Centrifugal casting and characterisation of primary silicon and Mg2Si dispersed aluminium functionally graded materials

Abstract

Aluminium based FGM rings, reinforced by in-situ primary Si and primary Si/ Mg2Si hybrid reinforcement were successfully fabricated by centrifugal casting and micro structural, chemical, hardness and corrosion characteristics were evaluated. It was observed that in Al-20Si ring the primary Si particles were present mostly in inner region and few in outer region where as in Al-20Si-3Mg ring both the primary silicon and Mg2Si were completely found in the inner region only resulting in a graded FGM structure. The hardness values were measured along radial direction of samples and variations corresponding to micro structural variation were analysed. Optical Emission spectroscopic studies have revealed the remarkable compositional changes along radial direction. Corrosion characteristics were also evaluated both in particle rich and depleted regions. � (2015) Trans Tech Publications, Switzerland.