A theoretical insight into H accumulation and bubble formation by applying isotropic strain on the W–H system under a fusion environment. (23rd February 2018)

• Record Type: Journal Article
• Authors: Han, Quan-Fu; Liu, Yue-Lin; Zhang, Ying; Ding, Fang; Lu, Guang-Hong
• Is Part Of: Nuclear fusion. Volume 58:Number 4(2018:Apr.)
• Publication Date: 2018-02-23
• Subjects: tungsten -- hydrogen -- temperature effect -- first-principles calculations; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/aaad16
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: The solubility and bubble formation of hydrogen (H) in tungsten (W) are crucial factors for the application of W as a plasma-facing component under a fusion environment, but the data and mechanism are presently scattered, indicating some important factors might be neglected. High-energy neutron-irradiated W inevitably causes a local strain, which may change the solubility of H in W. Here, we performed first-principles calculations to predict the H solution behaviors under isotropic strain combined with temperature effect in W and found that the H solubility in interstitial lattice can be promoted/impeded by isotropic tensile/compressive strain over the temperature range 300–1800 K. The calculated H solubility presents good agreement with the experiment. Together, our previous results of anisotropic strain, except for isotropic compression, both isotropic tension and anisotropic tension/compression enhance H solution so as to reveal an important physical implication for H accumulation and bubble formation in W: strain can enhance H solubility, resulting in the preliminary nucleation of H bubble that further causes the local strain of W lattice around H bubble, which in turn improves the H solubility at the strained region that promotes continuous growth of the H bubble via a chain-reaction effect in W. This result can also interpret the H bubble formation even if no radiation damage is produced in W exposed to low-energy H plasma.