Huston L Q, Velisavljevic N, Smith J S, Gray G T, Sturtevant B T
Shock and Detonation Physics, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America.
High Pressure Collaborative Access Team, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, United States of America.
J Phys Condens Matter. 2021 Nov 12;34(5). doi: 10.1088/1361-648X/ac33dd.
Hafnium (Hf) is an industrially important material due to its large neutron absorption cross-section and its high corrosion resistance. When subjected to high pressure, Hf phase transforms from its hexagonal close packed α-Hf phase to the hexagonal ω-Hf phase. Upon further compression, ω-Hf phase transforms to the body centered cubic β-Hf phase. In this study, the high pressure phase transformations of Hf are studied by compressing and decompressing a well-characterized Hf sample in diamond anvil cells up to 120 GPa while collecting x-ray diffraction data. The phase transformations of Hf were compared in both a He pressure transmitting medium (PTM) and no PTM over several experiments. It was found that the α-Hf to ω-Hf phase transition occurs at a higher pressure during compression and lower pressure during decompression with a helium (He) PTM compared to using no PTM. There was little difference in the ω-Hf to β-Hf phase transition pressure between the He PTM and no PTM. The equation of state was fit for all three phases of Hf and under both PTM and no-PTM.
铪（Hf）因其较大的中子吸收截面和高耐腐蚀性而成为一种具有重要工业价值的材料。在高压作用下，铪会从其六方密堆积的α-Hf相转变为六方ω-Hf相。进一步压缩时，ω-Hf相转变为体心立方β-Hf相。在本研究中，通过在金刚石对顶砧中对一个特征明确的铪样品进行压缩和解压，直至120吉帕，并同时收集X射线衍射数据，来研究铪的高压相变。在多个实验中，对在氦压力传递介质（PTM）和无PTM两种情况下铪的相变进行了比较。结果发现，与不使用PTM相比，在使用氦（He）PTM时，α-Hf到ω-Hf的相变在压缩过程中发生的压力更高，而在减压过程中发生的压力更低。在He PTM和无PTM情况下，ω-Hf到β-Hf的相变压力几乎没有差异。对铪的所有三个相以及在有PTM和无PTM两种情况下的状态方程进行了拟合。
