(哈爾濱理工大學(xué) 機械動力工程學(xué)院，哈爾濱 150080)
摘 要: 為了研究Inconel625高溫合金在較高溫度和應(yīng)變率變化范圍內(nèi)的熱變形行為，采用CSS電子萬能試驗機和分離式霍普金森壓桿試驗裝置對Inconel625高溫合金進行準靜態(tài)試驗和霍普金森壓桿試驗，在溫度為20~800 ℃、應(yīng)變率為0.001~8000 s-1范圍內(nèi)得到Inconel625高溫合金的真實應(yīng)力—應(yīng)變曲線。結(jié)果表明：隨著溫度的升高，Inconel625高溫合金的流動應(yīng)力與屈服應(yīng)力并不單一地隨應(yīng)變率增大而增大，同一溫度條件下，隨著應(yīng)變率的增加，Inconel625高溫合金的真實應(yīng)力先增大后減小(分界線是應(yīng)變率為6000 s-1)；同一應(yīng)變率條件下，Inconel625高溫合金的真實應(yīng)力隨著溫度的升高而減小。基于Johnson-Cook模型對其真實應(yīng)力-應(yīng)變曲線進行擬合分析，經(jīng)過計算得到模型的預(yù)測值與實驗值的相關(guān)性和絕對誤差，并進一步改進Inconel625高溫合金的Johnson-Cook本構(gòu)模型，使模型能夠更好地反映Inconel625高溫合金在較高溫度和應(yīng)變率變化范圍內(nèi)的熱變形規(guī)律。
關(guān)鍵字: Inconel 625高溫合金；Johnson-Cook本構(gòu)模型；應(yīng)變；熱變形
（School of Mechanical Engineering, Harbin University of Science and Technology, Harbin 150080, China）
Abstract:In order to study the thermal deformation behavior of Inconel625 superalloy at high temperature and strain rate range, the quasi-static test and Hopkinson pressure bar test of Inconel625 superalloy were carried out by using CSS electronic universal testing machine and split type pressure bar test device. The true stress-strain curves of Inconel625 superalloy were obtained in the range of 20-800 ℃ centigrade and strain rate of 0.001-8000 s-1. The experimental results show that the low stress and yield stress of Inconel625 superalloy do not increase with the increase of strain rate. Under the same temperature, the true stress of Inconel625 superalloy increases first and then decreases with the increase of strain rate (the dividing line is strain rate of 6000 s-1). While under the same strain rate, the true stress of Inconel625 superalloy decreases with the increase of temperature. Based on the Johnson-Cook model, the true stress-strain curves are fitted and analyzed. The correlation coefficient and the absolute error between the predicted value and the experimental value are obtained by calculation. By improving the Johnson-Cook constitutive model of Inconel625 superalloy, the model can be used to characterize the themal deformation of Inconel625 superalloy at high temperature and strain rate range.
Key words: Inconel625 superalloy; Johnson-Cook constitutive model; strain; thermal deformation
