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.

这项工作通过晶体塑性研究了 NT 微结构中空隙生长引起的内部损伤。该框架结合了长度尺度效应，并明确模拟了孪生边界迁移。使用多孔单胞的有限变形、平面应变有限元计算，我们分析了孪晶尺寸、塑性各向异性和孪晶边界迁移对一系列受控双轴应力状态下的空隙演化的作用。模拟提供了对 NT 微结构中孔隙生长的晶体学方面的见解。重点放在通过内部颈缩关联失效的微观力学。无论晶体塑性各向异性水平如何，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。发现结晶塑性各向异性会导致扭结带不稳定性，从而影响空隙生长。再加上孪晶边界流动性、孪晶尺寸和结晶塑性各向异性，形成了丰富的失效特征景观，作为应力状态的函数。