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论文类型：期刊论文

发表时间：2020-04-01

发表刊物：NUCLEAR FUSION

收录刊物：SCIE

卷号：60

期号：4

ISSN号：0029-5515

关键字：tensile stress; ion irradiations; W fuzz; He bubble

摘要：Although W fuzz is formed in the divertor region of the fusion reactor, no theory may clearly explain the W fuzz growth mechanism. In this study, we observe the growth process of W fuzz over W crystal under ITER-relevant He ion irradiations. We propose the tensile stress-driven cracking of nano-structured fuzz during the initial growth of W fuzz. We demonstrate that the existence of tensile stress is due to the swelling of He nano-bubbles in the fuzz. After this cracking, the W fuzz breaks away from the planar network and grows over the W surface, where the micro-stress in the W surface layer acts as the driving force.