(1. 中南林業(yè)科技大學(xué)機(jī)電工程學(xué)院，長(zhǎng)沙 410004；
2. 中南大學(xué)粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 采用等溫?zé)釅嚎s實(shí)驗(yàn)研究DP工藝Inconel 718合金在變形溫度為900~1060 ℃，應(yīng)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(duì)真應(yīng)力-真應(yīng)變曲線的影響，并對(duì)摩擦引起的流變應(yīng)力誤差進(jìn)行了修正，建立了基于應(yīng)變量的應(yīng)變本構(gòu)模型。結(jié)果表明：隨著應(yīng)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(yīng)變量的函數(shù)。對(duì)引入應(yīng)變量參數(shù)建立的用于預(yù)測(cè)工藝處理的Inconel 718合金不同變形量時(shí)的流變應(yīng)力本構(gòu)模型進(jìn)行誤差分析，其實(shí)驗(yàn)值與預(yù)測(cè)值的相關(guān)性系數(shù)為0.998，平均相對(duì)誤差絕對(duì)值為3.87%，能夠用于準(zhǔn)確預(yù)測(cè)不同變形量時(shí)合金的流變應(yīng)力值。
關(guān)鍵字: Inconel 718合金；DP工藝；流變行為；應(yīng)力修正；本構(gòu)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
