Slip geometry of dislocations related to cutting of the γ′ phase in a new generation single-crystal superalloy

Abstract The superdislocations in the γ′ phase of a fourth-generation single-crystal TMS-138 superalloy have been characterized after creep rupture at a stress of 137 MPa under different temperatures. The number of slip dislocations increases with the increase of creep temperatures from 1100 to 1150 °C. The dominant cutting mode of the γ′ phase is dislocation pairs coupled by an antiphase boundary (APB). The popular superdislocations in the γ′ phase show screw character with Burgers vectors or . Also, observed in the γ′ phase are 60° or screw superdislocations in either [1 1 0] or [ 1 1 0 ] directions, and [0 0 1] edge superdislocations. Stacking faults are seen from the dissociation of superdislocations. These superdislocations are related to the damage of the rafted structure in the superalloy.