7475 is an improved alloy of 7075 and 7175. It is basically a high-purity version of 7075, with lower iron and silicon content and slightly lower copper and magnesium upper limits. Chemical composition limitation reduces the amount of second phase components, resulting in higher fracture toughness at the same level of strength and corrosion resistance.
In the over-aged condition, 7475-T7x resists exfoliation and stress corrosion, which is associated with lower limits on silicon, iron, manganese and titanium content.
| Main composition | Zn | Mg | Cu | Cr | Si | Al |
|---|---|---|---|---|---|---|
| 7475 | 5.6 | 2.2 | 1.5 | 0.21 | Low | Balance |
| 7475 composition (wt.%) | Min | Max |
|---|---|---|
| Cu | 1.2 | 1.9 |
| Mg | 1.9 | 2.6 |
| Mn | -- | 0.06 |
| Fe | -- | 0.12 |
| Si | -- | 0.10 |
| Zn | 5.2 | 6.2 |
| Cr | 0.18 | 0.25 |
| Ti | -- | 0.06 |
| Other impurities | ||
| each | -- | 0.05 |
| total | -- | 0.15 |
| Al | Balance | |
Mechanical properties：
| Alloy | T.S. (MPa) | Y.S. (MPa) | Elongation (%) | Density (gcm3) |
|---|---|---|---|---|
| 7475-T7651 | 531 | 462 | 12 | 2.81 |
| 7475-T7351 | 496 | 421 | 13 | 2.81 |
Application：
It can be used for extruded profiles and general aircraft parts, missile parts, bars for forging, worm gears and other products.
References：
- AIWT, Aerospace Structural Metals Handbook, Nonferrous Alloys, 7475Al,
- Matweb, datasheet.
