Development of process maps for superplastic forming of Weldalite™ 049

Abstract The activation energy under superplastic forming (SPF) conditions for the Al–Cu–Li alloy Weldalite™ 049 (W049) had been reported in a few publications with insufficient information to establish the material constitutive equation. In the present work, the constitutive equation of the alloy was developed through superplastic uniaxial testing with the main axis of the specimen parallel, perpendicular, and at 45° to the rolling direction. The results of the investigation showed that the activation energy was not a function of orientation with respect to the rolling direction, but a function of the strain rate. The data generated from the tests was used to generate process maps for W049 which correlate the processing conditions to the available formability and the developed microstructure. The formability map shows that the alloy exhibits its maximum formability in the region bounded by a temperature of 485°C and a strain rate of 5×10 −4 s −1 . The formability drops to much lower values, at slower strain rates.