Dependence of strain rate sensitivity upon deformed microstructures in nanocrystalline Cu
Dependence of strain rate sensitivity upon deformed microstructures in nanocrystalline Cu
复制标题
应变率敏感性对纳米晶铜变形微观结构的依赖性
DOI：
10.1016/j.actamat.2010.05.055
复制
发表时间：
2010-09-01
期刊：
影响因子：
9.4
通讯作者：
Lu, T. J.
中科院分区：
文献类型：
--
作者：
Huang, P.;Wang, F.;Lu, T. J.
纳米晶铜的蠕变行为的实验特征与纳米压痕使用两个顺序的制度，即，装载和保持。显着增强的应变速率敏感性被发现在一个异常狭窄的范围内的蠕变速率保持制度，这是由于在加载制度期间产生的变形的微观结构。通过定量分析NC Cu在保温状态下的蠕变速率和速率敏感性指数，发现晶界滑移和位错活动是导致该异常行为的主要原因，晶界滑移的贡献随晶粒尺寸的增大而减小，随加载应变速率的减小而增大.这些发现提供了一种潜在的方式来调整纳米晶金属的机械性能的预应变。(C)2010 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The creep behavior of nanocrystalline copper was experimentally characterized with nanoindentation using two sequential regimes, i.e., loading and holding. Significantly enhanced strain rate sensitivity was found within an unusually narrow range of creep rate in the holding regime, which is attributed to the deformed microstructure generated during the loading regime. By quantitatively analyzing the creep rate and rate sensitivity exponent of NC Cu in the holding regime, both the grain boundary sliding (GBS) and dislocation activities are found to be responsible for the observed abnormal behavior, with the contribution of GBS decreasing with increasing grain size and increasing with decreasing loading strain rate. These findings provide a potential way of adjusting the mechanical properties of nanocrystalline metals by pre-straining. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.