Tungsten carbide – Titanium carbide composite preparation by arc plasma melting and its characterization

Abstract

WC-TiC composite with six different values of TiC in the range 1–15 wt% was prepared by arc plasma (Ar) melting. Characterizations of the in situ melt-cast composite as well as its powder by XRD, FESM, TEM, SAED and EDS show the composite to consist of related carbide, sub-carbide and mixed carbide phases [WC, W2C, TiC, TiC0.981 /TiC1-x, TiWC2 /(Ti,W)C] besides presence of minor phases such as carbon (graphite), W, and TiO2 in traces in few cases. The composite exhibits high hardness and a maximum value of 3650 ± 75 VHN is observed in the case of WC-12 (WC+15 wt% TiC) sample. Improved hardness is attributed to the presence of phases like TiC, TiC0.981 /TiC1-x and TiWC2/(Ti,W)C. While total pore volume of open pores in the composite (measured by BET method) lies in the range 0.0002–0.0097 cm³ /g. TEM study of the microstructures shows absence of meso and macro pores in the samples. In the light of these findings, the composite may be called zero porosity material for practical usage. Young's modulus for different compositions of the composite shows significantly high values in the range of 540–703 GPa. Simultaneous improvement in hardness and Young's modulus value of the composite may be attributed both to growth of new mixed carbide phases of W and Ti as stated above and porosity free nature of the samples. The new composite has good scope for use in cast cutting tools, grinding wheels, bullet-proof vests, etc.