(1. 中南大学 材料科学与工程系， 长沙 410083；
2. 西南铝加工厂， 重庆 401326)
摘 要: 对地铁列车车体用7005铝合金进行了在线挤压淬火实验和微观组织分析，研究了挤压温度、挤压速度、淬火方式以及时效条件对合金力学性能的影响。实验结果表明：降低挤压速度和淬火速度可在一定程度上提高合金力学性能，但对力学性能影响最大的两个因素是挤压温度和时效时间。透射电镜分析表明，较低的挤压温度，适当短一些的时效时间，可使合金中的强化η＇相颗粒细小、分布均匀，且晶界附近无沉淀带窄，因而易使合金获得高的力学性能。过高的挤压温度和过长的时效时间均易使合金产生过时效，析出相颗粒粗大，无沉淀带宽，导致合金力学性能恶化。
关键字: 地铁列车； 7005铝合金； 在线挤压；淬火； 二级时效
of 7005 alloys employed in underground railway trains
（1. Department of Materials Science and Engineering,
Central South University， Changsha 410083， P.R.China；
2. Southwestern Aluminum Fabrication Plant，
Chongqing 401326， P.R.china）
Abstract: The effects of the extrusion temperature, extrusion speed, quenching way and aging conditions on the mechanical properties of 7005 alloys were studiedby the on-line extrusion experiments and transmitted electron m, icroscopic analysis. The results show that reducing extrusion speed and quenching speed can improve the mechanical properties of the alloys to a certain extent, but the most obvious factors on the mechanical properties of the alloys are extrusion temperature and aging conditions. Higher mechanical properties can be acquired on lower extrusion temperature and shorter aging time. Transmitted electron microscopic analysis shows that η＇precipitated phase is smaller in size and evenly distributed and PFZ near grain boundary is narrow on lower extrusion temperature and shorter aging time, so the mechanical property of alloys can be improved. Overaging can be generated on higher extrusion temperature and longer aging time, and the coarse η＇precipitated phase distributed unevenly arises, which can result in worse mechanical property.
Key words: underground railway trains； 7005Al alloys； online extrusion； quenching； secondary aging
