(中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 通過力學(xué)性能和顯微組織檢測分析，研究了分級(jí)時(shí)效工藝對(duì)新型Al-Cu-Li合金組織與性能的影響。結(jié)果表明：經(jīng)先高溫后低溫的雙級(jí)時(shí)效處理和先低溫后高溫再低溫的三級(jí)時(shí)效工藝處理的合金強(qiáng)度均比T6態(tài)的高，但比T8態(tài)的稍低；對(duì)于先高溫后低溫的雙級(jí)時(shí)效制度，合金在165 ℃高溫時(shí)效析出了δ′、θ′、T1相和σ相，然后，在130 ℃二次時(shí)效后析出大量細(xì)小彌散針狀強(qiáng)化相，從而提高了合金的強(qiáng)度；對(duì)于先低溫后高溫再低溫的三級(jí)時(shí)效工藝制度，在150 ℃預(yù)時(shí)效形成GP區(qū)和過渡相，從而在165 ℃時(shí)效析出了較多的第二相，經(jīng)130 ℃的第三級(jí)時(shí)效后析出了細(xì)小的第二相，從而使合金具有較好的綜合力學(xué)性能。
關(guān)鍵字: 鋁鋰合金；分級(jí)時(shí)效；顯微組織；力學(xué)性能
（Key Laboratory of Nonferrous Materials Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The effects of multi-stage ageing treatments on the microstructures and mechanical properties of Al-Cu-Li alloys were investigated. The results show that, the alloys with higher mechanical properties by two-stage and three-stage ageing treatments can be obtained. When the alloy is aged at higher temperature(165 ℃), δ′, θ′, T1 and σ phases are precipitated, and the fine and dispersed phases are precipitated at 130 ℃, which improves the strength of alloy. The GP zones or transition phases are preferentially precipitated when the alloy is pre-aged at 150℃, and many second-phases are precipitated at 165 ℃, the fine phases are precipitated under the third stage treatments, which results in higher combined strength properties.
Key words: Al-Li alloy; multi-stage ageing; microstructure; mechanical property
