Abstract The high temperature creep behavior of a single crystal Ni-based superalloy was studied by combined experimental and numerical methods. The creep test results showed that the creep curves exhibited a three-stage feature. The qualitative explanations for each stage of the creep curves were carried out based on the microstructure characterizations of γ/γ′ phases and dislocations. An elastoplasticity incorporated phase-field model was developed to provide quantitative understanding on directional coarsening (rafting) of γ′ phase. The simulation results showed that the directionality of γ′ coarsening was induced by both dislocation activity in γ channels and elastic inhomogeneity between γ and γ’ phases, therein the dislocation activity played a major role. This findings provide new insights into the design of novel single crystal superalloys with improved creep properties.

中文翻译：

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单晶高温合金的高温蠕变机制：相场模拟和微观结构表征

摘要 采用实验和数值方法相结合的方法研究了单晶镍基高温合金的高温蠕变行为。蠕变试验结果表明蠕变曲线呈现三级特征。基于γ/γ'相和位错的显微组织表征，对蠕变曲线各阶段进行了定性解释。开发了一种包含弹塑性的相场模型，以提供对 γ' 相定向粗化（漂流）的定量理解。模拟结果表明，γ' 粗化的方向性是由 γ 通道中的位错活动和 γ 和 γ' 相之间的弹性不均匀性引起的，其中位错活动起主要作用。