ABSTRACT Tungsten is widely used as a plasma-facing material in nuclear fusion reactors due to its favorable properties; however, the extensive exposure of energetic particles could lead to severe degradations on its surface. Therefore, we studied the surface modification resulted from helium implantation on the mechanically and electrochemically polished tungsten at an elevated temperature. Samples of both types were implanted with helium ions to a fluence of at . Compared with electrochemically polished tungsten, fewer and smaller blisters was identified on mechanically polished sample by means of scanning electron microscopy (SEM). Combined with the focused ion beam (FIB) facility, cross-sectional SEM and transmission electron microscopy (TEM) analyses were conducted, and elongated cavities along the grain cracks were confirmed in the mechanically polished sample. Both SEM and TEM observations confirmed that these cavities can connect the damaged layer and sample surface, and effectively exhaust the accumulated He gas. Subsequently, the possible correlation between blistering reduction and the helium-induced cavities in mechanically polished tungsten was discussed.

中文翻译：

---

机械和电化学抛光钨的氦注入表面改性对比研究

摘要 钨因其良好的特性而被广泛用作核聚变反应堆中的面向等离子体的材料。然而，高能粒子的大量暴露可能导致其表面严重退化。因此，我们研究了在高温下在机械和电化学抛光的钨上注入氦引起的表面改性。两种类型的样品都注入了氦离子，通量为 at 。与电化学抛光的钨相比，通过扫描电子显微镜 (SEM) 在机械抛光的样品上发现了更少和更小的气泡。结合聚焦离子束 (FIB) 设施，进行了横截面 SEM 和透射电子显微镜 (TEM) 分析，在机械抛光的样品中证实了沿晶粒裂纹的细长空腔。SEM 和 TEM 观察均证实这些空腔可以连接损坏层和样品表面，并有效地排出积聚的 He 气体。随后，讨论了机械抛光钨中起泡减少与氦诱导空腔之间可能的相关性。