An Insight Into Use of Hollow Fly Ash Particles on the Properties of Magnesium

Abstract

In the recent years, magnesium based materials has received wide acceptability and attention owing to their attractive properties like high specific strength, high specific stiffness, low density, excellent machinability, castability, and good damping properties. Therefore, they have become a promising choice for applications in the automotive, transport, aerospace and electronic packaging industries [1, 2]. Magnesium is also a biocompatible material and is an important constituent of the bone. The volume of scientific publications on the research of magnesium as a biomaterial has increased exponentially in the past 8–10 years. Further, when compared to other light metals, the Young’s modulus of magnesium based materials (40–45 GPa) is comparable to that of natural bone (3–20 GPa). This property of magnesium materials assists in mitigation of stress shielding effects with possibility to eliminate secondary surgery for the implant removal especially for clinical applications [3]. However, costs incurred during the synthesis of these materials are a major limitation. Fly ash cenospheres are alumino-silicate particles which are mainly a by-product of coal combustion in thermal power plants with an extremely low density of about 0.4–0.8g/cc [4]. The incorporation of fly ash particles into magnesium is an encouraging option for light-weight applications as the replacement of magnesium matrix by fly ash particles can further decrease the density of the composite and also the overall cost of raw materials [5]. The addition of hollow particles like cenospheres into polymeric or metallic matrices results in a special type of closed cell foams known as syntactic foams. For the past decade, a lot of research has been carried out mainly on aluminium syntactic foams and researchers have reported enhanced compressive strength and modulus, isotropic behaviour, high energy absorption and attractive strength to weight ratio [6, 7]. Moreover, the addition of fly ash cenosphere particles in composites is an effective way to reduce the carbon emissions and thereby finding applications in automotive, aerospace and military applications. The effect of fly ash cenosphere particles addition in magnesium based alloys and composites have become an encouraging area for researchers for the past 10 years. As magnesium is expanding into more critical structural applications, there is a need to tailor the properties of magnesium syntactic foams for potential use in lightweight energy absorbing components. This paper focuses on magnesium matrix syntactic foams which contain porosity in the form of hollow fillers and a review of our recent findings in the study of magnesium syntactic foams synthesized by disintegrated melt deposition technique.