Characteristics of Heat Expansion of Aluminum Composites Reinforced Al2O3 Particles

Abstract

Aluminum oxide particles (Al₂O₃) are ceramic particles which have a smaller thermal expansion than aluminum. Aluminum as matrix, which is a relatively low-cost metal, has good compatibility when reinforced with ceramic particles. By adding Al₂O₃ particles into aluminum to become a metal matrix composite material.  Varying the amount of Al₂O₃ particles was carried out to determine the effect of adding Al₂O₃ on the coefficient of linear thermal expansion of metal matrix composite.  Aluminum matrix composite (AMC) specimens reinforced with Al₂O₃ particles, produced by casting technique preceded by smelting with mixing called compocasting technique with variations of reinforcing particles of 5%, 10%, 15%. The tests carried out were the thermal expansion test of the AMC material and the metallographic test to determine the distribution of the AMC reinforcing particles.  Adding Al₂O₃ can reduce the thermal expansion of the resulting composite.  The measurement results of the technique linear thermal expansion of the AMC  resulting from the compocasting process are smaller than the aluminum matrix thermal expansion.  The decrease in the technique linear thermal expansion was greater with increasing composition of Al₂O₃ in the AMC. The lowest value of the coefficient of technique linear thermal expansion  α(27⁰C, 210⁰C) occurs in AMC with a content of 15% Al₂O₃, which is equal to 6.6 E-6/⁰C.