著者

小林 直弘

出版者

明治大学大学院

雑誌

文学研究論集 (ISSN:13409174)

巻号頁・発行日

no.47, pp.89-110, 2017

著者

小林 直弘 小山 元道 小林 憲司 北條 智彦 秋山 英二

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.85, no.2, pp.49-58, 2021-02-01 (Released:2021-01-25)

参考文献数

35

被引用文献数

6 5

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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.