Grain boundary bulging during tempering in lath-martensltic steel

Masahide Natori, Toshihiro Tsuchiyama, Setsuo Takaki

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

    1 Citation (Scopus)


    Ultralow carbon martensitic steel undergoes discontinuous recrystallization through the grain boundary bulging during tempering that occurs after quenching. In this study, the crystallographic character of the recrystallized grains was examined with Crystal Orientation Maps (COM) obtained by EBSP method in a ultralow carbon martensitic steel (Fe-1.5%Mn-0.0018%B). In addition, the strain distribution in the recovered martensite and recrystallized grain was observed with Image Quality Maps (IQM). The COM and IQM analysis revealed that the recrystallized grains (area where the bulging boundary swept) completely inherit the crystallographic orientation of the original martensite, the strain (dislocation density) in the newly formed recrystallized grains is found to be quite low, It was also found that the direction of boundary migration is dependent on the difference in dislocation density between both grains adjacent to the migrating boundary; the grain boundary always migrates to the grain with higher dislocation density. Each grain of martensite tends to be recovered differently, that is, the dislocation density becomes different in each grain after tempering even though the lath martensite originally has uniform distribution of dislocation density. This inhomogeneous recovery leads to the generation of driving force of the grain boundary migration.

    Original languageEnglish
    Title of host publicationRecrystallization and Grain Growth III - Proceedings of the Third International Conference on Recrystallization and Grain Growth, ReX and GG III
    PublisherTrans Tech Publications Ltd
    Number of pages5
    EditionPART 1
    ISBN (Print)087849443X, 9780878494439
    Publication statusPublished - 2007
    Event3rd International Conference on Recrystallization and Grain Growth, ReX GG III - Jeju Island, Korea, Republic of
    Duration: Jun 10 2007Jun 15 2007

    Publication series

    NameMaterials Science Forum
    NumberPART 1
    ISSN (Print)0255-5476
    ISSN (Electronic)1662-9752


    Other3rd International Conference on Recrystallization and Grain Growth, ReX GG III
    Country/TerritoryKorea, Republic of
    CityJeju Island

    All Science Journal Classification (ASJC) codes

    • General Materials Science
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering


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