Optimization of high-temperature compression of as-cast Al–Cu eutectic alloy

AbstractThe superplastic characteristics achieved after compressive predeformation at high temperature of as-cast Al–Cu eutectic alloy have been studied as function of the predeformation speed Vp. The stress–strain-rate curve was found to be shifted towards higher strain rates as the predeformation speed becomes higher, so that the maximum superplastic strain rate is found to increase with Vp’ with however a tendency for stabilization at high Vp. This phenomenon can be explained by the combined effect of homogeneity of transformation of the initial lamellar structure in the compressed specimen and of the size of the equiaxed structure developed in the transformed regions. The influence of Vp on the subsequent superplastic characteristics of the material allows optimization of that predeformation speed to achieve a given total strain under conditions of minimum energy and/or time of deformation. The effect of the cooling rate of the as-cast material was also examined and is discussed in terms of superplast...