Critical role of in-situ formed wide-graphene nanoribbons (Wide-GNRs) on the mechanical and thermal shock behaviors of spark plasma sintered titanium carbide composites

3^rd International Conference and Expo on Ceramics and Composite Materials

June 26-27, 2017 Madrid, Spain

Sribalaji M, Biswajyoti Mukherjee, Srinivasa Rao Bakshi and Anup Kumar Keshri

Indian Institute of Technology, Patna, India
Indian Institute of Technology, Madras, India

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

Carbon nanotubes/CNTs (2 wt.%) reinforced titanium carbide (TiC) ultra high temperature ceramic with 3.5 wt.% of tungsten carbide (WC) as sintering aid was fabricated using spark plasma sintering (SPS) technique at 1600�°C and 50 MPa pressure. In-situ formation of wide graphene nanoribbons (wide-GNR) was observed after sintering. High resolution transmission electron microscopy (HR-TEM) and Raman spectroscopy techniques confirmed the presence of in-situ formed wide-GNRs. Mechanical properties of TiC, TiC-WC and TiC-WC-CNT sintered pellets were evaluated using an instrumented microindenter at a load of 49 N. No significant change was observed in the hardness of TiC after the reinforcement of WC and CNT. However, the reinforcement of CNT and in-situ formation of GNR in TiC-WC-CNT pellet has showed a drastic improvement of ~126% and ~ 98% when compared to TiC and TiC-WC sintered pellets respectively. This significant enhancement in the fracture toughness of TiC-WC-CNT pellet can be attributed to the novel toughening mechanisms like GNR pull out, GNR grain wrapping, GNR crack bridging, crack bifurcation, CNT pull out and CNT grain gluing. Further, the thermal shock behaviour of TiC, TiC-WC and TiC-WC-CNT sintered pellets was determined at 1700�°C using conventional water quenching test. The results from the thermal shock analysis showed that TiC-WCCNT pellet has higher resistance to thermal shocks compared to other TiC composites. The microstructural investigations after thermal shock test indicate that higher thermal resistance is strongly dependent on the reduced formation of oxide phases.

Biography :

Email: Sribalaji.pms13@iitp.ac.in