Interactions between particles and low-angle dislocation boundaries during high-temperature deformation

Abstract

Abstract Stability and motion of low-angle dislocation boundaries in an array of particles is investigated. The 2D model considers discrete dislocations and circular precipitates with and without coherency stress fields. Dislocation – dislocation interactions, superimposed with precipitate stress fields and an externally applied stress, drive glide and climb of the dislocations. Results show that, in the case of a simple external shear loading, a single-valued critical applied shear stress exists which separates stable and unstable low-angle boundary configurations. This critical stress can differ considerably from the Orowan stress. More complicated applied stress states result in less clearly defined transitions between stable and unstable boundary regimes. Dislocation – dislocation interactions that stabilize low-angle dislocation boundaries thus may influence the high-temperature strength of particle-strengthened alloys.