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 N2 and Ar. The effect of different N2: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 N2:Ar flow ratio. With the increase of N2: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 N2: Ar flow ratio, the sputtering rate of the film decrease, the hardness and elastic modulus first increased and then decreased. Especially, when N2:Ar flow ratio was 3:4, the maximal hardness and elastic modulus of 34.9 GPa and 323.8 GPa were reached, respectively.