Thermal Properties of Reinforced QE22 Magnesium Alloy

Abstract

The effect of temperature on the thermal diffusivity, thermal conductivity and thermal expansion of QE22 alloy and three composites QE22+15 vol% SiCp, QE22+25 vol% SiCp and QE22 + 20 vol% Saffil fibres were investigated over the range 20 to 300 °C. The addition of SiC particles in the QE22 alloy causes a reduction in the thermal conductivity at any temperature. The results clearly show that heating up to 300 °C leads to expansion of plastic zones (dislocations) into the metal matrix at a certain temperature. The coefficient of thermal expansion starts to decrease at the temperature at which the thermally induced elastic–plastic transition starts. The thermal behaviour of SiC and Saffil reinforced composites are different during the thermal loading. This difference is obviously a consequence not only of the geometry and kind of reinforcement but also a result of the difference in their manufacture. The present results indicate that the kind and volume fraction of reinforcement may very effectively influence the thermal conductivity and coefficient of thermal expansion.