(1. 北京有色金屬研究總院 國家有色金屬及電子材料分析測試中心, 北京100088;
2. 北京有色金屬研究總院 有色金屬材料制備加工國家重點(diǎn)實(shí)驗(yàn)室, 北京100088)
摘 要: 通過維氏硬度、電導(dǎo)率及拉伸性能測試和TEM觀察研究欠時效狀態(tài)7150合金的高溫回歸時效行為。結(jié)果表明：回歸過程對合金的硬度和電導(dǎo)率影響顯著。隨著回歸溫度的提高，回歸曲線上的谷值點(diǎn)變低，達(dá)到谷值點(diǎn)所需的時間變短；在190 ℃回歸超過30 min后，晶界析出相明顯粗化，并且斷開；經(jīng)過(110 ℃，16 h)+(190 ℃，120 min)+(120 ℃，24 h)的三級時效處理后，合金的抗拉強(qiáng)度為595 MPa，屈服強(qiáng)度為565 MPa，伸長率為12.5%，電導(dǎo)率為21.9 MS/m。采用此三級時效制度，合金的電導(dǎo)率較高，強(qiáng)度損失較小。此三級時效處理具有較長的第二級高溫時效時間，適宜工業(yè)化操作。
關(guān)鍵字: 7150合金；回歸；維氏硬度；顯微組織；電導(dǎo)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
