(中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 通过力学性能和显微组织检测分析，研究了分级时效工艺对新型Al-Cu-Li合金组织与性能的影响。结果表明：经先高温后低温的双级时效处理和先低温后高温再低温的三级时效工艺处理的合金强度均比T6态的高，但比T8态的稍低；对于先高温后低温的双级时效制度，合金在165 ℃高温时效析出了δ′、θ′、T1相和σ相，然后，在130 ℃二次时效后析出大量细小弥散针状强化相，从而提高了合金的强度；对于先低温后高温再低温的三级时效工艺制度，在150 ℃预时效形成GP区和过渡相，从而在165 ℃时效析出了较多的第二相，经130 ℃的第三级时效后析出了细小的第二相，从而使合金具有较好的综合力学性能。
关键字: 铝锂合金；分级时效；显微组织；力学性能
（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
