Effects of heat shocking on microstructure and creep performance of a directionally solidified Ni₃Al base alloy

Infrared rapid heating system was used to study the effects of heat shocking on microstructure and creep performance of a directionally solidified Ni₃Al base alloy. After heat shocking for 200, 400, 600 and 800 cyc at 1100°C, the sample's creep performances at 980°C, 218 MPa were tested. Observation of the microstructure indicated that γ′ precipitates coarsened after heat shocking, at the same time, the MC carbides at boundary and interdendritic decomposed to M₆C and γ′. Creep life of the alloy decreased largely after heat shocking due to coarsening of γ′ precipitate and reducing of γ′ volume.