2618 is a wrought aluminum alloy that can be age-hardened heat treatment. It was originally developed for forging applications. Mainly used in the aircraft industry in the form of forgings. It has moderate strength and ductility, good general corrosion resistance, high temperature properties, and formability and machinability. Optimal composition and heat treatment methods improve resistance to intergranular corrosion. The room temperature strength of 2618 alloy is better than 2014-T6, but slightly lower than 7075-T6.
The solution heat treatment of forgings is 510 to 521oC, holding for at least 6 hours, and quenching in boiling water. The aging conditions of T61 are 182 to 187oC for 20 hours.
| Main composition | Cu | Mg | Ni | Fe | Si | Ti | Al |
|---|---|---|---|---|---|---|---|
| 2618 | 2.5 | 1.5 | 1.2 | 1.0 | 0.2 | 0.1 | Balance |
| 2618composition (wt.%) | Min | Max |
|---|---|---|
| Cu | 1.9 | 2.7 |
| Fe | 0.9 | 1.3 |
| Mg | 1.3 | 1.8 |
| Ni | 0.9 | 1.2 |
| Si | -- | 0.25 |
| Ti | 0.04 | 0.10 |
| Other impurities | ||
| each | -- | 0.05 |
| total | -- | 0.15 |
| Al | Balance | |
Mechanical properties：
| Alloy | T.S. (MPa) | Y.S. (MPa) | Elongation (%) | Density (gcm3) |
|---|---|---|---|---|
| 2618-T61 | 441 | 372 | 10 | 2.76 |
| 2618-T61 Die forging-axial | 400 | 310 | 4 | 2.76 |
Application：
2618 alloy can be used in large aircraft engine parts and compressor blades.
References：
1.AIWT, Aerospace Structural Metals Handbook, Nonferrous Alloys, 2618Al
2.Matweb, datasheet.
