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

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 <0 1 1> or <1 0 1>. Also, observed in the γ′ phase are 60° or screw superdislocations in either [1 1 0] or [1 1̄ 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.