A comparative study of processing route, microstructures, fracture analysis and phase formation of Al-Si/Mg ₂ Si functionally graded composites: an overview

The current study critically presented overviews on Al-Mg2Si functionally graded composites (FGCs), processing, and gradient distribution of particles, fracture analysis, scope and applications. After a literature study, it was found that Al-Mg2Si in-situ FGCs were produced with many fabrication routes. Among these, the centrifugal casting method (CCM) has an economical approach to the produce like tubular objects. In the centrifugal casting route, the tubular products can be fabricated with desired specific properties. It was observed that the in-situ formed Mg2Si primary particles are segregated in the inner core of the cast tubes due to their lower density. The segregation of Mg2Si particles depends on their relative lower densities (ρMg2Si = 1.99 g.cm−3) compared to that of (ρAl = 2.37 g.cm−3) matrix materials. The enrichment of hard Mg2Si phases into the inner surface of the cast tubular product is highly desired in engine cylinder liners. It was also found that some of the products like disc brakes or cylinders needed high wear resistance and mechanical properties towards the surface. In this case, highly dense reinforced particles (TiB2, or SiC) can be used during centrifugal casting. The current review paper outlined insightful concepts for future research in the area of FG-composites.