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Ni-Cr-Al系高温合金作为一种常用的新型航空发动机密封材料,通过调整Cr、Al含量可以提高耐高温及热腐蚀性能,但同时也会影响合金的热加工性。通过热模拟压缩试验,分析了Cr,Al含量分别在15%～25%,4%～5%(质量分数,下同)范围调整时,对合金高温变形特性的影响规律。结果表明,Cr、Al含量的提高会不同程度缩小合金的安全热加工区域。通过热力学平衡相计算和组织观察发现,成分变化影响热加工性的主要原因是晶界胞状碳化物的形态及析出量变化。综合考虑热变形试验、组织观察结果以及耐高温腐蚀的因素,20%Cr和4%Al是比较合适的成分选择。
Ni-Cr-Al superalloy, as a commonly used new aeroengine sealing material, can improve the high temperature resistance and hot corrosion resistance by adjusting Cr and Al contents, but also affects the hot workability of the alloy. Through the thermal simulation compression test, the influence of the Cr, Al content on the high temperature deformation properties of the alloy was analyzed when the contents of Cr and Al were adjusted in the ranges of 15% ~ 25% and 4% ~ 5% respectively. The results show that the increase of Cr and Al contents will reduce the safe hot working area of the alloy to varying degrees. By thermodynamic equilibrium phase calculation and microstructure observation, it is found that the main reason that the compositional changes affect the hot workability is the change of morphology and precipitation amount of the grain boundary cellular carbides. Considering the thermal deformation test, microstructure observation results and the factors of high temperature corrosion resistance, 20% Cr and 4% Al are more suitable components to choose from.