Elastoplastic behavior of the γ-phase in Ni-based single crystal superalloys: A molecular dynamics study considering Re and temperature effect

Recent investigations suggest that the addition of trace Re element has a significant influence (the so-called Re effect) on the mechanical properties of Ni-based single crystal superalloys. Nevertheless, the mechanisms for this Re-effect at different service temperatures are still unclear. The present work studied the elastoplastic deformation behavior of the gamma phase in Ni-based single crystal superalloys by molecular dynamics, with the emphasis on Re-associated mechanisms at a wide range of Re contents (from 0 at.% to 9 at.%) and temperatures (from 300 K to 1100 K). The results indicate that the Re content and temperature have an obvious effect on the elastic modulus of the gamma phase, the higher the Re content and temperature, the lower the elastic modulus. The yield stress and strain decrease with the increase of Re content and temperature. Both the temperature and Re content affect the formation and propagation of dislocations, which further leads to a correlation between the evolution of dislocations and stress-strain. In addition, the effects of size and strain rate on elastoplastic behavior are also studied.