Fabrication And Properties Of Carbon Fiber Toughening Al₂O₃-Ni?Ni₃Si? Ceramics Composites Materials

Alumina ceramics in the mechanical,high temperature and chemical stability,and so has a good overall performance,and the production of raw materials from a sufficient source,low manufacturing cost,suitable for large-scale industrial production,is currently the world's most widely used ceramic materials,Can replace metal and alloy as high temperature,corrosion-resistant,wear-resistant mechanical parts and materials,can also be used as circuit substrate materials and tool materials,widely used in structural ceramics,electronic ceramics,bioceramics?such as human joints?And other areas.However,the lower fracture toughness of alumina ceramics limits its application in many fields and becomes the main reason for its further development.Therefore,the strengthening and strengthening of alumina ceramics is of great significance in practical application.Metal particles and intermetallic compound has a good toughening effect on alumina ceramics.At present,the alumina metal ceramic composite materials is the most commonly used preparation methods of powder metallurgy method,due to the limitation of powder metallurgy method itself,determines the service life of the sample can not reach ideal level.After introducing fiber available fiber itself is the outstanding performance,make the metal ceramic composite materials overcome the defects caused by sintering method,improving strength,especially the performance improving resistance to cracking,thus improving its service life.In this paper,Cf/Al₂O₃-Ni?Ni₃Si?composites were prepared by sol-gel method and hot-pressing method.The influence of the volume fraction of Cf and the mechanical fraction of Cf on the mechanical properties of the composites was studied.Get the following conclusions:1.In the preparation of Cf/Al₂O₃-N composites,the introduction of alumina and dispersed carbon fibers by sol-gel method not only can disperse the fibers evenly into the matrix,but also improve the wettability of carbon fiber and matrix interface,The process can effectively protect the fiber from being burned.2.With the increase of carbon fiber volume fraction,the hardness of Cf/Al₂O₃-Ni composites decreases,and the flexural strength and fracture toughness increase first and then decrease.When the carbon fiber volume fraction is 10%,the bending strength and fracture toughness reach a peak.The addition of carbon fibers in the appropriate content of the composite material to improve the strength and toughness,carbon fiber content is too high,strength and toughness decreased.The main toughening mechanism of Cf/Al₂O₃-Nicermet-based composites prepared is the mechanism of carbon fiber pulling,bridging and debonding.3.In the preparation of Cf/Al₂O₃-Ni₃ Si composites,the density of Cf/Al₂O₃-Ni₃ Si composites decreased with the increase of fiber content,and the hardness,flexural strength and fracture toughness were all increased with the increase of carbon fiber volume fraction.When the carbon fiber mass fraction is 3%,the flexural strength and fracture toughness reach the peak.The addition of carbon fiber can improve the strength and toughness of the composites.The carbon fiber content is too high,the strength and toughness are decreased.4.The main reason for the damage of carbon fiber in the Cf/Al₂O₃-Ni₃ Si matrix composites reinforced by carbon fiber is that Ni₃ Si is unstable at high temperature,and the carbon fiber reacts,which results in the damage of the fiber.5.Because in the Cf/Al₂O₃-Ni₃ Si in the preparation of composite materials,carbon fiber was badly damaged in a sample,get the carbon fiber toughening of Cf/Al₂O₃-Ni₃ Si data can not fully reflect the effect of the composite material.As a result,the carbon fiber for alumina-metal and aluminum oxide and intermetallic compound materials the pros and cons of the toughening effect of not fully reflected.Therefore,in the future to further improve the methods to improve the result.