| Nearly ten years, The development of aerospace, automation and sports products industrial has greatly pushed the metal matrix composites of research and application, the metal matrix composites showing more and more powerful vitality. Discontinuous reinforced metal matrix composites become an important development direction of metal matrix composites (MMCs) due to their desirable characteristics such as high strength, high hardness, high modulus of elasticity, high-temperature resistance, good wear resistance, and good dimensional stability. With the short carbon fiber reinforced metal matrix composite materials as a representative of the continuous reinforced metal matrix composite materials become an important branch of metal matrix composites (MMCs) due to their desirable characteristics such as low cost, simple operation, good mechanical properties and the machining deformation, the method of preparing materials concentrates chiefly at powder metallurgy, press infiltration and extrusion casting processes. Owing to the fact that the technology was simple and its low cost, scientific research workers had attached importance to the stir casting process more and more. In this paper, aluminum alloy for extensive use was selected as the matrix material, and the stir casting process was adopted to prepare good quality short carbon fiber reinforced aluminum alloy composites.The test use of a melt mixing casting method for aluminum composite material. According to the function of the composites, the optimum process parameters were obtained: stirring temperature740℃, stirring time4-6mins, vacuum furnace temperature750℃,vacuum degree0.02-0.04MPa, vacuum degassing time4mins.In the fabrication process, mixing using paddle with level top and tilt blades, which can avoid involved in large amounts of gas, and can make the carbon fiber evenly dispersed.The interface condition was observed through Scan Electron Microscopy (SEM) in this test, results showed that carbon fiber and alloy combined closely in the composites prepared by stir-casting process. Carbon fiber no bloody injury that carbon fiber surface copper coating with carbon fiber and aluminum to solve the problem of the melt the surface not infiltration, Make carbon fiber and aluminum matrix combined with good, this to raises fiber reinforced aluminum matrix composites performance play a very significant role.According to strengthening mechanism of short fiber, the structure and property of Cf/Al alloy matrix composites was inspected from the three factors including the carbon fiber quality fraction, the length of copper plating carbon fiber and heat preservation time. Results indicated that carbon fiber quality fraction with6%, the length of nickel plating carbon fiber with2mm and heat preservation time of20mins could made composite material with close combination between matrix alloy and carbon fibers, and good mechanical property in the process of preparing composite material by stir-vacuum-casting. The fatigue test of composites showed that the fatigue strength of composites reinforced with carbon fiber with5×106circulation was raised29%than the matrix alloy, according to Scanning Electron Microscopy (SEM) analysis, it was known that carbon fibers in composites could prevent the fatigue crack extension, and raise the fatigue resistance of composites. The wear-resisting of compound material performance tests found that of the composite material wear divided into three stages, rapid wear period, smooth period and unstable wear period. Wear first reduced with the increase of carbon fiber content, then to a certain value it raised.The composites rolling test indicated that the rolling temperature must be controlled rigorously between420-460℃.Both of the strength and the hardness of composites raised obviously after the rolling and extruding treatment. Comparing the strength and the hardness under the identical heat treatment condition, the extruding composites were better than the rolling composites. |
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