Hydrogen embrittlement behavior induced by dynamic martensite transformation of Ni-Ti superelastic alloy

Ken'ichi Yokoyama*, Miho Tomita, Jun'ichi Sakai

*この研究の対応する著者

    研究成果: Article査読

    48 被引用数 (Scopus)

    抄録

    The hydrogen embrittlement behavior induced by the martensite transformation of Ni-Ti superelastic alloy subjected to a dynamic cyclic tensile test with hydrogen cathodic charging has been investigated by hydrogen thermal desorption analysis. The critical stress for the martensite transformation steeply decreases with increasing number of deformation cycles, whereas the critical stress for the reverse transformation only slightly changes. The dynamic stress-induced martensite transformation markedly enhances hydrogen absorption, compared with that of the martensite phase itself. The hydrogen concentration at the surface layer of the specimen is evaluated to be above 3500 mass ppm; nevertheless, no fracture associated with the stress-induced martensite transformation occurs. In addition, no hardening is observed at the surface layer of the specimen despite the formation of the hydride and hydrogen enrichment. The hydrogen thermally desorbed at a low temperature markedly increases, indicating that the hydrogen states are changed by the dynamic martensite transformation. Note that interactions between hydrogen and the phase transformation are probably irreversible, although the phase transformation is reversible. The present study shows, for the first time, that the hydrogen embrittlement behavior of the alloy strongly depends on the dynamic change of the hydrogen states accompanied by the martensite transformation.

    本文言語English
    ページ(範囲)1875-1885
    ページ数11
    ジャーナルActa Materialia
    57
    6
    DOI
    出版ステータスPublished - 2009 4

    ASJC Scopus subject areas

    • セラミックおよび複合材料
    • 金属および合金
    • ポリマーおよびプラスチック
    • 電子材料、光学材料、および磁性材料

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