Effect of interfacial microstructure on the thermal-mechanical properties of mesophase pitch-based carbon fiber reinforced aluminum composites

Four unidirectional carbon fiber (67.9%–70.0% volume fraction) reinforced aluminum composites (P100/1199, P100/6063, P120/1199, and P120/6063) were fabricated by pressure infiltration and thermo-mechanical properties of these composites were investigated. We found interfacial microstructures, especially free of carbide, precipitations and interfacial gaps, are important for the properties of the composites. With proper addition of Mg and Si element, P100/6063 composite possessed moderate interface. Thus, thermal conductivity (TC), bending strength and elastic modulus of that were improved prominently. TC along fiber direction of P100/6063 was (391±1)W/mK, which was close to 95% of the role of mixtures (ROM) model. The coefficient of thermal expansion values (CTE) along fiber direction of all the specimens varied between −1×10⁻⁶/K and 1×10⁻⁶/K. The bending strength and the elastic modulus of P100/6063 composite exhibited a 31.6% and 14.3% increase respectively in comparison to those of P100/1199 composite. High TC, low CTE value, and excellent mechanical properties make this material promising for microelectronic chips production.