Grain size altering yielding mechanisms in ultrafine grained high-Mn austenitic steel: Advanced TEM investigations

Chang Yu Hung, Yu Bai, Nobuhiro Tsuji, Mitsuhiro Murayama

研究成果: Contribution to journalArticle査読

3 被引用数 (Scopus)

抄録

The underlying mechanism of discontinuous yielding behavior in an ultrafine-grained (UFG) Fe-31Mn-3Al-3Si (wt.%) austenitic TWIP steel was investigated by the use of advanced TEM technique with taking the plastic deformation mechanisms and their correlation with grains size near the macroscopic yield point into account. Typical yield drop mechanisms such as the dislocation locking by the Cottrell atmosphere due to the presence of interstitial impurities cannot explain the origin of this phenomenon in the UFG high-Mn austenitic TWIP steel. Here, we experimentally revealed that the plastic deformation mechanisms in the early stage of deformation, around the macroscopic yield point, show an obvious association with grain size. More specifically, the main mechanism shifts from the conventional slip in grain interior to twinning nucleated from grain boundaries with decreasing the grain size down to less than 1 μm. Our observation indicates that the grain size dependent deformation mechanisms transition is also deeply associated with the discontinuous yielding behavior as it could govern the changes in the grain interior dislocation density of mobile dislocations around the macroscopic yield point.

本文言語英語
ページ(範囲)192-203
ページ数12
ジャーナルJournal of Materials Science and Technology
86
DOI
出版ステータス出版済み - 9 30 2021

All Science Journal Classification (ASJC) codes

  • セラミックおよび複合材料
  • 材料力学
  • 機械工学
  • ポリマーおよびプラスチック
  • 金属および合金
  • 材料化学

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