Effects of thermal exposure on microstructure and properties of Al-Li alloy with different aging treatments
ZHANG Shuying1, JIANG Bo2, XIAO Pan1
1. College of Materials and Advanced Manufacturing, Hunan University of Technology, Zhuzhou 412000, China; 2. School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
Abstract The effects of thermal exposure on microstructure and properties of 2A97 Al-Li alloy in different aging states were studied by means of scanning electron microscope, X-ray diffraction, transmission electron microscope, and hardness test. The results show that the phase types and morphologies of T6 and T8 alloys are similar after thermal exposure. With the increase of thermal exposure temperature, θʹ phase (Al2Cu) coarsens and decreases in quantity, T1 phase (Al2CuLi) changes to equilibrium phase, and the thermal stability of the alloy deteriorates. Different from T8 alloy, the strengthening phase in T6 alloy is not only T1 and θʹ phases, but also cubic phase, but the strengthening effect of this phase is much lower than that of T1 and θʹ phases. After exposure at 200 ℃, the quantity of cubic phase increases, and after exposure at 300 ℃, it redissolves into the matrix. Therefore, the thermal stability of T6 alloy after low temperature thermal exposure is better than that of T8 alloy, but the thermal stability of the two aging state alloys after high temperature thermal exposure is basically the same. The hardness of T8 alloy is significantly higher than that of T6 alloy, and the hardness decrease of T8 alloy is greater than that of T6 after low temperature thermal exposure. However, the hardness decrease of the two alloys after high temperature thermal exposure is basically the same.
ZHANG Shuying,JIANG Bo,XIAO Pan. Effects of thermal exposure on microstructure and properties of Al-Li alloy with different aging treatments[J]. Materials Science and Engineering of Powder Metallurgy, 2023, 28(5): 473-480.
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2023, Vol. 28 
