6061 and 7075 are the two most common aluminum alloys, but they serve very different roles. 6061 is the versatile workhorse; 7075 is the high-strength aerospace alloy.
| Property | undefined | undefined |
|---|---|---|
| Yield strength | 276 MPa (40 ksi) | 503 MPa (73 ksi) |
| Tensile strength | 310 MPa (45 ksi) | 572 MPa (83 ksi) |
| Density | 2.70 g/cc | 2.81 g/cc |
| Weldability | Excellent | Poor |
| Corrosion resistance | Good | Fair |
| Machinability | Good | Good |
| Cost | Lower | Higher |
| Typical use | General structural, frames | Aerospace, high-stress parts |
Which should you choose
Choose 6061 for general fabrication where you need to weld, bend, or resist corrosion at a reasonable cost. Choose 7075 when strength-to-weight is critical and the part can be machined rather than welded.
7075 is roughly 80 percent stronger but gives up weldability and some corrosion resistance, and it costs more.
Strength versus weldability. 7075 wins on raw strength; 6061 wins on welding, corrosion, and cost. Match the alloy to whether the part is welded or machined.
Compare data sheets: 6061-T6 Aluminum and 7075-T6 Aluminum.