Effects of He+ energy and W temperature on the initial W fuzz growth under the fusion-relevant He+ irradiation

• Published in: Journal of nuclear materials 2025-02, Vol.606, p.155630, Article 155630
• Main Authors: Liu, Weifeng, Niu, Chunjie, Ni, Weiyuan, Liu, Dongping
• Format: Article
• Language: English
• Subjects: Helium ion energy; Temperature; tungsten nanofuzz
• ISSN: 0022-3115
• DOI: 10.1016/j.jnucmat.2025.155630

The growth of tungsten nanofuzz (W fuzz) induced by helium ions (He+) irradiation is a critical issue for fusion devices such as ITER. In our study, we investigated the behavior of tungsten (W) under helium ion (He+) irradiation, focusing on the conditions that promote the growth of tungsten fuzz (W fuzz). A comprehensive model was utilized to analyze the impact of varying He+ energies and W temperatures on the W fuzz formation and growth. It was found that W fuzz was formed in a low-energy range from ∼10 eV to 200 eV and a higher-energy range of >5 keV. W fuzz growth was facilitated below the He-W sputtering threshold energy while sputtering erosion became a significant hindrance just above this threshold. At He+ energies reaching hundreds of eV, W fuzz growth was entirely suppressed due to the enhanced sputtering erosion. However, at higher He+ energies around 5 keV, the He+ penetration reduced the impact of sputtering erosion, allowing He bubbles to grow in the deeper W layer. W temperature varying in the range of 1000 – 2000 K played a crucial role in forming He bubbles – induced tensile stress in the W surface layer, therefore affecting W fuzz growth which strongly depended on the He+ energy. These insights provided a detailed understanding of the energy-temperature relevance for W fuzz formation, which was crucial for predicting the performance and lifetime of W components in future fusion reactors.