Synthesis, Microstructure And Mechanical Properties Of Ti₃SiC₂/SiC Composite

Ti3SiC2 is a novel layered ceramic material, which combines many of the best attributes of both metals and ceramics. It has been studied more and more recently for its good properties. TisSiC2/SiC composite enhanced the mechanical properties of Ti3SiC2, which made it have an advantage to be used as a structural material.In this paper, Ti3SiC2 material and Ti3SiC2/SiC composites, which were fabricated by non-pressing sintered and hot-pressing sintered methods are mentioned and the effects of the synthesis conditions on the phase composition, microstructure and mechanical properties were investigated.In the section of non-pressing sintered, the influence of different raw material system and sintered temperature on the phase composition of the material were studied. And two conclusions were achieved. The one is that it is good for phase composition design and control because the final phase composition of the material fabricated by Ti, SiC and C raw material system is comparatively stable. The other one is that 1500 is advisable for the synthesis of composites for this temperature leads less minor phase in the material.Hot-pressing sintered was used to obtain the dense TisSiCa/SiC composite, during which Ti, SiC and C system was mainly attempted and the relative density of the dense material that fabricated by hot-pressing sintered method is about 98%. Meanwhile, the effects of different synthesis conditions and particle size of SiC on the phase composition, microstructure and mechanical properties were studied. Therefore, the conclusion that narrowing particle size distribution of the start powders is helpful to enhancing density of material was reached. The flexural strength and fracture toughness of Ti3SiC2 material obtained by hot-pressing is 223MPa and 5.1 MPa m1/2 respectively; The mechanisms of grain bending, grain delamination, crack deflection inside the layered grain, crack deflection and branch, pull out grain are main energy absorbing mechanisms. Further more, the TiC pinned at the tips of the crack and impeded the crack propagation. Ti3SiC2 material has damage-tolerance.Adding the SiC in to Ti3SiC2 can improve the flexural strength of the material. Whenthe content of the SiC is up to 15vol%, the composite has the best flexural strength which is 345MPa, and the fracture toughness of the composite was 5.9 MPa m1/2. When the content of the SiC is above 15vol%, as the content of the SiC increases, the fracture toughness of the composite degrades, hi that case, the adding of the SiC introduces new mechanisms into Ti3SiC2. However, going with the increase of the content of SiC, the influence of brittleness of it to the composite also increases.