Strong amorphization of AlCrNiTiV high-entropy alloy films deposited by cofilter cathode vacuum arc deposition

AlCrNiTiV high-entropy alloy amorphous films (HEAAFs) were synthesized by a novel cofilter cathode vacuum arc deposition (Co-FCVAD). The systematical experiments demonstrate that the microstructure of the AlCrNiTiV HEAAFs intently rely on the negative bias voltage (NBV). When the NBV increases from 0 V to 150 V, the dense and smooth films with amorphous structure can be obtained. As increasing the NBV to 200 V, the dual-phase structure, which short range ordered nanocrystalline are separated by a glass bell, can be found. It is proposed that the amorphous structure and the quasi-dislocation-free dual phase structure result in a significantly enhanced hardness (12.54 +/- 0.65 GPa), which is higher than that of most reported high entropy alloy (HEA) films, and contribute to the promising resistance against corrosion in 5% H2SO4 (Icorr is on the order of 10(-7) A.cm(-2)). It is worth noting that the AlCrNiTiV HEAAF with low compressive residual stresses and amorphous structure can achieve excellent properties of flexibility, self-supporting and thermal stability. Such films have a great application prospect.