(1. 中南林业科技大学机电工程学院，长沙 410004；
2. 中南大学粉末冶金国家重点实验室，长沙 410083)
摘 要: 采用等温热压缩实验研究DP工艺Inconel 718合金在变形温度为900~1060 ℃，应变速率为0.001~0.5 s-1条件下的高温流变行为，分析摩擦因数和绝热温升对真应力-真应变曲线的影响，并对摩擦引起的流变应力误差进行了修正，建立了基于应变量的应变本构模型。结果表明：随着应变速率的增大和变形温度的降低，摩擦因数的影响趋于明显，变形激活能和材料常数是应变量的函数。对引入应变量参数建立的用于预测工艺处理的Inconel 718合金不同变形量时的流变应力本构模型进行误差分析，其实验值与预测值的相关性系数为0.998，平均相对误差绝对值为3.87%，能够用于准确预测不同变形量时合金的流变应力值。
关键字: Inconel 718合金；DP工艺；流变行为；应力修正；本构模型
（1. College of Mechanical and Electrical Engineering,
Central South University of Forestry and Technology, Changsha 410004, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The flow behavior of delta-processed (DP) Inconel 718 was studied by revised hot deformation at temperature range of 900-1060 ℃ and strain rate range of 0.001-0.5 s-1. The effects of friction coefficient and temperature on the compressive deformation behavior, such as true stress-strain curves, were investigated, and the flow stress error caused by friction was revised. Then, the constitutive equation considering the compensation of strain was established. The results show that the effect of the friction is obvious with the increasing strain rate and the decreasing deformation temperature. The influence of strain was also incorporated by considering the variation of material constants as a function of strain. The prediction accuracy of developed constitutive modeling was assessed using standard statistical formulae. The correlation coefficient is 0.998 and the average absolute relative error is 3.87%. It is revealed that the proposed deformation constitutive equation gives an accurate estimate for the flow stress of delta-processed Inconel 718 alloy.
Key words: Inconel 718 alloy; delta process; flow behavior; stress revise; constitutive modeling
