Strengthening effects of various grain boundaries with nano-spacing as barriers of dislocation motion from molecular dynamics simulations

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• 作者：FuPing Yuan
• 关键词：molecular dynamics ; grain boundary strengthening ; dislocations ; nanoindentation ; metals
• 刊名：Science China Physics, Mechanics & Astronomy
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：60
• 期：3
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics, general; Classical and Continuum Physics; Astronomy, Observations and Techniques;
• 出版者：Science China Press
• ISSN：1869-1927
• 卷排序：60

文摘

Strengthening in metals is traditionally achieved through the controlled creation of various grain boundaries (GBs), such as low-angle GBs, high-angle GBs, and twin boundaries (TBs). In the present study, a series of large-scale molecular dynamics simulations with spherical nanoindentation and carefully designed model were conducted to investigate and compare the strengthening effects of various GBs with nano-spacing as barriers of dislocation motion. Simulation results showed that high-angle twist GBs and TBs are similar barriers and low-angle twist GBs are less effective in obstructing dislocation motion. Corresponding atomistic mechanisms were also given. At a certain indentation depth, dislocation transmission and dislocation nucleation from the other side of boundaries were observed for low-angle twist GBs, whereas dislocations were completely blocked by high-angle twist GBs and TBs at the same indentation depth. The current findings should provide insights for comprehensive understanding of the strengthening effects of various GBs at nanoscale.