Effect of nanosized titanium and silicon carbides on synthesis and consolidation of titanium silicon carbide during spark plasma sintering

Abstract

Using spark plasma sintering method, at temperature T = 1400°C and load of 30 MPa samples of composite material Ti3SiC2/TiC were obtained. Before SPS powder mixtures with molar ratio 3Ti-1.25SiC-0.75C with addition of up to 4% wt of nanopowders of titanium carbide or silicon carbide were mechanically activated in a planetary mill. Material structure was studied using X-ray structural analysis, hardness and fracture toughness was evaluated on basis of Vicker’s indentation results. It was established that introduction of nanocarbides up to 1% wt significantly reduces contents of Ti3SiC2, and further on practically has no influence on phase composition. Increase of isothermal time from 5 to 15 min leads to an increase in the TixSiy secondary phases to 11–14%. Introduction of nano-TiC and nano-SiC into mixtures increases crack fracture toughness to 7.06–7.55 MPa·m1/2 for samples after 5 min of SPS and practically does not change it after 15 min of SPS.