{"title":"锆氢化物断裂的微观力学","authors":"Saiedeh Marashi, Hamidreza Abdolvand","doi":"10.1016/j.actamat.2024.120143","DOIUrl":null,"url":null,"abstract":"<div><p>Zirconium alloys are susceptible to hydrogen embrittlement and hydride precipitation. The precipitation of hydrides is accompanied by a transformation strain, but the contribution of this strain to the fracture of hydrides is not well-understood. In this study, deformation mechanisms and the micromechanics of fracture of hydrides are investigated by conducting in-situ and interrupted ex-situ tensile experiments on hydrided zirconium specimens. Electron backscatter diffraction (EBSD) is used to measure the macro-EBSD maps that contain the grains located in the gauge section of the specimens’ surfaces. Further, high spatial resolution EBSD is used to determine orientation variations induced by the precipitation of hydrides and by the external mechanical load. The measured grain orientations are mapped into a crystal plasticity finite element (CPFE) model to examine the performance of eight different crack initiation criteria. It is shown that a multiscale approach is essential for studying the fracture of hydrides as the details of hydride morphology, orientation, local grain neighborhood, and hydride-hydride interactions are important in such analysis. It is shown that neglecting the effects of hydride-induced transformation strain leads to inaccuracies in predicting both the location and direction of microcracks within hydrides. Among the examined methods, the combination of resolved shear stress and resolved shear strain on slip systems, i.e., the highest shear energy density, consistently predicts the correct locations of hydride microcracks as well as their propagation direction. Further, it is shown that the significant deformation that takes place within hydrides is the main driving force for the fracture of hydrides.</p></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":null,"pages":null},"PeriodicalIF":8.3000,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The micromechanics of fracture of zirconium hydrides\",\"authors\":\"Saiedeh Marashi, Hamidreza Abdolvand\",\"doi\":\"10.1016/j.actamat.2024.120143\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Zirconium alloys are susceptible to hydrogen embrittlement and hydride precipitation. The precipitation of hydrides is accompanied by a transformation strain, but the contribution of this strain to the fracture of hydrides is not well-understood. In this study, deformation mechanisms and the micromechanics of fracture of hydrides are investigated by conducting in-situ and interrupted ex-situ tensile experiments on hydrided zirconium specimens. Electron backscatter diffraction (EBSD) is used to measure the macro-EBSD maps that contain the grains located in the gauge section of the specimens’ surfaces. Further, high spatial resolution EBSD is used to determine orientation variations induced by the precipitation of hydrides and by the external mechanical load. The measured grain orientations are mapped into a crystal plasticity finite element (CPFE) model to examine the performance of eight different crack initiation criteria. It is shown that a multiscale approach is essential for studying the fracture of hydrides as the details of hydride morphology, orientation, local grain neighborhood, and hydride-hydride interactions are important in such analysis. It is shown that neglecting the effects of hydride-induced transformation strain leads to inaccuracies in predicting both the location and direction of microcracks within hydrides. Among the examined methods, the combination of resolved shear stress and resolved shear strain on slip systems, i.e., the highest shear energy density, consistently predicts the correct locations of hydride microcracks as well as their propagation direction. Further, it is shown that the significant deformation that takes place within hydrides is the main driving force for the fracture of hydrides.</p></div>\",\"PeriodicalId\":238,\"journal\":{\"name\":\"Acta Materialia\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":8.3000,\"publicationDate\":\"2024-06-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Acta Materialia\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1359645424004944\",\"RegionNum\":1,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Materialia","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1359645424004944","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
The micromechanics of fracture of zirconium hydrides
Zirconium alloys are susceptible to hydrogen embrittlement and hydride precipitation. The precipitation of hydrides is accompanied by a transformation strain, but the contribution of this strain to the fracture of hydrides is not well-understood. In this study, deformation mechanisms and the micromechanics of fracture of hydrides are investigated by conducting in-situ and interrupted ex-situ tensile experiments on hydrided zirconium specimens. Electron backscatter diffraction (EBSD) is used to measure the macro-EBSD maps that contain the grains located in the gauge section of the specimens’ surfaces. Further, high spatial resolution EBSD is used to determine orientation variations induced by the precipitation of hydrides and by the external mechanical load. The measured grain orientations are mapped into a crystal plasticity finite element (CPFE) model to examine the performance of eight different crack initiation criteria. It is shown that a multiscale approach is essential for studying the fracture of hydrides as the details of hydride morphology, orientation, local grain neighborhood, and hydride-hydride interactions are important in such analysis. It is shown that neglecting the effects of hydride-induced transformation strain leads to inaccuracies in predicting both the location and direction of microcracks within hydrides. Among the examined methods, the combination of resolved shear stress and resolved shear strain on slip systems, i.e., the highest shear energy density, consistently predicts the correct locations of hydride microcracks as well as their propagation direction. Further, it is shown that the significant deformation that takes place within hydrides is the main driving force for the fracture of hydrides.
期刊介绍:
Acta Materialia serves as a platform for publishing full-length, original papers and commissioned overviews that contribute to a profound understanding of the correlation between the processing, structure, and properties of inorganic materials. The journal seeks papers with high impact potential or those that significantly propel the field forward. The scope includes the atomic and molecular arrangements, chemical and electronic structures, and microstructure of materials, focusing on their mechanical or functional behavior across all length scales, including nanostructures.