重固溶-不同溫度T8再時效2195鋁鋰合金的力學性能與顯微組織演化重固溶-不同溫度T8再時效2195鋁鋰合金的力學性能與顯微組織演化Microstructural evolution and mechanical properties of 2195 Al-Li alloy during T8 re-aging at various temperatures following re-solution 以5.2 mm厚度2195-T8鋁鋰合金為對象，進行重固溶、4.5%預變形后不同溫度(145C~160 ℃)的T8再時效處理，研究其力學性能與晶內顯微組織演化。結果表明：重固溶處理后的晶粒形態與原始2195-T8態晶粒形態一樣，仍然保持為拉長的帶狀晶粒組織。重固溶并經4.5%預變形后，再采用適當的溫度和時間進行T8時效處理，2195鋁鋰合金可以回復到原始T8態的顯微組織和力學性能，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性能。2195鋁鋰合金的晶內時效析出相包括T1相(Al2CuLi)、δ′相(Al3Li)、θ′相(Al2Cu)及θ″相(Al2Cu)，其中優先析出相為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″相轉化為θ′相并減少，δ′相消失；時效溫度提高可促進該轉變過程，加快鋁鋰合金的時效響應速度。 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.
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