Optimisation of rebetatising time and temperature for lowering martensitic transformation temperature in Cu- Zn-4% A1 shape memory alloy

Cu-Zn-Al shape memory alloy (SMA) is a new class of smart engineering materials which can be incorporated in varieties of heat sensitive devices. Its martensitic transformation temperature is very sensitive to alloy composition which can be raised to some extent by incorporating a bias spring or by dezincification. However, lowering this temperature, once obtained, poses problems. The present paper reports that martensitic transformation temperature could also be lowered to some extent (∼ 20°C) without much adverse effect on the shape memory response in Cu-Zn-Al (4 wt% Al) shape memory alloys, by rebetatising the material at lower temperature.