γFe - αFe等温相变晶粒连续形核长大的遗传算法
enetic Algorithm Simulation of γFe-αFe Grain Continuous Nucleation and Growth in Isothermal Transformation
左 飞, 张根元
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作者单位：河海大学 机电工程学院, 江苏 常州 213022
中文关键字：晶粒形核； 晶粒长大； 遗传算法； 模拟
英文关键字：grain nucleation; grain growth; genetic algorithm; simulation
中文摘要：建立了γFe ?邛 αFe等温相变晶粒连续形核长大模拟的物理模型，确立了相变晶粒形核和长大规则，引入遗传算法模拟了相变晶粒连续形核长大的组织演化过程。晶界迁移轨迹符合晶粒长大理论；系统自由能ΔG数据表明，新晶粒从系统热力学角度上能长大；组织转变动力学符合Avrami方程，指数n在1.9～2.3变化；相变结束时晶粒平均半径(面积)分布具有Weibull函数形式，5～7边数晶粒数目最多，余次之；新相或初始组织晶粒的平均边数呈现先增加到最大值后下降分别趋于6或归零，两相晶粒平均半径r呈现持续增长、趋于稳定或单调下降后归零。各边数的新相晶粒半径ri随其边数增加而变大；随着模拟步数增加，初始组织各边数晶粒平均半径单调下降，并按低边数向高边数顺序消失。
英文摘要：Physical simulation model of γFe?邛αFe grain nucleation and growth in isothermal transformation was established. The rule of new grain nucleation proportion in different location by simulation step and grain growth's boundary migration was drawn up. The genetic algorithm method was introduced in the process of grain nucleation and growth. The grain boundary migration agrees with the theory of grain growth; Simulation data of the system free energy ΔG indicates that new nucleus can grow up in thermodynamic state. Isothermal transformation kinetics is according with Avrami equation, transformation kinetics exponent (n) changes between 1.9 and 2.3. New phase grain's average radius (area) agrees well with the Weibull function at the end of transformation, 5 to 7 sides grain number are more, the other less. Average side number of new or parent phase grain increases at the beginning, and then maximum, reduces to 6 or zero at last. The two phase grain's average radius (r) increase monotonously and then maximum, or reduces zero in the process of transformation. grain's ri value increases obviously with the increase of its side number. The parent phase grain's average radius which have 3 to 9 sides decreases monotonously with the increase of simulation step, and disappears from lower to high sides grain.