Modeling the generation, equilibrium, and emission of dislocations at elastically misfitted particles

Abstract

The generation, equilibrium, and emission of dislocations from an elastically mismatched particle–matrix interface under the combined effects of thermal and mechanical loading have been studied. Energy considerations are used to compute the generation, equilibrium, and instability conditions, and force balance is used to find the equilibrated loop shape. When the mismatch strain exceeds the generation limit, which is particle size dependent, the generation of dislocations lowers the system energy, and a stable dislocation loop segment will be generated and bulge out from the particle–matrix interface. Upon reaching instability, also particle size dependent, the dislocation will be emitted from the particle. Analytic expressions describing the generation, equilibrium, and instability are derived. A dislocation generation mechanism map is obtained for the analysis and design of particle-reinforced composites under thermo-mechanical loading.