An investigation was made of the relationship between the strain rate and the ductility and the underlying deformation mechanisms in an ultrafine-grained Al6082 alloy. At room temperature the uniform elongation of the material exhibited a marked increase with decreasing strain rate. This effect was related to the activation of micro shear banding, which was controlled by grain boundary sliding. The contribution of these mechanisms to uniform elongation was estimated. It was proposed that the grain boundary sliding suppresses the transformation of micro shear bands into macro shear bands. The activity of other deformation mechanisms during plastic deformation of the ultrafine-grained material was also considered.

Tensile Deformation of an Ultrafine-Grained Aluminium Alloy - Micro Shear Banding and Grain Boundary Sliding. I.Sabirov, Y.Estrin, M.R.Barnett, I.Timokhina, P.D.Hodgson: Acta Materialia, 2008, 56[10], 2223-30