An insight into the strain rate dependence of tensile ductility of an ultrafine grained Cu matrix nanocomposite

In this study, we observed a strong strain rate dependence of tensile ductility for an ultrafine grained Cu-5vol% Al2O3 nanocomposite prepared by powder compact extrusion. This dependency of tensile ductility of the material to strain rate, combined with detailed materials characterization, suggests that the strain at which nearly ideal plastic deformation occurs is associated with the magnitude of the flow stress. The measured apparent activation volume and observed alignment of Cu grains suggest that plastic deformation during this nearly perfect deformation stage is dominated by the co-operative grain boundary sliding.