7075-T6 Aerospace Aluminum: High-Strength Zn-Mg-Cu Alloy
ASTM B209/B211 · Updated: 2026-05-25
7075-T6 is a high-strength aluminum-zinc alloy developed for aerospace, with 5.1-6.1% zinc as the primary alloying element. Its yield strength of 503 MPa rivals many structural steels at one-third the weight, making it the preferred material for aircraft fuselage frames, wing spars, and high-performance bicycle components. However, 7075 has significantly lower corrosion resistance than 6061 and is generally considered unweldable by fusion welding—friction stir welding is the preferred joining method. For corrosion protection, 7075 is often clad with pure aluminum (Alclad) or anodized. Not recommended for marine environments without protective coating systems.
Quick Facts
| Category | Aluminum Alloy |
| Standard | ASTM B209/B211 |
| Density | 2.81 g/cm³ |
| Yield Strength | 503 MPa (73 ksi) |
| Tensile Strength | 572 MPa (83 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN AW-7075 | Compare |
| AlZn5.5MgCu | Compare |
| A7075 | Compare |
| AA7075-T6 | Compare |
| ISO AlZn5.5MgCu | Compare |
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Frequently Asked Questions
Why can't 7075 aluminum be welded?
7075 is highly susceptible to hot cracking during fusion welding due to its high zinc and copper content creating a wide solidification range. The HAZ also experiences severe over-aging, losing up to 50% strength. Friction stir welding is the only commercially viable welding method for 7075. For weldable high-strength aluminum, consider 7020 or 2219 instead.