Preparation And Performance Study On Sic_f/ti Matrix Composites

SiC fiber reinforced titanium matrix composites combine the high strength, high stiffness and high creep resistance of SiC fiber with high damage tolerance of titanium and titanium aluminized compound in one. In addition, the SiC fibers introduced into the titanium matrix material can further reduce the density. Therefore, this kind of lightweight material which can withstand extremely high mechanical load at room temperature and high temperature will undoubtedly lead to technological revolution in engine design, mechanical engineering and other high technological area.This paper made use of uncoated SiC fibers, TiN coated SiC fiber and Ti-6Al-4V foil to prepare SiCf/Ti-6Al-4V and SiCf/TiN/Ti-6Al-4V composite materials by using foil-fiber-foil method. Using scanning electron microscopy, energy dispersive spectroscopy to observe and analyze the microstructure of the composite material and interfacial reaction. The results showed that the thickness of the interfacial reaction layer of SiCf/Ti-6Al-4V composite was about 0.5μm, while there was nearly no interface layer in SiCf/TiN/Ti-6Al-4V indicating that TiN played a very good barrier coating effect. The vacuum heat treatment was performed to the two composite materials at 960℃for 9h and 25h. The interfacial reaction become gradually intense with time prolonged. But in this case, TiN played an active role on interfacial reaction.The interfacial strength of the two composite materials was studyed, the results showed that the interfacial strength of the uncoated SiC fiber reinforced composite was higher, up to 205MPa; while the interfacial strength of SiCf/TiN/Ti-6Al-4V was 146MPa. In addition, interfacial strength at the edge of composite was lower than that at the center.The mechanical property of SiCf/Ti-6Al-4V composite was tested. Its strength was about 900MPa, was higher than the original Ti-6Al-4V foil. The main reason was that the reaction of fiber and the matrix produced brittle material at the interface, causing brittle fracture at the interface of the composite material. As the main role of carrying load, the surface of fiber was damaged due to the interfacial reaction in the preparation process, resulting in a serious decline in its strength.A slurry casting method was used to prepare SiCf/Ti composite materials. SiC fiber and matrix combined well, there is no "canthus" or other flaws existed in the interface, but only some small pore flaws dispersed in the matrix because of press conditions which can be improved by changing parameters. Comprehensive analysis, It is a promising low-cost preparation method.