Heavy carbon alloyed FCC-structured high entropy alloy with excellent combination of strength and ductility

The effects of carbon content on the microstructure and room-temperature mechanical properties of Fe₄₀Mn₄₀Co₁₀Cr₁₀ high-entropy alloy (HEA) were systematically investigated. The results showed that heavy carbon alloyed HEA could possess supreme combination of high tensile strength (935 MPa) and high ductility (~ 74%). The excellent mechanical properties were ascribed to as follows: the high content interstitial carbon atoms strengthens the matrix greatly through suppressing dislocation motion and promoting the deformation-induced twinning at room temperature, which enhance the strength and ductility. Simultaneously, the ductility is further secured for single FCC structure maintained due to appropriate carbon alloying. Our findings provide a novel strategy for developing HEAs with excellent mechanical properties.