Thermal properties of a magnesium hybrid composite: QE22 alloy reinforced with 20 Vol% SiC particles and 5 Vol% Al2O3 fibres

Abstract

Thermal expansion of a hybrid composite QE22 + 20 vol% SiCp + 5 vol% Al2O3 (Saffil) fibres was measured in the temperature range from 20 to 375°C. The thermal expansion coefficient (CTE) of this hybrid composite is compared with CTE of three composites: QE22/ 15 vol% SiCp, QE22/ 25 vol% SiCp and QE22/ 20 vol% Saffil. A decrease of CTEs at certain temperatures above 240°C indicates the thermally-induced elastic-plastic transition. The transition temperature is the highest for the hybrid composite. The lowest transition temperature has been estimated for QE22 reinforced with 25 vol% SiC. The experimental results indicate that the kind and volume fraction of reinforcement may very effectively influence the elastic-plastic transition temperature. The effect of temperature on the thermal diffusivity and thermal conductivity of the hybrid composite QE22 + 20 vol% SiCp + 5 vol% Saffil fibres was investigated in the temperature range from 20 to 300°C. The addition of SiC particles and Saffil fibres into magnesium alloy QE22 causes a reduction in both the thermal diffusivity and thermal conductivity at any temperature. The thermal diffusivity of this hybrid composite will be compared with those of QE22/ 25 vol% SiCp and of QE22/ 20 vol% Saffil estimated in our prior study.