High-pressure structural behavior and elastic properties of U3Si5: A combined synchrotron XRD and DFT study

JOURNAL OF NUCLEAR MATERIALS

卷:540

Article

Baker, Jason L.¹  Wang, Gaoxue²  Ulrich, Tashiema³  White, Josh T.³  Batista, Enrique R.²  Yang, Ping²  Roback, Robert C.¹  Park, Changyong⁴  Xu, Hongwu¹ 

[1] Los Alamos Natl Lab, Earth & Environm Sci Div, Los Alamos, NM 87545 USA

[2] Los Alamos Natl Lab, Theoret Div, Los Alamos, NM 87545 USA

[3] Los Alamos Natl Lab, Mat Sci & Technol Div, Los Alamos, NM 87545 USA

[4] Argonne Natl Lab, High Pressure Collaborat Access Team, Xray Sci Div, 9700 S Cass Ave, Argonne, IL 60439 USA

关键词: Uranium silicide;    Crystal structure;    Bulk modulus;    High pressure;    Synchrotron X-ray diffraction;    Diamond anvil cell;    Density functional theory;   

DOI  :  10.1016/j.jnucmat.2020.152373

来源: Elsevier

【 摘 要 】

We present an integrated experimental and theoretical study of the structural behavior of U3Si5 at high-pressure conditions using angle-dispersive synchrotron X-ray diffraction (XRD) in a diamond anvil cell (DAC) and density functional theory (DFT) calculations. On increasing pressure, the ambient hexagonal structure of U3Si5 with space group P6/mmm remains stable up to 16.7 GPa, the maximum pressure tested with DAC. The bulk modulus and the a- and c-axial moduli of U3Si5 were experimentally determined to be 126 +/- 4 GPa, 173 +/- 8 GPa and 79.7 +/- 4.3 GPa, respectively. Thus an anisotropy in the axial compressibility of U3Si5 is observed with its c-axis being more compressible than the a-axis. Our DFT calculation results are in general agreement with the experimental values, including reproducing the compressibility anisotropy. A comparison of the bulk modulus of U3Si5 to those of other U-Si compounds reveals a general trend that the bulk modulus of U-Si decreases with increasing U/(U + Si) ratio. (C) 2020 Elsevier B.V. All rights reserved.

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