摘要:
用磁控溅射技术制备不同调幅波长(L)的 W(Mo)/Cu 纳米多层膜,所制膜系在60 keV 氦离子(He+)辐照条件下注入不同剂量：0,1×1017 He+/cm2,5×1017 He+/cm2.用 X 射线衍射仪(XRD)和高分辨透射电子显微镜(TEM)表征 W(Mo)/Cu 纳米多层膜辐照前后微观结构.研究结果表明：1) He+离子轰击引起温升效应是导致沉积态亚稳相β-W 转变成稳态α-W 相的主因,而与调幅波长无明确关联；2)纳米多层结构中 W(Mo)和 Cu 膜显现出的辐照耐受性与调幅波长相关,调幅波长越小,抗 He+的辐照性能越强；3)在5×1017 He+/cm2注入条件下,观察到 He 团簇/泡在纳米结构 W(Mo)和 Cu 膜中的积聚行为存在明显差异：在 W (Mo)膜中 He 团簇/泡的分布与晶粒取向相关, He 团簇/泡倾向于沿 W (211)晶面分布；而 Cu 膜非晶化且 He 团簇/泡在其体内呈均匀分布.
Abstract:
W(Mo, 9.8 at.%)/Cu nanometer multilayer films of different individual layer thickness were prepared by RF magnetron sputtering, which were irradiated by 60 keV He+ ions at ion fluence from 0 to 5 × 1017 He+/cm2. Microstructures of nanometer multilayer W(Mo)/Cu films were investigated by high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD) before and after irradiation. Experimental results indicate that: (1) The phase transformation of β-W (A-15) into steady state α-W can be attributed to the bombardment effect of energetic He ions on the surface of films, leading to phase-transition temperature during irradiation. (2) The irradiation tolerance of W(Mo)/Cu multilayer film was found to depend on the individual layer thickness. (3) At the fluence of 5×1017 He+/cm2, the HRTEM results reveal that the behavior of helium cluster/bubble in the W(Mo) film is obviously different from that in the Cu film. It is interesting that the distribution of helium cluster/bubble is related to the grain orientation of W(Mo) film and tends to distribute along W (211) plane. However, Cu film is completely amorphized and helium cluster/bubble is evenly distributed in it.
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