The 7-series alloy is usually used as a material for welding members, or as an aircraft material, and is represented by a super-hard aluminum alloy 7075 alloy. The 7075 aluminum plate is mostly used to manufacture aircraft structures and other high-stress structural members that require high strength and high corrosion resistance, such as upper and lower airfoil panels and bulkheads. After solution treatment, the plasticity is good, the heat treatment strengthening effect is particularly good, the strength is lower than 150 degrees, and the low temperature strength is particularly good, the welding performance is poor, and there is a tendency of stress corrosion cracking.
In recent years, sporting goods such as ski poles and golf clubs have also been produced using such alloys. For the heat treatment of 7075 aluminum alloy, T651 is used. This treatment can make the residual stress after T6 treatment uniformized by stretching correction to prevent the workpiece from being twisted and deformed during processing. T73 treatment will reduce the mechanical properties, but it has the effect of reducing the tendency of stress corrosion.