A stress–strain model for a two-phase ultrafine-grained aluminum alloy

Two-phase ultrafine-grained (UFG) aluminum alloys with different precipitate and low-angle boundary distributions were examined for their monotonic stress–strain behavior. Precipitates in combination with low-angle grain boundaries were found to determine the deformation micromechanism. It is proposed that thermally activated vacancy movement plays a central role in this regard. The experimental stress–strain curves matched well with the trend predicted by a modified Blum–Zheng model based on vacancy-assisted dislocation annihilation mechanism.