Mixed-sputter deposition of Ni-Ti-Cu shape memory films

Ni-Ti-Cu shape memory films were mixed-sputter deposited from separate nickel, titanium, and copper targets, providing increased compositional flexibility. Shape memory characteristics, examined for films with 7 at. % Cu and 41--51 at. % Tl, were determined with temperature controlled substrate curvature measurements, and microstructure was studied with transmission electron microscopy. The Ni-Ti-Cu films were found to have shape memory properties comparable to bulk materials, with transformation temperatures between 20 and 62{degree}C, a 10--13{degree}C hysteresis, and up to 330 MPa recoverable stress.