著者

飛鷹 秀幸 木村 勇次 高木 節雄

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.85, no.1, pp.52-58, 1999-01-01

被引用文献数

6

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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 10nm 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 10nm. This volume fraction of cementite is just correspondent to that in Fe-2mass%C alloy.