Aluminium 7075 belongs to the 7xxx series, whose main alloying element is zinc. In the T6 temper it has one of the highest strengths of any aluminium alloy, which is why it is used in aerospace and heavily loaded parts.
Main chemical composition
- Zinc (Zn): about 5.1–6.1%
- Magnesium (Mg): about 2.1–2.9%
- Copper (Cu): about 1.2–2.0%
- Chromium (Cr): about 0.18–0.28%
Advantages
- A very high strength-to-weight ratio
- Good fatigue resistance
- Good machinability
Limitations
- Poor fusion weldability; usually joined with rivets or bolts
- Lower corrosion resistance than the 5xxx and 6xxx series
- More expensive than general-purpose alloys
Applications
Aircraft structural parts, plastic injection moulds, professional sports equipment, bicycle components and heavily loaded industrial parts.
To learn about the other series, read our guide to aluminium alloy series and the comparison of 6061 and 6063.