A Theoretical Investigation on the Cross-Slip Conditions of <110> Screw Dislocations in L12 Ni3Al at Finite Temperatures

Abstract

The influence of temperature on the cross-slip conditions of <110> superpartial dislocations from the {111} glide plane to the {001} cube plane was investigated based on the elastic constants and generalized stacking fault energies of L1₂ Ni₃Al at temperatures up to 1500 K obtained by the combination of first-principles calculation with quasiharmonic approximation. The obtained values in this study are in agreement with available theoretical and experimental data. The results show that the relative stability of antiphase boundary (APB) to superlattice intrinsic stacking fault (SISF) on the {111} plane, the cross-slip driving force of 1/2<110> screw superpartials from {111} to the {001}, and the activation enthalpy required for cross-slip from {111} to {001} decrease with increasing temperature, and the APB remains stable against SISF on the {111} plane within the temperature range from 0 to 1500 K. The present results are helpful for better understanding the anomalous yield behavior of L1₂ Ni₃Al.