On the Electrical and Thermal Conductivities of Cast A356/Al 2 O 3 Metal Matrix Nanocomposites

Abstract

To assess the effect of the dispersion of Al2O3 nanoparticles into A356 Al alloy on both the electrical and thermal conductivities, A356/Al2O3 metal matrix nanocomposites (MMNCs) were fabricated using a combination of rheocasting and squeeze casting techniques. Two different sizes of Al2O3 nanoparticles were dispersed into the A356 Al alloy, typically, 60 and 200 nm with volume fractions up to 5 vol%. The effect of the nanoparticles size and volume fraction on the electrical and thermal conductivities was evaluated. The results revealed that the A356 monolithic alloy exhibited better electrical and thermal conductivities than the MMNCs. Increasing the nanoparticles size and/or the volume fraction reduces both the thermal and electrical conductivities of the MMNCs. The maximum reduction percent in the thermal and electrical conductivities, according to the A356 monolithic alloy, were about 47% and 38%, respectively. Such percentages were exhibited by A356/Al2O3MMNCs containing 5 vol% of nanoparticles having 60 and 200 nm, respectively.