Abstract Scope |
Recently, medium-entropy alloys (MEAs) combining high hardness with excellent ductility have attracted numerous attentions. Here we synthesize a series of Co-Ni-V and Co-Ni-V-Al MEA thin films by magnetron sputtering at room temperature with deposition power from 60 W to 350 W. The film microstructure, morphology, and mechanical properties depended remarkably on atomic fluence, proportional to deposition power. With increasing atomic fluence, the amorphous phase fraction experienced a process of first decreasing and then increasing, and fully amorphous structure was obtained at 300 W for Co-Ni-V-Al and 350 W for Co-Ni-V. Surface diffusion is dominated in low incident atomic energy range, while deposition rate effect is dominant over surface diffusion effect in high incident atomic energy range, resulting in the crossover in phase selection. Our current work could pave a way for a controlled synthesis of high-performance MEA thin films via tuning deposition power. |