Crystallography of lath-shaped bainite from (γ+α) dual-phase structure

Hiroyuki Kawata, Kunio Hayashi, Natsuko Sugiura, Naoki Yoshinaga, Manabu Takahashi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Although bainite transformation in steels is strongly affected by the initial microstructurc, the effect of the secondary phase existing before bainite transformation is not yet well understood. In the previous study, we investigated the effect of pre-existing marlcnsitc on the kinetics of bainite transformation and confirmed that the crystallographic orientations of bainitic ferrite laths were affected by neighboring martcnsitc. The aim of this work is to clarify the effect of pre-existing martcnsitc on the block size and crystallographic features of bainite. Lath-shaped bainite structures grown from mixed initial structures of austenite and martcnsitc were investigated in Fc-0.2C-8Ni alloy transformed at various temperatures. At high temperatures, 723 K and 693 K, pre-existing marlcnsitc makes a huge bainite block around itself and coarsens other fine blocks. This coarscning of bainite block size results from the variant selection rule added to bainitic ferrite laths by pre-existing martcnsitc. On the other hand, at low temperatures, 643 K, these effects of pre-existing martcnsitc on bainite block size are inconspicuous. This weakening of the cffcct of martcnsitc with the decrease in transformation temperature is understandable with the increase in driving force of bainitic ferrite nucleation.

Original languageEnglish
Title of host publicationProceedings of the 17th IFHTSE Congress
PublisherThe Japan Society for Heat Treatment (JSHT)
Number of pages4
ISBN (Electronic)9780000000002
Publication statusPublished - 2008
Externally publishedYes
Event17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008 - Kobe, Japan
Duration: Oct 26 2008Oct 28 2008

Publication series

NameProceedings of the 17th IFHTSE Congress


Other17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008

All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Mechanics of Materials


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