Recovery behavior of point defects after low-dose neutron irradiation at ∼423 K of sintered 6H–SiC by lattice parameter and macroscopic length measurements
Recovery behavior of point defects after low-dose neutron irradiation at ∼423 K of sintered 6H–SiC by lattice parameter and macroscopic length measurements
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DOI：
10.1016/j.jnucmat.2013.01.296
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发表时间：
2013-11
影响因子：
3.1
通讯作者：
T. Yano;Yusuke Futamura;Saishun Yamazaki;T. Sawabe;Katsumi Yoshida
中科院分区：
文献类型：
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作者：
T. Yano;Yusuke Futamura;Saishun Yamazaki;T. Sawabe;Katsumi Yoshida
为了评估中子辐照引起的晶体缺陷及其热稳定性，使用日本材料试验堆在~423 K的低温下对主要由6H多型体组成的α-SiC烧结体进行中子辐照，中子辐照强度高达1.9 × 1023n/m2（E> 0.1 MeV）。由于低温下辐照剂量非常低，引起晶格的预期缺陷应该只是简单的点缺陷。测量了室温和 1673 K 之间长达 6 小时的辐照后等温退火所导致的晶格参数和宏观长度的变化。 α-SiC 样品的宏观体积膨胀与晶胞体积变化非常吻合，表明仅存在简单的缺陷。宏观长度和晶格参数的恢复行为表现出几乎相同的趋势，尽管在低于 1273 K 的温度下，thec 轴长度的残余变化略大于 thea 轴长度的变化。在高于 1273 K 的温度下，这些轴长度的差异减小。在每个等温退火步骤中使用膨胀计通过精确长度测量获得的活化能的计算表明，473 和 1573 K 之间的长度恢复行为可以几乎可以完全用一级反应和活化能分别为 0.14、0.26 和 1.13 eV 的三个阶段来解释。活化能的变化与晶格参数变化的行为有关。结果表明存在多种点缺陷，其中一些引起各向异性晶格膨胀。
To evaluate neutron-irradiation-induced crystalline defects and its thermal stability, α-SiC sintered bodies consisting of mainly 6H polytype were neutron irradiated using the Japan Materials Testing Reactor up to 1.9 × 1023n/m2(E> 0.1 MeV) at a low temperature of ∼423 K. Due to very low dose irradiation at low temperature, expected defects induced into crystalline lattice should only be simple point defects. Changes in the lattice parameters and macroscopic lengths resulting from post-irradiation isothermal annealing up to 6 h between room temperature and 1673 K were measured. Macroscopic volume swelling of α-SiC specimens coincided well to those of unit cell volume changes, indicating the presence of only simple defects. The recovery behavior of the macroscopic length and lattice parameters showed almost the same tendencies, although residual changes in thec-axis length slightly exceeded that of thea-axis length at temperatures lower than 1273 K. Difference in these axes lengths diminished at temperatures above 1273 K. Calculation of activation energies, obtained from precise length measurement using a dilatometer during each isothermal annealing step, revealed that length recovery behavior between 473 and 1573 K could almost be completely explained by a first-order reaction, and three stages with activation energies of 0.14, 0.26, and 1.13 eV. Changes in activation energy were related to the behavior of lattice parameter changes. The results indicated the presence of several kinds of point defects, some of which induced anisotropic lattice expansion.