It was recalled that recent tests, as well as dislocation dynamics simulations, had revealed that plastic flow in materials which exhibited a largely dominant slip system exhibited scale-free intermittent dynamics that were characterized by dislocation avalanches with a power-law distribution of amplitudes. In order to explore further the complexity of dislocation dynamics during plastic flow, a statistical analysis was made of dislocation avalanche correlations and avalanche triggering. It was shown that the rate of avalanche triggering, immediately after any avalanche, was larger than the background activity due to uncorrelated events. This self-induced triggering increased in intensity, and remained above the background rate for longer times, as the amplitude of the main shock increased. The analysis suggested that stress redistributions, and the associated collective dislocation rearrangements, might be responsible for after-shock triggering in the complex process of plastic deformation.

Dislocation Avalanche Correlations. J.Weiss, M.C.Miguel: Materials Science and Engineering A, 2004, 387-389, 292-6