High temperature neutron diffraction investigation of U3Si2
High temperature neutron diffraction investigation of U3Si2
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DOI：
10.1016/j.mtla.2019.100580
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发表时间：
2020-03
期刊：
影响因子：
3.4
通讯作者：
T. Ulrich;S. Vogel;J. White;D. Andersson;E. S. Wood;T. Besmann
中科院分区：
文献类型：
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作者：
T. Ulrich;S. Vogel;J. White;D. Andersson;E. S. Wood;T. Besmann
U-Si系统由于其作为事故容忍核燃料的组成部分的前景而正在积极进行研究。在这项工作中，研究了U-Si系统中U3 Si 2化合物的晶体结构作为温度的函数，从室温到1298 K，样品约为42.02 at.% Si成分和1373 K的样品具有约42.10 at.% Si在Los Alamos中子科学中心（LANSCE）的高压择优取向（HIPPO）衍射仪上使用高温飞行时间中子衍射。对来自五个HIPPO探测器背面（40°、60°、90°、120°和145°）的五个直方图的同时Rietveld细化提供了晶格参数、各向异性原子位移参数和原子位置随温度变化的数据集。为了探索均匀性范围的可能性，分析了两种样品组成，40.02 at.% Si（接近化学计量比）和潜在的超化学计量比（40.10原子%）的硅。Si）样品。虽然观察到两个样品之间的各向异性原子位移参数的微小差异，但在整个研究温度范围内，没有发现指示单相样品和U3 Si 2化合物适应非化学计量的能力的额外相，这表明U3 Si 2化合物不是确认先前确定的线化合物。然而，在两种组合物之间鉴定的平均线性热膨胀系数中观察到的差异保证了未来的研究。
The U-Si system is actively undergoing studies due to its promise as a component of an accident tolerant nuclear fuel. In this work, the crystal structure of the U3Si2 compound in the U-Si system was investigated as a function of temperature from room temperature to 1298 K for a sample of approximately 42.02 at.% Si composition and 1373 K for a sample with approximately 42.10 at.% Si using high temperature time-of-flight neutron diffraction on the High-Pressure Preferred Orientation (HIPPO) diffractometer at Los Alamos Neutron Science Center (LANSCE). The simultaneous Rietveld refinement of five histograms from the five HIPPO detector backs (40°, 60°, 90°, 120°, and 145°) provided datasets for the lattice parameters, anisotropic atomic displacement parameters, and atomic positions as a function of temperature. To explore the possibility of a homogeneity range, two sample compositions were analyzed, a 40.02 at.% Si (near stoichiometric) and a potentially hyperstoichiometric (40.10 at.% Si) sample. While minor differences in the anisotropic atomic displacement parameters between the two samples were observed, over the entire investigated temperature range no additional phases were found indicative of a single phase sample and the ability of the U3Si2 compound to accommodate nonstoichiometry, suggesting that the U3Si2 compound is not a line compound confirming previous determinations. However, the differences observed in the average coefficient of linear thermal expansion identified between the two compositions warrant future investigation.