純 Ni および Ni–Cr 合金における水素脆化挙動の結晶粒径依存性

Translated title of the contribution: Hydrogen embrittlement behavior of pure ni and ni–20cr alloy with different grain sizes

Naohiro Kobayashi, Motomichi Koyama, Kenji Kobayashi, Tomohiko Hojo, Eiji Akiyama

Research output: Contribution to journalArticlepeer-review

Abstract

The grain size effects on the hydrogen embrittlement susceptibility of pure Ni and Ni–20Cr alloy were investigated. The hydrogen embrittlement susceptibility was evaluated by tensile testing under electrochemical hydrogen charging. Relative elongation, defined as the elongation under hydrogen charging divided by elongation in air, increased with increasing grain size in pure Ni (the grain size was in the range of 11–22 µm). In contrast, the relative elongation of Ni–20Cr alloy increased with decreasing grain size from 13 to 1.8 µm. Correspondingly, intergranular fracture was suppressed by grain coarsening in pure Ni and grain refinement in the Ni–20Cr alloy. In addition, the intergranular fracture surface in pure Ni showed curved slip lines, and in the Ni–20Cr alloy showed straight line marks. These fractographic features imply that the mechanisms of the hydrogen–assisted intergranular crack growth were different in pure Ni and Ni–20Cr alloy and this can be attributed to the difference in stacking fault energy.

Translated title of the contributionHydrogen embrittlement behavior of pure ni and ni–20cr alloy with different grain sizes
Original languageJapanese
Pages (from-to)49-58
Number of pages10
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume85
Issue number2
DOIs
Publication statusPublished - 2021

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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