Twin boundary spacing effects on shock response and spall behaviors of hierarchically nanotwinned fcc metals

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	Twin boundary spacing effects on shock response and spall behaviors of hierarchically nanotwinned fcc metals
	Yuan FP(袁福平); Chen L; Jiang P(姜萍); Wu XL(武晓雷)
刊名	Journal of Applied Physics
	2014-02-14
通讯作者邮箱	fpyuan@lnm.imech.ac.cn; chenliu@imech.ac.cn; jping@imech.ac.cn; xlwu@imech.ac.cn
卷号	115 期号:6 页码:63509
ISSN号	0021-8979
通讯作者	Yuan, FP (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, 15 North 4th Ring,West Rd, Beijing 100190, Peoples R China.
产权排序	[Yuan, Fuping; Chen, Liu; Jiang, Ping; Wu, Xiaolei] Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
合作状况	国内
中文摘要	Atomistic deformation mechanisms of hierarchically nano-twinned (NT) Ag under shock conditions have been investigated using a series of large-scale molecular dynamics simulations. For the same grain size d and the same spacing of primary twins lambda(1), the average flow stress behind the shock front in hierarchically NT Ag first increases with decreasing spacing of secondary twins lambda(2), achieving a maximum at a critical lambda(2), and then drops as lambda(2) decreases further. Above the critical lambda(2), the deformation mechanisms are dominated by three type strengthening mechanisms: (a) partial dislocations emitted from grain boundaries (GBs) travel across other boundaries; (b) partial dislocations emitted from twin boundaries (TBs) travel across other TBs; (c) formation of tertiary twins. Below the critical lambda(2), the deformation mechanism are dominated by two softening mechanisms: (a) detwinning of secondary twins; (b) formation of new grains by cross slip of partial dislocations. Moreover, the twin-free nanocrystalline (NC) Ag is found to have lower average flow stress behind the shock front than those of all hierarchically NT Ag samples except the one with the smallest lambda(2) of 0.71 nm. No apparent correlation between the spall strength and lambda(2) is observed in hierarchically NT Ag, since voids always nucleate at both GBs and boundaries of the primary twins. However, twin-free NC Ag is found to have higher spall strength than hierarchically NT Ag. Voids can only nucleate from GBs for twin-free NC Ag, therefore, twin-free NC Ag has less nucleation sources along the shock direction when compared to hierarchically NT Ag, which requiring higher tensile stress to create spallation. These findings should contribute to the understandings of deformation mechanisms of hierarchically NT fcc metals under extreme deformation conditions. (C) 2014 AIP Publishing LLC.
学科主题	Physics
分类号	二类/Q2
收录类别	SCI ; EI
资助信息	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, 51301187, and 11021262). The simulations reported were performed at Supercomputing Center of Chinese Academy of Sciences.
原文出处	http://dx.doi.org/10.1063/1.4865738
语种	英语
WOS记录号	WOS:000331839800019
公开日期	2014-05-09
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/48790]
专题	力学研究所_非线性力学国家重点实验室
推荐引用方式 GB/T 7714	Yuan FP,Chen L,Jiang P,et al. Twin boundary spacing effects on shock response and spall behaviors of hierarchically nanotwinned fcc metals[J]. Journal of Applied Physics,2014,115(6):63509.
APA	Yuan FP,Chen L,Jiang P,&Wu XL.(2014).Twin boundary spacing effects on shock response and spall behaviors of hierarchically nanotwinned fcc metals.Journal of Applied Physics,115(6),63509.
MLA	Yuan FP,et al."Twin boundary spacing effects on shock response and spall behaviors of hierarchically nanotwinned fcc metals".Journal of Applied Physics 115.6(2014):63509.