Microstructure and texture gradient in copper deformed by equal channel angular pressing

Abstract

The aim of this paper was to examine the gradient in the microstructure and texture that develops during equal channel angular pressing (ECAP). Copper of 4N purity was subjected to ECAP deformation at room temperature by using three passes of Route A. The local microstructure and texture were investigated by orientation imaging microscopy and high-energy synchrotron radiation, respectively. The refined microstructure consists of elongated grains inclined in the direction of extrusion. The texture is characterized by typical shear components of face-centred cubic metals which deviate from their ideal positions. Inclination of the grain long axis and the texture components with respect to the extrusion direction depend on the distance from the top of the extruded bar and change from pass to pass. The texture gradient is modelled with the flow line model using the viscoplastic self-consistent polycrystal approach. Microstructure formation and reasons for the texture gradient are discussed.