Molecular dynamics simulations were presented which were aimed at examining crack-tip dislocation emission in face-centered cubic solids. The results were analyzed in terms of previous continuum formulations of the problem. In mode-II, Au, Pd and Pt exhibited a new and unexpected mechanism of crack-tip dislocation emission which involved the creation of a pair of Shockley partials on a slip plane that was one plane below the crack-plane. In mode-I, and for all of the above materials, Rice's continuum formulation underestimated the stress intensity for dislocation emission by a factor of almost 2. Surface-stress corrections to the emission criterion decreased the disparity between continuum predictions and simulations to less than 20%.

Crack Tip Dislocation Nucleation in Face-Centered Cubic  Solids. J.Knap, K.Sieradzki: Physical Review Letters, 1999, 82[8], 1700-3