Guides/Comparisons
6061 vs 7075 aluminium
6061-vs-7075-aluminiumAluminium alloy 6061 and Aluminium alloy 7075-T6 at a glance
This page compares Aluminium alloy 6061 and Aluminium alloy 7075-T6 using only values that carry a source, a test condition and an evidence level. Ranges run across temper, heat treatment and product form, measured at room temperature where the source says so.
- Composition: Magnesium (6061 0.8 to 1.2%; 7075 2.5%), Copper (6061 0.15 to 0.4%; 7075 1.6%), Chromium (6061 0.04 to 0.35%; 7075 0.3%).
- Yield strength: 7075 is higher (6061 276 MPa; 7075 503 MPa), about 1.8 times the midpoint of 6061.
- Tensile strength: 7075 is higher (6061 310 MPa; 7075 572 MPa), about 1.8 times the midpoint of 6061.
- Density: 7075 is higher (6061 2.7 g/cm³; 7075 2.8 g/cm³), a difference of under 10% at the midpoint.
- Young's modulus: 7075 is higher (6061 68.9 GPa; 7075 71 to 71.7 GPa), a difference of under 10% at the midpoint.
- Thermal conductivity: 6061 is higher (6061 167 W/(m·K); 7075 130 W/(m·K)), about 1.3 times the midpoint of 7075.
- Thermal expansion: the ranges overlap (6061 23.6 ppm/K; 7075 23.4 to 23.6 ppm/K).
- Yield strength for each unit of density (calculated from each grade's midpoint values): Aluminium alloy 6061 102 MPa per g/cm³; Aluminium alloy 7075-T6 180 MPa per g/cm³.
"Higher" means the whole range is higher, not just one value. Where a value is a specified minimum, the table says "at least".
Side by side
| Property | Aluminium alloy 6061 | Aluminium alloy 7075-T6 |
|---|---|---|
| Yield strength | 276 MPa | 503 MPa |
| Tensile strength | 310 MPa | 572 MPa |
| Density | 2.7 g/cm³ | 2.8 g/cm³ |
| Young's modulus | 68.9 GPa | 71 to 71.7 GPa |
| Thermal conductivity | 167 W/(m·K) | 130 W/(m·K) |
| Melting point | no data | 532 to 635 °C |
| Thermal expansion | 23.6 ppm/K | 23.4 to 23.6 ppm/K |
| Yield strength per densitycalculated | 102 MPa per g/cm³ | 180 MPa per g/cm³ |
Composition
| Element | Aluminium alloy 6061 | Aluminium alloy 7075-T6 |
|---|---|---|
| Aluminium | balance | balance |
| Magnesium | 0.8 to 1.2% | 2.5% |
| Silicon | 0.4 to 0.8% | not listed |
| Copper | 0.15 to 0.4% | 1.6% |
| Chromium | 0.04 to 0.35% | 0.3% |
| Zinc | not listed | 5.6% |
Shares are as printed in the sources, by weight.
When to use which
| Material | Best for | Weakest at |
|---|---|---|
| Aluminium alloy 6061 | A light, workable structural metal with good corrosion resistance (the NASA handbook ranks 6061 best of the heat-treatable aluminium alloys for corrosion) | Galvanic attack when coupled to more noble metals, especially in sea water (NASA handbook); typical strength values are marked not for design |
| Aluminium alloy 7075-T6 | High-strength aluminium parts where low mass and wrought forms such as tube, plate, bar or forging are useful | Stress-corrosion cracking in the short-transverse direction in T6, and relatively poor corrosion resistance in industrial and marine environments |
Where each is used
| Material | Use |
|---|---|
| Aluminium alloy 6061 | Launch vehicle and spacecraft structures (aluminium alloys, 6061 named as a structural alloy) |
| Aluminium alloy 6061 | Simulated propellant tanks of 6061-T3 sheet (ground impact tests, not flown) |
| Aluminium alloy 6061 | Fittings, couplings, hinge pins, valves and valve parts, and hydraulic and brake pistons |
| Aluminium alloy 7075-T6 | Aircraft structures and airframe parts |
| Aluminium alloy 7075-T6 | High-pressure hydraulic units |
| Aluminium alloy 7075-T6 | Launch vehicles and spacecraft |