Microstructures and mechanical properties of CoCrFeNiAl0.3 high-entropy alloy thin films by pulsed laser deposition

Recently much attention has been paid to high-entropy alloy thin films (HEATFs) due to their excellent physical and chemical properties. Simultaneously, pulsed laser deposition (PLD) is an increasingly focused method for thin film preparation due to its remarkable advantages. In this study, CoCrFeNiAl0.3 HEATFs were prepared on silicon substrates in a high vacuum chamber at room temperature for different deposition time by PLD. The microscopic morphologies, chemical composition, elastic modulus, nanohardness and corrosion behaviors of the CoCrFeNiAl0.3 HEATFs were systematically investigated. The microscopic morphology shows that there are some nanoscale granules on the surface of the HEATFs. The nanoindentation results indicated that the CoCrFeNiAl0.3 HEATFs have higher nanohardness but lower elastic modulus than the bulk counterparts. With increasing the deposition time, elastic modulus and nanohardness become higher initially and then decrease, which reaches at highest as the deposition time for 2 h. Corrosion behaviors experiments verified that CoCrFeNiAl0.3 HEATFs have higher corrosion resistance than 316 L stainless steel in NaCl solution. Our results could provide a new advanced method for preparing HEATFs, and in-depth understanding the mechanics and corrosion behaviors of HEATFs for future application.