EN AW 7075 and EN AW 2017A are two high-strength grades of aluminium. Both are used in aerospace and both harden by heat treatment — but they rely on different main alloying elements.
Zinc, or copper?
7075 is a 7000 series alloy: its main alloying element is zinc (5.10–6.10%), alongside 2.10–2.90% magnesium and 1.20–2.00% copper. The zinc–magnesium system gives the highest strength attainable in aluminium.
2017A is a 2000 series alloy: its main element is copper (3.50–4.50%), alongside 0.40–1.00% magnesium and manganese. Copper-based alloys are not as strong as the 7000 series but they machine better and are more stable at high temperature.
The difference on our datasheets is clear: the yield strength of 7075 is 410 MPa and its tensile strength 510 MPa. In 2017A those are 270 and 390 MPa. 7075 is also heavier (2.81 against 2.79 g/cm³) and gives lower elongation (8% against 15%).
Both alloys are considered non-weldable; joining is done with rivets or bolts. The classic form of use for 2017A is in fact the rivet.
Comparison in numbers
| PROPERTY | EN AW 7075 | EN AW 2017A |
|---|---|---|
| Zinc (Zn) | 5.10 – 6.10% | max 0.25% |
| Copper (Cu) | 1.20 – 2.00% | 3.50 – 4.50% |
| Magnesium (Mg) | 2.10 – 2.90% | 0.40 – 1.00% |
| Manganese (Mn) | max 0.30% | 0.40 – 1.00% |
| Chromium (Cr) | 0.18 – 0.28% | max 0.10% |
| Silicon (Si) | max 0.40% | 0.20 – 0.80% |
| Iron (Fe) | max 0.50% | max 0.70% |
| Tensile strength | 510 MPa | 390 MPa |
| Yield strength | 410 MPa | 270 MPa |
| Shear strength | 300 MPa | — |
| Elongation | 8% | 15% |
| Density | 2.81 g/cm³ | 2.79 g/cm³ |
| Modulus of elasticity | 72 GPa | 72 GPa |
| Thermal conductivity | 155 W/m·K | 140 W/m·K |
| Electrical conductivity | 33% IACS | — |
| AMS | 4078 · 4124 | 4110 · 4116 · 4118 |
Values are taken from our product datasheets; section thickness and the applied heat treatment regime change the result.
Which one, and when?
EN AW 7075 is required — aircraft structural members, wing and fuselage frames, defence industry parts, high-performance mould plates, racing car components, weapon parts. Anywhere the highest strength attainable in aluminium is wanted.
EN AW 2017A is preferred — rivets and fasteners, machined components, hydraulic parts, medium-strength aerospace parts. Its machinability is very good and it is more economical than 7075.
Note: 7075 is susceptible to stress corrosion cracking; for critical applications overaged tempers such as T73 or T7351 are therefore preferred.
Neighbouring grades
For lower strength but weldability, see our EN AW 6082 – 6060 comparison; for marine environments, EN AW 5083.
Technical datasheets
EN AW 7075 — chemical composition, mechanical values, standard equivalents
EN AW 2017A — chemical composition, mechanical values, standard equivalents
Both grades are supplied to order in round bar, flat bar, plate, sheet, pipe and forged forms. Contact us for a quotation.