A Novel Method of Light Weighting Aluminium Using Magnesium Syntactic Composite Core

Abstract

In this study, hybrid composite consisting of aluminium (Al) shell and magnesium/glass microballoon (Mg-20 wt.% GMB) syntactic composite core was fabricated in a shell-core pattern by combining powder metallurgy and disintegrated melt deposition (DMD) techniques. Physical, microstructural and mechanical properties of as-cast Al and Al/Mg-20GMB hybrid composite were examined. Approximately 13% reduction in density (with respect to aluminium) was realized through the use of a syntactic composite core. Microstructural investigations revealed reasonable interfacial integrity between aluminium shell and Mg-GMB core material and the presence of Al, Mg and GMB phases. The interface region showed a hardness of 109 ± 2 Hv in comparison to the hardness of Al shell region (68 ± 4 Hv) and Mg-20GMB core region (174 ± 5 Hv). In comparison to as-cast Al, the yield strength and ultimate compressive strength of the as-cast Al/Mg-20GMB hybrid composite increased by ~65.4% and ~60%, respectively. Further, the energy absorption under compressive loading for the Al/Mg-20GMB hybrid composite was ~26% higher compared to pure Al. This study validated that Al/Mg-20GMB hybrid composite with superior absolute and specific mechanical properties can be fabricated and used for weight critical applications.