Ni-based superalloys are typically strengthened with ordered fcc \( \gamma^{\prime} \) precipitates (L1₂ structure) which impart a number of hardening mechanisms including anomalous hardening due to cross slip from {111} to {010} planes. On the other hand, the presence of shearable \( \gamma^{\prime} \) precipitates promotes cyclic softening and slip localization. The onset of cyclic softening and slip localization processes in \( \gamma^{\prime} \)-strengthened Ni-based superalloys is still poorly understood and has not been modeled. In this investigation, the salient mechanisms responsible for cyclic softening and slip localization in Ni-alloys containing \( \gamma^{\prime} \) precipitates are reviewed and the pertinent information is utilized to develop mechanistic models for predicting the cyclic response, slip localization, and fatigue life of this class of engineering alloys. Mechanistic modeling reveals that cyclic softening and slip localization can be attributed to three processes: (1) stable expansion of superkinks with subcritical kink heights, (2) shearing, and (3) bowing of \( \gamma^{\prime} \) precipitates. The onset of cyclic softening commences in the microplastic regime and occurs when the accumulated shear strain along the operative {111} plane exceeds the average \( \gamma^{\prime} \) size. The roles of cyclic softening and slip localization in reducing high-cycle fatigue strength and fatigue life are elucidated and discussed.

镍基高温合金通常通过有序的fcc \（\ gamma ^ {\ prime} \）析出物（L1 ₂结构）进行强化，这些析出物赋予许多硬化机制，包括由于从{111}到{010}平面的交叉滑移而引起的异常硬化。 。另一方面，可剪切\（\ gamma ^ {\ prime} \）沉淀的存在会促进循环软化和滑移局部化。\（\ gamma ^ {\ prime} \）强化的镍基高温合金中循环软化和滑移局部化过程的发生仍然知之甚少，尚未建模。在这项研究中，显着机制负责包含\（\ gamma ^ {\ prime} \）的镍合金的循环软化和滑移局部化对沉淀物进行了审查，并利用相关的信息开发了机械模型，以预测此类工程合金的循环响应，滑移局部化和疲劳寿命。机理建模表明，循环软化和滑移局部化可归因于三个过程：（1）具有超临界扭折高度的超级扭结的稳定膨胀，（2）剪切和（3）弯曲（\ gamma ^ {\ prime} \）沉淀。循环软化的开始是在微塑性状态下开始的，并且在沿有效{111}平面累积的剪切应变超过平均\（\ gamma ^ {\ prime} \）大小时开始发生。阐明并讨论了循环软化和滑移局部化在降低高周疲劳强度和疲劳寿命中的作用。