(1. 内蒙古科技大学 材料与冶金学院，包头 014010；
2. 钢铁研究总院特殊钢所，北京 10081)
摘 要: 利用Gleeble-3800热模拟试验机，在温度为950~1150 ℃、应变速率为0.01~10 s-1、变形量为60%条件下，研究汽轮机叶片用GY200镍基合金的高温塑性变形及动态再结晶行为，并绘制了合金的热加工图。结果表明：GY200合金的真应力–应变曲线具有动态再结晶特征，峰值应力随变形温度的降低或应变速率的升高而增加，发生动态再结晶的临界应变随温度增加而降低。在真应力–应变曲线的基础上，建立了材料热变形本构方程，其热激活能为353.792 kJ/mol，表明利用W替代合金中的Mo后，降低了合金的热激活能。合金的最佳热加工的温度区间为1000~1150 ℃，应变速率0.01~0.1 s-1，效率值达到0.3以上。
关键字: 叶片；GY200镍基合金；本构方程；热激活能；热加工图
（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
