(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083；
3. 常州亿和航宇材料科技有限公司，常州 213017)
摘 要: 采用显微硬度测试、室温拉伸试验，电导率测试和透射电镜等方法，对不同室温停放时间经过人工时效后的Al-Zn-Mg合金的力学性能、电导率和透射微观组织进行研究。结果表明：Al-Zn-Mg铝合金不经过室温停放时性能最优，强度、伸长率和硬度可以达到502.71 MPa、10.20%和173.20 HV；不同的室温停放时间Al-Zn-Mg合金的晶内析出相尺寸、数量以及晶界析出形貌和无沉淀析出带(PFZ)的宽度不同，室温停放3~6 h合金的综合性能优良，强度均能达到450 MPa以上，晶内析出相为亚稳相η′和平衡相η，晶界分布着断续的平衡相，PFZ宽度约为40~50 nm；室温停放的时间会影响后续人工时效GP区的形核。
关键字: Al-Zn-Mg铝合金；停放时间；析出相；力学性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China;
3. Changzhou Yihe Hangyu Material Technology Co., Ltd., Changzhou 213017, China）
Abstract:The mechanical properties, electrical conductivity and transmission microstructure of Al-Zn-Mg alloy after artificial aging for different parking time were investigated using micro-hardness test, room temperature tensile test, conductivity test and transmission electron microscope. The results show that Al-Zn-Mg aluminum alloy has the best performance without being parked at room temperature, and its strength, elongation and hardness can reach 502.71 MPa, 10.20% and 173.20 HV, respectively. The intragranular Al-Zn-Mg alloy, size and number of precipites, precipitates morphology of grain boundaries and width of precipitation free zone (PFZ) are different at different room temperature parking time. The comprehensive performance is excellent when parked at room temperature for 3-6 h, and the strength can reach more than 450 MPa. The intragranular precipitates are metastable phase η′ and equilibrium phase η. The grain boundaries are distributed with intermittent equilibrium phases, and the width of PFZ is about 40-50 nm. The parking time at room temperature will affect the nucleation of GP zone with subsequent artificial aging.
Key words: Al-Zn-Mg aluminum alloy; parking time; precipitates; mechanical properties
