(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: 采用透射電子顯微鏡觀察(TEM)和力學(xué)性能測(cè)試研究7150鋁合金三級(jí)過時(shí)效熱處理制度中各階段對(duì)合金組織和力學(xué)性能的影響，并比較三級(jí)過時(shí)效熱處理制度與單級(jí)峰時(shí)效、雙級(jí)過時(shí)效、常規(guī)回歸再時(shí)效(RRA)處理的組織和力學(xué)性能。結(jié)果表明：采用(110 ℃, 16 h)欠時(shí)效制度作為合金的預(yù)時(shí)效制度，比采用(120 ℃, 24 h)峰時(shí)效制度作為合金的預(yù)時(shí)效制度更有利于晶內(nèi)析出相的回溶；采用(190 ℃, 2 h) 作為第二級(jí)高溫時(shí)效制度，可以使合金晶內(nèi)析出相部分回溶，晶界析出相充分?jǐn)嚅_；采用(110 ℃, 16 h)+ (190 ℃, 2 h)+(120 ℃, 16 h)三級(jí)過時(shí)效制度時(shí)，在同一電導(dǎo)率水平下，合金的抗拉強(qiáng)度損失明顯低于采用雙級(jí)過時(shí)效制度時(shí)合金的抗拉強(qiáng)度損失。
關(guān)鍵字: 7150鋁合金；三級(jí)過時(shí)效；顯微組織；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
