Grain boundary network plasticity: Reduced-order modeling of deformation-driven shear-coupled microstructure evolution
Grain boundary network plasticity: Reduced-order modeling of deformation-driven shear-coupled microstructure evolution
复制标题
晶界网络塑性：变形驱动剪切耦合组织演化的降维模拟
DOI：
10.1016/j.jmps.2024.105541
复制
发表时间：
2023-06
影响因子：
5.3
通讯作者：
Daniel Bugas;B. Runnels
中科院分区：
文献类型：
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作者：
Daniel Bugas;B. Runnels
已知结构材料中的微结构演变响应于机械载荷而发生，并且通常可以通过晶界（GB）的耦合运动来容纳实质性的塑性变形。这可以产生期望的行为，例如增加的延展性，或不期望的行为，例如机械诱导的粗化。在这项工作中，开发了一种新的，多尺度模型，用于捕获多个GB同时介导的可塑性的综合效果。这种模型被称为“晶界网络塑性”。用图论的数学框架描述了微结构的连通性，并将微结构的演化表示为沿着图的体积流。利用最小耗散势原理，这是以前应用到晶界迁移，一组演化方程，转移体积和特征变形沿着图形边缘在物理上一致的方式。它示出，高阶几何效应，如钉扎效应的三重点，可以占通过合并的几何硬化，导致几何诱导GB停滞。其结果是一个计算效率的降阶模型，可用于模拟初始运动的多晶体中的晶界与原子模拟告知的参数。该模型的有效性证明通过比较多双晶体原子模拟，以及从文献中获得的GB工程和非GB工程数据的选择数量。通过力学响应测试和屈服面检查来证明剪切耦合晶界网络的影响。
Microstructural evolution in structural materials is known to occur in response to mechanical loading and can often accommodate substantial plastic deformation through the coupled motion of grain boundaries (GBs). This can produce desirable behavior, such as increased ductility, or undesirable behavior such as mechanically-induced coarsening. In this work a novel, multiscale model is developed for capturing the combined effect of plasticity mediated by multiple GBs simultaneously. This model is referred to as “grain boundary network plasticity”. The mathematical framework of graph theory is used to describe the microstructure connectedness, and the evolution of microstructure is represented as volume flow along the graph. By using the principle of minimum dissipation potential, which has previously been applied to grain boundary migration, a set of evolution equations are developed that transfer volume and eigendeformation along the graph edges in a physically consistent way. It is shown that higher-order geometric effects, such as the pinning effect of triple points, may be accounted for through the incorporation of a geometric hardening that causes geometry-induced GB stagnation. The result is a computationally efficient reduced order model that can be used to simulate the initial motion of grain boundaries in a polycrystal with parameters informed by atomistic simulations. The effectiveness of the model is demonstrated through comparison to multiple bicrystal atomistic simulations, as well as a select number of GB engineered and non-GB engineered data obtained from the literature. The effect of the network of shear-coupling grain boundaries is demonstrated through mechanical response tests and by examining the yield surfaces.