Microstructure and mechanical properties of (AlCrTiZrV)Nx high-entropy alloy nitride films by reactive magnetron sputtering

The (AlCrTiZrV)N high-entropy alloy nitride film was prepared on a silicon wafer using reactive magnetron sputtering in a mixed gas of N-2 and Ar. The effect of different N-2:Ar flow ratios (0:4, 1:4, 3:4, 1:1, 5:4, 3:2) on the microstructure and mechanical properties of the films was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and nano-indentation techniques. The results show that the AlCrTiZrV high-entropy alloy film presents an amorphous state and the hardness and elastic modulus were at a low value, When sputtered at a low N-2:Ar flow ratio. With the increase of N-2:Ar flow ratio, the appearance of (200) and (220) peaks in the XRD patterns and the preferential growth of (200) crystal plane indicated that crystallinity of the films was improved. With the increase of the N-2: Ar flow ratio, the sputtering rate of the film decrease, the hardness and elastic modulus first increased and then decreased. Especially, when N-2:Ar flow ratio was 3:4, the maximal hardness and elastic modulus of 34.9 GPa and 323.8 GPa were reached, respectively.