7075

7075 is a heat-treatable aluminum alloy in the 7xxx series, with zinc as the primary alloying element and substantial additions of magnesium and copper. It is regarded for one of the highest strength-to-weight ratios among common aluminum alloys, which makes it a preferred material for aerospace structural components, high-stress mechanical parts, and high-performance sporting goods. Typical composition includes zinc roughly 5–6%, magnesium about 2–3%, and copper around 1–3%, with small amounts of silicon, iron, chromium, and other elements to balance properties.

7075 is available in several tempers, most notably T6, which is solution heat treated and artificially aged to achieve high strength. Other common tempers include O (annealed) and T73, which offer improved corrosion resistance and dimensional stability at some expense to strength. The alloy is widely supplied in bars, plates, sheets, and extruded shapes.

In use, 7075 provides excellent strength and good machinability but has some limitations. It is more susceptible to stress corrosion cracking in certain environments than some other aluminum alloys, and its natural corrosion resistance is inferior to alloys such as 6061 when not coated. It is also less weldable, often requiring mechanical fastening or specialized welding approaches and post-weld treatment. Heat treatment and protective coatings can enhance performance where corrosion resistance and longevity are critical.

Common applications include aircraft components, gears, structural members, missile and space hardware, bicycle frames, and other high-strength, lightweight parts. The alloy’s high strength-to-weight ratio continues to drive its adoption in demanding applications, with attention to corrosion protection and fabrication methods.