Effects of Nickel on the Microstructure, Mechanical properties and Corrosion Resistance of CoCrFeNixAl0.15Ti0.1 High Entropy Alloy

The present work investigates the effect of Ni on the microstructure, mechanical properties, and corrosion resistance of CoCrFeNixAl0.15Ti0.1 high-entropy alloys. It was found that the appropriate addition of Ni element in the alloy is beneficial to reduce the average grain size of the alloy. The yield strength and tensile strength of the alloy under fine-grain strengthening have also been increased, while the ductility of the system in this study has not been significantly affected. In terms of corrosion resistance, CoCrFeNixAl0.15Ti0.1 high-entropy alloys form a dense passive film at open circuit potential, possessing good corrosion resistance. However, with the excessive addition of Ni content in the alloy, the pitting corrosion resistance of the alloy in the environment of chloride ions will decrease due to the relative decrease of the relative content of Cr element. This work also can provide guidances for the design and development of new precipitation-strengthened CoCrFeNi-based high-entropy alloys with excellent comprehensive properties.