Unstable shear failure in a 7075 aluminum alloy

The occurrence of localised shear failure has been investigated in an AlZnMg alloy. An explanation of the occurrence of this failure mode is offered in terms of the topography of the γ−ϵ−ϵϵ surface and the onset of negative strain rate sensitivity. A failure map is propos the regime of localised shear failure to be defined relative to the competitive modes of failure such as ductile or intergranular fracture.