Zr在αU中的溶解焓和过剩熵的第一性原理计算研究  

First-Principles Calculations of the Solution Enthalpy and the Excess Entropy of Zr inαU

作　　者：屈哲昊[1] 冯伟[2] 高春来 Qu Zhehao;Feng Wei;Gao Chunlai(Reactor Engineering Technology Research Institute,China Institute of Atomic Energy,Beijing 102413,China;Department of Nuclear Engineering Design,China Institute of Atomic Energy,Beijing 102413,China;Faculty of Mathematics and Physics,Huaiyin Institute of Technology,Huai’an 224001,China)

机构地区：[1]中国原子能科学研究院反应堆工程技术研究所,北京102413 [2]中国原子能科学研究院核工程设计研究所,北京102413 [3]淮阴工学院数理学院,江苏淮安224001

出　　处：《稀有金属材料与工程》2024年第12期3398-3406,共9页Rare Metal Materials and Engineering

摘　　要：针对U-Zr相图中富U端Zr在αU中的固溶度曲线所需的溶解焓和过剩熵,分别进行了第一性原理计算并与实验数据进行了对比分析。对于Zr-αU固溶体转变为δUZr_(2)时对应的溶解焓和过剩熵,采用SQS模型得到每个Zr原子对应的结果为1.437eV/Zratom和1.060k_(B)/Zratom,采用disorder模型得到每个Zr原子对应的结果为1.420eV/Zratom和0.732k_(B)/Zratom。基于实验数据,分析拟合得到的每个Zr原子的溶解焓为-0.823±0.712meV/Zratom,过剩熵为5.880±9.976k_(B)/Zratom。对比理论计算和拟合实验数据的结果发现,振动熵对固溶度的影响不可忽略,并且理论和实验数据相差较大的原因可能与理论计算中设置的δUZr_(2)中Zr的位置与实验中的具体结构位置参数不尽相同有关。The solution enthalpy and the excess entropy of Zr inαU have been calculated based on first principles calculations in order to achieve U-rich solubility curves for U-Zr phase diagram.The enthalpy and the excess entropy of the Zr atom corresponding to Zr-αU transforming from solution state intoδUZr_(2) are 1.437 eV/Zr atom and 1.060 kB/Zr atom by using the SQS model,which are 1.420 eV/Zr atom and 0.732 k_(B)/Zr atom with the disorder structure forδUZr_(2).But based on the experimental data,the fitted solution enthalpy and excess entropy are-0.823±0.712 meV/Zr atom and 5.880±9.976 k_(B)/Zr atom,respectively.Through comparing the theoretical calculations and the experimental fitting results,it is found that the effect of the vibrational entropy on solubility could not be ignored.This discrepancy between the theoretical results and the experimental data might be related to the fact that the positions of Zr inδUZr_(2) in the theoretical calculations are not well consistent with the specific structural parameters of the the experimental samples.

关 键 词：第一性原理 溶解焓 过剩熵 振动熵 

分 类 号：TL27[核科学技术—核燃料循环与材料]