EXTENDED ABSTRACT: High-entropy alloys (HEAs) composed of five or more principal elements, offer a wide range of compositions compared to conventional materials. To effectively design and screen these complex HEAs, we employed the first-principles calculations based on density functional theory, CALPHAD (Computational Phase Diagram) methods to predict the phase stability, microstructure and properties of ZrNbTi-based refractory high-entropy alloys, and then selected Zr, Nb, Ti, Cr, and Cu as the principal elements for further investigation. The ZrNbTiCrCu high-entropy alloy thin films were synthesized using magnetron sputtering under various parameters, and the relationship between the microstructure and properties was investigated. The results revealed that the ternary ZrNbTi alloy exhibits a single-phase body-centered cubic (BCC) crystal structure. After the addition of Cr and Cu, the ZrNbTiCrCu HEA thin films predominantly formed a nanocrystalline BCC structure, Laves phases with C15 and C14 structure, and Cu clusters due to the slow diffusion and thermodynamic effects (positive enthalpy of mixing with Zr, Nb, and Cr). The hardness of the ZrNbTiCrCu HEA thin films can reach 20.43 GPa owing to the interaction between lattice distortion and the high dislocation density.
Keywords：High entropy alloy films; Magnetron sputtering; First principles calculations; CALPHAD; Cu clusters