Modeling the interfacial plastic strain incompatibilities associated with dispersed particles in high strength aluminum alloys

A new formulation based on an eigenstrain representation of Orowan looping was developed, and was coupled with a dislocation density based crystalline plasticity formulation and a specialized finite element framework to model the unrelaxed plastic strain and interfacial behavior associated with dispersed particles in high strength aluminum alloys. This representation accounts for the increased stresses associated with Orowan looping at interfacial locations, where extra half-planes due to Orowan loops occur at opposite particle corners. Plastic relaxation of the Orowan loops was modeled using the incompatibility of the lattice rotations between the particles and the alloy matrix. The predictions indicate that the orientations and morphologies of the particles with respect to the most active slip plane are the critical factors in the relaxation of the eigenstrains associated with the loops.