固溶处理对7050高强铝合金显微组织和机械性能的影响

Effects of Solid Solution Treatment on Microstructure and Mechanical Properties of 7050 High Strength Aluminum Alloy

为了获得7050高强铝合金较为理想的固溶处理制度，通过组织观察（光学显微镜和扫描电镜）、洛氏硬度测试、拉伸力学性能测试、能谱分析等方法研究了固溶处理对7050高强铝合金显微组织和性能的影响。结果表明，在430-470℃范围内，随固溶温度的增加或固溶时间的延长，合金的粗大相逐渐回溶入基体组织中，固溶效果增强，经过淬火后组织过饱和度增大，经人工时效后的基体强化效果增强，强度逐渐提高。然而，随着固溶温度进一步提高或延长固溶时间，造成了晶粒的长大，过剩相减少，析出相的弥散强化作用减弱，基体强度逐渐降低。所得7050高强铝合金较为理想的固溶处理制度为470℃×60min。

In order to develop proper solid solution treatment process of 7050 high strength aluminum al- loy, the effects of solid solution treatment on micro- structure and mechanical properties of 7050 aluminum alloy were studied by using optical microscope （ OM）, scanning electron microscope （ SEM）, hardness test, tensile test, and energy dispersive X-ray spectrometer （EDS）. The results showed that the coarse phases dis- solved into the matrix gradually, and the effect of solid solubility, saturation, and strength increased with the increase of the solid solution temperature or the solid solution time in the rang of 430 - 470℃. However, when the solid solution temperature or the solid solu- tion time increased further, the grains grew larger, and the number of surplus phases reduced, the strengthening effect of dispersive phases decreased, hence the strength decreased gradually. The optimum solid solution treatment process of 7050 high strength aluminum alloy was annealing at 470 ℃ for 60 min.