Experiments and theories have suggested the evolution of intragranular back stress is primarily dependent on the characteristics and development of dislocation substructure in face-centered cubic (FCC) metals and alloys. Despite this, continuum modeling of complex cyclic loading phenomena such as inelastic ratchet strain accumulation typically appeals to one of several phenomenological back stress forms with weak connections to physical mechanisms. In the current work, a micromechanically-based back stress evolution law is derived and implemented in a crystal plasticity framework for FCC metals that directly considers the evolution of dislocation substructure. The model is used in a case study of stainless steel 316L (SS316L), and good agreement is found with experiments on single- and poly-crystalline specimens subjected to monotonic, fully-reversed cyclic loading, and stress-controlled cyclic loading with mean stress. Ratcheting is attributed to dislocation substructure formation, dissolution, and stabilization within this physically-based framework.

实验和理论表明，晶内背应力的演变主要取决于面心立方 (FCC) 金属和合金中位错亚结构的特征和发展。尽管如此，对复杂循环载荷现象（例如非弹性棘轮应变积累）的连续建模通常会采用与物理机制连接较弱的几种现象学背应力形式之一。在目前的工作中，基于微机械的背应力演化规律被推导出并在 FCC 金属的晶体塑性框架中实现，该框架直接考虑位错亚结构的演化。该模型用于不锈钢 316L (SS316L) 的案例研究，与单晶和多晶试样的实验结果吻合良好，完全反向循环加载，以及具有平均应力的应力控制循环加载。在这个基于物理的框架内，棘轮效应归因于位错子结构的形成、溶解和稳定。