Optimizing and characterization of Aluminium based functionally graded Silicon Nitride composite
R. Ambigai, S. Prabhu
Abstract
In the present study Aluminium alloy (ADC-14) reinforced with the spatial distribution of Silicon Nitride particles are fabricated through centrifugal casting. L4 orthogonal array was used to optimize the rotation speed of the mould for which two levels of 800RPM and 1200RPM was chosen. For the optimized mould speed again L4 orthogonal array was used to optimize the two factors ie. size of reinforcement and the volume fraction of Silicon Nitride. The two levels were 8% and 12% and size of reinforcement of 50microns and 100microns. Optical microscopic images were used to characterize the graded distribution of the fabricated functionally graded metal matrix composites (FGMMCs). The results show that there is an increase in hardness of 19% in the outer zone and 7% in the middle zone when compared with the inner zone ie. core of the casting. Highest hardness was obtained for the 12% reinforcement and 50microns of the reinforcement. The Regression equation and ANOVA analysis were carried out to predict the hardness and the most influencing parameter. SEM and EDS were also used to characterize the Silicon nitride reinforced FGM.