低成本二代镍基单晶高温合金的研究进展

Due to their excellent high temperature mechanical properties, Ni-based single crystal superalloys have been widely used in the preparation of single crystal turbine blades in aeroengines. The addition of Re element significantly improves creep properties of single crystal superalloys. However, Re addition significantly increases the cost of single crystal superalloys. Therefore, it is of great significance to design new type single crystal superalloys with low Re content (low cost) and excellent creep properties. In this paper, the medium temperature and high temperature creep properties of several low-cost second-generation single crystal superalloys and typical second-generation single crystal superalloy CMSX-4 were compared. Meanwhile, main controlling factors of medium temperature and high temperature creep properties of second-generation single crystal superalloys were analyzed from three aspects: solid solution strengthening degree of γ and γ′phases, γ/γ′misfit and effective diffusion coefficient. The main controlling factors of high temperature creep properties are solid solution strengthening degree of γ phase and γ/γ′misfit, while the main controlling factors of medium temperature creep properties are solid solution strengthening degree of γ′phase. Based on this rule, the alloy design strategy for low-cost second-generation single crystal superalloys was proposed.