Molecular dynamics simulations were made of crack-tip dislocation emission in face-centered cubic solids. The results were analyzed in terms of recent continuum formulations of the problem. In mode-II, the present metals exhibited a new and unexpected mechanism - for 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, Rice's continuum formulation underestimated the stress intensity - for dislocation emission - by a factor that approached 2. Surface-stress corrections to the emission criterion made the continuum predictions and simulations agree to within 20%.

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