24 July 2021 7000 Series Aluminum Alloy
7079 Aluminum Alloy Coil
7079 aluminium alloy (UNS designation A97079) is a high strength, heat treatable wrought aluminium alloy used in the aircraft industry. Age-hardening heat treatment enhances the characteristics of AL 7079, eliminating variations in characteristics seen in Aluminium 7075. Age-hardening heat treatment enhances the characteristics of Aluminum 7079, a high-strength alloy that eliminates variations in characteristics seen in Aluminum 7075. Aluminum 7079 has proven to be ideally suited for highly stressed parts and serves the aircraft industry.
Chemical Composition:
| Cu | Mg | Mn | Fe | Si | Zn | Ti | Cr | Other | Al |
|---|---|---|---|---|---|---|---|---|---|
| 0.4-0.8 | 2.9-3.7 | 0.1-0.3 | 0.4 | 0.3 | 3.8-4.8 | 0.10 | 0.1-0.25 | <0.15 | Balance |
Mechanical Properties:
| Hardness, Brinell | 150 | 150 | AA; Typical; 500 g load; 10 mm ball |
|---|---|---|---|
| Hardness, Knoop | 191 | 191 | Converted from Brinell Hardness Value |
| Hardness, Rockwell A | 53.5 | 53.5 | Converted from Brinell Hardness Value |
| Hardness, Rockwell B | 87 | 87 | Converted from Brinell Hardness Value |
| Hardness, Vickers | 175 | 175 | Converted from Brinell Hardness Value |
| Ultimate Tensile Strength | 572 MPa | 83000 psi | AA; Typical |
| Tensile Yield Strength | 503 MPa | 73000 psi | AA; Typical |
| Elongation at Break | 11 % | 11 % | AA; Typical; 1/16 in. (1.6 mm) Thickness |
| Elongation at Break | 11 % | 11 % | AA; Typical; 1/2 in. (12.7 mm) Diameter |
| Modulus of Elasticity | 71.7 GPa | 10400 ksi | AA; Typical; Average of tension and compression. Compression modulus is about 2% greater than tensile modulus. |
| Poisson's Ratio | 0.33 | 0.33 | |
| Fatigue Strength | 159 MPa | 23000 psi | AA; 500,000,000 cycles completely reversed stress; RR Moore machine/specimen |
| Fracture Toughness | 20 MPa-m½ | 18.2 ksi-in½ | K(IC) in S-L Direction |
| Fracture Toughness | 25 MPa-m½ | 22.8 ksi-in½ | K(IC) in T-L Direction |
| Fracture Toughness | 29 MPa-m½ | 26.4 ksi-in½ | K(IC) in L-T Direction |
| Machinability | 70 % | 70 % | 0-100 Scale of Aluminum Alloys |
| Shear Modulus | 26.9 GPa | 3900 ksi | |
| Shear Strength | 331 MPa | 48000 psi | AA; Typical |
Thermal Properties:
| CTE, linear 68°F | 23.6 µm/m-°C | 13.1 µin/in-°F | AA; Typical; Average over 68-212°F range. |
|---|---|---|---|
| CTE, linear 250°C | 25.2 µm/m-°C | 14 µin/in-°F | Average over the range 20-300ºC |
| Specific Heat Capacity | 0.96 J/g-°C | 0.229 BTU/lb-°F | |
| Thermal Conductivity | 130 W/m-K | 900 BTU-in/hr-ft²-°F | AA; Typical at 77°F |
| Melting Point | 477 - 635 °C | 890 - 1175 °F | AA; Typical range based on typical composition for wrought products 1/4 inch thickness or greater. Homogenization may raise eutectic melting temperature 20-40°F but usually does not eliminate eutectic melting. |
| Solidus | 477 °C | 890 °F | AA; Typical |
| Liquidus | 635 °C | 1175 °F | AA; Typical |
Process Properties:
| Annealing Temperature | 413 °C | 775 °F |
|---|---|---|
| Solution Temperature | 466 - 482 °C | 870 - 900 °F |
| Aging Temperature | 121 °C | 250 °F |
HEAT TREATMENT OF ALUMINUM 7079
- Solution treatment
- Aging treatment
- Annealing treatment
APPLICATIONS OF ALUMINUM 7079
- Aircraft parts, including wing panels and bulkhead assemblies
- Mobile industry equipment
- Hydraulic units
MACHINABILITY OF ALUMINUM 7079
- Alloy 7079 T-6 provides qualities comparable to alloy 7075-T6
- -F condition provides acceptable results
- Improved machinability compared to fabricated and annealed tempers
WORKABILITY OF ALUMINUM 7079
- Can be formed similar to 7075
- Annealing provides superior formability and noticeable decline in workability following solution heat treatment
- Form in “as-quenched” condition for best results