The microstructure and superplastic behavior at 450℃ and 500℃ were investigated using optical microscopy and a tensile test in Cu-Al-Mn-Ni shape memory alloy. It was found that a fine α(fcc) + β(bcc) two-phase structure with grain size of 3μm in diameter can be obtained by annealing at 600℃. The flow stress of the Cu-Al-Mn-Ni alloy is dependent on both the strain rate and the test temperature where the strain rate sensitivity is over 0.3 which exhibits superplasticity with the elongation of over several hundred percents. For the test temperature at 500℃ and the strain rate of 5×10^<-4> sec^<-1>, the maximal elongation of 1150% was obtained.
