Reciprocating Wear Analysis of Magnesium-Modified Hyper-eutectic Functionally Graded Aluminium Composites

Abstract

Functionally graded materials are a new class of inhomogeneous materials, where the composition or the microstructure is locally varied within a component in order to achieve the desired location-specific material properties. In the present study, the tribological characteristics of hyper-eutectic A390 functionally graded aluminium alloy modified by the addition of 2% and 4% of magnesium are examined. Functionally graded aluminium metal matrix composites (FGAMMC’s) rings are produced by vertical centrifugal casting technique. Centrifugal casting is proved to be a versatile casting method for producing different types of FGM components based on property requirements. The centrifugal force moves the primary silicon and Mg2Si towards the inner radius due to their lesser density than that of aluminium showing a gradation, inner to the outer periphery. This gradation increases the hardness and wear resistance towards the inner. During the process, the microstructure got refined with respect to that of gravity casting. The detailed microstructures, composition analysis and wear study reveal the morphology of the FGM. The dry reciprocating wear analysis on various loads reveals that the behaviour of 2% Mg modification completely shows a eutectic nature and the wear rate is similar to the base A390 alloy. Also, it is found that the wear linearly increases with the applied load and the wear resistance offered by the zone with more Mg2Si precipitates is high.