Precipitation of niobium carbonitrides in ferrite: chemical composition measurements and thermodynamic modelling
Precipitation of niobium carbonitrides in ferrite: chemical composition measurements and thermodynamic modelling
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DOI：
10.1080/09500830701427003
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发表时间：
2007-08
影响因子：
1.2
通讯作者：
M. Perez;E. Courtois;D. Acevedo;T. Epicier;P. Maugis
中科院分区：
文献类型：
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作者：
M. Perez;E. Courtois;D. Acevedo;T. Epicier;P. Maugis
用高分辨电子显微镜和电子能量损失谱研究了不同析出阶段Fe-Nb-C-N模型合金铁素体中Nb碳氮化物的结构和化学成分。实验似乎表明存在两种类型的析出物：纯Nb氮化物和混合亚化学计量比Nb碳氮化物。为了了解这些沉淀物的化学成分，发展了一个热力学公式来评估形核和生长速率(经典的形核理论)以及形核和现有沉淀物的化学成分。基于热力学和动力学方程的数值解模型，计算了在给定温度下析出相尺寸分布的演化。预测的成分与实验结果吻合较好。
High-resolution transmission electron microscopy and electron-energy loss spectroscopy have been used to characterize the structure and chemical composition of niobium carbonitrides in the ferrite of a Fe–Nb–C–N model alloy at different precipitation stages. Experiments seem to indicate the coexistence of two types of precipitates: pure niobium nitrides and mixed sub-stoichiometric niobium carbonitrides. In order to understand the chemical composition of these precipitates, a thermodynamic formalism has been developed to evaluate the nucleation and growth rates (classical nucleation theory) and the chemical composition of nuclei and existing precipitates. A model based on the numerical solution of thermodynamic and kinetic equations is used to compute the evolution of the precipitate size distribution at a given temperature. The predicted compositions are in very good agreement with experimental results.