(1. 北京有色金属研究总院 国家有色金属及电子材料分析测试中心, 北京100088;
2. 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: 通过维氏硬度、电导率及拉伸性能测试和TEM观察研究欠时效状态7150合金的高温回归时效行为。结果表明：回归过程对合金的硬度和电导率影响显著。随着回归温度的提高，回归曲线上的谷值点变低，达到谷值点所需的时间变短；在190 ℃回归超过30 min后，晶界析出相明显粗化，并且断开；经过(110 ℃，16 h)+(190 ℃，120 min)+(120 ℃，24 h)的三级时效处理后，合金的抗拉强度为595 MPa，屈服强度为565 MPa，伸长率为12.5%，电导率为21.9 MS/m。采用此三级时效制度，合金的电导率较高，强度损失较小。此三级时效处理具有较长的第二级高温时效时间，适宜工业化操作。
关键字: 7150合金；回归；维氏硬度；显微组织；电导率
under-aged 7150 aluminum alloy
（1. National Analysis and Testing Center for Nonferrous Metals and Electronic Materials,
Central Research Institute for Nonferrous Metals, Beijing 100088, China;
2. State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The Vickers hardness, electrical conductivity, tensile properties testing and TEM were used to investigate the high-temperature retrogression behavior of under-aged 7150 aluminum alloy. The results indicate that the hardness and electrical conductivity are strongly influenced by retrogression process. The valley values of retrogression curves become lower and the time to reach the valley values becomes shorter with the increase of retrogression aging temperature. After retrogression at 190 ℃ for 30 min, the precipitates on the grain boundaries become coarse and are sparsely distributed. After (110 ℃, 16 h)+(190 ℃, 120 min)+(120 ℃, 24 h) aging treatment, the ultimate strength, yield strength, elongation and electrical conductivity of the alloy are 595 MPa, 565 MPa, 12.5% and 21.9 MS/m, respectively. The electrical conductivity of the alloy can be increased with less reduction in strength by this triple step aging treatment. This triple aging treatment is suitable for industry because of a relative long time of the second step aging.
Key words: 7150 aluminum alloy; retrogression; Vickers hardness; microstructure; electrical conductivity
