Large strain behaviour of a superplastic copper alloy—I. Deformation

The effect of strain hardening (which results from strain induced grain growth) on the flow behaviour of a superplastic copper alloy, Coronze 638, has been analyzed. To do this, we measure the strain induced grain growth as a function of strain and strain rate. Then, by using a constitutive equation relating grain size and flow stress, the effective hardening rate can be calculated. The work shows that grain growth at low strain rates causes …