A Revisiting to Re-Effects on Dislocation Slip Mediated Creeps of the γ′-Ni3Al Phase at High Temperature via a Hybrid Model

The anomalous flow behavior of the γ′-Ni3Al phase at high temperature is closely related to a cross-slip of 1/2110111 super-partial dislocations. The acceleration of cross-slips induced by the addition of rhenium (Re) is known as Re-effects. In this work, by means of a series of lattice transitions, a hybrid model including a preexisting anti-phase boundary APB111 was constructed to assess the difficulty of cross-slips of 1/2110111 super-partial dislocations from 111 planes to 001 planes in the γ′-Ni3Al phases, and the impact of the addition of Re on these dislocation mediated creep resistances was reinvestigated by first-principles calculations. The results showed that the addition of Re at preferential Al sublattice sites was indeed beneficial for the cross-slip of the first leading 1/2110111 super-partial dislocations, and the existence of APB111 could promote cross-slip of second leading 1/2110111 super-partial dislocations. A detailed calculation of stacking fault energies demonstrated that an obvious Suzuki segregation of Re existed at APB111 and APB001, and Re preferentially occupied Ni sublattice sites. It is found Re-segregations at APB111 were disadvantageous for the cross-slip of new 1/2110111 super-partial dislocations, but the formation of more Kear-Wilsdorf dislocation locks could benefit from Re-segregations at APB001.