Superplasticity of 5083 Aluminum Alloy Induced by Strain Rate Cycling at High Temperatures

The 5083 aluminum alloy specimens with different roughnesses of cutting surface were tested on a tensile tester using the strain rate cycling method, the constant strain rate method and the constant velocity method at 450,475 ℃ and 500 ℃. The influences of temperature, tensile methods and roughness of cutting surface on the superplasticity of the alloy as well as the microstructure of the alloy after tensile test in strain rate cycling method were studied. The results show that the optimal elongations of the 5083 aluminum alloy through the three tensile methods were respectively 131% at 475 ℃, 108% at 500 ℃, and 145% at 500 ℃. And the elongations of the samples with rough surface were much less than those of the samples with smooth cutting surface. In the strain rate cycling method tensile test, the original strip structure of 5083 aluminum alloy began to fracture and tended to be shorter, and eventually became an equiaxed structure with the increase of deformation temperature.