Texture evolution during multi-pass equal channel angular extrusion of copper: Neutron diffraction characterization and polycrystal modeling

Experimental characterization and polycrystal modeling of texture evolution in pure copper during equal channel angular extrusion (ECAE) via routes BC (1, 2, 4, 8 and 16 passes) and C (1-4 passes) are conducted. Rigorous analysis of bulk textures measured by neutron diffraction is performed for the two routes. Textures in route BC show orientation concentrations along fibers that consist of the {1 1 1}(theta) and (left angle barcket)1 1 0(right angle barcket) (theta) partial fibers, yet the locations and orientation densities of the main texture components vary significantly with pass number. For route C, the first pass texture is retained in subsequent passes, apart from slight variations in the strengths of the main texture components. Quantitatively good texture predictions for all passes in route BC and odd-numbered passes in route C are obtained using a viscoplastic self-consistent model with a grain co-rotation scheme and a simple shear deformation history though they are further improved when the deformation is provided by finite element (FE) simulations. For the even-numbered passes in route C, however, the simple shear deformation is not sufficient; the complex and inhomogeneous deformation captured by FE simulations is important for reproducing the retained shear texture. Regardless of the deformation history used, the full constraints Taylor model is shown to be insufficient for texture predictions in multi-pass ECAE.