DEVELOPMENT OF RECOVERED DISLOCATION SUBSTRUCTURES DURING PLASTIC FLOW.

A study has been made of the macroscopic and microstructural changes which occur during the hot extrusion of a single phase Al-5% Mg alloy. The load/displacement curve exhibits a typical peak in load after a small ram displacement. A quasi-static deformation zone is not fully established until a short time after this peak, and no significant deformation occurs in the rear of the billet until this state is achieved. The attainment of steady state extrusion is associated with dynamic recovery leading to the formation of an equiaxed subgrain structure in the deformation zone. The heterogeneous nature of the deformation determines the positions at which dynamic recovery occurs.