Ultra grain refining of steels and dissolution capacity of cementite by super-heavy deformation

Hideyuki Hidaka, Yuuji Kimura, Setsuo Takaki

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    24 Citations (Scopus)

    Abstract

    Mechanical milling using high energy planetary ball mill was applied to Fe-C alloy powders with (ferrite+cementite) two-phase structures to give an ultimate large strain into the powders. Dissolution behavior of cementite during mechanical milling was investigated in relation to ultra grain refining of ferrite matrix, and dissolution capacity of cementite was discussed in terms of carbon content in the powders. Ultra grain refining of ferrite matrix to about 10 nm results in full dissolution of cementite in the powders with carbon up to 2 mass% C. Most of carbon, which has been rejected from decomposed cementite, is suggested to segregate at grain boundary to form amorphous layer. Thus, it was proposed that the dissolution limit of cementite depends on both volume fraction of the grain boundary amorphous layer and carbon concentration therein. For example, as the maximum carbon content of the grain boundary amorphous layer was to be about 4.2 mass% C, the dissolution limit of cementite was estimated at 30 vol% from the mass valance for carbon content in the case ferrite grains were refined to around 10 nm. This volume fraction of cementite is just correspondent to that in Fe-2 mass%C alloy.

    Original languageEnglish
    Pages (from-to)52-58
    Number of pages7
    JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
    Volume85
    Issue number1
    DOIs
    Publication statusPublished - 1999

    All Science Journal Classification (ASJC) codes

    • Condensed Matter Physics
    • Physical and Theoretical Chemistry
    • Metals and Alloys
    • Materials Chemistry

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