On the evaluation of mechanical properties and ballistic performance of two variants of boron carbide

A comparative study on the microstructure, rate-dependent compressive behavior, and ballistic performance of commercially available pressureless sintered boron carbide-titanium diboride (material Z) and hot-pressed boron carbide (material S) was conducted. Under quasi-static compression at rates of 1.4 to 1.6 x 10-4 s-1, the strength was found to be 3.07 ? 0.11 GPa for material Z and 4.72 ? 0.14 GPa for material S. At dynamic strain rates ranging from 185 to 1152 s-1, the compressive strength ranged from 3.56 to 4.07 GPa for material Z and 5.24 to 5.97 GPa for material S. Depth of penetration testing was performed using 7.62 mm AP M2 projectiles. The normalized ballistic efficiency of the two materials were found to be comparable at 932 m/s, while material S was superior to material Z at an impact velocity of 1078 m/s. Based on post-mortem SEM analysis of ballistic tile fragments, the inferior mechanical properties and ballistic performance of material Z are attributed to an uneven distribution of silicon impurities and a significant level of porosity.