MICRISTRUCTURAL PROCESSES OF PLASMA INJECTION EFFECTS IN FUSION PLASMA-FACING MATERIALS

为了研究等离子体粒子注入对聚变堆面向等离子体组件的影响，对低能氢离子辐照钼和钨的微观组织演变进行了原位观察。在钼中观察到微观结构的演变与离子能量有很强的相关性。在4keV及以上的离子作用下，观察到了环的产生、增长、缠绕和网络的形成。另一方面，在2keV及以下观察到氢团簇。然而，在钨中，在2keV及更低的电压下没有观察到显著的微结构变化。比较了辐照后退火热处理过程中的组织演变和退火热处理过程中的气体解吸光谱。在光辐照退火过程中，钨出现了表面位错环的逃逸现象。在热解吸谱过程中观察到的峰值温度与环路逃逸发生的位置很好地对应。这一事实表明，被困在环路或附近基质中的氢与环路一起逃出了表面。对高纯钨和低纯钨进行了比较。在低纯钨中形成的毛圈更稳定，抗滑移到表面。与高纯钨相比，低纯钨的氢原保留率较高。因此，有必要考虑高Z金属材料的制造工艺，即用作面向等离子体的材料的杂质水平。

In-situ observations of microstructural evolution in molybdenum and tungsten were carried out during irradiation with low energy hydrogen ions for the purpose of investigating the effect of plasma-particle injection to plasma-facing components of fusion reactors. A strong dependence of microstructural evolution on the ion energy was observed in molybdenum. Loop generation, growth, tangling and the resulting network formation were observed with ions of 4ke V and above. On the other hand hydrogen clusters were observed at 2keV and below. In tungsten, however, no remarkable microstructural evolution was observed at 2keV and below. Comparisons were made between the microstructural evolution during post-irradiation annealing and gas desorption spectrometry during annealing. The escape of dislocation loops at the surfaces occuured in tungsten during the oppst-irradiation annealing. The peak temperature observed during the thermal desorption spectrometry corresponded well with that where the loop escape took place. This fact suggests that hydrogen trapped at the loops or nearby matrices escaped out of the surfaces together with the loops. The comparison was made between the high-purity and the low-purity tungsten. The loops formed in the low-purity tungsten were more stable, resistant against the slipping to the surfaces. The hudrogen retention was found to be high in the low purity tungsten relative to that in the high purity one. Thus it is needed to examine the high Z metallic materials considering their fabrication processes, i. e. impurity level for use as plasma-facing materials.