Comparative study of Uranium diffusion in Zry-4 and pure α-Zr

ABSTRACT Throughout the α-spectrometry U diffusion in pure Zry-4 was studied and compared with pure α-Zr in the temperature range 843-1093 K in order to analyze the diffusion process in both matrices. D values are systematically higher in Zry-4 and its temperature dependence obeys the Arrhenius law being: D0 = (3,2 ± 1,1) m2/s and Q = (316 ± 9) kJ mol-1, whereas in α-Zr U diffusion present an apart to this law, consistent in a downward curvature in the ln(D) vs 1/T plot. Below 873 K U solubility in Zry4 is lower than in pure Zr.摘要 本研究采用α能谱法（α-spectrometry），在843~1093 K的温度范围内，对纯Zry-4合金中的铀扩散行为开展研究，并与纯α相锆（α-Zr）进行对比，以分析两种基体中的扩散过程。研究结果显示，Zry-4中的扩散系数D值整体高于纯α相锆，其温度依赖性符合阿伦尼乌斯定律（Arrhenius law），相关参数为：D₀=(3.2±1.1) m²/s，活化能Q=(316±9) kJ·mol⁻¹；而纯α相锆中的铀扩散行为则偏离该定律，在ln(D)对1/T的作图中呈现向下弯曲的趋势。在873 K以下的温度区间内，铀在Zry-4中的溶解度低于其在纯锆中的溶解度。