Consideration of dislocation core effects in dislocation-precipitate interaction analysis using dislocation dynamics

To achieve rational alloy design, it is essential to accurately model the interaction between dislocations and precipitates. Previous studies have used the Peierls-Nabarro model to reproduce core effects to simulate the interactions with high accuracies, where many fractional dislocations are introduced. However, it requires a high computational cost and does not have a numerical stability. Therefore, we propose a new method that can account for dislocation core effects with a low computational cost and a high numerical stability. In our model, fractional dislocations are virtually put at each integration point on the dislocation. Because our model requires no fractional dislocations, it needs a less computational cost. Moreover, the relaxation of micro-dislocations at each timestep can be efficiently handled by using the FIRE2.0 algorithm, which drastically reduced the number of calculation steps required for convergence. We applied our method to a three-dimensional dislocation–precipitate interaction between a superdislocation and γ precipitates in the γ' phase of a nickel-based superalloy. As a result, the relationship between the diameter of spherical γ precipitates and the critical resolved shear stress (CRSS) was quantitatively consistent with Nembach’s theoretical prediction. Therefore, our method can account for dislocation core effects using only a single dislocation in dislocation-precipitate interaction simulations.