Engineering · Comparison
The three most-cited aerospace aluminum alloys serve very different roles. 6061 is the workhorse. 7075 is the strength champion. 2024 is the fatigue champion. Picking between them is rarely a free choice — but understanding the differences helps when there's flex on the spec.
| Property | 6061-T6 | 7075-T6 | 2024-T3 |
|---|---|---|---|
| UTS | 310 MPa (45 ksi) | 572 MPa (83 ksi) | 470 MPa (68 ksi) |
| Yield | 276 MPa (40 ksi) | 503 MPa (73 ksi) | 324 MPa (47 ksi) |
| Density | 2.70 g/cc | 2.81 g/cc | 2.78 g/cc |
| Modulus | 68.9 GPa | 71.7 GPa | 73.1 GPa |
| Machinability | Excellent (90) | Good (70) | Good (80) |
| Weldability | Excellent | Poor | Poor |
| Corrosion (no anodize) | Good | Moderate | Poor |
| Anodize quality | Excellent | Good | Moderate |
| Fatigue resistance | Moderate | Good | Best (classic skin alloy) |
| Stress-corrosion | Best (T6 fine) | Worst (T7 needed) | Moderate |
| Cost ($/lb, Q1 2026) | $4–6 | $7–9 | $7–9 |
6061-T6
If the part doesn’t need 7075’s strength or 2024’s fatigue resistance, use 6061. Easy to machine, weldable, anodizes beautifully, corrosion-resistant. Covers the bulk of brackets, fixtures, drone airframe, and general structural work.
Common AMS: 4027 (sheet & plate), 4117 (bar/rod)
7075-T6 / T7
~85% higher tensile than 6061. Pick for high-load structural components — primary aircraft structure, weapon platforms, drone landing gear. T6 has SCC issues; for harsh environments, T7351 (overaged) trades strength for stability.
Common AMS: 4045 (sheet), 4078 (T7351 plate), 4124 (T7351 bar/rod)
2024-T3
Outstanding fatigue resistance from copper alloying. The classic aircraft fuselage and wing-skin alloy. Doesn’t weld; corrosion-prone without alclad surface. Pick when fatigue cycles dominate the design.
Common AMS: 4037 (sheet/plate)
Decision rule
~80% of structural aluminum jobs work fine in 6061. It’s cheaper, easier to machine, weldable, and anodizes the best. Don’t pay for 7075 if 6061 covers the load.
Specifically when 6061-T6’s 276 MPa yield isn’t enough. Use T7351 instead of T6 when stress-corrosion is a concern (marine, humid environments).
Aircraft skin, wing spars, repeating-load brackets. The copper alloying gives 2024 substantially better fatigue life than 6061 or 7075.
If you need long-term flatness and stability (optical mounts, metrology fixtures), neither 6061-T6 nor 7075 wrought plate is the right choice.
Keep exploring
Full properties for the structural-aluminum workhorse.
The high-strength aerospace alloy in detail.
The fatigue-resistant skin alloy in detail.
Speeds, feeds, and workholding for 6061.
Machining notes for the harder, stronger alloy.
When stability beats strength — MIC-6 / ATP-5 vs 6061.
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