Diffusion and interaction of prismatic dislocation loops simulated by stochastic discrete dislocation dynamics
Abstract
Body-centered cubic metals and alloys irradiated by energetic particles form highly mobile prismatic
dislocation loops with a/2█<111>█-type Burgers vectors. We show how to simulate thermal diffusion of prismatic
loops using a discrete dislocation dynamics approach that explicitly includes the stochastic forces associated with
ambient thermal fluctuations. We find that the interplay between stochastic thermal forces and internal degrees
of freedom of loops, in particular the reorientation of the loop habit planes, strongly influences the observed loop
dynamics. The loops exhibit three fundamental types of reactions: coalescence, repulsion, and confinement by
elastic forces. The confinement reactions are highly sensitive to the internal degrees of freedom of the loops.
Depending on the orientation of the loop habit planes, the barrier to enter an elastically confined bound state is
lowered substantially, whereas the lifetime of the bound state increases by many orders of magnitude.
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