(1. 北京宇航系統(tǒng)工程研究所，北京 100076;
2. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 以5.2 mm厚度2195-T8鋁鋰合金為對象，進(jìn)行重固溶、4.5%預(yù)變形后不同溫度(145C~160 ℃)的T8再時效處理，研究其力學(xué)性能與晶內(nèi)顯微組織演化。結(jié)果表明：重固溶處理后的晶粒形態(tài)與原始2195-T8態(tài)晶粒形態(tài)一樣，仍然保持為拉長的帶狀晶粒組織。重固溶并經(jīng)4.5%預(yù)變形后，再采用適當(dāng)?shù)臏囟群蜁r間進(jìn)行T8時效處理，2195鋁鋰合金可以回復(fù)到原始T8態(tài)的顯微組織和力學(xué)性能，即2195鋁鋰合金采用重固溶-T8再時效處理不會明顯損害其力學(xué)性能。2195鋁鋰合金的晶內(nèi)時效析出相包括T1相(Al2CuLi)、δ′相(Al3Li)、θ′相(Al2Cu)及θ″相(Al2Cu)，其中優(yōu)先析出相為T1相；較低溫度及較短時間時效可形成較多δ′相和θ″相；隨著時效時間延長，T1相生長，θ″相轉(zhuǎn)化為θ′相并減少，δ′相消失；時效溫度提高可促進(jìn)該轉(zhuǎn)變過程，加快鋁鋰合金的時效響應(yīng)速度。
關(guān)鍵字: 鋁鋰合金；重固溶；再時效；顯微組織；力學(xué)性能
（1. Beijing Institute of Aerospace Systems Engineering, Beijing 100076, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Based on 2195-T8 Al-Li alloy with 5.2 mm thickness, the mechanical properties and intragranular microstructural evolution during T8 (4.5% pre-deformation) re-aging at 145-160 ℃ after re-solution were investigated. The results show that the grain after re-solution still maintains as elongated pancake-like appearance, which is the same as that of original 2195-T8. The micro-structures and mechanical properties can recover to those of the original 2195-T8 Al-Li alloy through using appropriate T8 re-aging temperature and time. Re-solution and T8 re-aging treatment do not obviously damage 2195 Al-Li alloy mechanical property. The intragranular precipitates include T1(Al2CuLi), δ′(Al3Li), θ′(Al2Cu) and θ″(Al2Cu), among which the preferential precipitates are T1 phases. Re-aging at lower temperature or for shorter time, much more δ′ and θ″ precipitates are formed. With time extension, T1 precipitates grow, but θ″ precipitates are transformed to θ′ precipitates, and δ′ precipitates disappear. As re-aging temperature is elevated, the transformation process is accelerated, and the aging response is promoted.
Key words: Al-Li alloy; re-solution; re-aging; microstructure; mechanical property
