It was noted that a full analysis of the mechanisms via which dislocations by-passed particles was difficult because of the complexities which were associated with elastic interactions between dislocation segments, their interactions with particle stress field, the flexibility of the dislocation line in 3 dimensions and the 3-dimensional topological changes that occurred. The results of full 3-dimensional dislocation dynamics simulations, based upon the level set method, were presented here. They accounted naturally for all of these factors. An examination was made of by-passing mechanisms for penetrable misfitting particles and impenetrable particles; with and without misfit. The simulations revealed a wide range of by-passing mechanisms including: particle cutting, dislocation loop formation and their various combinations. Loops were observed to form ahead of and behind particles, on the sides of particles, between particles and around particles; in various combinations. Some of the by-passing mechanisms were classical, and others had never been previously reported. A novel dislocation multiplication mechanism was also observed which was associated with misfitting particles.

Level Set Simulations of Dislocation-Particle By-Pass Mechanisms. Y.Xiang, D.J.Srolovitz, L.T.Cheng, E.Weinan: Acta Materialia, 2004, 52[7], 1745-60