Effect of Ta on Creep Behavior of a Sort of Ni-Based Single Crystal Superalloy

Ni-based superalloys with different Ta contents were prepared by using screw selecting method. The effects of Ta on creep property and creep mechanism of the alloys at conditions of 850 ℃, 441 MPa and 950 ℃, 250 MPa were investigated. Results show that with the increasing of Ta content, the dislocation net at γ/γ′ interface facilitated and the creep rupture life of the alloys increased. When Ta content rose, the creep mechanism of the alloy transformed from dislocations sliding and cutting to stacking faults at 850 ℃, 441 MPa, and transformed from stacking faults to climbing of the dislocations at 950 ℃, 250 MPa.