Superplastic-like behavior of the equiaxed and coarse grained Al-2 mol%Cu solid solution

High temperature tensile deformation behavior of Al-2 mol% Cu solid solution consisting of coarse and equiaxed grains has been investigated with a special reference to the occurrence of Class I superplasticity. Enhanced ductility up to about 260% is confirmed at the modulus compensated stress, sigma(TS)/E, below 1.6 x 10(-4). The superplastic-like behavior should be attributed to a moderately strain rate sensitive deformation process which is governed by the solute drag of dislocations. The plastic instability or necking resistance is quantitatively discussed in relation to the strain rate sensitivity and work hardening rate. The role of grain boundary sliding is briefly described.