镍基单晶高温合金是现代航空发动机涡轮叶片的关键材料，在服役过程中承受力热等复杂载荷的耦合作用，易发生极复杂的损伤和失效行为。筏化的单晶合金中相界失配应力（或错配度）在蠕变损伤演化中的作用机制仍不清楚。本项目结合国家重大需求，全面系统的开展扫描透射电子显微镜（STEM）纳米云纹技术研究，创新发展基于电子层析原理的STEM三维云纹法，以及开展基于STEM云纹法的原子晶格大面积反演技术研究。利用发展的方法和技术实验研究单晶合金纳观共格相界面失配应变/应力分布及其高温下演化规律，探索单晶合金不同预先筏化方向对蠕变力学性能的影响机制，揭示预筏化单晶合金中相界失配应力（或错配度）在蠕变变形、微损伤萌生/演化中的作用机制，为高温下单晶叶片工作可靠性评估以及为推动单晶叶片制备工艺优化奠定坚实基础。

Ni-based single crystal superalloy is the key material of modern aero-engine’s turbine blades. Subjected to very complicated thermo-mechanical coupling loads during service, the Ni-based single crystal blades are vulnerable to the extremely complex damage and failure behaviors. During creep damage evolution in rafted single crystal superalloy，the mechanism of phase boundary mismatch stress (or mismatch) is still unclear. In combination with our national major demand, this project intends to carry out a comprehensive and systematic research on STEM nano-moiré technology, innovative research on STEM 3D moiré method based on the principle of electron tomography, and research on large area inversion technique of atomic lattice based on STEM moiré method. By using the developed methods, this project focuses on the following issues: experimental studies of the mismatch strain/stress distribution and its evolution under high temperature at the nano-coherent phase interface; exploration of the mechanism of different pre-rafted directions on creep mechanical properties of single crystal superalloy; and revelation of the mechanism of phase boundary mismatch stress (or mismatch) on creep deformation and micro-damage initiation/evolution of pre-rafted single crystal superalloy. The execution of this project will lay a solid foundation for the reliability evaluation of single crystal blade at high temperature and the optimization of the preparation process of single crystal blade.