2024-T3 Aerospace Aluminum: High-Strength Cu-Mg Alloy
ASTM B209 / AMS 4037 · Updated: 2026-05-25
2024-T3 is a high-strength aluminum-copper-magnesium alloy (3.8-4.9% Cu, 1.2-1.8% Mg) providing superior fatigue resistance and fracture toughness—the primary aircraft fuselage skin material for over 70 years. It achieves strength through natural aging at room temperature after solution treatment (T3 temper). However, 2024 has poor corrosion resistance and must be protected by cladding with pure aluminum (Alclad 2024) or anodizing for service. Not weldable by conventional methods; joining is by rivets, fasteners, or adhesive bonding. The benchmark material for damage tolerance in aerospace design.
Quick Facts
| Category | Aluminum Alloy |
| Standard | ASTM B209 / AMS 4037 |
| Density | 2.78 g/cm³ |
| Yield Strength | 345 MPa (50 ksi) |
| Tensile Strength | 483 MPa (70 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN AW-2024 | Compare |
| AlCu4Mg1 | Compare |
| A2024 | Compare |
| AA2024-T3 | Compare |
| ISO AlCu4Mg1 | Compare |
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Frequently Asked Questions
Why is 2024 used for fuselage skin instead of 7075?
2024 offers superior fatigue crack growth resistance and fracture toughness—critical for fuselage skins that must withstand repeated pressurization cycles over decades of service. A small crack in 2024 grows slower and more predictably than in 7075. 7075 is used where ultimate strength governs (wing upper skins under compression), while 2024 is chosen where fatigue and damage tolerance govern (fuselage skins under tension from pressurization).