Modelling texture development during equal channel angular extrusion of aluminium Original Research Article

The deformation textures that develop in aluminium during ECAE (without rotation of the billet) have been investigated experimentally and modelled using the FC-Taylor approach, for two different die angles (90 and 120°), by using actual deformation histories measured from scribed marker grids. This has shown that the deformation during ECAE can best be described in terms of streamline coordinates and involves a simple shear parallel to the streamline, which becomes aligned with the final extrusion direction, and a plane strain tension and compression component that develops as the material enters and leaves the dies deformation zone. The textures observed were similar to those found following torsion straining and had the main components {001}〈110〉 and {112}〈110〉 along a B partial fibre. However, in the case of ECAE, the positions of maximum intensity were rotated by ~15–20° about the transverse direction (TD). Similar textures were seen for even and odd numbers of extrusion passes, suggesting that the TD rotation is not caused by alignment of the fibre direction with the die’s ‘shear plane’, as has been previously reported. In contrast, texture simulations showed that this rotation occurs as a consequence of the additional plane strain compression component in ECAE deformation.