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针对高压涡轮导向叶片服役性能需求特点研发了一种低密度、低成本、高强度Ni3Al基单晶合金IC21.该合金的Re含量不大于1.5%,密度小于8.0 g/cm3.金相法测得合金的初熔温度约为1345℃.经过标准热处理后,IC21合金中γ’相分布均匀,体积分数为80%左右,尺寸约为420 nm,具有较高的γ’相立方化程度和排列有序度.IC21单晶合金在1100℃下抗拉强度为490 MPa,屈服强度为470 MPa,在1100℃,140 MPa条件下的持久寿命可达170.5 h,1150℃,100 MPa条件下的持久寿命可达110.0 h.IC21单晶合金具有良好的高温组织稳定性和较好的抗高温氧化性,1080℃长期热暴露后,没有拓扑密堆相析出,在1100和1150℃大气中100 h的氧化动力学曲线遵循抛物线规律,氧化增重速率分别为0.015和0.045 mg/(cm2·h).组织结构分析表明,该单晶合金的高温强度主要来源于高的γ’相含量、高的合金错配度和致密的界面位错网结构.γ’
A low density, low cost and high strength Ni3Al-based single crystal alloy IC21 has been developed for service performance requirements of high-pressure turbine guide vanes. The Re content of this alloy is not more than 1.5% and the density is less than 8.0 g / cm3. The initial melting temperature is about 1345 ° C. After the standard heat treatment, the γ ’phase of IC21 alloy is uniformly distributed with a volume fraction of about 80% and a size of about 420 nm, and has a high cubic degree of γ’ phase and an orderly degree .IC21 single crystal alloy has a tensile strength of 490 MPa and a yield strength of 470 MPa at 1100 ° C and a sustained life of 170.5 h at 1100 ° C and 140 MPa and a durable life of 1150 ° C and 100 MPa 110.0 h.IC21 single crystal alloy has good high-temperature microstructure and good high temperature oxidation resistance. After the long-term thermal exposure at 1080 ℃, there is no topologically dense phase precipitation. The oxidation kinetics at 1100 and 1150 ℃ for 100 h The curves follow the parabolic law and the rates of weight gain and oxidation are 0.015 and 0.045 mg / (cm2 · h), respectively. The microstructure analysis shows that the high temperature strength of the single crystal is mainly due to the high γ ’phase content and the high alloy misfit And dense interfacial dislocation network structure.