Nb-Si金属间化合物基超高温合金研究进展

Research Progress on Ultra-high-temperature Nb-silicide-based Alloys

Nb Si金属间化合物基超高温合金（Nb-Si基合金）具有高熔点、低密度和良好的加工性能,目标使用温度达到1 200～1 400℃,成为用于新一代高推重比航空发动机热端部件最有潜力的候选材料.主要介绍了北京航空航天大学在Nb Si金属间化合物基超高温合金领域的研究成果,包括合金化、加工制备技术（电弧熔炼、感应熔炼、定向凝固和粉末冶金）、组织控制与性能表征和热防护涂层材料体系设计与制备技术等.发展了Y2 O3坩埚真空感应熔炼和Y2O3模壳精密成型顺序凝固技术,成功制备了涡轮叶片模拟件;发展了Al2O3/Y2O3、Y2O3/Y2O3陶瓷坩埚/模壳液态金属冷却定向凝固技术,实现了Nb-Si基合金的定向凝固组织控制和强韧化匹配;发展了热防护涂层材料体系和制备技术,在合金基体和涂层的高温抗氧化方面均取得了较大的进展.

With higher melting points,relatively lower densities and good processability,Nb-Si based alloys show great promise for application as the next generation turbine airfoil materials with the operating temperature of 1 200-1 400 ℃.This paper introduces main research achievements of Beihang University in the field of ultra-high-temperature Nb-Si based alloys,mainly including alloying design,processing technologies （arc melting,induction melting,directional solidification,powder metallurgy）,thermal protection coating material design and preparation technology and so on.Vacuum induction melting and precision molding with Y2O3 crucible are developed and used for successful preparation of simulated turbine blade.The liquid metal cooling directional solidification with Al2 O3/Y2O3,Y2 O3/Y2O3 crucible/mould is developed,with which the microstructures of directionally solidified Nb-Si based alloy are optimized to attain the balance of strength and toughness.Thermal protection coating material design and preparation technology are studied and great progress in high temperature oxidation resistance of alloy substrate and coating are attained.