Preparation Of Layered Cf/A1 Composites And Research Of The Microstructure And Mechanical Properties

In recent years,carbon fiber reinforced aluminum(Cf/Al)composites have become a new type of materials that is focused on in various fields because of their high specific strength,specific modulus,structure designability and good thermodynamic properties.At present,onedimensional Cf/Al composites with excellent microstructure and properties can be prepared,but their applications are limited.The two-dimensional layered continuous Cf/Al composite with excellent microstructure and properties can satisfy the multi-directional loading,which has become the hot spot of current research.Therefore,the vacuum ultrasonic vibration method was used to prepare layered Cf/Al composites.The preheating devices of layered carbon fiber preform and layered carbon fiber preform were designed,and the technological parameters of layered Cf/Al composites were optimized by simulation and experiment.Scanning electron microscope(SEM)and multifunctional electronic drawing machine were used to analyze the microstructure and the mechanical properties of the composites.The results show that the distance between ultrasonic vibration head and carbon fiber layer can affect the fiber distribution and infiltration effect of the composites.By changing the distance between the ultrasonic vibration head and the fiber layer,the single-layer Cf/Al composites with different microstructures can be obtained.When the distance between the ultrasonic vibration head and the fiber layer is too small,the fiber distribution in the singlelayer Cf/Al composites is non-uniform.When the distance between the ultrasonic vibration head and the fiber layer is too large,the single-layer Cf/Al composites can appear noninfiltration defect.When the distance between the ultrasonic vibration head and the fiber layer is 30 mm,the fiber distribution in the composite is very uniform,and the infiltration effect of the composite is good.At the same time,the highest tensile strength can reach 187.6 MPa.It is found that the change of the distance between the ultrasonic vibration head and the fiber layer causes the uneven stress of the fiber under ultrasonic vibration.If the distance is too small or too large,the stress of the fiber is uneven,and the fiber distribution is non-uniform or non-infiltration defect appears.When the distance between the ultrasonic vibration head and the fiber layer is 30 mm,the stress of the fiber is even,so the fibers distribution is uniform,and the aluminum liquid can fully infiltrate the carbon fibers gap.The spacing of fiber bundles can affects the infiltration and mechanical properties of the double-layer Cf/Al composites.With the increase of fiber bundles spacing,the infiltration effect of carbon fibers is improved.While the tensile strength of the composites increases first and then decreases.When the fiber bundles spacing is 3 mm,the carbon fibers are uniformly distributed in the matrix.The infiltration effect of the composite is good,and the highest tensile strength can reach 225.4 MPa.It is found that the small spacing of the fiber bundles causes the uneven stress of the fiber.The non-infiltration defect appears,and the tensile strength is low.When the fiber bundles spacing is too large,the number of fibers within a unit volume capable of being subjected to tensile loads at the same time less,and the tensile strength of the composites is low.When the spacing of fiber bundles is 3 mm,the stress of the fiber is even.The number of fibers that can be loaded at the same time is the largest.Therefore,the fibers distribution is uniform and the tensile strength is the largest in the composites.