Effect of albite particles on the coefficient of thermal expansion behavior of the Al6061 alloy composites

Abstract

An investigation has been made for the change in coefficient of thermal expansion (CTE) of albite reinforced 6061 aluminum composites. The composites were prepared by the liquid metallurgical technique for varying percentages of albite reinforcement in steps of 0, 2, 4, and 6 pct by weight. This article tries to bring an overall view of fundamentals of various approaches made to measure the CTE of composites including experimental and theoretical methods such as the Turner model, Kerner’s model, Schapery’s model, and the Eshelby model. The result shows the CTE significantly increased with increasing temperature but decreased with increasing reinforcement. The CTE was expected to vary with relative residual strains, which in turn is dependent on the percentage of reinforcement when cooled from 500 °C to room temperature. The CTE values were found to be comparable with theoretical results. The Eshelby model (showed conformance with experimental results) was well suited with the experimental results. The observed behavior of these particulate composites are described on the basis of the thermal residual stresses developed as a result of the difference in the CTE between matrix and reinforcement. This residual stress relaxation is more difficult in the higher weight (above 6 pct) percentage composites at high temperatures, but upon cooling, the residual stresses are found to be relaxed.