Zirconium In Low-voltage Shock Phase Transition Studies

Phase transition research is very important for a better understanding the dynamic behavior of materials in shock wave physics. More attentions have focused on the metal Zirconium (Zr) because of the low αâ†'ω transition pressure and rich structures, but the experiments data are still limited and its transition pressures to be reported are various. The main objective of this work is to investigate the phase transition of the Zr at some impurity levels (oxygen 520ppm) combining experiments with numerical simulation.There are many useful information of the Zr under the shock loading conditions: On the timescale of Shock wave experiments, it is observed that αâ†'ω transition pressure varied and increased with the impact pressure; The compositions of the Zr, especially for oxygen element, play an important role on αâ†'ω transition of the Zr, and the transition pressure decreased with the increasing material purity at the same impact pressure. At same time, the shock wave velocity and particle velocity of the Zr were measured through the light gas gun experiments, and the experiment results have a good agreement with the LANL shock-compression data. By the way, the stress-strain curves of the α -Zr and the ω -Zr were obtained by MTS tests and SHPB tests, and the parameters of Johnson-Cook model were determined through these experiment results.What's more, basing on the model considered the effects of shear on the shock induced structure phase transition (Ref. Zhang Lin. A new model for prediction of dynamic damage and fracture, structure phase transition on ductile materials. Doctoral Thesis. Beijing: CAEP, 2005.), our experiments containing αâ†'ω transition of the Zr can be fit well. Furthermore, the simulation considering dynamic damage and fracture were taken to experiments at 4.3GPa and 5.1 GPa peak pressure, and the comparison indicates the dynamic parameters of the α-Zirconium are valid.