A new constitutive equation predicting the evolution of oxide thickness is proposed and implemented in a crystal plasticity framework with a hardening-based damage density function. The oxidation model depends on the initial surface roughness as well as on the amount of accumulated plastic strain and stress triaxiality. The description for the effect of oxidation on the mechanical behavior and damage is at the flow-stress level by modifying the amplitude of the kinematic hardening. The oxidation-altered kinematic hardening can predict the effect of oxidizing environments on mechanical behavior, specifically the plastic strain rate in the secondary creep stage, and lifetime. Finally, the oxidation model is verified to predict surface roughness and oxide thickness distributions by performing a finite-element simulation on a notched specimen subjected to creep and developing a complex multiaxial stress field.

提出了一个新的预测氧化物厚度演变的本构方程，并在具有基于硬化的损伤密度函数的晶体可塑性框架中实现了该方程。氧化模型取决于初始表面粗糙度以及累积的塑性应变和应力三轴性。通过修改运动硬化的幅度，可以在流动应力水平上描述氧化对机械性能和损伤的影响。氧化改变后的运动硬化可以预测氧化环境对机械性能的影响，特别是在次级蠕变阶段的塑性应变率和寿命。最后，