Influence of temperature on crater and ejecta size following hypervelocity impact of aluminum alloy spheres on thick aluminum alloy targets

The influence of temperature on crater shape and ejecta fragment size in thick aluminum alloy targets was investigated for impact velocities ranging from approximately 0.9–3.5 km/s using a two-stage light-gas gun. The diameter, depth, and volume of the crater increased with increasing temperature. Observation of the witness plates showed that the scatter diameters and angles of the ejecta were slightly smaller at high temperatures than at low and room temperatures. Temperature affected the size and mass of ejecta fragments collected from the chamber only when the impact velocity was 1.5 km/s (the velocity at which the projectile fragmentation started). As the temperature increased, its influence on the mass of ejecta fragments decreased. Temperature affected the length and the axial ratios of ejecta fragments only at an impact velocity of 1.5 km/s. Regardless of the temperature and impact velocity, the axial ratios, c/a, were less than 0.6.