Abstract: High temperature mechanical behaviors of zirconium at high strain rate of 10³ s^-1 were studied by split Hopkinson pressure bar (SHPB). The influences of strain rate and temperature on the micro-structural evolution, as well as the occurrence of shear localization and subsequent fracture, were also investigated. It's found that the compressive stress-strain response depends sensitively on the applied strain rate and test temperature. Micro-structural observations revealed that the density of the twinning grains reduced as the temperature increased, and increased in response to increasing strain rate. Optical observation of the fracture surfaces showed evidence of adiabatic shear localization along the fracture planes prior to crack formation. Finally, a special form of the Zerilli-Armstrong model was used to describe the mechanical response of zirconium.

Key words: Zirconium, High temperature, Strain rate