Micromechanics-based strain hardening model in consideration of dislocation-precipitate interactions

A micromechanics-based model to predict yield strength and plastic work hardening is proposed. To simplify the problem, additional strengthening by dislocation-dislocation interaction is assumed to be related only to the resistance to the motion of dislocations by uniformly distributed precipitates. The interaction between the mobile dislocations and precipitate particles is facilitated in a physically based approach. The main parameters of the proposed model are the size and strength of the precipitate under different aging conditions and microstructural parameters along with the stress state around the idealized precipitate. For verification purposes, the proposed hardening model was calibrated with previously published data and applied to the prediction of the yield stress and flow curve for precipitated alloys under different aging conditions. In particular, the existence of a transient region in the hardening rate from positive to negative could be reproduced well.