Transformation behavior and shape memory characteristics of Ti-40Ni-10Cu(at.%) alloy ribbons

Ti-40Ni-10Cu(at.%) alloy ribbons have been fabricated by melt spinning with a linear velocity of 31 m s-1. Their microstructures, transformation behavior, shape memory characteristics and superelasticity were investigated. As-spun ribbons prepared at the melt spinning temperature of 1873 K were amorphous and crystalline mixtures, below which they were crystal. The B2-B19-B19' transformation occurred in the ribbons and the maximum temperature gap between Ms' (B2-B19' transformation start temperature) and Ms (B19-B19' transformation start temperature) was 46 K. Ti-40Ni-10Cu alloy ribbons showed perfect shape memory effects even at 160 MPa and perfect superelasticity over a temperature range of 13 K. The transformation hysteresis of Ti-40Ni-10Cu alloy ribbons associated with the B2-B19 transformation was 8 K. Rapid solidification was found to be effective in increasing the critical stress for slip of a Ti-40Ni-10Cu alloy without overlapping the B2-B19 and B19-B19' transformations