AlZnMgCu

AlZnMgCu, commonly referred to as the 7xxx series, designates a family of aluminum alloys whose defining alloying elements are zinc as the primary additive with magnesium and copper as major contributors. This combination enables precipitation hardening, yielding high strength-to-weight ratios that are among the highest for non-heat-treated aluminum alloys. The term often appears in discussions of high-strength structural alloys used in demanding applications.

Typical composition ranges for these alloys place zinc around 5–7%, magnesium around 2–3%, and copper around 1–2%, with aluminum as the balance. Other elements such as chromium or zirconium may be added in small amounts to refine grain structure, improve toughness, and enhance corrosion resistance. Individual alloys within the family (for example, 7075 and 7050) have specific ranges and designations.

Strength is achieved primarily through solution heat treatment and artificial aging, designated by temper codes such as T6 (solution heat-treated and artificially aged). Other tempers, including T73, may be used to improve corrosion resistance or toughness at the expense of some strength. These alloys are heat-treatable but can be more challenging to weld and form than other aluminum families; friction stir welding is commonly employed for structural joints, and protective coatings or anodizing are used to mitigate corrosion.

Applications include aerospace structures, aircraft fittings, high-strength structural components, and performance-oriented consumer products (for example, bicycle frames). While offering exceptional strength, AlZnMgCu alloys require careful protection in corrosive environments and precise processing control to maintain and exploit their mechanical advantages.