AN IN SITU X-RAY DIFFRACTION STUDY OF THE GROWTH OF TiNbZrTaHf HIGH-ENTROPY ALLOY THIN FILMS USING SYNCHROTRON RADIATION

The aim of this study was to analyze the phase composition of metal films formed by plasma-assisted vacuum arc deposition due to evaporation of a near-equiatomic TiNbZrTaHf cathode. High-temporal-resolution data were obtained by an in situ X-ray diffraction analysis using synchrotron radiation. The use of this technique made it possible to identify the time interval of formation of the films and that of change in their phase composition. It was revealed that the film growth occurred in three stages. At the first stage of film deposition, β phase (bcc lattice, а = 0.34748 nm) was identified. At the second stage, an amorphous-crystalline phase formed, as evidenced by the rise in the background of the diffraction line in the angular range of 2Θ = 24-25 deg. At the third, final stage, the diffraction lines of ω phase (hexagonal lattice; a = 0.46636 nm and c = 0.27872 nm) and α phase (hcp lattice; a = 0.31261 nm and c = 0.47846 nm) were detected. After completion of the deposition process, the films contained 84 wt.% β phase, 14 wt.% α phase, and 2 wt.% ω phase.