Effect of Cu content on electrical resistivity, mechanical properties and corrosion resistance of AlCu NiTiZr0.75 high entropy alloy films

AlCu x NiTiZr 0.75 high entropy alloy (HEA) films were deposited by magnetron sputtering with an alloy target in combination with a pure Cu metal target. The purpose of this study was to reduce electrical resistivity of the HEA films while maintaining mechanical properties and corrosion resistance by adjusting Cu content of the HEA. We found that the AlCu x NiTiZr 0.75 HEA films were amorphous and displayed a homogeneous or columnar microstructure along the cross sections. The increase of Cu content changed the electronic structure of the HEA films, so that the resistivity decreased sharply to 66 μΩ·cm at x = 1.4. The hardness-to-elastic modulus ration H/E, an indicator of a material's ductility, attained the maximum value at x = 1.4. Although the corrosion current densities increased with x , they were all below 10 −6 A/cm 2 in 3.5 wt% NaCl solution, indicating good corrosion resistance. These findings assumably help expand industrial application of HEA films, particularly when conductivity is required for the functionality of the films. • Amorphous AlCuxNiTiZr 0.75 high entropy alloy films were deposited by co-sputtering. • AlCuxNiTiZr 0.75 films maintained high hardness and good corrosion resistance. • The electronic structure of AlCuxNiTiZr 0.75 films were changed, and the lowest resistivity was 66 μΩ·cm.