Cathodic arc deposition of high entropy alloy thin films with controllable microstructure

High entropy alloys (HEAs) are a novel class of materials exhibiting properties of high strength, high corrosion and oxidation resistance, and superb thermal stability. Cathodic arc deposition is an established physical vapor deposition (PVD) technology offering high deposition rate and high degrees of plasma ionization with control-lable ion kinetic energy. Here we employed cathodic arc deposition to fabricate AlCrFeCoNiCu0.5 HEA thin films. To elucidate the growth mechanisms and microstructures of the HEA thin film microstructures, we varied arc and duct currents. The crystallography of the films was investigated using X-ray diffraction (XRD). The film chemistry and microstructure of the film-substrate interphase were comprehensively studied using transmission electron microscopy (TEM). Atomic force microscopy (AFM) was applied to study the surface morphology, and me-chanical properties were evaluated using nanoindentation. It is demonstrated that the grain size in HEA thin films can be effectively controlled by the deposition rate, while the HEA film hardness and surface roughness are modulated by the grain size. The results presented here have important implications for the fabrication of HEA thin films using cathodic arc deposition as an industrially scalable technique.

Automated summary

High entropy alloys (HEAs) are a new class of materials with high strength, high corrosion and oxidation resistance, and superb thermal stability. In this study, AlCrFeCoNiCu0.5 HEA thin films were fabricated using cathodic arc deposition, and the growth mechanisms and microstructures of the films were investigated by varying arc and duct currents. The crystallography of the films was analyzed using X-ray diffraction (XRD), and the film chemistry and microstructure of the film-substrate interphase were comprehensively studied using transmission electron microscopy (TEM). The results show that the grain size, hardness, and surface roughness of the HEA thin films can be effectively controlled. This study has important implications for the industrial-scale fabrication of HEA thin films using cathodic arc deposition.