Aluminium–zinc alloys
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Aluminium brass is a technically rather uncommon term for high-strength and partly seawater-resistant copper-zinc cast and wrought alloys with 55–66% copper, up to 7% aluminium, up to 4.5% iron, and 5% manganese. Aluminium bronze is technically correct as bronze, a zinc-free copper-tin casting alloy with aluminium content.
The term "special brass" is much more common for this, which then also includes alloys that add further characteristic elements to the copper-zinc base. In addition to the already mentioned elements of iron and manganese, lead, nickel and silicon can also be found as alloy components.
Due to their aluminium content, which is susceptible to oxidation at the usual melting temperatures in the range of 900 °C, the alloys require careful melting and melting treatment. Even when potting, attention must be paid to any oxides forming.
7000 series
[edit]7000 series are alloyed with zinc, and can be precipitation hardened to the highest strengths of any aluminium alloy. Most 7000 series alloys include magnesium and copper as well.
| Alloy | Al contents | Alloying elements | Uses and refs |
|---|---|---|---|
| 7005 | 93.3 | Zn 4.5; Mg 1.4; Mn 0.45; Cr 0.13; Zr 0.14; Ti 0.04 | Extrusions |
| 7010 | 93.3 | Zn 6.2; Mg 2.35; Cu 1.7; Zr 0.1; | Aerospace |
| 7022 | 91.1 | Zn 4.7; Mg 3.1; Mn 0.2; Cu 0.7; Cr 0.2; | plate, molds[1][2] |
| 7034 | 85.7 | Zn 11.0; Mg 2.3; Cu 1.0 | Ultimate tensile strength 750 MPa[3] |
| 7039 | 92.3 | Zn 4.0; Mg 3.3; Mn 0.2; Cr 0.2 | Aerospace armour plate |
| 7049 | 88.1 | Zn 7.7; Mg 2.45; Cu 1.6; Cr 0.15 | Universal, aerospace |
| 7050 | 89.0 | Zn 6.2; Mg 2.3; Cu 2.3; Zr 0.1 | Universal, aerospace |
| 7055 | 87.2 | Zn 8.0; Mg 2.3; Cu 2.3; Zr 0.1 | Plate, extrusions, aerospace[4] |
| 7065 | 88.5 | Zn 7.7; Mg 1.6; Cu 2.1; Zr 0.1 | Plate, aerospace[5] |
| 7068 | 87.6 | Zn 7.8; Mg 2.5; Cu 2.0; Zr 0.12 | Aerospace, Ultimate tensile strength 710 MPa |
| 7072 | 99.0 | Zn 1.0 | Sheet, foil |
| 7075 & 7175 | 90.0 | Zn 5.6; Mg 2.5; Cu 1.6; Cr 0.23 | Universal, aerospace, forgings |
| 7079 | 91.4 | Zn 4.3; Mg 3.3; Cu 0.6; Mn 0.2; Cr 0.15 | – |
| 7085 | 89.4 | Zn 7.5; Mg 1.5; Cu 1.6 | Thick plate, aerospace[6] |
| 7090 | Al-Zn-Mg-Cu with Co 1.5% | high strength, ductility and resistance to stress corrosion cracking[7] | |
| 7091 | Al-Zn-Mg-Cu with Co 0.4% | high strength, ductility and resistance to stress corrosion cracking[7] | |
| 7093 | 86.7 | Zn 9.0; Mg 2.5; Cu 1.5; O 0.2; Zr 0.1 | Aerospace |
| 7116 | 93.7 | Zn 4.5; Mg 1; Cu 0.8 | Heat-treatable |
| 7129 | 93.2 | Zn 4.5; Mg 1.6; Cu 0.7 | – |
| 7150 | 89.05 | Zn 6.4; Mg 2.35; Cu 2.2; O 0.2; Zr 0.1 | Aerospace |
| 7178 | 88.1 | Zn 6.8; Mg 2.7; Cu 2.0; Cr 0.26 | Universal, aerospace |
| 7255 | 87.5 | Zn 8.0; Mg 2.1; Cu 2.3; Zr 0.1 | Plate, aerospace[8] |
| 7475 | 90.3 | Zn 5.7; Mg 2.3; Si 1.5; Cr 0.22 | Universal, aerospace |
References
[edit]- ^ Placzankis, Brian E. (September 2009). General Corrosion Resistance Comparisons of Medium- and High-Strength Aluminum Alloys for DOD Systems Using Laboratory-Based Accelerated Corrosion Methods (Report). U.S. Army Research Laboratory. DTIC ADA516812; ARL-TR-4937. Retrieved 11 August 2018 – via Internet Archive.
- ^ Sahamit machinery 7022
- ^ "RSP alloys datasheet" (PDF). Archived from the original (PDF) on 2022-03-10. Retrieved 2023-02-25.
- ^ "7055 Alloy -T7751 Plate and -T77511 EXTRUSIONS" (PDF). Archived from the original (PDF) on 2017-12-22. Retrieved 2023-02-25.
- ^ "Aluminum alloy 7065" (PDF). Archived from the original (PDF) on 2017-12-22. Retrieved 2023-02-25.
- ^ "Aluminum alloy 7085 High strength, high toughness, corrosion-resistant thick plate" (PDF). Archived from the original (PDF) on 2017-12-22. Retrieved 2023-02-25.
- ^ a b Davis, Joseph R; Handbook Committee, ASM International (1 May 2000). "Cobalt". Nickel, cobalt, and their alloys. ASM International. p. 354. ISBN 978-0-87170-685-0.
- ^ "Aluminum alloy 7255-T7751 Very high strength, fatigue-resistant plate" (PDF). Archived from the original (PDF) on 2017-12-22. Retrieved 2023-02-25.
Further reading
[edit]- Publication series of the DKI, Berlin, number L5 "Copper-Zinc alloys".
- Foundry lexicon. 17. Edition, Schiele and Schön, Berlin, ISBN 3-7949-0606-3