Microstructure and tribological property of laser melt deposited α/Fe₉Cr₉Si₂ metal silicide alloys

The ternary intermetallic compound Fe₉Cr₉Si₂ is expected to be a promising wear and corrosion resistant material due to its inherent high hardness, covalent-dominated strong atomic bonds and high Cr and Si content. Room temperature brittleness is currently the main obstacle preventing it from industrial applications. In order to improve the ductility of Fe₉Cr₉Si₂, the Fe-base solid solution toughened Fe₉Cr₉Si₂ alloys were designed and fabricated by laser melting/deposition manufacturing process. Microstructure of the alloys was characterized by optical microscopy (OM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Vickers microhardness measurement. Microstructure of the alloys consists of Fe₉Cr₉Si₂ primary dendrite and the interdendritic Fe-base solid solution α. Friction coefficient of the alloys was evaluated under dry sliding friction condition. Volume fraction of Fe₉Cr₉Si₂ primary dendrite and average hardness of the alloys increases with the increasing Cr content. Friction coefficient of the alloys decreases with the increasing of Fe₉Cr₉Si₂ primary dendrite volume friction.