Superplasticity-like deformation of a coarse-grained Al5052 alloy

In the present paper, hot forming properties of a commercially available coarse-grained A15052 alloy under uniaxial and biaxial stress states were examined. In hot tensile tests, the alloy exhibits a superplastic-like behaviour with a maximum tensile elongation of 194% at a temperature of 873K and at an initial strain rate of 2.08×10-1 s-1. Dislocation slip and grain boundary sliding were considered to be the deformation mechanisms. The alloy was also bulged at a constant polar strainrate of 2.0×10-1 s-1 and at an optimum temperature of 873 K using elliptical dies with aspect ratios of 1:1, 4:3, 2:1, 8:3 and 4:1. The strain distributions revealed that the strain gradient obtained in the minor axis was much greater than that in major axis. Moreover, it was shown that the deformation behavior of the alloy was basically isotropic and the volume strain of the alloy sheet did not equal to zero which was considered to relate to its cavitation behaviour.