Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg
I1 stacking faults (SFs) in Mg alloys are regarded as the nucleation sites of 〈c+a〉 dislocations that are critical for these alloys to achieve high ductility. Previously it was proposed that the formation of I1 SFs requires the accumulations of a large number of vacancies, which are difficult to ach...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co., Ltd.
2022-10-01
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| Series: | Journal of Magnesium and Alloys |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2213956722001591 |
| _version_ | 1797984268404654080 |
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| author | Yong-Jie Hu Vaidehi Menon Liang Qi |
| author_facet | Yong-Jie Hu Vaidehi Menon Liang Qi |
| author_sort | Yong-Jie Hu |
| collection | DOAJ |
| description | I1 stacking faults (SFs) in Mg alloys are regarded as the nucleation sites of 〈c+a〉 dislocations that are critical for these alloys to achieve high ductility. Previously it was proposed that the formation of I1 SFs requires the accumulations of a large number of vacancies, which are difficult to achieve at low temperatures. In this study, molecular dynamics (MD) and molecular statics (MS) simulations based on empirical interatomic potentials were applied to investigate the deformation defect evolutions from the symmetric tilt grain boundaries (GBs) in Mg and Mg-Y alloys under external loading along 〈c〉-axis. The results show the planar faults (PFs) on Pyramidal I planes first appear due to the nucleation and glide of 〈12c+p〉 partial dislocations from GBs, where 〈p〉=13〈101¯0〉. These partial dislocations with pyramidal PFs interact with other defects, including pyramidal PFs themselves, GBs, and 〈p〉 partial dislocations, generating a large amount of I1 SFs. Detailed analyses show the nucleation and growth of I1 SFs are achieved by atomic shuffle events and deformation defect reactions without the requirements of vacancy diffusion. Our simulations also suggest the Y clusters at GBs can reduce the critical stress for the formation of pyramidal PFs and I1 SFs, which provide a possible reason for the experimental observations that Y promotes the 〈c+a〉 dislocation activities. |
| first_indexed | 2024-04-11T07:00:02Z |
| format | Article |
| id | doaj.art-6a98d1613887470daf99836677a34e09 |
| institution | Directory Open Access Journal |
| issn | 2213-9567 |
| language | English |
| last_indexed | 2024-04-11T07:00:02Z |
| publishDate | 2022-10-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Journal of Magnesium and Alloys |
| spelling | doaj.art-6a98d1613887470daf99836677a34e092022-12-22T04:38:49ZengKeAi Communications Co., Ltd.Journal of Magnesium and Alloys2213-95672022-10-01101027172729Formation of I1 stacking fault by deformation defect evolution from grain boundaries in MgYong-Jie Hu0Vaidehi Menon1Liang Qi2Department of Materials Science and Engineering, University of Michigan, Ann Arbor 48109, USA; Department of Materials Science and Engineering, Drexel University, Philadelphia 19104, USADepartment of Materials Science and Engineering, University of Michigan, Ann Arbor 48109, USACorresponding author.; Department of Materials Science and Engineering, University of Michigan, Ann Arbor 48109, USAI1 stacking faults (SFs) in Mg alloys are regarded as the nucleation sites of 〈c+a〉 dislocations that are critical for these alloys to achieve high ductility. Previously it was proposed that the formation of I1 SFs requires the accumulations of a large number of vacancies, which are difficult to achieve at low temperatures. In this study, molecular dynamics (MD) and molecular statics (MS) simulations based on empirical interatomic potentials were applied to investigate the deformation defect evolutions from the symmetric tilt grain boundaries (GBs) in Mg and Mg-Y alloys under external loading along 〈c〉-axis. The results show the planar faults (PFs) on Pyramidal I planes first appear due to the nucleation and glide of 〈12c+p〉 partial dislocations from GBs, where 〈p〉=13〈101¯0〉. These partial dislocations with pyramidal PFs interact with other defects, including pyramidal PFs themselves, GBs, and 〈p〉 partial dislocations, generating a large amount of I1 SFs. Detailed analyses show the nucleation and growth of I1 SFs are achieved by atomic shuffle events and deformation defect reactions without the requirements of vacancy diffusion. Our simulations also suggest the Y clusters at GBs can reduce the critical stress for the formation of pyramidal PFs and I1 SFs, which provide a possible reason for the experimental observations that Y promotes the 〈c+a〉 dislocation activities.http://www.sciencedirect.com/science/article/pii/S2213956722001591Magnesium alloysI1 stacking faults〈c+a〉 dislocationsGrain boundariesDefect nucleation and evolutionMolecular dynamics simulations |
| spellingShingle | Yong-Jie Hu Vaidehi Menon Liang Qi Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg Journal of Magnesium and Alloys Magnesium alloys I1 stacking faults 〈c+a〉 dislocations Grain boundaries Defect nucleation and evolution Molecular dynamics simulations |
| title | Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg |
| title_full | Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg |
| title_fullStr | Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg |
| title_full_unstemmed | Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg |
| title_short | Formation of I1 stacking fault by deformation defect evolution from grain boundaries in Mg |
| title_sort | formation of i1 stacking fault by deformation defect evolution from grain boundaries in mg |
| topic | Magnesium alloys I1 stacking faults 〈c+a〉 dislocations Grain boundaries Defect nucleation and evolution Molecular dynamics simulations |
| url | http://www.sciencedirect.com/science/article/pii/S2213956722001591 |
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