The effect of microstructure on the creep behavior of a low rhenium-containing single crystal nickel-based superalloy

A low rhenium-containing single crystal nickel-based superalloy designated DD6 with different γ′ morphologies induced by discrepant aging treatments crept at 1100 °C/137 MPa and 850 °C/660 MPa. The test results and TEM observations showed that creep mechanism varies with microstructure and test temperature. For creep at 1100 °C/137 MPa, the dislocation network on γ/γ′ interface plays a key role in prolonging creep life. The sample with the lager cubical γ′ precipitate got the longest rupture life. For creep at 850 °C/660 MPa, the morphology of γ′ phase and the width of the γ channels dominate the deformation behavior. The sample with smaller γ′ particles and narrower γ channel exhibited the highest creep life due to the inhomogeneous activations of multiple 〈112〉 {111} slip systems.