This article presents a mechanistic approach for modeling the strain hardening response of polycrystalline Ni-based superalloys such as ME3, RR 1000, Alloy 720 Li, and IN 100. The mechanistic approach considers strain hardening in Ni-based superalloys in two stages: (a) self-hardening of individual {111} slip systems in the low plastic strain regime and (2) latent hardening of multiple {111} slip systems in the high plastic strain regime. Both strain hardening regimes have been modeled on the basis of interactions of superkinks with Kear–Wilsdorf locks and related to pertinent microstructural parameters such as the volume fractions of γ′ precipitates, grain orientation, and dislocation substructure. The mechanistic strain hardening model predicts that the strain hardening exponents in both the low plastic strain (n₁) and the high plastic strain (n₂) regimes increase with increasing values of the sum of the squares of the volume fractions of the primary and secondary γ′ precipitates, the number of {111} and {010} slip systems activated, and the critical height of the superkinks. A comparison of model predictions against experimental strain hardening exponents indicates good agreement between model predictions and experimental data. Implications of the operative strain hardening mechanisms during low-cycle fatigue and high-cycle fatigue are elucidated.

本文提出了一种用于模拟多晶镍基高温合金如ME3，RR 1000，合金720 Li和IN 100的应变硬化响应的机制方法。该机制方法考虑了镍基高温合金的应变硬化分为两个阶段：（a ）在低塑性应变状态下对各个{111}滑移系统进行自硬化，以及（2）在高塑性应变状态下对多个{111}滑移系统进行潜在硬化。两种应变强化机制均基于超级扭结与Kear-Wilsdorf锁的相互作用进行建模，并与相关的微观结构参数（例如γ的体积分数）相关'析出，晶粒取向和位错亚结构。机械应变硬化模型预测，低塑性应变（n ₁）和高塑性应变（n ₂）两种状态下的应变硬化指数都随着一次和二次体积分数平方和的增加而增加。γ '析出，激活{111}和{010}滑移系统的数量，以及超级纽结的临界高度。模型预测与实验应变硬化指数的比较表明，模型预测与实验数据之间具有良好的一致性。阐明了在低周疲劳和高周疲劳中操作应变强化机制的含义。