Origin of increased helium density inside bubbles in Ni_(1–$$x$$)Fe_$$x$$ alloys

Journal Article · Fri Jan 15 00:00:00 EST 2021 · Scripta Materialia

DOI:https://doi.org/10.1016/j.scriptamat.2020.08.051· OSTI ID:1694366

Granberg, Fredric ^[1]; Wang, Xing ^[2]; Chen, Di ^[3]; Jin, Ke ^[4]; Wang, Yongqiang ^[3]; Bei, Hongbin ^[4]; Weber, William  ^[5]; Zhang, Yanwen  ^[5]; More, Karren  ^[2]; Nordlund, Kai ^[1]; Djurabekova, Flyura ^[6]

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1. Univ. of Helsinki (Finland)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division; Univ. of Tennessee, Knoxville, TN (United States)
6. Univ. of Helsinki (Finland); Helsinki Inst. of Physics (Finland)

Due to virtually no solubility, He atoms implanted or created inside materials tend to form bubbles, which are known to damage material properties through embrittlement. Higher He density in nano-sized bub- bles was observed both experimentally and computationally in Ni_(1–$$x$$)Fe_$$x$$-alloy samples compared to Ni. The bubbles in the Ni_(1–$$x$$)Fe_$$x$$-alloys were observed to be faceted, whereas in elemental Ni they were more spherical. Molecular dynamics simulations showed that stacking fault structures formed around bubbles at maximum He density. Higher Fe concentrations stabilize stacking fault structures, suppress evolution of dislocation network around bubbles and suppress complete dislocation emission, leading to higher He density.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA); European Commission (EC)
• Grant/Contract Number: AC05-00OR22725; 633053; 89233218CNA000001
• OSTI ID: 1694366
• Alternate ID(s): OSTI ID: 1740000
• Report Number(s): LA-UR-20-24354
• Journal Information: Scripta Materialia, Vol. 191; ISSN 1359-6462
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
He-bubbles
NiFe-alloys
electron energy loss spectroscopy (EELS)
molecular dynamics (MD)