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Isothermal decomposition behavior of the high nitrogen concentration γ-Fe[N] prepared from pure iron
Zhijun Jiang, Xiaoling Li, Jianfeng Gu, Mingjuan Hu, Zuchang Zhu
Abstract: The isothermal decomposition characteristic of the homogeneous high nitrogen austenitic samples prepared by a new multi-stage nitriding process was investigated by SEM and TEM in this paper. Lamellar-structure precipitations arranged on the decomposed austenite grain boundaries (GBs) and the flaky γ’ particles and network-structure precipitations appeared inside of the γ matrix. The extra high Vickers hardnessmore than 800 HV was found in the 5-h aged samples, which was different from those of the bainitic/martensitic structures in Fe–C alloys. The SAED analysis indicates the γ’ has the coherent relation with the parent γ-Fe[N] phase and the interstitial nitrogen atoms are inclined to aggregate on {1 1 0}γ’/γ planes, which also contributes to the hardness of the matrix.
2008蒋志俊Applied-surface-science
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