Dislocation dynamics based modelling of dislocation-precipitate interactions in bcc metals

The influence of dislocation core on the interaction between an edge dislocation and a spherical precipitate was investigated using the combination of the parametric dislocation dynamics and the boundary element method with a dislocation core model. In the results of the simulations, the dislocation core of the edge dislocation behaves differently between inside and outside the precipitate. The calculated critical resolved shear stress is strongly affected by the dislocation core. Therefore, it could be found that the influence of dislocation core is a dominant factor in determining the strength of the interaction. Then, we derived an equation for evaluating the influence of dislocation core on the critical resolved shear stress. The derivation was done using the difference between the γ-surface energy in iron and that in copper, because there is a significant difference in-between. The equation can be solved without any simulation runs. The result of the equation was then compared to that of the simulations, which showed that the equation gives a good evaluation of the influence of dislocation core. Since the equation is derived without any limitation on the kind of materials, it can be applicable to the evaluation of the strength of the other alloys with precipitates.