Effect of carbon on recrystallised microstructures and properties of CoCrFeMnNi-type high-entropy alloys

Abstract

The effect of carbon content (x = 0, 0.5, and 2.0 at.%) on the phase composition, microstructure, and mechanical properties of thermomechanically processed CoCrFeMnNi system high-entropy alloys was studied. The molar fraction of Cr in the program Co₁Cr₀.₂₅Fe1Mn1Ni1 alloy was reduced to 0.25 compared with the equiatomic alloy to increase the solubility of carbon in the face-centred cubic solid solution. The as-cast alloys were cold rolled to 80% thickness reduction and then annealed at 600e1000 C for 1 h. The addition of carbon to the CoCrFeMnNi alloys resulted in an increase in the temperature at which recrystallisation starts and in the precipitation of the Cr-rich M₂₃C₆ carbide particles. The volume fraction of the second phase increased with an increase in the carbon content and decreased with increasing annealing temperature