Sintered Fe-Mo-Cu-Ni-Si-C Composites Produced by SiC, Nickel, and Copper Additions to Fe-Mo Powder

Silicon carbide can be used as a source of alloying silicon and carbon elements for making sintered composites. The addition of 4 wt.% silicon carbide to iron or iron-based powders can lead to the formation of ductile iron microstructures in sintered composites, whose matrices can be furthered modified by chemistry manipulation. In this work, copper and nickel powders, as austenite stabilizing alloying elements, were added to sintered Fe-0.85Mo+4.0 wt.% silicon carbide composite to produce different ductile iron microstructures with different ausferrite features. The reference sintered composite was produced from powder mixture of Fe-0.85Mo+4.0 wt.% silicon carbide and 4.0 wt.% copper powders. The nickel additions (0.5, 1.0, 1.5, and 2.0 wt.%) to the reference sintered composite led to the decrease of black particle count, the decrease of ferrite halo thickness, the reduction of ausferrite component thickness, and the increase of martensite fraction. This indicates that Ni promotes the reduction of ausferrite component thickness and the martensite transformation. The presence of martensite reduced tensile strength and elongation values. Macrohardness values of sintered nickel-added composites showed less sensitivity to microstructural changes.