Chen Ji , Liang Zhu , Bangzhao Yin , Shengwen Bai , Lawrence E. Murr , Peng Wen , Bin Jiang , Fusheng Pan , Kun Li
{"title":"激光粉末床熔敷WE43非均晶合金的变形与断裂机制","authors":"Chen Ji , Liang Zhu , Bangzhao Yin , Shengwen Bai , Lawrence E. Murr , Peng Wen , Bin Jiang , Fusheng Pan , Kun Li","doi":"10.1016/j.jallcom.2025.181288","DOIUrl":null,"url":null,"abstract":"<div><div>Laser powder bed fusion (LPBF), as an emerging advanced metal manufacturing technology, alters the microstructural characteristics of Mg alloys through its unique non-equilibrium solidification effects, thereby influencing their mechanical responses, especially at high temperatures. In this context, this study characterizes the microstructure and temperature-dependent quasi-static tensile behavior of laser powder bed fused (LPBFed) WE43 alloy. The inherent remelting and thermal cycling processes of LPBF lead to the in-situ precipitation of β′, β<sub>1</sub>, and β phases, as well as the formation of a bimodal grain structure, resulting in unique high-temperature mechanical properties. High-temperature tensile tests show that the LPBFed WE43 alloy maintains good strength at 200–250°C, but its tensile strength significantly decreases at 300°C. Additionally, the LPBFed WE43 alloy exhibits anomalous elongation at 250°C. EBSD technology was used to systematically further reveal the unique deformation mechanisms of the LPBFed WE43 alloy. The results indicate that the presence of various dispersed in-situ precipitates, which act as nucleation sites for recrystallization, leads to recrystallization being the primary deformation mode of the LPBFed WE43 alloy during high-temperature tensile testing at 200–300°C. Simultaneously, the existence of these dispersed precipitates also restricts the formation of twins. During this process, both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) occur simultaneously, with DDRX becoming dominant as the temperature increases. Moreover, significant stress concentration is observed only at 250°C, which is responsible for the anomalous elongation and the activation of pyramidal II<c+a> slip. At 300°C, the grain boundary strength of fine grains significantly decreases, leading to pronounced grain boundary sliding (GBS). GBS greatly alleviates stress concentration but also significantly reduces strength. Different deformation mechanisms ultimately lead to different failure behaviors of LPBFed WE43 alloy. At 200°C, failure predominantly originates from microcrack propagation induced by elemental segregation at melt pool boundaries. At this critical temperature of 250°C, the insufficient activation of DRX behavior and GBS creates a 'mechanistic gap', resulting in untimely strain accommodation near oxides. When the temperature reaches 300°C, a fundamental transition in crack propagation mode occurs due to significantly enhanced dynamic recrystallization processes, with intergranular cracking becoming the predominant failure mechanism. This work reveals the temperature-dependent deformation and fracture behaviors of the LPBFed WE43 alloy and provides new insights for its application in high-temperature environments.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1033 ","pages":"Article 181288"},"PeriodicalIF":6.3000,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Temperature-dependent mechanical behaviors of laser powder bed fused WE43 alloy with heterogeneous grain structure: Deformation and fracture mechanisms\",\"authors\":\"Chen Ji , Liang Zhu , Bangzhao Yin , Shengwen Bai , Lawrence E. Murr , Peng Wen , Bin Jiang , Fusheng Pan , Kun Li\",\"doi\":\"10.1016/j.jallcom.2025.181288\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Laser powder bed fusion (LPBF), as an emerging advanced metal manufacturing technology, alters the microstructural characteristics of Mg alloys through its unique non-equilibrium solidification effects, thereby influencing their mechanical responses, especially at high temperatures. In this context, this study characterizes the microstructure and temperature-dependent quasi-static tensile behavior of laser powder bed fused (LPBFed) WE43 alloy. The inherent remelting and thermal cycling processes of LPBF lead to the in-situ precipitation of β′, β<sub>1</sub>, and β phases, as well as the formation of a bimodal grain structure, resulting in unique high-temperature mechanical properties. High-temperature tensile tests show that the LPBFed WE43 alloy maintains good strength at 200–250°C, but its tensile strength significantly decreases at 300°C. Additionally, the LPBFed WE43 alloy exhibits anomalous elongation at 250°C. EBSD technology was used to systematically further reveal the unique deformation mechanisms of the LPBFed WE43 alloy. The results indicate that the presence of various dispersed in-situ precipitates, which act as nucleation sites for recrystallization, leads to recrystallization being the primary deformation mode of the LPBFed WE43 alloy during high-temperature tensile testing at 200–300°C. Simultaneously, the existence of these dispersed precipitates also restricts the formation of twins. During this process, both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) occur simultaneously, with DDRX becoming dominant as the temperature increases. Moreover, significant stress concentration is observed only at 250°C, which is responsible for the anomalous elongation and the activation of pyramidal II<c+a> slip. At 300°C, the grain boundary strength of fine grains significantly decreases, leading to pronounced grain boundary sliding (GBS). GBS greatly alleviates stress concentration but also significantly reduces strength. Different deformation mechanisms ultimately lead to different failure behaviors of LPBFed WE43 alloy. At 200°C, failure predominantly originates from microcrack propagation induced by elemental segregation at melt pool boundaries. At this critical temperature of 250°C, the insufficient activation of DRX behavior and GBS creates a 'mechanistic gap', resulting in untimely strain accommodation near oxides. When the temperature reaches 300°C, a fundamental transition in crack propagation mode occurs due to significantly enhanced dynamic recrystallization processes, with intergranular cracking becoming the predominant failure mechanism. This work reveals the temperature-dependent deformation and fracture behaviors of the LPBFed WE43 alloy and provides new insights for its application in high-temperature environments.</div></div>\",\"PeriodicalId\":344,\"journal\":{\"name\":\"Journal of Alloys and Compounds\",\"volume\":\"1033 \",\"pages\":\"Article 181288\"},\"PeriodicalIF\":6.3000,\"publicationDate\":\"2025-05-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Alloys and Compounds\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S092583882502849X\",\"RegionNum\":2,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Alloys and Compounds","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S092583882502849X","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Temperature-dependent mechanical behaviors of laser powder bed fused WE43 alloy with heterogeneous grain structure: Deformation and fracture mechanisms
Laser powder bed fusion (LPBF), as an emerging advanced metal manufacturing technology, alters the microstructural characteristics of Mg alloys through its unique non-equilibrium solidification effects, thereby influencing their mechanical responses, especially at high temperatures. In this context, this study characterizes the microstructure and temperature-dependent quasi-static tensile behavior of laser powder bed fused (LPBFed) WE43 alloy. The inherent remelting and thermal cycling processes of LPBF lead to the in-situ precipitation of β′, β1, and β phases, as well as the formation of a bimodal grain structure, resulting in unique high-temperature mechanical properties. High-temperature tensile tests show that the LPBFed WE43 alloy maintains good strength at 200–250°C, but its tensile strength significantly decreases at 300°C. Additionally, the LPBFed WE43 alloy exhibits anomalous elongation at 250°C. EBSD technology was used to systematically further reveal the unique deformation mechanisms of the LPBFed WE43 alloy. The results indicate that the presence of various dispersed in-situ precipitates, which act as nucleation sites for recrystallization, leads to recrystallization being the primary deformation mode of the LPBFed WE43 alloy during high-temperature tensile testing at 200–300°C. Simultaneously, the existence of these dispersed precipitates also restricts the formation of twins. During this process, both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) occur simultaneously, with DDRX becoming dominant as the temperature increases. Moreover, significant stress concentration is observed only at 250°C, which is responsible for the anomalous elongation and the activation of pyramidal II<c+a> slip. At 300°C, the grain boundary strength of fine grains significantly decreases, leading to pronounced grain boundary sliding (GBS). GBS greatly alleviates stress concentration but also significantly reduces strength. Different deformation mechanisms ultimately lead to different failure behaviors of LPBFed WE43 alloy. At 200°C, failure predominantly originates from microcrack propagation induced by elemental segregation at melt pool boundaries. At this critical temperature of 250°C, the insufficient activation of DRX behavior and GBS creates a 'mechanistic gap', resulting in untimely strain accommodation near oxides. When the temperature reaches 300°C, a fundamental transition in crack propagation mode occurs due to significantly enhanced dynamic recrystallization processes, with intergranular cracking becoming the predominant failure mechanism. This work reveals the temperature-dependent deformation and fracture behaviors of the LPBFed WE43 alloy and provides new insights for its application in high-temperature environments.
期刊介绍:
The Journal of Alloys and Compounds is intended to serve as an international medium for the publication of work on solid materials comprising compounds as well as alloys. Its great strength lies in the diversity of discipline which it encompasses, drawing together results from materials science, solid-state chemistry and physics.