Abstract:Terminal ballistic tests using 7.62 mm armor-piercing incendiary (API) projectiles were performed to evaluate the resistance to penetration of Ti-5Al-5Mo-5V-3Cr-1Zr (Ti-55531) alloy. The dynamic properties were determined by a split Hopkinson pressure bar (SHPB) test system. Ti-55531 plates were subjected to two kinds of heat treatments, leading to the formation of high-strength and high-toughness plates. The results of SHPB test exhibit that the maximum impact absorbed energy of the high-strength plate at a strain rate of 2200 s^-1 is 270 MJ/m³; however, the maximum value for the high-toughness plate at a strain rate of 4900 s^-1 is 710 MJ/m³. The ballistic limit velocities for the high-strength and high-toughness plates with dimensions of 300 mm×300 mm×8 mm are 330 and 390 m/s, respectively. Excellent dynamic properties of Ti-55531 alloy correspond to good resistance to penetration. The microstructure evolution related to various impact velocities are observed to investigate the failure mechanism.

Key words: Ti-5Al-5Mo-5V-3Cr-1Zr alloy; dynamic property; split Hopkinson pressure bar; adiabatic shear band; ballistic behavior; ballistic limit