International Journal of Advancements in Mechanical and Aeronautical Engineering
Author(s) : B. C. PAI , E. JAYAKUMAR , MANJUNATH MAIYA U , NAGARAJA , RAMAKRISHNA VIKAS S , T. P. D. RAJAN
Functionally graded materials (FGM) are advanced class of engineering materials in which location specific properties are made use in components of specific applications in a more economical and performance efficient ways. Functionally graded metal matrix composites (FGMMC) have graded distribution of reinforcements; whose volume fraction varies continuously in a component leading to a tailored microstructure with continuously changing properties. AA 6061 FGMMC with 10 wt% silicon carbide particles (SiCp), of 23 μm sizes, reinforced composite is processed by liquid metal stir casting method followed by vertical centrifugal casting to obtain the FGM ring. The SiCp due to their higher density than the matrix diffuse towards the outer periphery giving a graded structure. While the porosities, impurities and agglomerates with lower densities accumulate towards the inner periphery and can be removed by machining. Microscopic image analysis shows higher volume percentage of SiC near the outer periphery of 45 % volume. The various mechanical characterizations confirm the presence of three different graded regions, namely particle rich, transition and particle depleted/ matrix rich regions. It is also found that the outer regions have better hardness, wear resistance and tensile properties compared to the inner region due to superficial reinforcement concentrations.