Abstract
The deformation and grain growth behavior during superplastic deformation was studied when the ternary element Cr was added to the microduplex superplastic Al-33%Cu eutectic alloy beyond its solubility.
In the superplastic region called region II, Cr bearing had no effect on flow stress, though in the lower strain rate region called region I, it made the flow stress large, the strain rate sensitivity small and the characteristics of region I distinct.
The deformation induced component of grain growth during deformation was independent of strain rate, initial grain size and static component of grain growth, and was proportional to the given strain. It was not affected by Cr bearing. On the other hand, the static grain growth was retarded by Cr bearing. The apparent flow hardening on the stress-strain curves was explained by the whole grain growth and the dependence of the flow stress on grain size.
