Strengthening effect of nanoprecipitates on twinned copper: a discrete dislocation dynamics simulation study

Abstract Introducing twin boundaries (TBs) and nanoprecipitates has emerged as a highly effective approach for enhancing the mechanical properties of metallic materials. In this paper, the dislocation–precipitate and dislocation-TB interaction models were incorporated into the three-dimensional discrete dislocation dynamics (DDD) framework. The effect of nanoprecipitates on the mechanical properties of single crystal and twinned copper under various loading direction angles was investigated. For single crystal copper containing precipitates, the synergistic strengthening effects of forest dislocations and precipitates were explored by theoretical models. For twinned copper, the TB strengthening effect is derived from DDD simulation results and theoretical models. Analyses revealed that when the loading direction angle is 0° and 90°, the introduction of precipitates has almost no impact on the TB strengthening effect. When the loading direction angle is 90°, the trans-twin dislocations spanning across two lamellae were identified, and the nanoprecipitates hindered the slip of the trans-twin dislocations. When the loading direction angle is 75°, the nanoprecipitates suppressed the strength softening caused by twinning deformation. Furthermore, the accumulation of twinning dislocations on TBs, facilitated by nanoprecipitates, increased the difficulty for dislocations to interact with TB. This study shows the potential of employing DDD for investigating plasticity mechanisms in materials with diverse microstructures, paving the way for future designs of metallic materials through DDD simulations.