Tensile properties of fine-grained 7475 aluminium alloy at various temperatures and strain rates

For a superplastic 7475 alloy, tensile properties are tested under various conditions in order to investigate the effects of the tensile conditions on the mechanical properties as well as on the microstructure after working. The results obtained here suggest a possibility of high-speed forming of this alloy. Under conditions of 400°C and 8.3×10⁻²s⁻¹ strain rate, a comparatively large elongation of about 200% can be attained. This may be due to the fact that the fine subgrains arise during the deformation. Also, mechanical properties at room temperature of the specimen prestrained under this condition are found to be fairly satisfactory.