An analysis was made of dislocation nucleation from a penny-shaped crack, of near-atomic dimensions, under a shear stress. By using a variational boundary integral method within the Peierls-Nabarro framework, the saddle-point configuration was determined for embryonic dislocation loops and their associated activation energies under stress levels which ranged up to the critical loading of athermal nucleation. The results showed that a crack facilitated dislocation nucleation not only by concentrating the stress, but also by supplying elastic strain energy.

Dislocation Nucleation from a Penny-Shaped Crack. G.Xu: Materials Science and Engineering A, 2001, 309-310, 365-9