双级时效工艺对7050铝合金组织与性能的影响

摘要

The two-stage long-term aging of 7050 aluminum alloy in the process of age-hardening properties and microstructure were studied by hardness test, tensile test, X-ray diffraction phase and scanning electron microscopy(SEM). The results show that two-stage long-term aging of 7050 aluminum alloy both of hardness and strength properties have double peaks, and the hardness and strengh of second peak are slightly higher than the first peak's. The relation model between the hardness with aging time and aging of the structure from melting has been established with the F-R source movement critical shear stress theory and explain the strengthen mechanism of second-phase particles in the second peak of the 7050 aluminum alloy.%采用洛氏硬度计、电子拉伸试验机、XRD物相分析、扫描电镜(SEM)等分析方法研究了7050铝合金双级长期时效过程中的时效硬化特性和显微组织.结果表明:7050铝合金双级时效硬度及强度具有双峰特点,且第2峰比第1峰的硬度、强度均略高.建立时效硬度与时效时间和脱溶相结构之间的关系模型,并引进F-R源动作的临界切应力理论,解释了7050铝合金第2峰第2相粒子强化机理.