Abstract Aging treatment is an important way to improve the mechanical properties of Al-Zn-Mg alloys. In this work, the Al-Zn-Mg (7 N01) alloy helical profile was extruded and treated by different kinds of isothermal and non-isothermal aging processes. It was found that the alloy had the peak strength at 39 h during the isothermal aging treatment. Its precipitation sequence was supersaturated solid solution (SSS) → GPII zones → metastable η′ phase, where the stable η phase had not been formed. The peak strength of the alloy during the non-isothermal aging reached at 4-5 h, but the peak strength was lower than those with isothermal aging treatment. The maximum temperature Tmax of non-isothermal aging played a key role on the mechanical properties: the higher the maximum temperature was, the longer time was required, and the lower the strength and the hardness were. The grain boundary structure of the alloy with Tmax = 185 °C was similar to that with isothermal aging, and the grain boundary precipitate (GBP) was rarer than that with Tmax = 200 °C and Tmax = 215 °C, where there was no obvious precipitate free zone (PFZ) in the alloy, which was conducive to improving the corrosion resistance of the alloy.

中文翻译：

---

等温和非等温时效处理对Al-Zn-Mg合金螺旋型材组织和性能的影响

摘要 时效处理是提高Al-Zn-Mg合金力学性能的重要途径。在这项工作中，Al-Zn-Mg (7 N01) 合金螺旋型材通过不同类型的等温和非等温时效工艺进行挤压和处理。发现合金在等温时效处理过程中在 39 h 具有峰值强度。其析出顺序为过饱和固溶体（SSS）→GPII区→亚稳η'相，其中没有形成稳定的η相。非等温时效处理时合金的峰值强度达到4-5 h，但峰值强度低于等温时效处理的峰值强度。非等温老化的最高温度Tmax对力学性能起着关键作用：最高温度越高，所需时间越长，强度和硬度越低。Tmax = 185 °C 时合金的晶界结构与等温时效相似，晶界析出物 (GBP) 比 Tmax = 200 °C 和 Tmax = 215 °C 时更少，其中没有合金中有明显的无析出区（PFZ），有利于提高合金的耐蚀性。