Response embedded atom model potential of Pb at finite temperature: application on the dislocation mobility

Abstract

Dislocation is a major carrier of plastic deformation for metal materials and are crucial. Understanding the mechanism of dislocation motion is beneficial for understanding the plastic deformation of materials under dynamic loading. In this work, a new response EAM (REAM) potential is developed for the applications under high pressure and finite temperature conditions. We use the REAM potential to investigate the behaviors of edge and screw dislocations in Pb by molecular dynamics (MD) simulations, and compare it with two commonly used EAM potentials. Specially, we examine the influence of the stacking fault energy and the temperature-dependent elastic constants on the dislocation motions. Our results show that the temperature-dependent elastic constants do not considerably affect the dislocation motion at the linear region of low stress, while the stacking fault energy plays a significant role. In the nonlinear region, the stacking fault energy and elastic constant together influence the dislocation motion. In subsonic and low transonic regimes, the dislocation width oscillates with time, but eventually fluctuates around equilibrium width.