Structure and Composition of a Novel Refractory Ni-Containing CrMoNbTaVW High-Entropy-Alloy Thin Film

The structure and composition of a refractory Ni-containing CrMoNbTaVW high-entropy-alloy (HEA) thin film were investigated. The HEA thin film with a thickness of 5 μm was grown via conventional direct current magnetron sputtering from a multiple-elemental compound target. The Ni-containing HEA thin film with a Ni concentration of 3.6 at. % exhibits a single-phase body-centered cubic (BCC) crystal structure with a lattice parameter of a = 0.316 nm. The grains in the HEA thin film are columns, extended in the growth direction. They are not aligned exactly perpendicular to the substrate surface. The thin film grows in a polycrystalline structure with a tendency to preferred orientation or texture. Energy-dispersive X-ray analyses of the HEA thin film show near-equal atomic concentrations of Cr, Mo, Nb, Ta, V, and W elements in the range 15-17 at. % with almost uniform distribution. In contrast, Ni is not uniformly distributed in the film, and grains with a different Ni concentrations were observed. The defects observed in the HEA thin film are mainly single dislocations or an assembly of dislocations, which could be caused by residual stresses in the layer forming during the growth of the HEA thin film.