Dispersoid stability in ion irradiated oxide-dispersion-strengthened alloy
Dispersoid stability in ion irradiated oxide-dispersion-strengthened alloy
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DOI：
10.1016/j.jnucmat.2018.07.015
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发表时间：
2018-10
影响因子：
3.1
通讯作者：
Hyosim Kim;J. Gigax;Tianyi Chen;S. Ukai;F. Garner;L. Shao
中科院分区：
文献类型：
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作者：
Hyosim Kim;J. Gigax;Tianyi Chen;S. Ukai;F. Garner;L. Shao
采用3.5MeVFe2+自离子辐照技术，在475 °C下，研究了Hf掺杂氧化物弥散强化合金中氧化物弥散体的辐射响应，研究了相干和非相干弥散体的尺寸随深度的变化。尽管在不同的表征深度下，每原子局部位移(Dpa)速率的差异高达2.6倍，但相干和非相干色散的大小与dpa峰值所在深度的dpa速率没有明显的依赖关系。为了解释实验观察，溶质原子的扩散必须考虑缺陷辅助扩散机制。较高的dpa速率会导致分散体溶解的增强。另一方面，由于缺陷的辅助扩散，提高了弥散相回复率。因此，这两种影响是平衡的，导致分散体大小对dpa速率相对不敏感。研究还表明，相干和非相干色散体在辐照过程中都会收缩，但相干色散体的最终平衡尺寸比非相干色散体的最终平衡尺寸小，这主要是由于它们的界面能不同所致。非相干分散体在辐照下的体积减小比相干分散体的体积减小更明显。
The radiation response of oxide dispersoids in a Hf-doped oxide-dispersion-strengthened (ODS) alloy was studied by using 3.5 MeV Fe2+self-ion irradiation at 475 °C. The size changes of coherent and incoherent dispersoids were studied as a function of depth. Although there was up to 2.6 times difference in local displacements-per-atom (dpa) rate at different characterization depths, the sizes of coherent and incoherent dispersoids did not show a noticeable dependence on dpa rate at depths up to the peak dpa position. In order to explain the experimental observations, the diffusion of solute atoms (dissolved from dispersoids) must take into consideration defect-assisted-diffusion mechanisms. A high dpa rate results in enhanced dispersoid dissolution. On the other hand, dispersoid recovery is increased due to defect-assisted diffusion. Therefore, the two effects are balanced, leading to a relative insensitivity of dispersoid size to dpa rate. The study further shows that both coherent and incoherent dispersoids shrink during irradiation but the final equilibrium sizes of coherent dispersoids are smaller than that of incoherent dispersoids, arising primarily from a difference of their interfacial energies. Incoherent dispersoids undergo more significant volume reduction under irradiation than do coherent dispersoids.