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

초록

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 hard-ening and transformation-induced plasticity, based on the calculation. The finally designed Co21Cr11Fe49Mn4-Ni4V2C1Mo3Si5 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 strength-ening 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%).

키워드