金在 355 GPa 冲击压缩下的结构相变与熔融。

Structural Transformation and Melting in Gold Shock Compressed to 355 GPa.

机构信息

Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA.

Dynamic Compression Sector, Institute for Shock Physics, Washington State University, Argonne, Illinois 60439, USA.

出版信息

Phys Rev Lett. 2019 Jul 26;123(4):045702. doi: 10.1103/PhysRevLett.123.045702.

DOI:10.1103/PhysRevLett.123.045702

PMID:31491271

Abstract

Gold is believed to retain its ambient crystal structure at very high pressures under static and shock compression, enabling its wide use as a pressure marker. Our in situ x-ray diffraction measurements on shock-compressed gold show that it transforms to the body-centered-cubic (bcc) phase, with an onset pressure between 150 and 176 GPa. A liquid-bcc coexistence was observed between 220 and 302 GPa and complete melting occurs by 355 GPa. Our observation of the lower coordination bcc structure in shocked gold is in marked contrast to theoretical predictions and the reported observation of the hexagonal-close-packed structure under static compression.

摘要

金被认为在静态和冲击压缩下能在非常高的压力下保持其环境晶体结构，从而使其广泛用作压力标记。我们对冲击压缩金的原位 X 射线衍射测量表明，它转变成体心立方（bcc）相，起始压力在 150-176GPa 之间。在 220-302GPa 之间观察到液相-bcc 共存，在 355GPa 时完全熔化。我们观察到冲击金中的低配位 bcc 结构与理论预测和静态压缩下报道的六方密堆积结构形成鲜明对比。