OPTIMIZATION OF REBETATISING TIME AND TEMPERATURE FOR LOWERING MARTENSITIC-TRANSFORMATION TEMPERATURE IN CU-ZN-4-PERCENT AL 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 dev ices. 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 temperatur e, once obtained, poses problems. The present paper reports that marte nsitic transformation temperature could also be lowered to some extent (similar to 20 degrees C) without much adverse effect on the shape me mory response in Cu-Zn-Al (4 wt% Al) shape memory alloys, by rebetatis ing the material at lower temperature.