Dislocation generation is studied in a generalized two-dimensional Frenkel-Kontorova model which allows consideration of dislocations of arbitrary Burgers vector and line shape. Two new mechanisms for dislocation generation at high stresses have been found: (1) heterogeneous nucleation of dislocations on preexisting dislocations and (2) generation of dislocation loops in the wake of a moving dislocation. These new mechanisms provide an understanding of how materials generate the density of dislocations required to accommodate arbitrary strains at high strain rates.

• Received 21 April 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.2702