| In recent years,carbon fiber reinforced aluminum(Cf/Al)composites have attracted wide attention in the fields of aerospace,defense and military due to their high specific strength and specific modulus,excellent thermal and electrical conductivity,and wide service range,which has become one of the key structural materials for development.Due to the poor wettability between carbon fiber and aluminum alloy melt,a certain degree of interfacial reaction at high temperature conditions.To improve the wettability of carbon fiber and aluminum melt and inhibit the interfacial reaction between Aluminum and carbon fiber are the first problems to be solved in the preparation of Cf/Al composites.At present,the main methods to solve the above problems include the preparation of coating on the surface of carbon fiber and the addition of alloying elements to matrix.In this paper,carbon fiber was pretreated by different deoiling treatment methods.The bonding capacity between nickel coating and carbon fiber with different thickness was tested by thermal shock experiment,and a good coating preparation process was obtained.In this paper electroless nickel plating is used to improve the wettability between carbon fiber and aluminum alloy matrix.and interfacial reaction problem is solved by adding Ti elements to the matrix.The influence of nickel coating and Ti elements on the microstructure and mechanical properties of Cf/Al composites are analyzed.Cf/Al composites with different Ti contents were prepared by ultrasonic vibration.The microstructure and mechanical properties of Cf/Al composites were observed and analyzed by means of scanning electron microscope(SEM),energy dispersive spectrometer(EDS),electron backscatter diffraction(EBSD)and electronic universal testing machine.To explore the effect of Ti elements on the microstructure and properties of Cf/Al composites.The results show that the number of broken roots of carbon fiber treated by organic solvent is less than that of high temperature burning and oil removal,and the adhesion caused by fracture is improved,which is more favorable for the subsequent treatment of carbon fiber surface.With the increase of coating time,the thickness of nickel coating on carbon fiber surface increases gradually.When the coating time is 3 minutes,the nickel coating can evenly wrap the carbon fiber.Through thermal shock experiments,it is found that the bonding effect between carbon fiber and nickel coating is the best.The nickel-plated carbon fiber was combined with aluminum alloy to make Cf/Al composite material.By observing the microstructure of composites,it was found that the aluminum alloy melt permeated the fiber completely,the fiber distribution in the matrix was uniform and there was no obvious casting defect.Ti elements were distributed around carbon fiber.By comparing the properties,it is found that with the increase of Ti content in the matrix,the bending properties of the composites are improved.The bending strength of the composite without Ti is only 172 MPa,and the bending strength of the Cf/Al composite is 280 when 1.0 wt.%Ti is added.Moreover,according to the analysis of fracture morphology,when the amount of Ti in the matrix is 0wt.%,0.1wt.%,0.3wt.%,0.5wt.%,the fracture surface of the composite is straight,no fiber is pulled out,and the interface does not effectively prevent the crack from spreading into the fiber.When the addition amount of Ti is 0.7wt.%,1.0wt.%,the fracture surface of the composite is uneven and the filamentous fiber is pulled out,and the fiber effectively assumes the load. |
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