Fe-C-Mn-Al系TRIP钢两相区奥氏体转变模拟

为了研究Fe-C-Mn-A1系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、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800℃与840℃的奥氏体化过程进行了数值求解.模拟结果表明:奥氏体转变初期受C元素在奥氏体中的扩散控制达到亚平衡,奥氏体转变速率较快；此时A1元素在奥氏体与铁素体界面处的浓度差较显著,Mn元素在奥氏体与铁素体界面处的浓度差不显著.奥氏体转变后期受Mn元素在铁素体内的扩散控制,转变速率较慢；此时A1元素在铁素体内已大量富集,Mn元素在奥氏体与铁索体界面处有较显著的浓度差.

Simulation of Austenization During Intercritical Annealing for Fe-C-Mn-Al TRIP-Aided Steel

In order to study the distribution of alloy elements in austenite and ferrite during intercritical annealing of a Fe-C-Mn-Al transformation-induced plasticity(TRIP) steel,based on the analysis of thermodynamics and dynamics for austenization during intercritical annealing of the TRIP steel using thermal dilatometer,optical microscopy and electron microprobe measurements,an austenization model was established and solved by using the explicit finite volume method at two austenite temperatures of 800 ℃ and 840 ℃.The simulated results show that the initial stage of austenite transformation,which reaches paraequilibrium,is controlled by carbon diffusion in austenite.The austenization rate in this stage is fast,and the concentration difference of aluminum at the interface between the austenite and ferrite is significant,while the concentration difference of manganese is not significant.The late stage of austenite transformation is controlled by manganese diffusion in ferrite.The austenization rate in this stage is very slow,and the enrichment of aluminum in ferrite is significant,the concentration difference of manganese at the interface in the austenite and ferrite is obvious.