Growth of helium (He) induced bubbles and fuzz in tungsten (W) and molybdenum (Mo) is investigated using samples of W films on Mo substrates and Mo films on W substrates exposed to He-containing plasma in the temperature range of 340 to 1075K, fluence range of 1.0–14 10²⁵ Hem⁻², and incident ion energy of <50eV. No fuzz (only up to 2nm diameter bubbles) and no material transport occur in W films at ⩽750K, while precursors-of or fully-developed fuzz and material mixing occur in W and Mo films at ⩾800K. This suggests that fuzz forms in multi-material systems as long as one material meets the conditions for fuzz formation, namely T _s/T _m ∼ 0.27–0.5 where T _s and T _m are the sample exposure and material melting temperatures, respectively. Larger He bubbles, more material mixing, and further-developed fuzz occur at higher temperature due to increased mobility of He atoms and small He clusters. Accumulation of substrate material at the surface of fuzzy W and Mo thin-film (<80nm) samples suggests fuzz growth by material transport from the bubble layer in the bulk up to the fiber tip, likely by a two-step process: (i) diffusion of punched dislocation loops in the bulk toward the fuzz base and (ii) diffusion of adatoms along the fuzz base and fiber surface (with effective transport of adatoms upwards due to trapping of adatoms at curved surfaces of fiber tips and/or due to the continuous generation of adatoms at the fuzz base). While the bubble size and fuzz thickness increase with reduced W concentration in Mo thin-film samples at 838K likely due to an increase in trap mutation and dislocation loop punching in Mo compared to W, the fuzz thickness decreases with reduced W concentration at 1075K despite an increase in the bubble size likely due to slower diffusion of interstitial loops in Mo.

使用暴露于 340 至 1075K 温度范围内的含 He 等离子体的 Mo 衬底上的 W 膜和 W 衬底上的 Mo 膜样品研究了氦 (He) 诱导气泡和绒毛在钨 (W) 和钼 (Mo) 中的生长，注量范围为 1.0–14 10 ²⁵ Hem ^-2，入射离子能量 <50eV。在 ⩽750K 下 W 薄膜中没有绒毛（仅直径最大为 2nm 的气泡）和材料传输，而在 ⩾ 800K 下 W 和 Mo 薄膜中发生前体或完全发展的绒毛和材料混合。这表明只要一种材料满足形成绒毛的条件，即T _s / T _m ∼ 0.27–0.5，其中T _s和Ť _米分别是样品暴露温度和材料熔化温度。由于 He 原子和小 He 簇的迁移率增加，在较高温度下会出现更大的 He 气泡、更多的材料混合和进一步发展的绒毛。在模糊的 W 和 Mo 薄膜 (<80nm) 样品表面上基底材料的积累表明，通过从本体中的气泡层到光纤尖端的材料传输，绒毛生长，可能通过两步过程：（i）体中冲压位错环向绒毛基部扩散和 (ii) 吸附原子沿绒毛基部和纤维表面的扩散（由于吸附原子在纤维尖端的曲面处被捕获和/或由于吸附原子的有效传输，吸附原子向上传输在模糊基部连续产生吸附原子）。