Shock compression behaviour of titanium diboride

Titanium diboride (TiB2) has excellent mechanical properties, and is expected to be used as crashworthy material. In this study, the Hugoniot-measurements were performed on the TiB2 polycrystal by means of the inclined-mirror method combined with the powder gun and two-stage gas gun to study the elastoplastic transition and to search phase transition. The Hugoniot-elastic limit (HEL) stress was measured to be approximately 12 GPa. The shock velocity (US) vs. particle velocity (UP) relation of the final phase was given by US=8.79+0.78UPkm/s in the plastic region of 0.6-3.0 km/s in particle velocity. The shock velocities were much large compared with the bulk sound velocity, and those in 0.24-0.6 km/s were further larger than the linear Hugoniot relation. This result showed that this material preserved the large shear strength also in the plastic region. No phase transition was observed up to 120 GPa.