Dislocation-precipitate interaction map

Abstract

The present research is the first attempt to systematically quantify the dislocation-precipitate interaction in terms of the applied shear stress, precipitate resistance, and required time to reach the critical state of dislocation-precipitate interaction when a dislocation line is about to pass through precipitates. A modified line dislocation dynamics is adopted to model the dislocation-precipitate interaction. In the present modeling approach utilizing three-dimensional dislocation dynamics simulations, thousands of data points on Cu are obtained accounting for various precipitate resistances, applied shear stresses, and precipitate spacing. A universal equation is found based on simulations to quantify dislocation-precipitate interactions in terms of the applied shear stress, precipitate resistance scale, and dislocation-precipitate interaction time. The dislocation-precipitate interaction time versus precipitate resistance and stress, referred to as “dislocation-precipitate interaction map,” determines the “pass” or “no-pass” state of the interaction. Using this map, we incorporate the dislocation-precipitate interaction time in a two-dimensional dislocation dynamics approach (DD) coupled with the finite element method (FEM). This framework, FEM-DD, is applied to model mechanical behavior of a free-standing copper thin film. Simulation results show a dual effect of the dislocation-precipitate interaction time on hardening behavior.