Grain refinement response during twist extrusion of an Al-0.13 % Mg alloy

Twist extrusion is a recently developed method of severe plastic deformation that principally uses torsion to generate high strains in a repeatedly extruded billet, while maintaining a constant cross-section. The method thus results in a deformation gradient across the billet section. To date, the grain refinement behaviour of alloys deformed by twist extrusion have only been investigated qualitatively. In this study high resolution electron backscattered diffraction has been used to quantify the deformation structures produced by twist extrusion, in a model, single-phase, Al-0.13 % Mg alloy, with the aim of investigating the potential of the technique for producing ultra-fine grained metals, as well as the homogeneity of the microstructure and strain distribution in processed billets.