On the micromechanics of voids in nanotwinned materials
On the micromechanics of voids in nanotwinned materials
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DOI：
10.1016/j.jmps.2022.104887
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发表时间：
2022-08
影响因子：
5.3
通讯作者：
Kartikey Joshi;S. Joshi
中科院分区：
文献类型：
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作者：
Kartikey Joshi;S. Joshi
本工作通过晶体塑性研究了NT微结构中空洞生长引起的内部损伤。该框架结合了长度尺度效应，并明确地模拟了孪生边界迁移。使用有限变形，平面应变有限元计算的多孔单胞，我们分析了作用的孪晶尺寸，塑性各向异性和孪晶边界迁移的控制双轴应力状态的范围内的孔隙演化。模拟提供了深入了解NT微结构中的孔隙率生长的晶体学方面。重点放在相关的内部颈缩失效的微观力学。无论晶体学塑性各向异性的水平，孪晶边界迁移有效地屏蔽了空隙生长过程，与非孪晶微结构相比，延迟了孔隙率的演变。研究发现，晶体学塑性各向异性引起的扭折带不稳定性，可以影响空洞的增长。再加上孪晶边界的流动性，孪晶尺寸和晶体学塑性各向异性创建一个丰富的景观作为应力状态的函数的故障特性。
This work investigates internal damage by void growth in NT microstructures via crystal plasticity. The framework incorporates length-scale effects and explicitly models twin boundary migration. Using finite-deformation, plane strain finite element calculations of porous unit cells, we analyze the roles of twin size, plastic anisotropy and twin boundary migration on void evolution over a range of controlled biaxial stress states. The simulations provide insights into crystallographic aspects of porosity growth in NT microstructures. Emphasis is placed on correlating the micromechanics of failure by internal necking. Irrespective of the level of crystallographic plastic anisotropy, twin boundary migration effectively shields the void growth process, delaying the porosity evolution compared to non-twinned microstructures. It is found that crystallographic plastic anisotropy causes kink band instability that can affect void growth. Coupled with twin boundary mobility, twin size and crystallographic plastic anisotropy create a rich landscape of failure characteristics as a function of the stress state.