Search and Control of self-healing mechanism in fusion reactor materials

聚变反应堆材料自修复机制的探索与控制

基本信息

批准号：
09308015
负责人：
MATSUI Hideki
金额：
$ 22.4万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

Self-healing property under particle irradiation is not uncommon to solid materials; many of the engineering materials keep their original shape even after several tens dpa, and this is exactly the result of self-healing property of the material. In this research, this intrinsic property, as well as extrinsic self-healing property given to these materials by adding precipitates, etc. is studied.Firstly, vanadium alloys that have been known to exhibit swelling decrease after going over a peak swelling at some intermediate dpa value. Precipitates in these materials have been examined closely, identifying their nature by utilizing selected area diffraction taken with imaging plates, EDS and PEELS. It became clear that interface between these precipitates and the matrix act as trapping sites, where interface-catalyzed recombination occurs, and play an important role in suppressing swelling. However, this phenomenon only cannot explain the observed decrease in swelling while dpa increases m … More onotonically. Increase in the precipitate density with dpa, caused by irradiation induced precipitation appears to be the mechanism explaining the decrease in swelling. Thus, it seems very important to give these precipitates good stability even after prolonged irradiation to high doses.One of the good example of self-healing property demonstrated under high dpa irradiation is the one observed in V-5Ti alloy. In this experiment, the specimen was first irradiated up to 17dpa in FFTF/MOTA. The specimen was further irradiated in JMTR up to 0.1dpa, which is much smaller to the irradiation in FFTF. The microstructure after 17dpa in FFTF/MOTA was indistinguishable to those in the specimen irradiated to 0.1dpa in JMTR. The microstructure basically consisted of tiny TiO2 precipitates. This means that this microstructure had been saturated below 0.1dpa and did not evolve even during the prolonged irradiation up to 17dpa. This observation is the result of remarkable self-healing mechanism due to the microstructure consisting of fine precipitates; the interface between the matrix and the precipitates act as catalysis for mutual recombination between self-interstitial atoms and vacancies.Computer code based on chemical rate theory has been developed in order to analyze the self-healing property observed experimentally. The input parameters have been obtained by using HVEM in situ irradiation technique. The result of the simulation was in good qualitative agreement while quantitative agreement was fair. The reason for this insufficient agreement between the theory and the experiment may partly be because of the insufficient approximation adopted in the theory. It is believed other mechanism is responsible for this and will be the topic of further research. Less

固体材料在粒子辐照下的自修复特性并不罕见，许多工程材料即使在数十dpa后仍能保持其原始形状，而这正是材料在本研究中的自修复特性的结果。研究了通过添加沉淀物等赋予这些材料的外在自愈性能。首先，已知钒合金在某些中间温度超过膨胀峰值后表现出膨胀减少对这些材料中的沉淀物进行了仔细检查，通过利用成像板、EDS 和 PEELS 拍摄的选定区域衍射来确定其性质，很明显，这些沉淀物和基质之间的界面充当捕获位点，其中界面催化重组。发生，并在抑制膨胀方面发挥重要作用，然而，这种现象只能解释观察到的膨胀减少，而 dpa 增加，沉淀物密度随 dpa 增加而增加。由辐照引起的沉淀引起的似乎是解释溶胀减少的机制，因此，即使在长时间高剂量辐照后，赋予这些沉淀物良好的稳定性似乎也非常重要。这是在高 dpa 下表现出的自修复性能的良好例子之一。辐照是在 V-5Ti 合金中观察到的，在本实验中，样品首先在 FFTF/MOTA 中辐照至 17dpa，然后在 JMTR 中进一步辐照。 0.1dpa，这比 FFTF 中的辐照要小得多。 FFTF/MOTA 中辐照 17dpa 后的微观结构与 JMTR 中辐照 0.1dpa 的样品中的微观结构基本由微小的 TiO2 沉淀组成。在低于 0.1dpa 时已饱和，即使长时间照射也不会演化17dpa。由于微细析出物组成的微观结构，该观察结果是显着的自修复机制的结果；基体和析出物之间的界面起到自填隙原子和空位之间相互重组的催化作用。基于化学速率的计算机代码发展了理论来分析实验观察到的自愈特性，并通过使用 HVEM 原位辐照技术获得了输入参数。理论和实验之间的一致性不够好，部分原因是理论中采用的近似不够充分，这将是进一步讨论的主题。研究较少。