(1. 湖南科技大學(xué) 材料科學(xué)與工程學(xué)院，湘潭411201；
2. 江麓機電集團有限公司，湘潭 411100)
摘 要: 通過硬度測試、拉伸測試、掃描電鏡以及透射電鏡研究了T6I6斷續(xù)時效對7B52疊層(7A62/7A01/7A52)鋁合金微觀組織和力學(xué)性能的影響。結(jié)果表明：大量細小η′相均勻析出，使7B52-T6I6時效態(tài)下的屈服強度和抗拉強度比T6態(tài)下的分別提高了22.5 MPa和20.5 MPa；由于較高的Mg、Zn含量，7A62層鋁合金在T6I6時效態(tài)下還發(fā)生了η′相的二次析出，引起額外強化作用，致使7A62層的屈服強度和抗拉強度比7A52層鋁合金分別高155.0 MPa和120.2 MPa。7A62層合金與7A01層合金具有較大的強度差異，使其界面結(jié)合強度弱；而7A52/7A01界面則具有較高的結(jié)合強度，界面周圍發(fā)生明顯塑性變形，斷裂處界面呈不平整狀。7B52疊層鋁合金的最佳斷續(xù)時效工藝為一級時效(120 ℃、2 h)+二級時效(65 ℃，20 d)+三級時效(120 ℃，18 h)。
關(guān)鍵字: 7B52疊層合金；斷續(xù)時效；微觀組織；力學(xué)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
