(北京有色金属研究总院 有色金属材料制备加工国家重点实验室，北京 100088)
摘 要: 采用透射电子显微镜观察(TEM)和力学性能测试研究7150铝合金三级过时效热处理制度中各阶段对合金组织和力学性能的影响，并比较三级过时效热处理制度与单级峰时效、双级过时效、常规回归再时效(RRA)处理的组织和力学性能。结果表明：采用(110 ℃, 16 h)欠时效制度作为合金的预时效制度，比采用(120 ℃, 24 h)峰时效制度作为合金的预时效制度更有利于晶内析出相的回溶；采用(190 ℃, 2 h) 作为第二级高温时效制度，可以使合金晶内析出相部分回溶，晶界析出相充分断开；采用(110 ℃, 16 h)+ (190 ℃, 2 h)+(120 ℃, 16 h)三级过时效制度时，在同一电导率水平下，合金的抗拉强度损失明显低于采用双级过时效制度时合金的抗拉强度损失。
关键字: 7150铝合金；三级过时效；显微组织；沉淀析出相
（State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The effects of each step of the triple over-aging treatment on the microstructure and mechanical properties of 7150 aluminum alloy were investigated by TEM and mechanical properties testing, and the microstructure and mechanical properties of alloys under one-step peak-aging, two-step over-aging, conventional RRA treatment and triple over-aging treatment conditions were compared. The results show that using (110 ℃, 16 h) as pre-aging treatment is more beneficial for the re-dissolution of precipitates in the matrix than using (120 ℃, 24 h) as pre-aging treatment. Using (190 ℃, 2 h) as the second high temperature aging, the matrix precipitates can dissolve partly, while the precipitates on the grain boundary disconnect completely. The tensile strength loss of the alloy treated by (110 ℃, 16 h)+(190 ℃, 2 h)+ (120 ℃, 16 h) triple over-aging is obviously less than that of the alloy treated by two-step over-aging at the same electrical conductivity level.
Key words: 7150 aluminum alloy; triple over-aging; microstructure; precipitate
