(1. 中南大學 材料科學與工程學院，長沙 410083； 2. 中南大學 有色金屬材料科學與工程教育部重點實驗室，長沙 410083； 3. 中南大學 有色金屬先進結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長沙 410083； 4. 輕質(zhì)高強結(jié)構(gòu)材料重點實驗室，長沙 410083)
摘 要: 通過掃描電鏡(SEM)、透射電鏡(TEM)和拉伸性能測試等方法系統(tǒng)研究固溶和時效工藝對2297鋁鋰合金組織和性能的影響。結(jié)果表明：實驗合金較為適宜的固溶制度為((535±5) ℃，1.5 h)，基體中的第二相得到比較充分的溶解，同時抑制再結(jié)晶晶粒長大。T6態(tài)的主要強化相為T1相和θ′相，T8態(tài)的主要強化相為T1相，時效前的預變形可以促進T1相的形成，提高合金的強度峰值，縮短合金達到峰值的時間，160 ℃時效后，未經(jīng)預變形的合金的強度峰值為392 MPa，到峰時間為48 h，變形量為7%時，合金的強度峰值最高，達到482 MPa，到峰時間為23 h。
關(guān)鍵字: 2297鋁鋰合金；固溶；時效；微觀組織；力學性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China; 3. Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Central South University, Changsha 410083, China; 4. Science and Technology on High Strength Structural Materials Laboratory, Changsha 410083, China）
Abstract:The effects of solid solution and aging process on structure and properties of 2297 Al-Li alloy were investigated by SEM, TEM and tensile tests systematically. The results show that the optimum solution treatment is determined as ((535±5) ℃, 1.5 h), and in this case, second phases can be more fully dissolved in the Al matrix and the sizes of recrystallized grains are moderate. The dominant strengthening phases during T6 are T1 phase and θ′ phase. Pre-deforming before aging can promote the nucleation of T1 phase, enhance the peak-aged strength and shorten the time to reach peak. The peak strength of the alloy under T6 state at 160 ℃ is 392 MPa after 48 h. The peak strength of the alloy at 7% pre-deformation is the highest strength which can reach 482 MPa after 23 h.
Key words: 2297 Al-Li alloy; solid solution; aging; microstructure; mechanical property
