Development and characterization of Aluminium AA7075 hybrid composite foams (AHCFs) using SiC and TiB2 Reinforcement

Abstract In this study AA7075/SiC/TiB2 closed-cell Aluminium hybrid composite foam (AHCFs) with different densities was fabricated by top-loaded bottom pouring stir casting technique. This technique uses oyster-shell powders (CaCO3 2.5 wt. % of composite with 60 μm size) as blowing agents and no viscosity-enhancing ingredient. The silicon carbide (SiC 0, 3, 6, 9, and 12 wt. % with 25 μm) and titanium di-boride (TiB2 3 wt. % with particle size 15 μm) are used as primary and secondary reinforcement agents. It has been noted that the addition of TiB2 and SiC enhanced the mechanical properties (modulus of elasticity, yield strength, and plateau strength) of AHCFs. The energy absorption capacity of AHCFs increases with the addition of SiC up to 3 wt. % and a further increase in SiC content leads to the reduction. It is observed that density and cell wall thickness increases with increasing the wt. % of SiC and Cell size and porosity decrease with an increase in wt. %. of reinforcement. It is also noted that Stirring temperature also strongly influenced the microstructural properties of AHCFs, and 750 0C of stirring temperature is sufficient for aluminium foaming.