Atomic-Scale Insights into Solute Drag Effects on Grain Boundary Motion in Mg-Al and Mg-Ca Alloys

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Auteurs principaux: Chen, Zhishun, He, Shudong, Zhang, Shuai, Bie, Xiaohan, Xie, Zhuoming, Yang, Tengfei, Hu, Wangyu, Deng, Huiqiu, Xu, Shiwei, Zeng, Zhuoran, Hou, Jie
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Publié: 2026
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author Chen, Zhishun
He, Shudong
Zhang, Shuai
Bie, Xiaohan
Xie, Zhuoming
Yang, Tengfei
Hu, Wangyu
Deng, Huiqiu
Xu, Shiwei
Zeng, Zhuoran
Hou, Jie
author_facet Chen, Zhishun
He, Shudong
Zhang, Shuai
Bie, Xiaohan
Xie, Zhuoming
Yang, Tengfei
Hu, Wangyu
Deng, Huiqiu
Xu, Shiwei
Zeng, Zhuoran
Hou, Jie
contents The slip behavior of dislocations and grain boundaries critically governs recrystallization and plastic deformation in Mg alloys and can be strongly influenced by solutes. However, the quantitative effects of solute distribution on defect mobility remain unclear. Using molecular dynamics and Monte Carlo simulations, we systematically investigate how Al and Ca solutes affect the motion of dislocations, low-angle grain boundaries (LAGBs), and high-angle grain boundaries (HAGBs) in Mg. Within the idealized framework of random solid-solution, solute drag is dominated by elastic interactions arising from atomic size mismatch, resulting in a stronger resistance from Ca than from Al. In contrast, under the more realistic condition where solute segregation occurs, the dominant mechanism shifts to chemically driven pinning, whose effectiveness is governed by the attainable segregation density. Owing to strong Ca-Ca repulsion, Al achieves substantially higher segregation concentrations than Ca and therefore exerts much stronger pinning effects. Notably, solute-induced retardation is significantly more pronounced for HAGBs than for LAGBs, leading to amplified solute effects during the late stages of recrystallization, where grain growth is controlled primarily by HAGB migration. These results provide atomic-scale insight into experimentally observed grain refinement in Mg alloys.
format Preprint
id arxiv_https___arxiv_org_abs_2601_15699
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Atomic-Scale Insights into Solute Drag Effects on Grain Boundary Motion in Mg-Al and Mg-Ca Alloys
Chen, Zhishun
He, Shudong
Zhang, Shuai
Bie, Xiaohan
Xie, Zhuoming
Yang, Tengfei
Hu, Wangyu
Deng, Huiqiu
Xu, Shiwei
Zeng, Zhuoran
Hou, Jie
Materials Science
The slip behavior of dislocations and grain boundaries critically governs recrystallization and plastic deformation in Mg alloys and can be strongly influenced by solutes. However, the quantitative effects of solute distribution on defect mobility remain unclear. Using molecular dynamics and Monte Carlo simulations, we systematically investigate how Al and Ca solutes affect the motion of dislocations, low-angle grain boundaries (LAGBs), and high-angle grain boundaries (HAGBs) in Mg. Within the idealized framework of random solid-solution, solute drag is dominated by elastic interactions arising from atomic size mismatch, resulting in a stronger resistance from Ca than from Al. In contrast, under the more realistic condition where solute segregation occurs, the dominant mechanism shifts to chemically driven pinning, whose effectiveness is governed by the attainable segregation density. Owing to strong Ca-Ca repulsion, Al achieves substantially higher segregation concentrations than Ca and therefore exerts much stronger pinning effects. Notably, solute-induced retardation is significantly more pronounced for HAGBs than for LAGBs, leading to amplified solute effects during the late stages of recrystallization, where grain growth is controlled primarily by HAGB migration. These results provide atomic-scale insight into experimentally observed grain refinement in Mg alloys.
title Atomic-Scale Insights into Solute Drag Effects on Grain Boundary Motion in Mg-Al and Mg-Ca Alloys
topic Materials Science
url https://arxiv.org/abs/2601.15699