LAUSR

Abstract Laser cladding of ( F e 0.497 C r 0.243 M o 0.084 B 0.093 C 0.084 ) 98 N b 2 on 45 steel substrate was fabricated by using a coaxial powder feeding method with the maximum thickness of 1 mm coating. The effect of the laser scanning speed on macromorphology, microstructure and microhardness of cladding layer and corrosion resistance was investigated. From the substrate to the upper layer, the growth structures of the coating are plane crystal, cellular crystal, columnar crystal, equiaxed crystal and amorphous, respectively. The amorphous content in the coatings is dependent upon laser scanning speed which will influence the dilution rate and actual cooling rate by changing the heat input. As scanning speed increasing, the coating revealed the property of higher hardness and better corrosion resistance, which can be attributed to fine-grain strengthening, dispersion strengthening and growth of the amorphous phase. Moreover, the amorphous phase (HV 1024) showed a much higher value of microhardness than that of the crystalline phase (HV 706), which indicate that the amorphous phase is the main contributor to the average hardness of laser deposited metallic glass.