Synthesis and characterization of Fe-based amorphous composite by laser direct deposition

Abstract

Fe-based metallic glasses can be potential structural materials owing to their combined superior strength, excellent corrosion and wear resistance properties. In this study, synthesis of Fe–Cr–Mo–W–Mn–C–Si–B metallic glass composite with a large fraction of amorphous phase is accomplished using laser direct deposition. X-ray diffraction (XRD) and transmission electron microscopy investigations reveal the existence of amorphous structure. Microstructure analyses by optical microscopy and scanning electron microscopy (SEM) indicate the periodically repeated microstructures of amorphous and crystalline phases. Partially crystallized structure brought by laser reheating and remelting during subsequent laser scans aggregated in the overlapping area between each scan. XRD analysis showed that the crystalline particle embedded in the amorphous matrix was Cr1.07Fe18.93 phase. The periodically repeated amorphous/crystalline composite microstructure remained the same from the first to the last layer. Microhardness of the amorphous phase (HV0.2 1591) showed a much higher value than that of the crystalline phase (HV0.2 947). Similar values of wall macrohardness and phase microhardnesses indicated that the amorphous phase is the main contributor to the average hardness of laser deposited metallic glass. Wear resistance property of deposited layers showed a significant improvement with the increased fraction of amorphous phase.