Plastic flow, structure and mechanical properties in pure Al deformed by twist extrusion

Twist extrusion (TE) is known as one of newly developed, but still moderately studied severe plastic deformation methods. This research was initiated to conduct a detailed study of structure-properties relationship evolution during TE processing. The evolution of macrostructure, Vickers hardness and tensile properties was studied in 99.99% purity aluminum during twist extrusion processing at room temperature up to 4 TE passes (total average equivalent strain of similar to 4.8). The process resulted in almost homogeneously refined structure that cannot be resolved optically. Significant increase in Vickers hardness, yield strength and ultimate tensile strength with moderate degradation in ductility of Al was observed. Apart from some structural inhomogeneity, all the mechanical properties were almost homogeneous and isotropic after four TE passes. (C) 2009 Elsevier B.V. All rights reserved.