Recovery Studies of Shocked Iron Single Crystals*

Time resolved, in-situ X-Ray diffraction measurements indicate that the bcc-hcp transition in single crystal iron occurs at about 13 GPa. These results also show that the high pressure phase is a polycrystal with two variants. Further studies on the recovered specimens using transmission electron microscopy show that these shocked samples surprisingly reverse transform from a high pressure polycrystal to the original single crystal structure upon release. These results will be discussed in the context of the time resolved data and theoretically based transformation pathways.