Dependence of critical stress on temperature and shear strain rate in grain boundary of W

The coupled grain boundary migration driven by shear stress is considered to be an important factor in grain growth. We carried out a molecular dynamic simulation to investigate the critical stress of this motion in a grain boundary of tungsten. It is revealed that the dependence of critical stress on temperature follows a sigmoidal-like curve at a temperature range from 10 to 1200 K. A high temperature is associated with a small critical stress. The shear strain, however, exhibits an independence of critical stress under the shear rate from 0·1 to 10 m/s^-1.