(1. 內(nèi)蒙古科技大學(xué) 材料與冶金學(xué)院，包頭 014010；
2. 鋼鐵研究總院特殊鋼所，北京 10081)
摘 要: 利用Gleeble-3800熱模擬試驗(yàn)機(jī)，在溫度為950~1150 ℃、應(yīng)變速率為0.01~10 s-1、變形量為60%條件下，研究汽輪機(jī)葉片用GY200鎳基合金的高溫塑性變形及動態(tài)再結(jié)晶行為，并繪制了合金的熱加工圖。結(jié)果表明：GY200合金的真應(yīng)力–應(yīng)變曲線具有動態(tài)再結(jié)晶特征，峰值應(yīng)力隨變形溫度的降低或應(yīng)變速率的升高而增加，發(fā)生動態(tài)再結(jié)晶的臨界應(yīng)變隨溫度增加而降低。在真應(yīng)力–應(yīng)變曲線的基礎(chǔ)上，建立了材料熱變形本構(gòu)方程，其熱激活能為353.792 kJ/mol，表明利用W替代合金中的Mo后，降低了合金的熱激活能。合金的最佳熱加工的溫度區(qū)間為1000~1150 ℃，應(yīng)變速率0.01~0.1 s-1，效率值達(dá)到0.3以上。
關(guān)鍵字: 葉片；GY200鎳基合金；本構(gòu)方程；熱激活能；熱加工圖
（1. Inner Mongolia University of Science and Technology, Baotou 014010, China;
2. Special Steel Institute of Central Iron and Steel Research Institute, Beijing 100081, China）
Abstract:The hot deformation characteristics of the GY200 Ni-based alloy at the temperature range of 950-1150 ℃ and strain rate range of 0.01-10 s–1 under deformation of 60% were investigated by means of hot compression tests with Gleeble-3800. The results show that the softening mechanism of the dynamic recrystallization is a feature of high-temperature flow stress-strain curves of the GY200 Ni-based alloy, the peak stress increases with the decrease of deformation temperature or the increase of strain rate, and the critical strain reduces with the decrease of deformation temperature. The constitutive equation for GY200 alloy was established on basis of the true stress–strain curves. The activation energy(Q) of the alloy is obtained as about 353.792 kJ/mol. Using W to replace Mo, the thermal activation energy of GY200 alloy is reduced. The processing map is developed based on the peak stress at different strain rate and showing variations of the efficiency of power dissipation related to temperature and strain rate. The instability zone on the processing map is located at the temperature range of 1030-1170 ℃ and stain rates of 1-10 s-1. The optimum hot working temperature and strain rate interval are 1000-1150 ℃ and 0.01-0.1 s-1, respectively.
Key words: blades; GY200 Ni-based alloy; constitutive equation; thermal activation energy; processing map
