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采用拉伸试验、硬度测试、电导率测试和透射电镜分析等方法研究了Al-Zn-Mg-Cu-Zr合金型材在180℃回归再时效阶段的析出行为。结果表明,合金在回归处理开始阶段,大部分的GPI区和部分尺寸细小的η’相迅速回溶到基体,合金的强度和硬度值降低至最小值;随着回归时间的延长,晶内析出了高温稳定性更好的η’相和GPII区,合金的强度和硬度值升高;进一步延长回归处理时间,合金中部分的η’相开始转变为η相,合金的强度和硬度值略有下降。再时效阶段,合金在较低的温度继续析出GPI区和较小尺寸的η’相,合金的强度和硬度值小幅增大。
The precipitation behavior of Al-Zn-Mg-Cu-Zr alloy profiles at 180 ℃ during the reheating stage was studied by means of tensile test, hardness test, electrical conductivity test and transmission electron microscopy. The results show that most of the GPI and some of the small η ’phase are rapidly dissolved back to the matrix at the beginning of the regression process, and the strength and hardness of the alloy decrease to a minimum. With the increase of the regression time, The high temperature stability of η ’phase and GPII zone, the alloy strength and hardness values increased; to further extend the regression processing time, the alloy part of the η’ phase began to change to η phase, the alloy strength and hardness values slightly decline. In the re-aging stage, the alloy precipitates the GPI region and the smaller size η ’phase at a lower temperature, and the alloy’s strength and hardness increase slightly.