Effect of alloy elements on microstructure and phase structure of laser cladding Fe-based coatings

Four types of Fe-based alloys were fabricated on 45 carbon steel substrate by CO₂ laser surface cladding,and the effect of alloy elements on the microstructure and carbides of the coatings was investigated. With the increasing of the elements V,Nb,Ti,CeO in turn,the structure of the coating was transformed from the columnar crystal to columnar dendrites,and finally to the dendrite. With the simultaneous addition of the two elements V,Nb in the coating,the long strip carbides in the interdendritic region split into blocky carbides. At last,the carbides in the interdendritic region of the coating can be refined and spheroidized by adding elements V,Nb,Ti,CeO. The tensile test results showed that the tensile strength and elongation rate of the coating with dendritic structure and spheroidized carbides in the interdendritic region increased greatly,and the coating had high strength-toughness properties.