Revealing extreme twin-boundary shear deformability in metallic nanocrystals.
Revealing extreme twin-boundary shear deformability in metallic nanocrystals.
复制标题
揭示金属纳米晶体的极端孪晶边界剪切变形能力
DOI：
10.1126/sciadv.abe4758
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发表时间：
2021-09-03
期刊：
影响因子：
13.6
通讯作者：
Wang J
中科院分区：
文献类型：
--
作者：
Zhu Q;Kong L;Lu H;Huang Q;Chen Y;Liu Y;Yang W;Zhang Z;Sansoz F;Zhou H;Wang J
孪晶纳米晶通过广泛的孪晶界滑动表现出约364%的剪切应变。含有丰富的共格孪晶界的金属由于剪切引起的孪晶界的迁移和滑动，能够在不断裂的情况下保持大量的塑性变形。然而，在这些金属中保持延展性已被证明是困难的，因为快速去孪晶在大变形时耗尽了Tb的迁移机制，而Tb的滑动仅被证明是在非常特定的晶体取向上加载的。在这里，我们用原位纳米力学测试和多尺度模拟揭示了纳米晶体中孪晶的本征剪切变形能力，并报告了Tb滑动高达364%的极端剪切变形能力。滑动诱导的塑性表现在通常预测有利于去孪生的取向上，并且显示出严重依赖于几何不均匀性。进一步研究了法向耦合和剪切耦合，以描绘从TB滑动到TB破裂的依赖于TB取向的转变。这些动态观察揭示了纳米晶体前所未有的力学性能，这对通过严重塑性变形改进金属加工具有重要意义。
Twinned nanocrystals exhibit approximately 364% shear strain via extensive twin boundary sliding. Metals containing abundant coherent twin boundaries (TBs) are able to sustain substantial plastic deformation without fracture due to shear-induced TB migration and sliding. Retaining ductility in these metals, however, has proven difficult because detwinning rapidly exhausts TB migration mechanisms at large deformation, whereas TB sliding was only evidenced for loading on very specific crystallographic orientations. Here, we reveal the intrinsic shear deformability of twins in nanocrystals using in situ nanomechanical testing and multiscale simulations and report extreme shear deformability through TB sliding up to 364%. Sliding-induced plasticity is manifested for orientations that are generally predicted to favor detwinning and shown to depend critically on geometric inhomogeneities. Normal and shear coupling are further examined to delineate a TB orientation-dependent transition from TB sliding to TB cracking. These dynamic observations reveal unprecedented mechanical properties in nanocrystals, which hold implications for improving metal processing by severe plastic deformation.
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DOI：
10.1088/0965-0393/18/1/015012
发表时间：
2010-01-01
影响因子：
1.8
作者：
Stukowski, Alexander
通讯作者：
Stukowski, Alexander
纳米孪晶金刚石具有前所未有的硬度和稳定性
影响因子：
64.8
作者：
Huang, Quan;Yu, Dongli;Tian, Yongjun
通讯作者：
Tian, Yongjun
影响因子：
4
作者：
Anderoglu, O.;Misra, A.;Zhang, X.
通讯作者：
Zhang, X.
影响因子：
4.4
作者：
Grochola, G;Russo, SP;Snook, IK
通讯作者：
Snook, IK
影响因子：
41.2
作者：
Ke, Xing;Ye, Jianchao;Sansoz, Frederic
通讯作者：
Sansoz, Frederic