(1. 中南林業(yè)科技大學機電工程學院，長沙 410004；
2. 中南大學粉末冶金國家重點實驗室，長沙 410083)
摘 要: 采用等溫熱壓縮實驗研究DP工藝Inconel 718合金在變形溫度為900~1060 ℃，應變速率為0.001~0.5 s-1條件下的高溫流變行為，分析摩擦因數(shù)和絕熱溫升對真應力-真應變曲線的影響，并對摩擦引起的流變應力誤差進行了修正，建立了基于應變量的應變本構模型。結(jié)果表明：隨著應變速率的增大和變形溫度的降低，摩擦因數(shù)的影響趨于明顯，變形激活能和材料常數(shù)是應變量的函數(shù)。對引入應變量參數(shù)建立的用于預測工藝處理的Inconel 718合金不同變形量時的流變應力本構模型進行誤差分析，其實驗值與預測值的相關性系數(shù)為0.998，平均相對誤差絕對值為3.87%，能夠用于準確預測不同變形量時合金的流變應力值。
關鍵字: Inconel 718合金；DP工藝；流變行為；應力修正；本構模型
（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
