Transformation of shock-compressed copper to the body-centered-cubic structure at 180 GPa
Surinder M. Sharma, Stefan J. Turneaure, J. M. Winey, Y. M. Gupta
Abstract
Using in situ x-ray diffraction measurements in shock-compressed copper (38--276 GPa), we show that the ambient face-centered-cubic (fcc) structure transforms to the body-centered-cubic (bcc) structure at \ensuremath{\sim}180 GPa. Additionally, stacking fault (SF) abundance in shock-compressed copper increases with compression, reaching \ensuremath{\sim}10% at the onset of the fcc-bcc phase transition. Both findings are consistent with recent results on shock-compressed gold and silver that showed the importance of SFs in facilitating the fcc-bcc transformation. In contrast to our results, copper was recently reported to retain the fcc structure to over 1000 GPa under ramp compression [Fratanduono et al., Phys. Rev. Lett. 124, 015701 (2020)]. Further studies are needed to understand why the fcc-bcc transformation in copper is observed under shock compression, but not under ramp compression.