Enhanced strength without sacrificing ductility in FeCrMnVSix high entropy alloys via controlling the ratio of metallic to covalent bonding

Abstract

It has been the pursuit of materials science to enhance strength without sacrificing the ductility of a material. By introducing the semi-metallic Si into the FeCrMnV high-entropy alloy (HEA) to control the ratio of metallic and covalent bonding, we obtained a FeCrMnVSix HEAs with high strength and favorable ductility from the perspective of interatomic bonding. First-principles calculation was employed to calculate the structural model, electronic environment, and mechanical properties. The theoretical calculations demonstrated that the covalent bonding had been obtained in the FeCrMnV HEA consisting of metallic bonding due to the addition of Si. Under the guidance of theoretical calculation, FeCrMnVSix HEAs were successfully prepared by laser cladding on 1Cr13 steel substrate. The nanoindentation, Vickers microhardness, and tensile tests were performed, and the results indicated that the strength of HEA was enhanced without sacrificing ductility. In addition, the as-prepared Si-containing HEA coatings exhibited excellent tribological properties. The mechanism of simultaneous formation of metallic and covalent bonds on the mechanical properties was analyzed. The enhanced strength without sacrificing ductility in FeCrMnVSix HEAs is attributed to the proper combination of metallic and covalent bonding, the metallic bonding facilitates favorable ductility while the covalent bonding contributes to excellent strength.