Microstructure and properties of Ti₃SiC₂/SiC nanocomposites fabricated by spark plasma sintering

High dense Ti₃SiC₂/SiC nanocomposites with different SiC volume contents were in situ fabricated by spark plasma sintering technique. It is found from microstructural observation that SiC distributes uniformly in the composites. Ti₃SiC₂ is about 2-10 μm in grain size, but the average grain size of SiC is about 100 nm for the composites containing SiC from 10 to 40 vol%. With the increasing SiC volume contents, Vickers hardness, fracture toughness, thermal conductivity and electrical resistivity of the composites are improved compared to those of monolithic Ti₃SiC₂. Although the flexural strength of Ti₃SiC₂/SiC composites decrease slightly, they are higher than reported values, indicating the residual stress caused by thermal expansion mismatch is reduced. The technological implication of this work is that, it not only provides an example for the in situ reactive synthesis of nanocomposites, but also extends the possible application of the novel ternary compound Ti₃SiC₂ by in situ adding nanosized SiC particles.