A novel high-entropy alloy with multi-strengthening mechanisms: Activation of TRIP effect in C-doped high-entropy alloy

Efforts have been made to intentionally activate multiple strengthening mechanisms in a single alloy because individual strengthening effects have not been sufficiently exhibited in previous alloys with multi-strengthening mechanisms. Here, we design a novel high-entropy alloy with multi-strengthening mechanisms through a stepwise design approach utilizing CALPHAD type thermodynamic calculation. The target strengthening mechanisms are introduced step by step, from solid solution strengthening, the addition of precipitation hardening and transformation-induced plasticity, based on the calculation. The finally designed Co₂₁Cr₁₁Fe₄₉Mn₄Ni₄V₂C₁Mo₃Si₅ alloy simultaneously benefits from solid solution strengthening due to Mo and V addition, precipitation hardening from nanoscale precipitates, grain boundary strengthening by grain refinement, and transformation-induced plasticity by BCC deformation-induced martensite transformation. Individual strengthening effects is sufficiently exhibited in the designed alloy, which leads to an excellent combination of yield strength (732 MPa), ultimate tensile strength (1100 MPa), and ductility (47.5%).