X-ray diffraction study of shock-induced phase transformations in zirconium and bismuth

Pulse X-ray patterns of polycrystalline zirconium and monocrystalline bismuth are obtained at the moment of shock-wave stimulation of samples. The exposure time of X-ray photography is 0.2-0.3 ms. Zirconium samples are investigated at shock pressures of 5, 9.5, 15, and 29 GPa. At P = 5 and 9.5 GPa, the structure of the initial alpha-phase is observed. At 15 and 29 GPa, the form of X-ray patterns varies, but they are difficult to interpret. A mixture of the alpha- and omega-phases is observed on the free surface of zirconium sample after it is loaded to 12 GPa and the unloading begins. Single crystals of bismuth, oriented parallel to the sample surface by the (100), (110), and (111) crystallooraphic planes, are investigated at shock pressures of 6.7, 8.5, 13.7, 22, and 27 GPa. At 6.7 GPa, a high-pressure phase of Bi-V is registered; at 8.5 and 13.7 GPa, a distorted body-centered crystal (bcc) structure. At a higher pressure (22 GPa), a disturbance of the Iong-range crystal order (arnorphization) is observed; at 27 GPa, the diffraction pattern disappears, which may be seen as melting.