Al-Zn-Mg-Sc-Zr合金的热变形行为及加工图

来源期刊:中国有色金属学报2011年第6期

论文作者:何振波 李慧中 梁霄鹏 尹志民

文章页码:1220 - 1228

关键词:Al-Zn-Mg-Sc-Zr合金;热变形;加工图

Key words:Al-Zn-Mg-Sc-Zr alloy; hot deformation; processing map

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 ε=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

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<ε<0.32 s-1 or 380 ℃<t<500 ℃ and 0.56 s-1<ε<10 s-1.

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