Structure and Properties of the B83 Babbit Alloy Based Composite Materials Produced by Extrusion

Resumo

Extruded bars of hardfacing B83 babbit alloy reinforced by silicon carbide particles with an average size of 40 μm and modified with shungite rock (MSR) were manufactured. Specimens of the powder mixture of babbit alloy and fillers produced by mechanical alloying were cold pressed, heated to the temperature of 310 ± 10 °C, exposed at this temperature for 30 min, and then extruded on a mechanical press at 320 ± 5 MPa. The structure, physical, mechanical, and tribological properties of produced composite material (CM) were studied. A uniform distribution of reinforcing fillers and changes in the morphology of intermetallic SnSb and Cu₃Sn phases with size reduced by 1.5–1.8 times were observed in the specimens produced by extrusion. The values of hardness, density, and elastic modulus measured by laser optoacoustic method were not worse than those for the cast B83 babbit alloy. Introduction of SiC and MSR particles into the babbit composition led to its strengthening and wear resistance increase by ~20% as compared with the cast material. The best wear resistance, 1.7 times greater than for the cast alloy, was obtained in SiC+MSR polyreinforced CM. This material was characterized by the least variation of the friction coefficients in the whole range of tribological loading studied and by the most stable process of friction.