Influential Mechanism of Cr3C2 Content and Process Parameters on Crack Generation of Fe3Al/Cr3C2 Composites

Abstract

In this paper, a brake cylinder coating comprising composite material of Fe3Al and Cr3C2 mixed powder was prepared by laser cladding onto carbon structural steel. The microstructure of the cladding materials was investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The influence mechanism of the Cr3C2 content and process parameters on crack generation of Fe3Al/Cr3C2 composites were studied. The crack is mainly caused by the mismatch between the plastic phase of Fe2AlCr, the brittle phase of Fe3Al, and Cr7C3 in the cladding layer. With the increase in Cr3C2 content, Fe2AlCr and Cr7C3 in the cladding layer increased, while Fe3Al decreased. When the content of Cr7C3 is low, the cladding layer mainly reflects the plastic increase brought by Fe2AlCr; when the content of Cr7C3 is too much, the property of the cladding layer is reflected as the brittleness of Cr7C3. The number of cracks reached the lowest value at 15 wt.%. The process parameters mainly affect the dilution rate of the cladding layer and thus affect the content of Fe2AlCr.