7075 alloy is an aluminum-zinc-magnesium-copper series high-strength deformable aluminum alloy that can be strengthened by heat treatment. It is the veteran of super duralumin, but it is not a big brother, because there are still stronger ones, and it can be used to process all semi-finished products. , used to manufacture a variety of structural parts, especially aerospace structural parts, is the most used high-strength aluminum alloy today, as large as the C919 large aircraft front fuselage long truss, passenger observation window frame forgings, medium aircraft Body bends and girders, keel beam webs, floor transition beams, middle and rear fuselage girders, passenger observation window frame forgings, cargo door frames, nose front pressure frame flanges, door frames, etc.; small to mobile phone casings. It has a variety of heat treatment states: T6, T73, T76, T77. T6 state materials have the highest mechanical strength properties, but their fracture toughness is low, they are sensitive to stress corrosion, and their toughness decreases with the decrease of temperature. Therefore, T6 state materials are not suitable for manufacturing low-temperature structural parts and workpieces; T73 materials have the lowest strength , but has quite high fracture toughness, good stress cracking resistance and exfoliation corrosion resistance; the strength of T76 material is higher than that of T73 material, and its resistance to stress corrosion cracking is higher than that of T6 material. The static strength performance of the 7075 alloy is higher than that of the 2024 and 2124 alloys, and the fatigue performance is comparable to them. O-state and W-state materials have good room temperature formability.
7075 aviation super duralumin is not suitable for fusion welding, and its resistance welding adaptability is not as good as that of 2024 alloy. The heat treatment process of 7075 alloy parts is carried out according to GJB1694, and the solution treatment holding time should be ≥ 25min, otherwise satisfactory strength will not be obtained, although the parking time between solid solution and artificial aging has an impact on the mechanical properties of various products and various heat treatment states of the alloy Not much, but it is best to perform artificial aging at any time after 4h or 48h after solution treatment.
The surface treatment process of 7075 alloy is the same as that of other aluminum alloys, and the alloy has good cutting and grinding properties under heat treatment.
