Extra-Thick Slabs Adopting Cellular Automaton-Finite Element Model","authors":"Kezai Yu, Minglin Wang, Haihan Fan, Zhonghua Zhan, Zixiang Ren, Lijun Xu","doi":"10.3390/met14091012","DOIUrl":"https://doi.org/10.3390/met14091012","url":null,"abstract":"The solidification structure characteristics are decisive for the production of extra-thick slabs. This study developed a solidification heat transfer model and a cellular automaton–finite element coupled model to investigate the solidification behavior and structure characteristics of a 475 mm extra-thick slab. The models were applied under various continuous casting process parameters and different alloy element content. The simulation results reveal that casting speed has the most significant effect on the solidification behavior of extra-thick slabs, surpassing the impact of specific water flow and superheat. The solidification structure characteristics of the 475 mm extra-thick slabs were investigated under various conditions. The findings indicate that at higher casting speeds and superheats, the average grain size increases and the grain number decreases. The average grain size initially decreases and then increases with the rise in specific water flow, reaching its minimum at approximately 0.17 L·kg−1. Additionally, the average grain radius first decreases and then slightly increases with an increase in carbon content, achieving the minimum value of about 0.17% carbon. Compared with carbon and manganese, silicon has a greater impact on the solidification structure of ultra-thick slabs, and a moderate increase in silicon content can effectively refine the grain size. This study provides a theoretical foundation for understanding the changes in solidification structure characteristics and optimizing continuous casting process parameters for 475 mm extra-thick slabs.","PeriodicalId":18461,"journal":{"name":"Metals","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142184943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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