Shock wave response of ammonium perchlorate single crystals to 6 GPa

Plane shock wave experiments were carried out on ammonium perchlorate singl e crystals compressed along [210] and [001] orientations to peak stresses r anging from 1.2 to 6.2 GPa. Quartz gauge and velocity interferometer techni ques were used to measure the elastic and plastic shock wave velocities, an d stress and particle velocity histories in the shocked samples. The measur ed Hugoniot elastic limit (HEL) was 0.48 +/- 0.09 GPa. Above the HEL and up to about 6 GPa, the data show a clear two-wave structure, indicating an el astic-plastic response. Time-dependent elastic precursor decay and plastic wave ramping are discernable and orientation dependent in the low stress da ta. However, the orientation dependence of the peak state response is small . Hence, data for both orientations were summarized into a single isotropic , elastic-plastic-stress relaxation model. Reasonable agreement was obtaine d between the numerical simulations using this model and the measured wave profiles. At a shock stress of about 6 GPa and for the time duration and cr ystal orientations examined, we did not observe any features that may be id entified as a sustained chemical reaction or a phase transformation. (C) 20 00 American Institute of Physics. [S0021-8979(00)04613-2].