Annealing temperature-induced variations in structure and mechanical attributes of Ti-based high-entropy metallic glass

The composition system of the Ti_47.3V₂₅Zr₁₁Nb₁₄Ta₂Mo_0.5B_0.2 alloy is designed by employing the “high entropy concept”. Magnetron sputtering generated high entropy metallic glass (HEMG) films, and vacuum annealing experiments evaluated how temperature influenced structure, surface morphology, and mechanical characteristics. XRD analysis shows that as the annealing temperature rises to 573 K, the thin film sample's atomic configuration becomes denser and more disordered; at 623 K, it becomes even more disordered; and as the temperature rises further, it becomes tighter and more ordered. For nanoindentation experiments, increasing annealing temperature caused nonlinear structure and characteristic changes. As annealing temperature increased, film hardness and modulus increased. Hardness and modulus declined at 623 K, contrary to the trend. Compared to the as-sputtered film, 623 K annealed samples had fewer crystalline-like regions, suggesting less internal ordering. The film's surface morphology before and after annealing showed that surface roughness reduced and subsequently grew as the annealing temperature climbed. Surface roughness largely changes due to annealing temperature's influence on surface atomic diffusion energy. As atomic diffusion changes the film's surface shape and atomic arrangement, its mechanical properties change. This work theoretically explains the association between HEMG microstructure and mechanical properties.