Deciphering the role of second phase precipitates on early-stage surface morphology development of dispersion-strengthened W alloys under low energy He irradiation

Eric Lang, Nathan Madden, Charles Smith, Jessica Anne Krogstad, Jean Paul Allain

Research output: Contribution to journalArticle

Abstract

Tungsten is the material of choice for plasma-facing components in the divertor region of future plasma-burning tokamak fusion reactors. However, under low energy helium irradiation at elevated temperatures, significant surface morphology changes are expected, including pores, blisters, and fuzz. Dispersion-strengthened tungsten materials with small additions of transition metal carbide dispersoids have been proposed as an alternative to pure tungsten, as they have shown enhanced thermomechanical properties and possible radiation damage tolerance. However, their response to low energy helium irradiation has yet to be fully elucidated. In this work, dispersion-strengthened tungsten alloys containing 1–10 wt.% tantalum carbide, titanium carbide, or zirconium carbide were exposed to 250 eV helium ions at 600 and 800 °C to a 1 × 10 20 cm −2 fluence to understand the early-stage irradiation response to helium bombardment. At 600 °C, nanostructuring is only observed on titanium carbide particles. As the temperature is raised to 800 °C, pores and ripples were developed on tungsten grains for all samples; fiber-form structures and isolated tendril growth is observed only on titanium carbide particles. Minimal surface morphology changes were observed on tantalum carbide and zirconium carbide particles. X-ray photoelectron spectroscopy of the alloyed specimens post-irradiation at 800 °C indicates the formation of zirconium and titanium oxides on the surface. Potential thermodynamic, sputtering, and composition-based formation mechanisms behind the novel nanostructuring and chemistry changes of the complex materials are discussed.

Original languageEnglish (US)
Pages (from-to)47-54
Number of pages8
JournalNuclear Materials and Energy
Volume19
DOIs
StatePublished - May 2019

Fingerprint

Helium
Tungsten
titanium carbides
Titanium carbide
Surface morphology
Precipitates
precipitates
tungsten
Tantalum carbide
tantalum carbides
zirconium carbides
Irradiation
Carbides
irradiation
helium
Zirconium
carbides
tungsten alloys
Tungsten alloys
minimal surfaces

Keywords

  • Dispersion-strengthened tungsten
  • Helium damage
  • Tungsten
  • Tungsten fuzz

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Materials Science (miscellaneous)
  • Nuclear Energy and Engineering

Cite this

Deciphering the role of second phase precipitates on early-stage surface morphology development of dispersion-strengthened W alloys under low energy He irradiation. / Lang, Eric; Madden, Nathan; Smith, Charles; Krogstad, Jessica Anne; Allain, Jean Paul.

In: Nuclear Materials and Energy, Vol. 19, 05.2019, p. 47-54.

Research output: Contribution to journalArticle

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