CuAlPd alloys for sensor and actuator applications

Currently available shape memory alloys (NiTi, CuAlNi, CuSnAl) lack the hig h transformation temperatures and long term thermal stability desired in ma ny commercial applications. This paper reports the results of an investigat ion in which Pd was substituted for Ni to obtain the shape memory ally CuAl Pd. The CuAlPd alloys were found to have an austenite transformation temper ature range of 115-370 degrees C depending on composition, heat treatment a nd working process. Optimal shape memory properties were found for a compos ition of Cu-13.1 wt% Al-2.4 wt% Pd. This alloy has a transformation tempera ture of 180 degrees C and a recoverable strain of 4.8%. CuAlPd alloys have excellent workability and exhibit fatigue properties comparable to NiTi sha pe memory alloys. Single crystals of CuAlPd alloys were produced using a mo dified Bridgeman technique. (C) 2000 Elsevier Science Ltd. All rights reser ved.