The effects of thermal activation upon dislocation emission from an atomistic crack tip were considered. Molecular dynamics simulations were carried out, at various constant temperatures, in order to investigate the thermal effects. The simulated results showed that the processes of partial dislocation generation and emission were temperature-dependent. As the temperature increased, the incipient duration of partial dislocation nucleation became longer, the critical stress intensity factor for partial dislocation emission was reduced and more dislocations were emitted at a given loading level. The dislocation velocity away from the crack tip, and the separations of the partial dislocations, did not appear to be temperature-dependent. The simulated results also showed that, as the temperature increased, the stress distribution increased slightly along the crack. Stress-softening at the crack tip, caused by thermal activation, did not occur in the present simulation.

The Effect of Thermal Activation on Dislocation Processes at an Atomistic Crack Tip. Y.W.Zhang, T.C.Wang, Q.H.Tang: Journal of Physics D, 1995, 28[4], 748-54