Radiation-induced amorphization of M23C6 in F82H steel: An atomic-scale observation
Radiation-induced amorphization of M23C6 in F82H steel: An atomic-scale observation
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DOI：
10.1016/j.jnucmat.2021.153345
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发表时间：
2021-10-29
影响因子：
3.1
通讯作者：
Abe, Hiroaki
中科院分区：
文献类型：
--
作者：
Kano, Sho;Yang, Huilong;Abe, Hiroaki
本研究的目的是阐明辐照下M23C6的不稳定性行为，特别是辐射诱导非晶化（RIA）的发生。在573 ~ 623 K的高温下，对低活化铁素体/马氏体钢（F82H）及其模型合金（Fe-8Cr-0.1C）进行了10.5 MeV-Fe3+离子辐照。在辐照的F82H试样中观察到由非晶边缘相和M23C6内晶核组成的颗粒的双层对比，但在模型合金中没有观察到。通过高分辨率电镜观察，在F82H样品中，辐照前W在M23C6晶格中的优先占位位点为8c位点，辐照后由于化学无序，W在M23C6晶格中的优先占位位点发生了转移。通过8c与M23C6的另一个位点8c/4a的强度比分析，发现W在非晶界面区域的无序程度比在粒子中心区域有所减轻。对于M23C6中非晶环形成机制的假设是，在当前情况下，由于辐照增强的扩散和/或弹道混合导致的局部界面化学计量组成的偏差，尽管实验和/或模拟研究的努力仍然需要进一步了解M23C6中的RIA行为。(C) 2021 Elsevier B.V.版权所有
The purpose of the present study is to clarify the instability behavior of M23C6 under irradiation, specifically the occurrence of radiation-induced amorphization (RIA). Ion irradiation of 10.5 MeV-Fe3+ at elevated temperatures from 573 to 623 K was conducted into the reduced activation ferritic/martensitic steels (F82H) and its model alloy (Fe-8Cr-0.1C). A bilayer contrast of the particle consisting of an amorphous-rim phase and inner crystalline core of M23C6 was observed in the irradiated F82H specimen, but not in the model alloy. From the high-resolution electron microscope observation, the preferential occupation site of W into M23C6 lattice was identified as 8c-site prior to irradiation in F82H specimen, which shifted to other sites due to chemical disordering upon irradiation. Evaluation of the intensity ratio between 8c and another site of M23C6, 8c/4a, then revealed that the extent of chemical disordering of W was mitigated at the amorphous-crystal interface region in comparison with the central of the particle. The hypothesis for the formation mechanism of an amorphous-rim in M23C6 was presumed as the deviation from the stoichiometric composition at the local interface due to the irradiation-enhanced diffusion and/or ballistic mixing under the current circumstances, although the efforts from experimental and/or simulation studies are still necessary to achieve a further understanding of the RIA behavior in M23C6. (C) 2021 Elsevier B.V. All rights reserved.