Tribo-mechanical characterization of spark plasma sintered chopped carbon fibre reinforced silicon carbide composites

Short carbon fibre (C-f) reinforced silicon carbide (SiC) composites with 7.5 wt% alumina (Al2O3) as sintering additive were fabricated using spark plasma sintering (SPS). Three different C-f concentrations i.e. 10, 20 and 30 wt% were used to fabricate the composites. With increasing C-f content from 0 to 20 wt%, micro-hardness of the composites decreased similar to 28% and fracture toughness (K-IC) increased significantly. The short C-f in the matrix facilitated enhanced fracture energy dissipation by the processes of crack deflection and bridging at C-f/SiC interface, fibre debonding and pullout. Thus, 20 wt% C-f/SiC composite showed > 40% higher K-IC over monolithic SiC (K-IC approximate to 4.51 MPa m(0.5)). Tribological tests in dry condition against Al2O3 ball showed slight improvement in wear resistance but significantly reduced friction coefficient (COF, mu) with increasing C-f content in the composites. The composite containing 30 wt% C-f showed the lowest COF. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.