GH3128合金热变形行为与唯象本构模型

Thermal deformation behavior and phenomenological constitutive model for GH3128 alloy

利用室温与高温拉伸实验,探究了GH3128合金在不同温度下的变形行为与微观组织演变规律,发现在温度为1050℃、应变速率为1 s^(-1)的条件下材料仍具有较好的硬化能力,且变形均匀。构建了GH3128合金室温和高温两套唯象本构模型:室温模型包括Ludwik模型、Ludwik简单修正模型和Ramberg-Osgood模型,高温模型包括Fields-Backofen(FB)模型和Johnson-Cook(JC)模型,利用构建的模型预测了不同温度与应变速率下GH3128合金的流变行为。结果表明:室温模型方面,Ludwik简单修正模型的预测精度最高,平均误差绝对值AARE为3.64%;高温模型方面,FB模型和JC模型由于唯象本构模型无法描述GH3128合金复杂的微观组织演变,预测精度有限。GH3128合金的热变形行为与唯象本构模型的研究为后续热成形工艺参数选择与有限元仿真提供了有效的指导。

The deformation behavior and microstructure evolution law of GH3128 alloy at different temperatures were investigated by room temperature and high temperature tensile tests,respectively,and it was found that the material still had good hardening ability and uniform deformation under the temperature of 1050℃ and the strain rate of 1 s^(-1).Then,two sets of phenomenological constitutive models of GH3128 alloy at room temperature and high temperature were constructed.The room temperature models included Ludwik model,Ludwik simple modified model and Ramberg-Osgood model,and the high temperature models included Fields-Backofen(FB)model and Johnson-Cook(JC)model.The rheological behavior of GH3128 alloy under different temperatures and strain rates was predicted by the built models.The results show that for the room temperature model,Ludwik simple modified model exhibits the highest prediction accuracy,and the absolute values of average error AARE is 3.64%.For the high temperature model,the prediction accuracy of both FB and JC models are limited because the phenomenological constitutive models cannot describe the complex microstructure evolution of GH3128 alloy.Thus,the study on the thermal deformation behavior and phenomenological constitutive model of GH3128 alloy provides effective guidance for the subsequent selection of hot forming process parameters and finite element simulation.