(1. 北京有色金属研究总院有色金属材料制备加工国家重点实验室,北京 100088;
2. 北京有色金属研究总院有色金属加工中心,北京 100088)
摘 要: 对2197铝锂合金进行形变热处理,采用HREM高分辨电镜观察合金欠时效和峰时效两个阶段的显微组织,研究T1相析出长大行为及其界面特征。结果表明:形变热处理2197合金在欠时效阶段主要存在δ′、θ′和T1相,T1相尺寸约为40 nm;峰时效阶段合金中δ′和θ′数量减少,主要析出相为T1相,其尺寸为50~150 nm,T1相可通过δ′相的溶解而长大。在欠时效和峰时效两阶段,T1相末端与基体共格,其他区域与基体非共格。T1相为六方晶系,与基体存在惯析关系:(0001)T1//(111)A1、[1010]T1//[110]A1,惯析面为{111}A1。
关键字: 2197 Al-Li合金;形变热处理;T1相;析出行为
(1. State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals, Beijing 100088, China;
2. Nonferrous Metals Processing Division, General Research Institute for Nonferrous Metals, Beijing 100088, China)
Abstract:2197 Al-Li alloy was thermo-mechanically treated, and the precipitation and growth of the T1 phase and the phase interface characteristics were studied. The microstructures of thermo-mechanical treated 2197 Al-Li alloy for under-aged and peak-aged states were observed by high resolution electron microscopy (HREM). The results show that during thermo-mechanical treatment, δ′, θ′ and T1 phases are the main phases of under-aged 2197 alloy, the size of T1 phase is about 40 nm. δ′ and θ′ phases number reduce at peak-aged state, while the main phase of peak-aged 2197 alloy is T1 phase with the size of 50-150 nm. The T1 phase grows up by the dissolving of δ′ phase. The end of T1 phase of peak-aged 2197 alloy is coherent with the matrix while the rest is non-coherent during under-aged and peak-aged states. Habit relationships between T1 phase which is hexagonal crystal system and the matrix is as follow: (0001)T1//(111)A1 and [1010]T1//[110] A1, and the habit plane is {111}A1.
Key words: 2197 Al-Li alloy; thermo-mechanical treatment; T1 phase; precipitation behavior