Characteristic of AA 7075-Reinforced Nano-SiC Composites Produced by Stir-Squeeze Casting and Open Die Cold Forging as An Armor Material Candidate

Abstract

This study presented the ballistic properties and impact strength of the aluminum alloy AA 7075-reinforced nano-SiC composites, which were produced by stir-squeeze casting and forging processes. Ballistic tests revealed that the samples met the National Institute of Justice (NIJ) Type II standard, except for samples that were not forged. The other characteristics examined were microstructural observations analyzed using optical and scanning electron microscopes. As a result of the pinning effect, the microstructure of the samples showed a decrease in grain size as the SiC content increased, except for samples with over 0.25 vf% of nano-SiC. This effect was observed in samples with and without forging. The forging process decreased grain size further, affecting ballistic and mechanical properties. The addition of 0.3 vf% nano-SiC improved the ballistic properties and impact strength, resulting in the highest impact value of 7.7 J, despite higher values of the average ballistic diameter of perforation (about 4.7 mm) and average indentation depth (about 17.22 mm) measured on this sample.