(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 东北轻合金有限责任公司，哈尔滨 150060)
摘 要: 在Gleeble−1500热模拟试验机上对Al-5.5Zn-1.5Mg-0.2Sc-0.1Zr铝合金进行高温等温压缩实验，研究该合金在变形温度为300~500 ℃、应变速率为0.01~10 s−1条件下的流变行为，建立合金高温变形的本构方程和加工图，采用电子背散射衍射(EBSD)分析变形过程中合金的组织特征。结果表明：流变应力随变形温度的升高而降低；当应变速率 =10 s−1，变形温度为300~500 ℃时，合金发生了动态再结晶。Al-5.5Zn-1.5Mg-0.2Sc-0.1Zr合金的高温流变行为可用Zener-Hollomon参数描述。在热变形过程中，随着真应变增加，合金的变形失稳区域增大。该合金适宜的变形条件如下：变形温度300~360 ℃、应变速率0.01~0.32 s−1，或变形温度380~500 ℃、应变速率0.56~ 10 s−1。
关键字: Al-Zn-Mg-Sc-Zr合金；热变形；加工图
Al-Zn-Mg-Sc-Zr alloy
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Northeast Light Alloy Co. Ltd, Harbin 150060, China）
Abstract:The flow stress features of Al-5.5Zn-1.5Mg-0.2Sc-0.1Zr aluminum alloy were studied by the isothermal compression of cylindrical specimen in the temperature range of 300−500 ℃ and strain rate range of 0.01−10 s−1 with Gleeble−1500 simulated machine. The high temperature deformation constitutive equations and processing map were established, furthermore, the microstructure characteristics were studied by electron back-scattered diffraction (EBSD) analysis. The results show that the flow stress decreases with increasing deformation temperature. The dynamic recrystallization occurs at the strain rate of 10 s−1 and in the temperature range of 300−500 ℃. The flow stress of Al-5.5Zn-1.5Mg-0.2Sc-0.1Zr alloy during high temperature deformation can be represented by Zener-Hollomon parameter. In the hot deformation process, the flow instability zone increases with increasing the true strain. The feasible deformation temperature and strain rate are 300 ℃＜t＜360 ℃ and 0.01 s−1＜ ＜0.32 s−1 or 380 ℃＜t＜500 ℃ and 0.56 s−1＜ ＜10 s−1.
Key words: Al-Zn-Mg-Sc-Zr alloy; hot deformation; processing map
