相场方法模拟AZ31镁合金的静态再结晶过程

来源期刊：金属学报2010年第10期

论文作者：高英俊 罗志荣 胡项英 黄创高

文章页码：1161 - 1172

关键词：相场模型； 静态再结晶； 塑性变形； 微观组织； AZ31镁合金

Key words：phase field model； static recrystallization； plastic deformation； microstructure； AZ31 Mg alloy

摘    要：为了获得合金静态再结晶前的变形晶粒组织,应用网格畸变模型与相场模型结合,生成变形合金再结晶前的初始晶粒组织;针对合金不同变形区域的特征和体系储存能分布不均匀的特点,分别引入反映不同变形区域的储存能分布的权重因子和变形区域的特征状态因子,构造多状态的非均匀自由能密度函数.在此基础上,应用相场动力学方程模拟了AZ31镁合金的静态再结晶过程的微结构演化,系统地分析了再结晶转变动力学曲线和Avrami曲线,以及储存能释放规律和再结晶晶粒尺度分布.模拟得到的动力学规律符合JMAK理论,所得的Avrami曲线可近似看成一条直线,对应于真应变ε=0.25,0.50,0.75和1.00,该直线的平均斜率分别为2.45,2.35,2.19和2.15.Avrami时间指数随变形量的增加而降低.变形程度大的合金,储存能释放的速度快,完成静态再结晶所需的时间短.基于本文提出的模型,结合相场方法计算模拟所得的结果与已有的理论结果和实验结果符合良好.

Abstract: In order to obtain the deformation grain structure for static recrystallization,an initial grain structure are produced by lattice deformation model;aiming at characteristics of different deformation regions and non-uniform distribution of the stored energy in deformed alloy,a multistate free energy (MSFE) function are proposed by introducing a weight factor for the stored energy and a characteristics state factor for different deformed regions.Based on these,the microstructure evolutions of static recrystallization for deformed Mg alloys are simulated by phase field model.The transformation dynamic curve of recrystallization,Avrami curve,and the regularity for stored energy releasing and distribution of grain size in recrystallization process are systematically analyzed.The dynamic regularity of static recrystallization obtained by simulating is in good accord with the JMAK theory,and the Avrami curve by simulating can be regard as a linear with average slopes 2.45,2.35, 2.19 and 2.15,respectively.The Avrami time index decreases with the true strain increasing.The stored energy releases faster,and the lasting time of static recrystallization process is shorter when the true strain is greater.Based on the established MSFE model,the simulation results here are in good agreement with the other theoretical results and experimental results.