15SiMn钢奥氏体等温相变的元胞自动机模拟

Cellular Automaton Modeling of Isothermal Transformation of Austenite in a 15SiMn Steel

建立了15SiMn钢奥氏体-铁素体相变的二维元胞自动机介观模型。模拟结果显示,对于某一给定温度,铁素体的长大速度在相变过程中逐渐降低。当生长速度接近0时,奥氏体相中相界面处平衡碳的质量分数为0.52395%。此外,模拟结果还显示,由于奥氏体晶界上的碳原子扩散和奥氏体-铁素体相界面移动都较奥氏体晶内更快,所以奥氏体晶界上铁素体晶粒形貌为椭圆形。

A two-dimensional meso-scale cellular automaton model was developed to simulate the transformation of austenite to ferrite in 15SiMn steel. The simulated results show that,at a given isothermal temperature,the average growth rate of ferrite is decreased gradually during the austenite transformation. With the ferrite growth rate decreasing to zero,the carbon concentration in the austenite at the interface reaches equilibrium carbon concentration of 0.52395%. In addition,the morphology of ferrite grains on austenite boundary exhibits ellipsoidal,which is attributed to carbon diffusion and movement of austenite-ferrite interface higher in the austenite boundaries than that in austenite interiors.