| 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); 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.
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| Source Publication | Journal of Applied Physics
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| 2014-02-14 | |
| Volume | 115Issue:6Pages:63509 |
| ISSN | 0021-8979 |
| Abstract | 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. |
| Subject Area | Physics |
| URL | 查看原文 |
| Indexed By | SCI ; EI |
| Language | 英语 |
| WOS ID | WOS:000331839800019 |
| Funding Organization | 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. |
| Department | LNM材料介观力学性能的表征 |
| Classification | 二类/Q2 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://dspace.imech.ac.cn/handle/311007/48790 |
| Collection | 非线性力学国家重点实验室 |
| Corresponding Author | 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. |
| Recommended Citation 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,&Yuan, FP .(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. |
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