One bi-layer Ni-Ti thin films with chemical compositions of Ni45TiCu5/Ni50.8Ti (numbers indicate at.%) determined by energy dispersive X-ray spectroscopy was deposited on Si substrates using RF magnetron sputtering. The structures and transformation temperatures of annealed thin films at 773 K for 1 h were studied using grazing incidence X-ray diffraction (GIXRD) and differential scanning calorimetry (DSC), respectively. Nanoindentation was used to characterize the mechanical properties.The DSC and X-ray diffraction results indicated the bi-layer was composed of austenitic and martensitic thin films. The bi-layer thin film exhibited a combined pseudo elastic behavior and shape memory effect at the same time similar to the austenitic and martensitic thin films, respectively. The combination of pseudo elastic with shape memory effect produces a two-way shape memory effect with a reduced hysteresis in the bi-layers.Keywords: NiTi bi-layer thin film, pseudo elastic, two-way shape memory effect
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