Effect Of Magnesium On Microstructure And Physical Properties Of Carbon Fiber Reinforced Aluminum Composite Materials

This paper is on the basis of spaceborne radar substrate’s actual needs.pitch-based Cf/Al-0Mg, Cf/Al-6.5Mg and Cf/Al-8.5Mg composites were fabricatedby pressure infiltration process. The effect of Mg content on the microstructure andphysical properties of Pitch-based Cf/Al composites is analyzed.P100pitch-based carbon fibers’ degree of graphitization is88%-91%. It canexhibit much higher thermal conductivity than that of PAN-based carbon fiber. Theeffect of pitch-based carbon fiber’s horizontal texture on fiber properties wasanalyzed and the effect of Mg content on the interface reaction of Cf/Al compositeswas calculated.The wettability studies have shown that: because of the inhibition of Mg on thegeneration of Al₄C₃, the interface between carbon fiber and Al changes from C toC+Al₄C₃. Therefore, the instantaneous contact angle between Al-Mg alloy andcarbon fiber decrease continuously. The Wetting process was a characteristic‘Decreasing Rate Spreading （DRS）’ stage. The pitch-based Cf/Al composites haveno obvious macroscopic defects such as cracks or voids. The interface betweencomposite reinforcement and matrix is clear and well combined. The main interfacereactants of Cf/Al composites were Al₄C₃. With the increase of Mg content, thegeneration amount and size of Al₄C₃decreased.Thermal conductivity test results show that: The thermal conductivity of radialP100/Al composites is twice as large as that of rational P100/Al composites. Withthe increase of Mg content, the interfacial thermal resistance decreases and thethermal conductivity of pitch-based Cf/Al composite increases. Its maximumlongitudinal thermal conductivity can reach386.7Wm^-1K^-1. With the increase ofMg content, the interfacial bonding is weakened and the coefficient of thermalexpansion of Cf/Al composite increases. The simulation and test results of terahertzelectromagnetic wave reflectivity theoretical show that: pitch-based Cf/Alcomposite samples’ reflectivity is greater than0.95in0.1-2THz.