Microstructure and Mechanical Properties of Co-Deposited Ti-Ni Films Prepared by Magnetron Sputtering

Ti-Ni films with various Ni contents (16.5, 22.0, 33.5 at. %) were deposited on Al alloy substrates using DC magnetron co-sputtering. The effects of Ni target power and substrate bias (-10, -70, -110 V) on morphologies, crystallography, nanomechanical properties and scratch behavior of films were studied. All the deposited Ti-Ni films exhibited a BCC structure of beta-Ti (Ni). The Ti-Ni films grew with a normal columnar structure with good bonding to substrates. When increasing the Ni target power and substrate bias, the grain size grew larger and the surface became denser. The as-deposited Ti-Ni films significantly improved the hardness (>4 GPa) of the Al alloy substrate. With the increase of bias voltage, the hardness and modulus of the film increased. The hardness and modulus of the Ti-22.0Ni film prepared at -70 V bias were 5.17 GPa and 97.6 GPa, respectively, and it had good adhesion to the substrate.