本项目以我国先进航空发动机高压涡轮叶片用第二代单晶高温合金DD432为研究对象，采用籽晶法制备 [011]和[111]取向不同偏离度的单晶试样。测试单晶合金试样高温拉伸和持久蠕变性能，然后利用金相显微镜、扫描电镜、高分辨透射电子显微镜、三维原子探针显微技术，分析合金元素作用、微观组织结构、变形组织演变和TCP相析出行为，研究取向偏离度对单晶合金[011]、[111]取向组织和性能的影响；在此基础上，研究[011]和[111]取向长期热暴露过程中组织稳定性及其力学性能变化规律，揭示[011]和[111]取向在热力耦合条件下TCP相析出行为及影响因素，建立取向-组织-性能-TCP相互依存关系模型；探索单晶叶片长寿命服役的最佳取向及偏离角度; 为提高长寿命单晶叶片性能奠定理论基础。

In this project, the second generation single crystal superalloy DD432 used as high pressure turbine blades of the domestic advanced aviation engine is investigated as the target. The single crystal specimens with the different deflection angle to [011] or [111] orientation are prepared by seed crystal method. High temperature tensile properties and stress rupture properties and creep properties are measured. By means of OM, SEM, X-ray diffraction, DSC, high resolution transmission electron microscope and three dimensional atomic probe microscopy, the analysis of alloy element action, various microstructures, evolvement of deformation microstructure and precipitation behavior of TCP phases are systemically carried out. The influence of deflection angles in the microstructure and properties of single crystal alloy with [011] or [111] orientation is systemically investigated. Further, the microstructure stability and mechanical properties evolvement of single crystal alloy with [011] or [111] orientation are investigated during long-term exposure. The mechanism of TCP phase precipitation under thermo-mechanical coupling condition will be revealed. The relationship model among orientation, microstructure, mechanical properties and TCP phases will be developed. The optimal orientation and its deflection angle to long-term service single crystal blades are explored. The safe reliability of single crystal blades during long term service will be improved. It provides the fundamentals for improving mechanical properties of long life blades.