(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)
摘 要: 采用温度数据采集系统采集得到盐浴炉等温保温过程中试样的温度变化曲线，通过硬度和电导率测试测定7050铝合金的时间－温度－性能(TTP)曲线。采用透射电镜和热分析仪对7050铝合金进行显微组织观察和分析。结果表明：合金TTP曲线鼻温大约在320 ℃，孕育期约为1.7 s。合金的淬火敏感温度区间为230~410 ℃，且在此温度区间内，合金硬度随时间的延长而迅速下降。等温保温过程中，合金晶内淬火平衡η相主要依附于晶内Al3Zr等弥散相和细小Al2Cu相形核长大；且随着保温时间延长，淬火析出相的体积分数逐渐增加，晶界析出相趋向于连续分布，无析出带逐渐宽化。等温保温合金经时效后，晶内析出GPⅡ区及η׳相数量随着等温保温时间的延长逐渐减少，使得合金性能降低，合金表现出一定淬火敏感性。
关键字: 淬火特性；TTP曲线；淬火敏感性；形核核心；时效析出相
（State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals，Beijing 100088, China）
Abstract:The time-temperature-property (TTP) curve of aluminum alloy 7050 was determined and the microstructure of the alloy under different processing was investigated. The results indicate that the nose temperature and incubation period of TTP curves is about 320 ℃, 1.7 s, respectively and the quench sensitive temperature range of TTP curve for 7050 alloy is 230−410 ℃. The volume of the coarse equilibrium η phases that precipitated at grain boundaries and in the grains during isothermal-holding increases with the isothermal-holding time, which results in the decrease of subsequent aging hardening precipitates(GPII zones and η׳ phases) for loss of solutes and vacancies. The grain boundary precipitates tend to distribute continuously with wider precipitation free zone. The primary nuclear sites for coarse equilibrium η phases are Al3Zr despersoids and Al2Cu particles in the grains.
Key words: hardenability characteristic; TTP curve; quench sensitivity; nuclear site; ageing precipitate
