Aluminum 6061 vs 7075: Which to Choose for Machined Parts
Aluminum 6061 is the default choice for general CNC parts: weldable, corrosion-resistant, and 30–40% cheaper than 7075. Choose 7075 only when you need maximum strength-to-weight (aerospace structural parts) — it is stronger but harder to machine, more expensive, and not weldable.
6061 and 7075 are the two most-specified aluminum alloys for machined parts. They look identical but behave very differently. Picking the wrong alloy can double your cost or cause part failure under load.
When to Choose 6061-T6
Use 6061-T6 for: - General mechanical parts and brackets - Welded fabrications (jigs, frames, enclosures) - Marine and outdoor parts (excellent corrosion resistance) - Anodized cosmetic parts (clean finish) - Cost-sensitive prototypes
When to Choose 7075-T6
Use 7075-T6 only when you need: - Maximum strength-to-weight ratio (aerospace structural) - High-stress machined fittings - Tooling and molds requiring hardness Avoid 7075 if the part will be welded, used in marine environments without coating, or anodized for cosmetic purposes (uneven finish).
Aluminum 6061-T6 vs 7075-T6 Properties
| Property | 6061-T6 | 7075-T6 |
|---|---|---|
| Tensile strength | 310 MPa | 572 MPa |
| Yield strength | 276 MPa | 503 MPa |
| Density | 2.70 g/cm³ | 2.81 g/cm³ |
| Machinability | Excellent | Good |
| Weldability | Excellent | Poor (do not weld) |
| Corrosion resistance | Excellent | Average |
| Anodizing quality | Excellent | Average |
| Cost (relative) | 1.0× | 1.4–1.7× |
Frequently asked questions
- Is 7075 always stronger than 6061?
- In tensile and yield strength, yes — 7075-T6 is roughly 1.8× stronger than 6061-T6. But 7075 is more brittle and has lower fatigue resistance in corrosive environments.
- Can I weld 7075 aluminum?
- No. 7075 is generally considered unweldable due to severe cracking risk. If your design requires welding, switch to 6061-T6 or 5052.
- Which aluminum is best for anodizing?
- 6061-T6 produces the cleanest, most uniform anodized finish. 7075 anodizes unevenly and is not recommended for cosmetic parts.
- How much more does 7075 cost than 6061?
- Material stock for 7075 is 40–70% more expensive than 6061. Combined with slower machining speeds, finished part cost is typically 1.5–2× higher.