Creep properties and deformation mechanism of the containing 4.5Re/3.0Ru single crystal nickel-based superalloy at high temperatures

摘要

By means of creep properties measurement and microstructure observation, an investigation has been made into the creep behaviors of a Re/Ru-containing single crystal nickel-based superalloy at high temperatures. Results show that after fully heat treatment, the microstructure of the Re/Ru-containing single crystal nickel-based superalloy consists of the cuboidal γ' phase about 0.4 μm in size coherent embedded in the γ matrix. The creep life of the superalloy at 137 MPa/1100 ℃ is measured to be 321 h. And the deformation mechanism of alloy during steady state creep are dislocations slipping in γ matrix and climbing over the rafted γ' phase. In the latter stage of creep at 1085 ℃, the dislocations shearing into γ' phase may cross-slip form {111} to {100} planes to form the K-W locks, which may restrain the slipping and cross-slipping of dislocations to improve the creep resistance of alloy. While the size of the rafted γ' phase in thickness diminshes as the creep temperrature rises, which may enhance the climbing rate of dislocations to decrease the creep lifetimes of alloy.