Università degli studi di Modena e Reggio Emilia

In this work, CoCrFeNiMox high entropy alloy (HEA) films were deposited by High Power Impulse Magnetron Sputtering (HiPIMS) using pure Mo and equiatomic CoCrFeNi targets. The effect of Mo content on the microstructure, residual stress state, and mechanical properties of the films was investigated in the range of 0–20 at.%. All films exhibited a columnar growth morphology and a high density of planar defects. Increasing the Mo content promoted the formation of a fine-grained structure and induced the transformation from a single face-centered cubic (FCC) phase to a mixture of FCC and body-centered cubic (BCC) phases. All produced films displayed a compressive residual stress state regardless of the Mo concentration. In terms of mechanical properties, the hardness of the films increased with increasing Mo content due to solid solution and grain boundary strengthening, along with the formation of a hard BCC phase. On the other hand, the elastic modulus decreased, likely due to the formation of an amorphous phase at higher Mo concentrations.

Within this work, MoNbTaVW high entropy alloy thin films were synthesized by dc magnetron sputter deposition, high power impulse magnetron sputtering and cathodic arc deposition to study the influence of the growth conditions on structure and properties of the films. For deposition angles ranging from 0 to 90°, the deposition rate, chemical composition, morphology and crystal structure as well as the mechanical properties were analyzed. All films showed the formation of a solid solution with body centered cubic structure regardless of deposition angle and method, whereas higher energetic growth conditions were beneficial for improved mechanical properties.