Interfacial effects on the thermal conductivity of QE22 alloy in SiC/QE22 composites

The thermal conductivity of unreinforced QE22 and reinforced SiC/QE22 alloys was studied in the temperature range from 20 to 300°C. The thermal conductivity of pure QE22 alloy was compared with that of the QE22 matrix in composites made from QE22 with 10, 15 and 25 vol.% SiC particles. The thermal conductivity of the QE22 matrix in QE22/10 vol.% SiC was nearly the same as that of the pure alloy in the whole temperature range studied. The values of the thermal conductivity of the QE22 matrix in QE22/15 vol.% SiC and in QE22/25 vol.% SiC are practically the same as those of pure QE22 alloy, but only up to 130 and 70°C, respectively. Above these temperatures the thermal conductivity of the QE22 matrix is lower than that of the pure alloy. At low temperatures the lattice defects in composites are localized near the interfaces and do not influence the thermal conductivity of the matrix. With the increasing temperature the defects expand into the matrix and reduce its thermal conductivity.