Influence of high-temperature annealing on the resistance to high strain rate and fracture of tantalum at temperatures of 20 and 500$^{\circ}$C

Two series of shock-wave experiments have been conducted in order to measure the Hugoniot elastic limit and determine the strain rate dependence of critical fracture stress for tantalum experiencing spall fracture. Tantalum specimens have been preannealed in vacuum at 1000$^{\circ}$C. The evolution of elastoplastic compression shock waves at room and elevated up to 500$^{\circ}$C temperatures has been presented from complete wave profiles recorded by a VISAR laser Doppler velocimeter. The spall strength dependence on the strain rate during the expansion of the material in a rarefaction wave has been determined.