冷轧TRIP钢两相区奥氏体化中合金元素的扩散

Diffusion of alloying elements during intercritical annealing for cold-rolled TRIP steel

为了研究TRIP钢两相区奥氏体化过程中合金元素在奥氏体和铁素体中的分布,利用热膨胀仪、金相显微镜和电子探针等仪器,在对TRIP钢两相区奥氏体化过程进行热力学与动力学分析的基础上,建立了两相区奥氏体化过程的扩散模型,采用显式有限体积法对770℃和800℃的奥氏体化过程进行了数值求解.模拟结果表明:奥氏体生长初期受C元素在奥氏体中的扩散控制达到亚平衡,此时Mn元素在奥氏体与铁素体界面处的质量浓度差不显著;而奥氏体生长后期受Mn元素在铁素体中的扩散控制而达到最终平衡,此时Mn元素在奥氏体与铁素体界面处有较显著的浓度梯度.

In order to study the distribution of alloying elements in austenite and ferrite during the intercritical annealing of a transformation-induced plasticity（TRIP） steel,a diffusion model of the austenization during intercritical annealing was established based on the thermodynamic and dynamic analysis for the austenization of the TRIP steel using thermal dilatometer,optical microscopy and electron microprobe.The austenization at 770 ℃ and 800 ℃ was numerically solved with the explicit finite volume method.The simulated results show that the initial stage of austenite growth is controlled by the diffusion of carbon in austenite and reaches the sub-equilibrium state,and the concentration difference of manganese at the interface between austenite and ferrite is not significant.The late stage of austenite growth is controlled by the diffusion of manganese in ferrite,and reaches the equilibrium state.The significant concentration gradient of manganese at the interface between austenite and ferrite is obvious.