GH4169合金动态再结晶的有限元模拟与实验研究

Thermal simulating experiment and finite element simulation of dynamic recrystallization of annealed GH4169 alloy

以热模拟实验为基础,建立固溶态GH4169合金的动态再结晶模型,应用DEFORM-3D有限元软件模拟圆柱状试样在不同压缩变形条件下的动态再结晶体积分数分布;结合金相定量分析、电子背散射衍射(Electron backsatter diffraction(EBSD))分析及有限元模拟结果,对比研究变形参数对圆柱状GH4169合金心部微观组织的影响。研究结果表明:升高变形温度及降低应变速率,均可促进圆柱状GH4169合金热模拟压缩试样变形的均匀性;应变速率的降低可加速GH4169合金中小角度晶界向大角度晶界的转变过程;GH4169合金的动态再结晶形核机制为以原始晶界为主的非连续动态再结晶,在试验变形条件下,孪晶界的演化对动态再结晶过程起重要作用;同时,分析实验结果与模拟结果之间的差异及其原因。

Dynamic recrystallization（DRX） model of the annealed GH4169 alloy was established based on the thermal-mechanical simulation tests. The finite element analysis software DEFORM-3D was introduced to simulating the DRX volume of the cylindrical annealed GH4169 alloy under different deformation conditions. Combined quantitative metallographic analysis, electron backscatter diffraction（EBSD） analysis with finite element analysis, the effects of the deformation parameters on the microstructures of the center for the cylindrical samples were investigated. The results show that increasing the deformation temperature and lowering the strain rate would promote the deformation homogeneity of the cylindrical samples during thermal-mechanical simulation tests. The transformation procedure of grain boundaries with low angles and with high angles is accelerated with decreasing the strain rate. The nucleation mechanism of the dynamic recrystallization for the alloy is the discontinuous one dominated mainly by the bulging of the original grain boundaries. Under the tested conditions, the evolution of twin boundaries plays an important role in the course of the dynamic recrystallization. Meanwhile, the differences between the experimental results and the simulation results as well as its reasons are also analyzed.