2024 aluminum is the aerospace high-strength alloy of the 2xxx series (copper-based). 6061 is the general-purpose 6xxx series (magnesium-silicon). 2024 is stronger but has serious corrosion issues and doesn't weld. 6061 is weaker but welds well and resists corrosion. Understanding when each applies prevents both over-spec and field failure.
| Property | 2024-T3 | 6061-T6 |
|---|---|---|
| Tensile strength | 485 MPa | 310 MPa |
| Yield strength | 345 MPa | 276 MPa |
| Elongation | 18% | 17% |
| Hardness | 120 HB | 95 HB |
| Density | 2.78 g/cm³ | 2.70 g/cm³ |
| Copper content | 3.8-4.9% | 0.15-0.4% |
| Fatigue strength (10⁷ cycles) | 140 MPa | 96 MPa |
| Weldability | Poor (cracks) | Excellent |
| Corrosion resistance (bare) | Poor (requires protection) | Good |
| Machinability rating | 70% | 50% |
| Cost ($/kg, plate) | $7-10 | $4-5 |
2024 is 56% stronger than 6061 at room temperature and has 45% better fatigue. That's why aerospace still specifies it. But the corrosion resistance and weldability problems make it inappropriate for most general applications.
2024's 4% copper content creates a dual-phase microstructure. Copper-rich precipitates form in the grain boundaries, creating galvanic cells between the precipitates (cathodic) and the adjacent aluminum matrix (anodic). Result: intergranular corrosion.
Without protection, 2024 in humid environments develops:
Solutions:
In aerospace, 2024 is always protected. In non-aerospace applications, 2024 is rarely worth the complexity.
Fuselage panels, wing skins, airframe components. Alclad 2024-T3 sheet is the industry standard. High strength + fatigue resistance critical for flight loads.
Fatigue-critical riveting and bolting. 2024 handles vibration and load cycles that would fatigue 6061 prematurely.
Compressor wheels (non-turbine), pump impellers that need light weight + strength. Protected from environment, 2024 delivers 56% more yield at minimal weight penalty.
When you need 6061-beating strength without the stress-corrosion concerns of 7075, 2024 is the middle ground. Better machinability than 7075. Used for tooling and fixtures.
2024 doesn't weld reliably. 6061 welds well with 4043 or 5356 filler. For any weldment, 6061 (or 5052 for better corrosion).
6061 forms passive oxide. 2024 requires active corrosion protection. For parts that will be unattended outdoors, 6061 is the safer default.
6061 (or better) for anything the consumer will touch or expose to weather. 2024 reserved for professional/aerospace applications.
Machine frames, brackets, plates. 6061 provides adequate strength for 95% of industrial applications at significantly lower cost and complication.
| Temper | Description | Used for |
|---|---|---|
| 2024-T3 | Solution heat-treated, cold worked, naturally aged | Standard aircraft sheet |
| 2024-T351 | T3 with stress-relieving stretch | Thick plate for machining |
| 2024-T4 | Solution heat-treated, naturally aged (no cold work) | General plate and bar |
| 2024-T6 | Solution heat-treated, artificially aged (higher strength) | Highest strength applications |
| 2024-T8 | Solution heat-treated, cold worked, artificially aged | Better corrosion resistance than T3 |
Email [email protected]. For aerospace AMS-certified 2024, we source certified material. For general structural, 6061 is usually the correct choice (and cheaper). We'll confirm based on your application.
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