Plastic deformation of nanocrystalline aluminum at high temperatures and strain rate
Plastic deformation of nanocrystalline aluminum at high temperatures and strain rate
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DOI：
10.1016/j.actamat.2009.12.003
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发表时间：
2010-04-01
期刊：
影响因子：
9.4
通讯作者：
Zhang, H.
中科院分区：
文献类型：
--
作者：
Gerlich, A. P.;Yue, L.;Zhang, H.
采用分子动力学模拟方法研究了纳米晶铝在相变温度达0.97℃时的变形行为。研究了多晶态和双晶态的显微组织和应力应变响应。利用Arrhenius关系将模拟数据与温度进行拟合，量化了位错基形变激活能以及晶界滑动和迁移激活能。流动应力响应的激活能表明，变形很大程度上是由晶界的滑动和迁移所调节的。这与模拟的微观结构一致，表明每个颗粒内的位错相互作用程度可以忽略不计，高应变率过程的微观组织观察也与这一结果一致。在屈服后的再结晶组织中，由于边界迁移和晶粒旋转机制，而不是通过基于扩散的位错攀升，保持了稳定的晶粒度。(C)2009年Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The deformation of nanocrystalline, aluminum was studied using molecular dynamics simulation at homologous temperatures up to 0.97. The microstructures and stress-strain response were examined in a polycrystalline and bicrystal configuration. The activation energies for dislocation-based deformation as well as grain boundary sliding and migration were quantified by fitting simulation data to temperature using an Arrhenius relation. The activation energy for the flow stress response suggests that deformation is largely accommodated by sliding and migration of grain boundaries. This is in agreement with simulated micro structures, indicating a negligible degree of dislocation interaction within each grain, and microstructural observations from high strain rate processes are also consistent with this result. A steady-state grain size is maintained in the recrystallized structure following yielding due to boundary migration and grain rotation mechanisms, rather than by diffusion-based dislocation climb. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.