镍对TiAl合金层片状组织分解的影响

Effects of Nickel on Dissolution of Lamellar Microstructure of TiAl Alloys

对镍原子百分数分别为０％，０．２％和０．５％的ＴｉＡｌ合金试样在１０５０℃和１１５０℃进行了层片组织分解退火实验。并对ＴｉＡｌ合金的铸态组织和不同条件下退火的组织进行了金相分析。结果表明：镍的加入细化了合金的铸态组织，促进了层片组织分解，显著缩短了分解退火时间。镍原子百分数为０．５％的ＴｉＡｌ合金在１１５０℃下退火１６８ ｈ即可获得均匀细小的等轴近γ组织。

Dissolving annealing experiments at 1 050 ℃ and 1 150 ℃ of lamellar microstructures of TiAl alloys containing Ni 0%, 0.2%, and 0.5% have been carried. And casting and annealing constructures have been observed by metallograph. Results showed: addition of Ni fines casting constructures, accelerates dissolution of lamellar constructures,and shortens remarkably dissolving annealing time of TiAl alloy. For the alloy containing Ni 0. 5 %,fine equiaxial near γ constructure can be obtained by annealing in 1150 ℃× 168 h conditions.