(1. 湖南科技大学 材料科学与工程学院，湘潭411201；
2. 江麓机电集团有限公司，湘潭 411100)
摘 要: 通过硬度测试、拉伸测试、扫描电镜以及透射电镜研究了T6I6断续时效对7B52叠层(7A62/7A01/7A52)铝合金微观组织和力学性能的影响。结果表明：大量细小η′相均匀析出，使7B52-T6I6时效态下的屈服强度和抗拉强度比T6态下的分别提高了22.5 MPa和20.5 MPa；由于较高的Mg、Zn含量，7A62层铝合金在T6I6时效态下还发生了η′相的二次析出，引起额外强化作用，致使7A62层的屈服强度和抗拉强度比7A52层铝合金分别高155.0 MPa和120.2 MPa。7A62层合金与7A01层合金具有较大的强度差异，使其界面结合强度弱；而7A52/7A01界面则具有较高的结合强度，界面周围发生明显塑性变形，断裂处界面呈不平整状。7B52叠层铝合金的最佳断续时效工艺为一级时效(120 ℃、2 h)+二级时效(65 ℃，20 d)+三级时效(120 ℃，18 h)。
关键字: 7B52叠层合金；断续时效；微观组织；力学性能；二次析出
（1. School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Jiang Lu Electromechanical Group Co., Ltd., Xiangtan 411100, China）
Abstract:The microstructure and mechanical properties of 7B52 (7A62/7A01/7A52) laminated aluminum alloy after T6I6 interrupted-aging were investigated by hardness test, tensile test, SEM and TEM. The results show that large amount of fine η′ precipitate in 7B52 after T6I6 peak-aging, and the yield and tensile strength increase by 22.5 and 20.5 MPa in comparison with those of alloy by T6 aging, respectively. Due to the high content of Mg and Zn, the secondary precipitation of η′ occurs in 7A62. This leads to extra reinforcement, and the yield and tensile strength of 7A62 are 155.0 and 120.2 MPa, Which are higher than those of 7A52. The remarkable difference of tensile strength between 7A62 and 7A01 results in weak interface bonding between them. By contrast, the bonding strength of 7A52/7A01 is relatively high, significant plastic deformation is observed near interface, and fracture section is irregular after tensile test. The best interrupted-aging process is pre-aging (120 ℃, 2 h)+two-stage aging (65 ℃, 20 d)+three-stage aging (120 ℃, 18 h).
Key words: 7B52 laminated aluminum alloy; interrupted aging; microstructure; mechanical property; secondary precipitation
