Activation energy of homogeneous nucleation of Zr hydride: Density functional theory calculation
Activation energy of homogeneous nucleation of Zr hydride: Density functional theory calculation
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DOI：
10.1016/j.commatsci.2022.111769
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发表时间：
2022-12
影响因子：
3.3
通讯作者：
A. Ishii
中科院分区：
文献类型：
--
作者：
A. Ishii
考虑到Zr氢化物的成核过程是由六方闭包（HCP）向面心四方（FCT）相转变的过程，我们利用密度函数理论计算和最小能量路径检测计算了Zr氢化物的均相成核过程的活化能和zr4h、zr2h、ZrH和ZrH 2成核过程中的原子重排。在0 K极限下，虽然ZrH和ZrH 2的化学势比zr4h和zr2h更低，能量更稳定，但后者的成核活化能较低。在有限温度下，活化能的交叉发生在300 K左右，ZrH成为活化能最低的最有可能的候选者。这可以用相变过程中原子重排的差异和声子频率的变化来解释。
Considering the nucleation process of Zr hydrides as phase transformation from hexagonal closed-packed (HCP) to face-centered tetragonal (FCT) structure, we calculated the activation energy of the homogeneous nucleation process of Zr hydrides and atomic rearrangement during nucleation for Zr 4 H, Zr 2 H, ZrH and ZrH 2 using density functional theory calculations and minimum energy path detection. At 0 K limit, although ZrH and ZrH 2 have lower chemical potentials and are more energetically stable than Zr 4 H and Zr 2 H, the latter have lower activation energies for nucleation. At finite temperatures, the crossover of activation energies occurs around 300 K, where ZrH becomes the most possible candidate with the lowest activation energy. This was explained by the difference in the atomic rearrangement and change in phonon frequency during phase transformation.