On the ballistic performance of the AA7075 based functionally graded material with boron carbide reinforcement

In this study, the functionally graded materials (FGMs) bearing three layers were produced via hot pressing to investigate their ballistic performances against 7.62 mm armor piercing (AP) projectile. In the FGM samples, the bottom layer was considered as unreinforced AA7075 alloy, whereas the middle and top layers were made of the AA7075 composite layers having various proportions of B4C particles. Prior to the ballistic testing, the hardness change in the layers with respect to aging time at different temperatures was determined. And then, the ballistic testing of the samples was performed at a ballistic laboratory using 7.62 mm AP projectile. In the ballistic testing, five separate specimens for each FGM group having fixed composition and thickness were used. The experimental results showed that the ballistic impact resistance of the investigated FGMs increased with increasing boron carbide content and the thickness in the layers. Moreover, there were no separations observed between the layers in the failed samples.