Superplasticity in the zinc-1 per cent aluminum system

A Zn - 1 wt % Al alloy has been studied in an attempt to relate tensile data and metallographic observations to assumed modes of superplastic deformation. Tensile testing, was carried out at a constant crosshead speed to determine the stress versus strain rate relationships as a function of grain size and temperature. Further analysis included activation energy determinations, low temperature (-100°C) deformation behavior, deformation grain growth characteristics, and surface and internal metallography. Stage II deformation was consistent with a process combining boundary sliding and migration and boundary diffusion. Deformation in stage I was characterized by a low strain rate sensitivity and a variable activation energy. Normal slip processes were operative during stage III deformation. Deformation grain growth and anisotropic grain shape changes were pronounced and variable in stages I and II.Applied Science, Faculty ofMaterials Engineering, Department ofGraduat