Microstructures and mechanical properties of CrMnFeCoNi high-entropy alloy prepared by laser surfacing

A well-formed CrMnFeCoNi surfaced layer was prepared by laser surfacing technology on Q235 steel. The phase,microstructure and chemical composition were studied by XRD,OM,SEM and EDS,while the mechanical properties were investigated by hardness and tensile tests. The results indicated that a FCC single solution phase with dentrite morphology formed in the surfacing layer. The alloying elements were homogeneously distributed,but slight elements differences existed between dendrite and interdendrite. Cr/Fe/Co gathered in the dendrite while Mn/Ni segregated in the interdendrite. The microhardness of the coating is 180 ～ 200 HV0. 5 or so,which slowly decreased from the surface to the bottom. The tensile properties were dependent on the temperature. The yield strength and ultimate tensile strength increased by ～60% and ～ 65% to 564 MPa and 891 MPa,respectively,while ductility increased from 26% to 36% with a decrease of temperature from 298K to 77 K.