Direct observation of Lomer-Cottrell locks during strain hardening in nanocrystalline nickel by in situ TEM.
Direct observation of Lomer-Cottrell locks during strain hardening in nanocrystalline nickel by in situ TEM.
复制标题
DOI：
10.1038/srep01061
复制
发表时间：
2013
影响因子：
4.6
通讯作者：
Wang, Haiyan
中科院分区：
文献类型：
--
作者：
Lee, Joon Hwan;Holland, Troy B.;Mukherjee, Amiya K.;Zhang, Xinghang;Wang, Haiyan
应变硬化能力对于金属材料在塑性变形期间实现高延展性是至关重要的。然而，除了少数例外，大多数纳米晶金属具有固有的低加工硬化能力。由于缺乏原位实验证据，对纳米晶金属加工硬化机制的解释仍存在争议。在这里，我们报告，通过使用原位透射电子显微镜纳米压痕工具，直接观察动态加工硬化事件在纳米晶镍。在应变硬化阶段，大量的L-C锁形成于纳米晶粒内部和孪晶界上。在L-C锁与孪晶界面的相互作用过程中，确定了两种主要机制。定量纳米压痕实验记录表明，在多个加载-卸载循环的屈服强度从1.64 GPa增加到2.29 GPa。 这项研究提供的证据来解释在小的长度尺度的加工硬化的根源和洞察未来的设计韧性纳米晶金属。
Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by using an in situ transmission electron microscope nanoindentation tool, the direct observation of dynamic work hardening event in nanocrystalline nickel. During strain hardening stage, abundant Lomer-Cottrell (L-C) locks formed both within nanograins and against twin boundaries. Two major mechanisms were identified during interactions between L-C locks and twin boundaries. Quantitative nanoindentation experiments recorded show an increase of yield strength from 1.64 to 2.29 GPa during multiple loading-unloading cycles. This study provides both the evidence to explain the roots of work hardening at small length scales and the insight for future design of ductile nanocrystalline metals.
登录
查看更多内容
影响因子：
41.2
作者：
Yamakov, V;Wolf, D;Gleiter, H
通讯作者：
Gleiter, H
DOI：
10.1016/0001-6160(81)90112-7
发表时间：
1981-01-01
期刊：
ACTA METALLURGICA
影响因子：
--
作者：
MECKING, H;KOCKS, UF
通讯作者：
KOCKS, UF
影响因子：
6
作者：
Li, Nan;Wang, J.;Zhang, X.
通讯作者：
Zhang, X.
影响因子：
56.9
作者：
Budrovic, Z;Van Swygenhoven, H;Schmitt, B
通讯作者：
Schmitt, B
影响因子：
8.6
作者：
Wu, X. L.;Zhu, Y. T.;Wei, Q.
通讯作者：
Wei, Q.