Roles of the grain-boundary characteristics and distributions on hydrogen embrittlement in face-centered cubic medium-entropy VxCr1-xCoNi alloys

Dae Cheol Yang, Sang Yoon Song, Han Jin Kim, Sang In Lee, Biswanath Dutta, Young Kyun Kim, Jae Hyeok Shim, Jin Yoo Suh, Young Sang Na, Seok Su Sohn

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

The issue of hydrogen embrittlement (HE) in face-centered (FCC) structured alloys is significant for H storage and transportation application due to unanticipated damage beyond its predicted service life. This unpredictable situation may harm human life and limit hydrogen to a reliable source of renewable energy in industrial fields. Recent research has suggested that multi-principal element alloys possess high resistance to HE. However, there has been limited exploration of how their unique properties affect the HE mechanisms. In this study, using simple model VCrCoNi alloys with analogous grain sizes, the reduction rate of ductility by hydrogen uptake was measured through a slow strain rate tensile test following electro-chemical H charging. Further, the origin of HE resistance was investigated by analyzing various factors such as hydrogen contents, fracture and deformation behaviors, and grain boundary properties using thermal desorption spectroscopy, scanning electron microscope, and electron backscatter diffraction. Despite the consistent trends of the H content, stacking fault energy, and stress with increasing V content, the resistance to HE is the highest for the alloy with an intermediate ratio of V and Cr, namely, for the V0.7Cr0.3CoNi alloy. Through the analysis of grain boundary characteristics, the high resistance is attributed to large fractions of special boundaries and special triple junctions and large twin-related domain size, which suppresses crack growth and interlinkage. The favorable grain boundary characteristics result from mechanical dynamic recovery, achieved by the competitive effects of solid-solution strengthening and stacking fault energy. Thus, the present study provides novel insights into enhancing HE resistance in FCC-structured alloys.

Original languageEnglish
Article number145028
JournalMaterials Science and Engineering: A
Volume873
DOIs
Publication statusPublished - 2023 May 17

Bibliographical note

Publisher Copyright:
© 2023 Elsevier B.V.

Keywords

  • Grain boundary characteristics
  • Hydrogen embrittlement
  • Medium-entropy alloy
  • Solid-solution strengthening
  • Stacking fault energy

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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