ABSTRACT

A new model has been developed to predict austenite $\leftrightarrow$ ferrite transformation kinetics in steels. For each alloying element, the concentration profile is computed solving a unique diffusion equation (including the 2 phases and the interface). The interface is described assuming linear variation of chemical potentials, saving thus computational time. Interface motion is driven by the minimisation of Gibbs energy. The model naturally reproduces the transition between thermodynamic equilibria (Para equilibrium, Local equilibrium with negligible partitioning, Local equilibrium) during heating. The validity of the model for reverse transformation has been validated on ternary and quaternary systems Fe-C-(Mn-Si-Mo) on decarburisation experiments.

摘要

已经开发出一种新的模型来预测奥氏体 $\leftrightarrow$钢中的铁素体转变动力学。对于每种合金元素，通过求解唯一的扩散方程（包括2个相和界面）来计算浓度分布。在假定化学势呈线性变化的情况下描述了该界面，从而节省了计算时间。界面运动是由吉布斯能量的最小化驱动的。该模型自然地再现了加热期间热力学平衡（帕拉平衡，可忽略分配的局部平衡，局部平衡）之间的过渡。在脱碳实验中，已经在三元和四元体系Fe-C-（Mn-Si-Mo）上验证了该逆向转换模型的有效性。