Simulations of the interactions between dislocations and solute atoms in different loading conditions

Abstract

Dynamic strain aging, i.e. the interaction between dislocations and solute atoms, affects the mechanical properties of alloys. In this paper, a 2D-kinetic Monte Carlo model relating to the interaction between dislocations and solute atoms is developed to simulate the motions of edge dislocations in four different conditions. In “single dislocation with constant stress rate” condition, single dislocation is pinned under low stress rate, moves continuously under high stress rate, and moves intermittently under middle stress rates. In “multi-dislocation with zero stress” condition, the solute atoms gather below positive dislocations and above negative dislocations. In “multi-dislocation with constant stress” condition, the influence of solute atoms on dislocation motion becomes stronger with stress decreasing. In “multi-dislocation with constant stress rate” condition, the collective pinning and unpinning result in the stepped curve of total displacement. The simulated results present the process of dynamic strain aging in a microscopic scale and are consistent with theoretical results.