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Vol.42, No.11, 845 ~ 854, 2004
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| Title |
| On the Crystallographic Features of Cr2N Precipitates in High-Nitrogen Austenitic Stainless Steel (1) -1. Precipitation Behavior of the Second Phases during Isothermal Aging at 900℃ |
| 이태호 Tae Ho Lee , 오창석 Chang Seok Oh , 이창길 Chang Gil Lee , 김성준 Sung Joon Kim , 고목절웅 Setsuo Takaki |
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| Abstract |
| In these sequential papers, the crystallographic features of Cr₂N precipitates in high-nitrogen austenitic stainless steel (HNS) were investigated with particular emphasis on the crystal structure of Cr₂N. In the first part of this study, the precipitation behavior of the second phases were examined utilizing electron microscopy and thermodynamic calculation. The precipitation sequence of the Cr₂N was found to be intergranular, cellular, and intragranular precipitation with aging time. Based on the analyses of SAD patterns, the orientation relationship between y and Cr₂N was found to be [011], [1100]_(Cr₂N) and (111)γ (0001)_(Cr₂N). On prolonged aging, the coarse a-phase with bet structure precipitated along grain and cell boundaries. The precipitation of a-phase could be explained by the mechanism that formation of nitrogen-depleted zone near Cr₂N induced nucleation of the a-phase, which was supported by thermodynamic calculation and electron microscopy. (Received August 23, 2004) |
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| Key Words |
| High nitrogen steel, HNS, Precipitation, Cr2N, σ-phase and Thermodynamic calculation |
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