(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 東北輕合金有限責任公司，哈爾濱 150060)
摘 要: 在Gleeble−1500熱模擬試驗機上對Al-5.5Zn-1.5Mg-0.2Sc-0.1Zr鋁合金進行高溫等溫壓縮實驗，研究該合金在變形溫度為300~500 ℃、應變速率為0.01~10 s−1條件下的流變行為，建立合金高溫變形的本構方程和加工圖，采用電子背散射衍射(EBSD)分析變形過程中合金的組織特征。結果表明：流變應力隨變形溫度的升高而降低；當應變速率 =10 s−1，變形溫度為300~500 ℃時，合金發(fā)生了動態(tài)再結晶。Al-5.5Zn-1.5Mg-0.2Sc-0.1Zr合金的高溫流變行為可用Zener-Hollomon參數(shù)描述。在熱變形過程中，隨著真應變增加，合金的變形失穩(wěn)區(qū)域增大。該合金適宜的變形條件如下：變形溫度300~360 ℃、應變速率0.01~0.32 s−1，或變形溫度380~500 ℃、應變速率0.56~ 10 s−1。
關鍵字: Al-Zn-Mg-Sc-Zr合金；熱變形；加工圖
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
