2009 Volume 50 Issue 12 Pages 2757-2762
A powder metallurgy (P/M) titanium matrix composite (TMC) reinforced with low cost carbon black was prepared by spark plasma sintering (SPS) and hot extrusion. Carbon black particles were added for the in situ formation of TiC dispersoids during the SPS process. Two kinds of titanium (Ti) powders, sponge and fine Ti, were coated with carbon black particles via a wet process using a zwitterionic solution containing carbon black spheres. The distribution of the particles on the Ti powder surface before the consolidation process was imaged using scanning electron microscopy (SEM). We evaluated the microstructure and mechanical properties of extruded pure Ti matrix composites reinforced with TiC particles. The morphology and distribution of the in situ TiC phases were investigated using optical microscopy and SEM with the help of an EDS analyzer. The mechanical properties of these composites were remarkably improved by adding a small amount of carbon black at 0.07∼0.16 mass%. The increases in the yield stress of the extruded sponge and fine TMC were 70.0 and 291 MPa, while the tensile strength increases were 67 and 231 MPa, respectively, compared to those of extruded pure Ti with no reinforcement. Finally, the fractured surfaces of TMC specimens after tensile testing were observed. The benefits of the wet process and the use of carbon black additives are discussed in detail.