24 July 2021 7000 Series Aluminum Alloy
7068 Aluminum Alloy Plate
7068 alloy is a 7000 series aluminium-zinc alloy registered with the US Aluminium Association and produced to AMS 4331 (chemical composition and mechanical properties) and AMS 2772 (heat treatment). 7068 alloy ‘A’ and ‘B’ tensile data and fatigue properties have been ratified for inclusion in MIL Handbook 5 / MMPDS. The standard supply temper condition is T6511. For applications requiring greater resistance to stress corrosion cracking
the T76511 condition is available to order.
The high-strength 7068 aluminum alloy was invented by Kaiser Aluminium & Chemical Comp., and has now been put into production by Advanced Metals International Group. The mechanical properties of this alloy are much higher than that of the traditional 7XXX series super alloys. Its yield strength is as high as 700N/mm2, which is 15%-20% higher than that of 7075 alloy. It can be used to manufacture valve bodies for aerospace vehicles and automobiles. Link rods, as well as bicycle and climbing equipment parts.
7068 aluminium alloy is one of the strongest commercially available aluminium alloys, with a tensile strength comparable to that of some steels. This material, also known as an aircraft alloy, is heat treatable.
7068-T6511 has typical ultimate tensile strength of 710 MPa (103 ksi) versus a similar product produced from 7075-T6511 that would have a typical ultimate tensile strength of 640 MPa (93 ksi). Typical yield strength for alloy 7068-T6511 is 683 MPa (99.1 ksi) versus 590 MPa (86 ksi) for a similar product produced from 7075-T6511. Strength allowables for this alloy are provided in Metallic Materials Properties Development and Standardization for design. The main alloying elements are zinc (7.3 to 8.3%), magnesium (2.2 to 3.0%), copper (1.6 to 2.4%) and zirconium (0.05 to 0.15%), with traces of silicon, iron, manganese, chromium, and titanium.
Chemical Composition:
| Chemical Elements | Metric | English |
|---|---|---|
| Aluminum, Al | 85.48 - 88.85 % | 85.48 - 88.85 % |
| Chromium, Cr | <= 0.050 % | <= 0.050 % |
| Copper, Cu | 1.6 - 2.4 % | 1.6 - 2.4 % |
| Iron, Fe | <= 0.15 % | <= 0.15 % |
| Magnesium, Mg | 2.2 - 3.0 % | 2.2 - 3.0 % |
| Manganese, Mn | <= 0.10 % | <= 0.10 % |
| Other, each | <= 0.050 % | <= 0.050 % |
| Other, total | <= 0.15 % | <= 0.15 % |
| Silicon, Si | <= 0.12 % | <= 0.12 % |
| Titanium, Ti | <= 0.10 % | <= 0.10 % |
| Zinc, Zn | 7.3 - 8.3 % | 7.3 - 8.3 % |
| Zirconium, Zr | 0.050 - 0.15 % | 0.050 - 0.15 % |
Mechanical Properties:
| Mechanical Properties | Metric | English | Comments |
|---|---|---|---|
| Hardness, Brinell | 190 | 190 | 500 kg, 10 mm |
| Tensile Strength, Ultimate | 710 MPa @Diameter 12.7 mm | 103000 psi @Diameter 0.500 in | |
| Tensile Strength, Yield | 683 MPa @Diameter 12.7 mm | 99100 psi @Diameter 0.500 in | |
| Elongation at Break | 9.0 % @Diameter 12.7 mm | 9.0 % @Diameter 0.500 in | 4D |
| Fracture Toughness | 16.5 MPa-m½ | 15.0 ksi-in½ | T-L |
| 27.5 MPa-m½ | 25.0 ksi-in½ | L-T | |
| Shear Strength | 365 MPa | 53000 psi |
Thermal Properties:
| Thermal Properties | Metric | English | Comments |
|---|---|---|---|
| CTE, linear | 23.4 µm/m-°C @Temperature 20.0 - 100 °C | 13.0 µin/in-°F @Temperature 68.0 - 212 °F | |
| Specific Heat Capacity | 1.05 J/g-°C @Temperature 100 °C | 0.250 BTU/lb-°F @Temperature 212 °F | |
| Thermal Conductivity | 190 W/m-K | 1320 BTU-in/hr-ft²-°F | |
| Melting Point | 476 - 635 °C | 889 - 1180 °F | |
| Solidus | 476 °C | 889 °F | |
| Liquidus | 635 °C | 1180 °F |