Al-8.79Zn-2.16Mg-2.11Cu-0.12Zr合金的本构关系和微观组织演变

Constitutive relationship and microstructure evolution of Al-8.79Zn-2.16Mg-2.11Cu-0.12Zr alloy

为解决高强度铝合金在工业化大生产过程中出现的挤压、冲压和锻造不合格现象,以Al-8.79AZn-2.16Mg-2.11Cu-0.12Zr合金为研究对象,利用热模拟实验机开展了合金的等温压缩变形测试,完成了合金高温热力学行为特征分析和微观组织演变分析,构建了Al-8.79Zn-2.16Mg-2.11Cu-0.12Zr合金的考虑应变补偿和未考虑应变补偿的两种本构关系,并进行了流变应力预测。研究结果表明:流变应力对应变速率和温度非常敏感,在低应变速率条件下,发生连续动态再结晶现象;考虑应变补偿的本构关系具有更高的预测精度;390℃/5 s^(-1)变形条件下的再结晶分数最大,约为17%,再结晶临界应力值最大,为65.28 MPa。

In order to solve the unqualified phenomenon of extrusion,stamping and forging of high-strength aluminum alloys in the process of industrial mass production,for Al-8.79Zn-2.16Mg-2.11Cu-0.12Zr alloy,its isothermal compression deformation test was carried out by thermal simulation machine,and the thermodynamic behavior characteristic and microstructure evolution of alloy at high temperature were analyzed.Then,two constitutive relationships of Al-8.79Zn-2.16Mg-2.11Cu-0.12Zr alloy with and without considering strain com-pensation were established,and the rheological stress prediction was conducted.The research results show that the rheological stress is very sensitive to strain rate and temperature,and continuous dynamic recrystallization occurs under low strain rate conditions.The consti-tutive relationship considering strain compensation has a higher prediction accuracy,the fraction of recrystallization under the deformation condition of 390 C/5 s^(-1) is the largest,which is about 17%,and the critical stress value of recrystallization is the largest,which is 65.28 MPa.