铁素体等温相变孕育期计算的经典形核模型

Classical Nucleation Model for Predicting Incubation Period of Ferrite Isothermal Transformation

采用类似小角度晶界比界面能的理论计算方法对半共格的奥氏体铁素体相界面比界面能和铁素体核坯形状系数进行了计算;并推导了核坯形状为旋转椭球、盒形和圆片时晶界面上形核的临界形核体积、临界形核功和孕育期的计算模型。通过模型对比分析以及与孕育期试验数据的比较,结果表明铁素体等温相变将优先以表面弯曲的旋转椭球核坯形核。计算结果进一步发展了经典形核理论,也提供了适用的铁素体等温相变孕育期计算的理论模型。

The theoretical way to compute the specific interfacial energy of small-angle grain boundary were used to calculate the interfacial energy of semi-coherent austenite-ferrite and the shape factor of ferritic nucleus. And mathematical models of critical nucleation volume, critical nucleation energy and incubation period on the boundary for the nucleus with shapes of rotating ellipsoid, box or cylinder were derived. By comparatively analyzing the developed models and comparing the calculated incubation periods with the measured ones, the results show that ferrite isothermal phase transformation will give priority to rotation ellipsoid nucleation with curved surface. It is successful that the classical nucleation theory is further developed and the applicable theoretical model to compute incubation period of ferrite isothermal transformation is constructed.