Study On The Interfaces And Properties Of Carbon Fiber Reinforced Titanium Matrix Composite

Since the modern high-tech demanding of high performance materials are more urgent,titanium matrix composites, who has high specific strength and specific stiffness, excellent corrosion resistance and high temperature creep resistance, etc., has huge research and potential applications and are well developed. In low cost Ti-C system, the reinforced phase TiC generated in situ has high melting point and good compatibility with the titanium, can greatly improve the matrix properties. Existing studies most focus on TiC particle reinforced titanium-based alloy. And in situ titanium carbide fiber reinforced titanium material, using the unidirectional orderly form of carbon fiber,is a new research direction. Researchers had produced short TiC fiber reinforced titanium matrix composites to improve material properties. If by synthesizing TiC fibers or TiC similar fiber can enhance the properties of the matrix material, that will make a big difference to reduce the cost and the production cycles of fiber reinforced titanium matrix composites to enhance the performance.In this paper, based on the idea of employing carbon fiber as a guide to generate TiC fiber-reinforced TMCs, we produce α-Ti and carbon fiber composite material samples by sintering in ordinary pressure argon atmosphere and study by the means of scanning electron microscopic observation, component analysis, X-ray diffraction analysis and other methods. Research results are as follows:(1) In the CF and Ti mixed sintering process, the reaction-diffusion of C and Ti generate TiC,and the formation of TiC similar fiber can be described as:(1)active C on fiber surface and Ti matrix generate TiC on interface;(2)partial C atoms in carbon fiber diffuse into the substrate and generate TiC layer;(3)the dense structure of carbon fiber are damaged, C atoms and Ti atoms diffuse mutually by TiC-rich region, and ultimately converted carbon fiber to TiC similar fiber.(2)With the sintering temperature higher, the depth of reaction deepens, the TiC shell on carbon fiber surface are changing: a layer adhered fine TiC particles �' loose tidbits like TiC layer �' dense and smooth TiC layer �' TiC shell consist of obvious unevenness TiC particles or the CF are all converted into TiC similar fiber. For the sample sintering at 1500 ℃, TiC particles tend to increasingly coarsening, TiC shell of uneven thickness or even turn into a TiC similar fiber or “welding” with TiC area before converting to TiC annular shell. Fibrous TiC grows into TiC pieces, the width of the TiC-rich regions are about 15μm, 20μm, 35μm for simples sintering respectively at1350 ℃, 1450 ℃, 1500 ℃.(3) Compared with stored fiber layers, the carbon fiber milled or chopped before mixing with titanium powder can finally be completely transformed in 他 o TiC particles or short fibrous TiC under lower sintering temperature., to generate uniformly distributed granular TiC, TiC class short fiber at lower temperatures.(4) Nickel-plating the carbon fibers can improve the binding effect of the fiber and the matrix and reduce the gap defects. Nickel-plate impede the diffusion reaction of Ti atom and C atom at the beginning of sintering. However, under a certain higher sintering temperature and after a long time, the coating will be depleted, the carbon fiber recrystallized and its dense structure will be damaged a lot, promoting the diffusion of C atom to external and the Ti or Ni atom to diffuse towards the inside filling the hole and generated to TiC. The carbon fiber interior messy loose serious, violent reaction, the resulting fiber surface "TiC layer" TiC particle coarsening. Elevated temperature.