粉末高温合金平衡相析出行为的热力学对比

Thermodynamic calculation of equilibrium phases for P/M superalloys

摘要: 利用热力学平衡相计算方法及相应的高温合金数据库对René95,René88DT和an741нп三种合金在平衡相析出温度范围和析出量以及之间的关联性进行了系统的热力学计算对比分析.结果表明:三种粉末高温合金的平衡相种类基本相同,主要平衡相为γ,γ'和碳化物M₂₃C₆,MC,M₆C.René95合金中的碳化物含量要高于其他两种合金.зп741нп有着较高的γ'相析出温度和较大的析出量.随温度降低,Co和Nb从γ'相中析出,在其周围富集,其中зп741нп合金中尤为明显.合金元素的偏聚度也和合金的初熔点与终熔点之差的大小有关,其熔解区间越大即初熔点和终熔点之差越大,合金元素的偏聚度越大.

Abstract: The precipitation temperature range and quantity in equilibrium phases of three P/M superalloys, René95, René88DT and зп741нп, were systematically calculated by using a thermodynamic calculation method and the relevant superalloy database. The calculated results show that the three alloys have the same major phases, such as γ,γ' and MC, M6C, M23C6 carbides. The quantity of carbides in René95 is more than the others. The γ' precipitation temperature of зп741нп is higher and the γ' amount is more than that of René95 or René88DT. The liquid segregation behaviors of the three alloys were compared and discussed.