Kinematics of slip-induced rotation for uniaxial shock or ramp compression
Kinematics of slip-induced rotation for uniaxial shock or ramp compression
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DOI：
10.1063/5.0038557
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发表时间：
2021-02-28
影响因子：
3.2
通讯作者：
Wark, J. S.
中科院分区：
文献类型：
--
作者：
Heighway, P. G.;Wark, J. S.
当金属试样发生塑性变形时，其下面的晶体结构必须经常旋转，以符合其宏观边界条件。有越来越多的兴趣在动态压缩社区内利用晶格旋转的X射线衍射测量来推断塑性机制的组合在单轴冲击或斜坡压缩晶体中起作用，从而在压力和应变率的最大极限下通知材料科学。然而，人们并没有广泛认识到，现有的几个模型链接旋转滑动活动是根本不适用于一个平面压缩的情况。我们提出的分子动力学模拟遭受真正的单轴应变的单晶，并表明，在传统的材料科学中使用的施密德和泰勒分析未能预测随之而来的晶格旋转。我们提出了一个简单的替代框架的基础上的弹塑性分解，成功地恢复所观察到的旋转这些单晶体，并可以进一步用于识别操作滑移系统和活动量上，他们在理想的情况下，单，双滑移。
When a metallic specimen is plastically deformed, its underlying crystal structure must often rotate in order to comply with its macroscopic boundary conditions. There is growing interest within the dynamic-compression community in exploiting x-ray diffraction measurements of lattice rotation to infer which combinations of plasticity mechanisms are operative in uniaxially shock- or ramp-compressed crystals, thus informing materials science at the greatest extremes of pressure and strain rate. However, it is not widely appreciated that several of the existing models linking rotation to slip activity are fundamentally inapplicable to a planar compression scenario. We present molecular dynamics simulations of single crystals suffering true uniaxial strain and show that the Schmid and Taylor analyses used in traditional materials science fail to predict the ensuing lattice rotation. We propose a simple alternative framework based on the elastoplastic decomposition that successfully recovers the observed rotation for these single crystals and can further be used to identify the operative slip systems and the amount of activity upon them in the idealized cases of single and double slip.