Effect of thermal exposure on the microstructure of the interface in a Gr _f /Al composite

Abstract The microstructure of the interface in a Gr _f /Al composite after exposure at high temperature was investigated. The graphite fiber reinforced aluminum matrix composite was prepared by the pressure infiltration method. After being heat treated at 550°C, 600°C and 640°C for different times, the microstructure of the interface in the composite was studied by using transmission electron microscopy (TEM). Furthermore, the content of Al ₄ C ₃ in the interface was examined using X-ray diffraction (XRD). The results showed that not only the micro morphology but also the content of Al ₄ C ₃ in the interface varied with the increase in temperature. When the composite was heat treated at 550°C and 600°C, Al ₄ C ₃ with a big length-to-diameter ratio was observed in the interface, while Al ₄ C ₃ with a small length-to-diameter ratio was found when the heat treatment temperature was 640°C. With the increase in the time, the content of Al ₄ C ₃ in the interface increased rapidly when the composite was heat treated at 640°C. Based on the dynamic calculation, the interface reaction diffusion rate constant of the Gr _f /Al composite increases rapidly when the temperature is higher than 600°C.