A discrete dislocation dynamics framework for coupled long- and short-range dislocation-precipitate interactions

Dispersoids, as well as precipitates formed during thermal aging or irradiation, can significantly strengthen metallic alloys by impeding dislocation motion through both long-range and short-range interactions. Depending on the specific alloy system, these inclusions vary in shape and phase, and may possess both coherency and modulus mismatch compared to the alloy matrix. In this work, we develop a unified numerical framework to concurrently model long-range and short-range dislocation-precipitate interactions. The long-range interaction is formulated using Eshelby’s equivalent inclusion method combined with a polyhedral discretization of the precipitate, enabling non-ellipsoidal geometries and spatially varying external stress fields to be treated numerically. Short-range resistance is incorporated through the generalized γ -surface of the precipitate phase. The implementation is validated using benchmark problems for spherical inclusions, spherical inhomogeneities, and dislocation-void interactions. It is then used to examine the separate effects of eigenstrain and elastic-modulus mismatch and to study interactions between a single dislocation and isolated χ - and σ -phase precipitates in W-Re alloys. For the χ -phase configurations considered, long-range elastic interactions provide the dominant contribution to the calculated obstacle resistance, whereas the high GSFE-derived resistance suppresses shearing of the σ -phase precipitate in the present simulations. The discrepancy with available atomistic results indicates that σ -phase shearing may be influenced by factors beyond the GSFE-derived resistance represented in the present model. Overall, the framework provides a mechanism-oriented approach for resolving and separating coupled long- and short-range interactions in controlled dislocation-precipitate configurations.