Strengthening and toughening of Ti5Si3 by TiC-coated short carbon fiber: Fabrication, interfacial control, and mechanism of reinforcement
Journal of the European Ceramic Society
Composites of Cf/Ti5Si3 were prepared by spark plasma sintering a mixture of TiC-coated short carbon fiber and pre-synthesized Ti5Si3 powder. The TiC coating protects the Cf and mediates a mild interdiffusion process between Cf and Ti5Si3, rather than an exothermic reaction. Compared with traditional in-situ fabrication, the use of a pre-synthesized Ti5Si3 powder as a raw material mitigated heat release from the Ti-Si reaction and consequent grain overgrowth. The spark plasma sintering process was completed within 15 min and the relative density of the product reached 99.2 %. The Cf/Ti5Si3 composite achieved a high fracture toughness of 7.57 MPa m1/2 and a flexural strength of 518.3 MPa, which reflected increases of 255 % and 270 %, respectively, compared with those properties of monolithic Ti5Si3. These improvements are attributable to the effects of the carbon fiber reinforcement, the TiC protective coating on the Cf, inhibition of grain overgrowth, and control of interfacial reaction.
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