Microstructure and mechanical properties of multiprincipal component CoCrFeNiMox alloys

► The CoCrFeNi alloy exhibited a single FCC solid solution. ► (Cr,Mo)-rich σ phase formed in FCC matrix after the addition of Mo to the alloy. ► (Mo,Cr)-rich μ phase appeared on the fringes of σ phase in CoCrFeNiMo0.85 alloy. ► Yield stress and compressive strength increased while the ductility decreased. ► Alloys were strengthened by solid-solution strengthening and the σ/or σ + μ phases.