中文摘要：

采用洛氏硬度计、显微硬度计、光学显微镜（OM）、电子拉伸试验机等技术对7075铝合金时效行为、力学性能及显微组织进行了系统研究。结果表明，7075合金的硬度及强度都具有时效双峰特征。两个时效峰的硬度和强度相差很小，在较低温度下时效第二峰的强度、硬度、塑性、韧性较高。

英文摘要：

The aging behavior,mechanical properties and microstructure of 7075 aluminum alloys after overlong aging were studied by means of Rochwell hardometer, microhardness tester, optical microscope （OM） and electronic tensile machine. The resuhs show that the hardness, strcngth properties all have double peaks with almost the same values of hardness and strength. At lower temperature, the strength, hardness, plasticity and ductility of the alloy at the second ageing peak are higher than those at the first one.