Martensitic transformation in thin-film (TiPd)(50)(TiNi)(50)

We have produced thin films of(TiPd)(50)(TiNi)(50) shape-memory alloy (SMA) by de magnetron sputtering at an elevated temperature. 'As-grown' films we re crystalline, requiring no post-deposition anneal. A SMA film, approximat ely 1.5 mu m thick, grown on a Si(100) cantilever, approximately 80 mu m th ick, showed a martensitic transformation near room temperature. The martens itic transformation was observed by measuring cantilever damping, cantileve r bending and X-ray diffraction (XRD) patterns, all as functions of tempera ture. The XRD patterns indicated that the film was purely austenite (B2 pha se) at high temperatures and was a mixture of austenite and martensite at l ow temperatures. Damping measurements suggest that the low-temperature mart ensite is a mixture of B19 and B19' phases. The transformation was reversib le and exhibited a temperature hysteresis of approximately 25 degrees.