Effects of martensitic transformability and dynamic strain age hardenability on plasticity in metastable austenitic steels containing carbon

Takuro Ogawa, Motomichi Koyama, Cemal Cem Tasan, Kaneaki Tsuzaki, Hiroshi Noguchi

研究成果: Contribution to journalArticle査読

26 被引用数 (Scopus)

抄録

We investigated the effects of solute carbon concentration on the mechanical properties of Fe–19Cr–8Ni–0.05C and Fe–19Cr–8Ni–0.14C metastable austenitic steels. These steels showed an FCC(γ) → HCP(ε) → BCC(α′) martensitic transformation, resulting in transformation-induced plasticity (TRIP). The presence of excess solute carbon reduced the transformability because of an increase in the austenite stability. However, the work hardening capability was enhanced by a combined effect of the TRIP and dynamic strain aging (DSA). DSA requires a high diffusivity of carbon. Thus, the FCC (low diffusivity) to BCC (high diffusivity) transformation favors DSA. The hardening capability of BCC-martensite per volume is enhanced by the dislocation pinning and solution hardening effect of the carbon atmosphere, despite a decrease in the transformation rate per strain by carbon addition. Moreover, carbon addition stabilizes the deformation-induced HCP-martensite against the BCC-martensite, improving the hardening capability of the HCP-martensite through suppression of the window effect, which affects the plastic accommodation mechanism. According to our study, the steel with a low carbon content demonstrated extraordinary work hardening rates owing to a high transformation rate per strain. In contrast, the steel with a high carbon content showed sustained and high work hardening rates because of DSA. Both the steels showed approximately the same tensile strength, but completely different work hardening behavior.

本文言語英語
ページ(範囲)7868-7882
ページ数15
ジャーナルJournal of Materials Science
52
13
DOI
出版ステータス出版済み - 7 1 2017

All Science Journal Classification (ASJC) codes

  • 材料科学(全般)
  • 材料力学
  • 機械工学

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