Research On Fabrication And Mechanical Behavior Of SiC Fiber Reinforced Ti/Ti₂AlNb Bio-inspired Laminated Composite

The SiC fiber reinforced Ti/Ti₂ AlNb bio-inspired laminated composite is a kind of advanced structural material,which is combined with fiber reinforced and bio-inspired laminated.The composite material can improve the toughness of the material by using the bio-inspired laminated structure,and can further improve the specific strength and specific stiffness of the material by using the ceramic SiC fiber to strengthen the metal layer,and which has a wide application prospect in aerospace,weapons,and other fields.In this paper,the preparation technology of the SiC fiber reinforced Ti/Ti₂ AlNb bio-inspired laminated composite was explored and optimized,and the microstructure and conventional mechanical behavior of the composite were analyzed and evaluated.The SiC fiber reinforced Ti/Ti₂AlNb bio-inspired laminated composite was fabricated through vacuum hot pressing technology combined with foil-fiber-foil method by using raw materials ceramic SiC fibers,Ti foils and Ti₂AlNb foils.The effect of hot pressing temperature,hot pressing pressure and hot pressing time on the microstructure of composite was analyzed and the composite preparation technology parameters were optimized at the same time.The phase composition and microstructure of the bio-inspired laminated composites were analyzed by scanning electron microscopy?SEM?,energy dispersive spectroscopy?EDS?and X-ray diffraction?XRD?.And the composite in preparation condition was mainly composed of ?-Ti,?-Ti,SiC,TiC,O and B₂ phase.The interface reaction product which between ceramic SiC fiber and Ti was mainly TiC,and the thickness of the interfacial reaction layer was 0.8 ?m,and the thickness of C coating was 1.3 ?m.The metal Ti foil andintermetallic Ti₂ AlNb foil formed a solid diffusion connection via mutual diffusion of Ti,Al and Nb,and ?-phase + ?-phase and B₂-rich phase were formed successively in Ti/Ti₂AlNb interface area.The SiC fiber reinforced Ti/Ti₂ AlNb bio-inspired laminated composite and Ti/Ti₂ AlNb bio-inspired laminated composite were respectively subjected to the room temperature tensile test,high temperature tensile test,three point bending test,fracture toughness test and impact toughness test.The mechanical behavior and failure mechanism of the above composites were analyzed under different kinds of external loads.The crack growth process and the crack propagation mode of the SiC fiber reinforced Ti/Ti₂AlNb bio-inspired laminated composite were studied by using the in situ three-point bending test technique.