Effect of thermodynamic coupled simulation condition on microstructure and stress rupture properties of DZ406 alloy

There is a problem about microstructure evolution and properties degradation for the superalloy turbine blades in long term service conditions. DZ406 alloy samples were pre-loaded to simulate the high temperature service environment of turbine blades. The thermodynamic coupling simulation conditions were 980 ℃/70 MPa, 980 ℃/110 MPa, 980 ℃/140 MPa and 980 ℃/180 MPa respectively. And then the samples were subjected to stress rupture property test at 980 ℃/275 MPa. The microstructure and 980 ℃/275 MPa rupture life of the samples under different service loading conditions were observed and analyzed. The results show that the heat treatment microstructure of DZ406 alloy is composed of carbides, residual γ +γ´ eutectic and regular γ´ phase. The morphology and size of carbides and eutectic have no obvious change with the increase of loading stress under simulated service conditions. The γ´ phase of the sample parallel to [001] direction presents different degrees of rafting, and the size of γ´ phase perpendicular to [001] direction obviously increases. The residual stress rupture life of the sample declines rapidly with the increase of service stress.