Research on splitting phenomenon of isochronal martensitic transformation in T91 ferritic steel |
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| Authors: | Chenxi Liu Dantian Zhang Zesheng Yan |
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| Institution: | School of Material Science and Engineering, Tianjin Key Laboratory of Advanced Jointing Technology , Tianjin University , Tianjin 300072 , P.R. China |
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| Abstract: | T91 steel is a representative type of ferritic heat-resistant steel currently used in power plant components, and is a potential candidate for structural steel in nuclear reactors. The isochronal martensitic transformation behaviors during continuous cooling after austenitization in T91 ferritic steel were systematically investigated by high-resolution dilatometry and microstructure observation. The splitting phenomenon of martensitic transformation is accompanied with the precipitation of needle-like M3C particles, which is suppressed by rapid cooling after austenitization. The appearance of this splitting is ascribed to the concentration gradient caused by the consumption of alloy element in process of the formation of M3C. This concentration gradient results in the appearance of wide martensitic laths ahead of the generation of normally narrow laths. These two types of martensitic laths possess different M s (martensitic start transformation) temperatures, which are attributed to the splitting transformation phenomenon. |
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| Keywords: | T91 ferritic steel splitting phenomenon martensitic transformation |
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