Hydrostatic pressure effects on deformation mechanisms of nanocrystalline fcc metals

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	Hydrostatic pressure effects on deformation mechanisms of nanocrystalline fcc metals
	Yuan FP(袁福平); Wu XL(武晓雷); Yuan,FP (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
发表期刊	COMPUTATIONAL MATERIALS SCIENCE
	2014
卷号	85 期号:1 页码:8-15
ISSN	0927-0256
摘要	A series of large-scale molecular dynamics (MD) simulations have been performed to investigate hydrostatic pressure effects, and the interplay between pressure and grain size, on the flow stress and the related atomic-level deformation mechanisms in nanocrystalline (NC) Cu. The strength of NC Cu increases with increasing hydrostatic pressures for all grain sizes studies in the present paper (3-15 nm). The critical grain size for maximum strength first shifts towards lower values with increasing hydrostatic pressure (0-5 GPa), and then shifts towards higher values as the hydrostatic pressure becomes even higher (5-80 GPa). Below the critical hydrostatic pressure, the dislocation behaviors increase with increasing hydrostatic pressure for all grain sizes and the dependency of effective modulus as a function of hydrostatic pressure is almost the same for all grain sizes, which should lead to the position shifting of maximum strength towards lower grain sizes. Above the critical hydrostatic pressure, the dislocation behaviors start to decrease with increasing hydrostatic pressure for small grain sizes, and continue to increase with increasing hydrostatic pressure for large grain sizes. The slopes of effective modulus as a function of hydrostatic pressure increase slightly with increasing grain size above the critical hydrostatic pressure. The position shifting of maximum strength towards larger grain sizes at large hydrostatic pressure should be attributed to these two observations. Moreover, GB thickening is observed to increase monotonically with increasing pressure for all grain sizes, and the NC Cu with 3 nm grain size has the trend to become amorphous state under hydrostatic pressure of 80 GPa, which gives a new way to produce crystalline-to-amorphous transition. The findings in the present study should provide insights to the potential applications of NC metals under extreme environments. (C) 2013 Elsevier B.V. All rights reserved.; A series of large-scale molecular dynamics (MD) simulations have been performed to investigate hydrostatic pressure effects, and the interplay between pressure and grain size, on the flow stress and the related atomic-level deformation mechanisms in nanocrystalline (NC) Cu. The strength of NC Cu increases with increasing hydrostatic pressures for all grain sizes studies in the present paper (3-15 nm). The critical grain size for maximum strength first shifts towards lower values with increasing hydrostatic pressure (0-5 GPa), and then shifts towards higher values as the hydrostatic pressure becomes even higher (5-80 GPa). Below the critical hydrostatic pressure, the dislocation behaviors increase with increasing hydrostatic pressure for all grain sizes and the dependency of effective modulus as a function of hydrostatic pressure is almost the same for all grain sizes, which should lead to the position shifting of maximum strength towards lower grain sizes. Above the critical hydrostatic pressure, the dislocation behaviors start to decrease with increasing hydrostatic pressure for small grain sizes, and continue to increase with increasing hydrostatic pressure for large grain sizes. The slopes of effective modulus as a function of hydrostatic pressure increase slightly with increasing grain size above the critical hydrostatic pressure. The position shifting of maximum strength towards larger grain sizes at large hydrostatic pressure should be attributed to these two observations. Moreover, GB thickening is observed to increase monotonically with increasing pressure for all grain sizes, and the NC Cu with 3 nm grain size has the trend to become amorphous state under hydrostatic pressure of 80 GPa, which gives a new way to produce crystalline-to-amorphous transition. The findings in the present study should provide insights to the potential applications of NC metals under extreme environments. (C) 2013 Elsevier B.V. All rights reserved.
关键词	Molecular Dynamics Nanocrystalline Metals Hydrostatic Pressure
学科领域	Materials Science
URL	查看原文
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000331724000002
项目资助者	The authors would like to acknowledge the financial support of the National Key Basic Research Program of China (Grants Nos. 2012CB932203 and 2012CB937500) and NSFC (Grants Nos. 11002151, 11222224, 11072243 and 11021262). The simulations reported were performed at Supercomputing Center of Chinese Academy of Sciences.
课题组名称	LNM材料介观力学性能的表征
论文分区	二类/Q2
引用统计	被引频次：15[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/48730
专题	非线性力学国家重点实验室
通讯作者	Yuan,FP (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Yuan FP,Wu XL,Yuan,FP . Hydrostatic pressure effects on deformation mechanisms of nanocrystalline fcc metals[J]. COMPUTATIONAL MATERIALS SCIENCE,2014,85,1,:8-15.
APA	Yuan FP,Wu XL,&Yuan,FP .(2014).Hydrostatic pressure effects on deformation mechanisms of nanocrystalline fcc metals.COMPUTATIONAL MATERIALS SCIENCE,85(1),8-15.
MLA	Yuan FP,et al."Hydrostatic pressure effects on deformation mechanisms of nanocrystalline fcc metals".COMPUTATIONAL MATERIALS SCIENCE 85.1(2014):8-15.

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