Thermal expansion coefficient and thermal fatigue of discontinuous carbon fiber-reinforced copper and aluminum matrix composites without interfacial chemical bond

Fully dense carbon fiber-reinforced copper and aluminum matrix (Cu-CF and Al-CF) composites were fabricated by hot press without the need for an interfacial chemical compound. With 30 vol% carbon fiber, the thermal expansion coefficients (TECs) of pure Cu and Al were decreased to 13.5 × 10 ^-6 and 15.5 × 10^-6/K, respectively. These improved TECs of Cu-CF and Al-CF composites were maintained after 16 thermal cycles; moreover, the TEC of the 30 vol% Cu-CF composite was stable after 2500 thermal cycles between -40 and 150 °C. The thermal strain caused by the TEC mismatch between the matrix and the carbon fiber enables mechanical enhancement at the matrix/carbon fiber interface and allows conservation of the improved TECs of Cu-CF and Al-CF composites after thermal cycles.