Improving tensile and compressive properties of magnesium alloy rods via a simple pre-torsion deformation

A simple method has been developed in order to improve the tensile and compressive properties of extruded AZ31 rod. The strategy is to apply pure shear strain to the extruded rods by a pre-torsion deformation. It is found that pre-torsion exhibits little influence on the shape and size of AZ31 rod, however largely enhances tensile and compressive yield strength and reduces yield asymmetry along extrusion direction. With increasing twisted angle, the compressive yield strength exhibits gradually increase, and the tensile yield strength exhibits a non-monotonous change. The changes in tensile and compressive properties are ascribed to the proliferation of dislocations, the generation of twin lamellae and the weakening of extrusion texture during pre-torsion. The corresponding mechanisms are addressed and discussed. (C) 2015 Elsevier Ltd. All rights reserved.