Superelasticity at low temperatures in Cu-17Al-15Mn (at%) shape memory alloy

Superelasticity at temperatures between 77K and 273K in Cu-17Al-15Mn alloy was investigated. In this alloy, where no thermallyinduced martensitic transformation appears, an excellent superelasticity with recovery strain of 8.5% was confirmed at 77 K. The critical stresses for stress-induced martensitic transformation decrease with decreasing temperature and its gradient becomes smaller at low temperatures due to the decrease of entropy change. The entropy change estimated at 77K is -0.46 J/(mol·K), which is almost one-third of that at 221 K.