Title: Microstructural Effects of High Dose Helium Implantation in ErD₂

Abstract

Metal hydrides can store hydrogen isotopes with high volumetric density. In metal tritides, tritium beta decay can result in accumulation of helium within the solid, in some cases exceeding 10 at.% helium after only 4 years of aging. Helium is insoluble in most materials, but often does not readily escape, and instead coalesces to form nanoscale bubbles when helium concentrations are near 1 at.%. Blistering or spallation often occurs at higher concentrations. Radioactive particles shed during this process present a potential safety hazard. This study investigates the effects of high helium concentrations on erbium deuteride (ErD₂), a non-radioactive surrogate material for erbium tritide (ErT₂). To simulate tritium decay in the surrogate, high doses of 120 keV helium ions were implanted into ErD₂ films at room temperature. Scanning and transmission electron microscopy indicated spherical helium bubble formation at a critical concentration of 1.5 at.% and bubble linkage leading to nanoscale crack formation at a concentration of 7.5 at.%. Additionally, crack propagation occurred through the nanocrack region, resulting in spallation extending from the implantation peak to the surface. Electron energy loss spectroscopy was utilized to confirm the presence of high-pressure helium in the nanocracks, suggesting that helium gas plays a predominant rolemore » in deformation. This work improves the overall understanding of helium behavior in ErD₂ by using modern characterization techniques to determine: the critical helium concentration required for bubble formation, the material failure mechanism at high concentration, and the nanoscale mechanisms responsible for material failure in helium implanted ErD₂.« less

Authors:

Taylor, Caitlin Anne  ^[1];

• Search DOE PAGES for author "Taylor, Caitlin Anne"
• Search DOE PAGES for ORCID "0000-0002-0614-7236"

Robinson, David B. ^[2]; Sugar, Joshua D. ^[2]; Lang, Eric ^[3]; Barr, Christopher M. ^[3]; Wang, Yongqiang  ^[4];

• Search DOE PAGES for author "Wang, Yongqiang"
• Search DOE PAGES for ORCID "0000-0002-2938-5640"

Snow, Clark S. ^[5]; Hattar, Khalid ^[3]

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Component Science, Engineering, and Production Center
2. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Chemistry, Combustion, and Materials Science Center
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material, Physical, and Chemical Sciences Center
4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
5. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Component Science, Engineering, and Production Center

Publication Date:

Wed Nov 24 00:00:00 EST 2021

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1834532

Alternate Identifier(s):

OSTI ID: 1834112; OSTI ID: 1862550

Report Number(s):

LA-UR-21-25919; SAND-2021-14964J
Journal ID: ISSN 2589-1529

Grant/Contract Number:  

89233218CNA000001; NA0003525; NA-0003525

Resource Type:

Accepted Manuscript

Journal Name:

Materialia

Additional Journal Information:

Journal Volume: 22; Journal ID: ISSN 2589-1529

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE