TiC strengthened CoCrNi medium entropy alloy: Dissolution and precipitation of TiC and its effect on microstructure and performance

Abstract

In order to improve the strength and corrosion resistance of CoCrNi medium entropy alloy, TiC strengthened CoCrNi medium entropy alloy (CoCrNi/(TiC)x (x=0.1, 0.2, 0.4)) was designed by addition of different amounts of TiC. The effects of TiC content on the microstructure, mechanical properties, and corrosion resistance of the alloy were investigated. It was found that the precipitation morphologies of TiC changed from lamellar eutectic to needle structure with the increase of TiC content, and finally formed mixed needled and bulk TiC particles. TiC appears as a dissolution−precipitation phenomenon in the CoCrNi alloy, which is important for the mechanical properties and corrosion resistance of the CoCrNi/(TiC)x alloy. The strength of alloy was enhanced obviously after the addition of TiC. The compressive yield strength of CoCrNi/(TiC)0.4 alloy reached 746 MPa, much larger than that of the CoCrNi medium entropy alloy, 108 MPa. Additionally, the addition of TiC was found to improve the corrosion resistance of CoCrNi medium entropy alloy in the salt solution.