A combination of low density and high strength make boron carbide a desirable material for protection applications. However, the ballistic performance of hot-pressed boron carbide is affected by its susceptibility to amorphization beyond the Hugoniot elastic limit (HEL) and by the presence of processing-induced carbonaceous inclusions which act as crack nucleation sites. To address the above shortcomings, two new varieties of boron carbide ceramics are prepared: 1) a boron carbide doped with silicon and reinforced with TiB2 to reduce amorphization; and 2) a boron carbide that uses amorphous boron in the starting powder to interact with residual carbon, resulting in no detectable carbonaceous inclusions in the boron carbide. The ballistic performance of these ceramics is compared with commercially available pressure-assisted densified (PAD) boron carbide through canonical sphere-on-plate impact experiments in the HyFIRE facility at the Hopkins Extreme Materials Institute. Tungsten carbide projectiles (3 mm diameter spheres) are launched at 9 mm thick ceramic plates, backed by a 6 inch thick aluminum block. Impact velocities are divided into two regimes: low (1.2 – 2 km/s) and high (3 – 4.5 km/s). Low impact velocities do not result in complete penetration of the boron carbide plate and material performance for these shots is characterized through impact crater attributes such as depth, volume, and area evaluated through X-ray microcomputed tomography (micro-CT). High velocities shots result in perforation of the boron carbide plate followed by penetration into the aluminum block. For these shots, penetration depth and crater volume of the aluminum blocks are obtained by micro-CT and used as the criteria for assessing ballistic performance.
2022-04-06 08:00:00
