Ag，Mg合金化对Al-Cu-Li合金时效特性和显微组织的影响

Effects of Ag, Mg Micro-Alloying on Aging Characteristics and Microstructure of Al-Cu-Li Alloy

摘要:

通过力学性能测试和显微组织观察研究微量Ag和Mg对Al-3.5Cu-1.0Li合金时效特性和显微组织的影响。结果表明：在175 ℃时效时，单独加Ag不影响合金的时效硬化效果，析出物形貌与Al-Cu-Li合金相似，峰值时效状态下均析出较粗大的T1相和θ′相；单独加Mg加快Al-Cu-Li合金的时效响应，提高合金的时效硬化效果，时效时析出GP区，θ′相和T1相；Ag和Mg同时添加的2050合金中，T1相的析出速度加快，析出密度增大，并以T1相为主要强化相，时效强化效果最大。Ag，Mg添加对合金的不同影响可通过溶质原子与空位、溶质原子与溶质原子之间的相互作用来解释。

Abstract:

The effect of small addition of Ag, Mg on the microstructure and the aging characteristics of Al-3.5Cu-1.0Li alloy has been studied by mechanical testing and transmission electron microscopy. The results indicate that only sliver addition has almost no effect on the age-hardening and strengthening of the baseline alloy upon aging at 175 ℃. At peak aging state the main precipitates are both coarse T1 and θ′ phases for the Ag-bearing alloy and the baseline alloy. The Mg-containing alloy has a faster aging response and higher aging-strengthening effect than the baseline alloy. GP zone, θ′ and T1 are formed at different aging stages. The combined addition of Ag and Mg to the alloy greatly accelerates T1 precipitation, resulting in increasing density of T1 precipitates. The high volume fraction of T1 phase causes 2050 alloy having the highest strength. The independent and combined roles of small addition of Ag and Mg can be interpreted in terms of the solute-vacancy interaction and solute-solute atom interaction.