What Is 7075-T6 Aluminum?
7075 aluminium alloy, with zinc as its primary alloying element, is widely known as aircraft aluminium or aerospace aluminium. It was the first high-strength Al-Zn-Mg-Cu alloy to successfully incorporate chromium, significantly improving resistance to stress-corrosion cracking in sheet products.
The chemical composition of 7075 aluminium consists of approximately 87.1–91.4% aluminum and 5–6% zinc, along with 2.1–2.9% magnesium and 1.2–2% copper. Minor elements such as silicon, titanium, chromium, iron, manganese, and others are each limited to no more than 0.5%.
7075-T6 aluminium refers to the 7075 alloy in the T6 temper. This condition is achieved through solution heat treatment, homogenization of the cast alloy at around 450°C for several hours, rapid quenching, and subsequent artificial aging at 120°C for approximately 24 hours. At this stage, the alloy reaches its standard mechanical property requirements and achieves peak strength.
What Makes 7075 Aluminium Stand Out Among Aluminium Alloys?
The alloying system of the 7075 series results in the highest strength among commercially available aluminum alloys, making its mechanical performance comparable to that of many steels. While its exceptional strength is one of its most notable advantages, it is the combination of properties-low density, excellent machinability, and good corrosion resistance-that makes 7075 aluminium particularly suitable for highly stressed structural components.
It should be noted that, compared with other aluminum alloys, the corrosion resistance of 7075 is relatively limited. However, it still performs significantly better than many alloys in the 2000 series.
In many applications, 7075 aluminium is considered alongside 2024 aluminium. When higher mechanical performance is required, 7075 remains the preferred choice.
7075 Aluminium Basic Properties
Density: 3.0 g/cm³ (190 lb/ft³)
Machinability: Excellent
Can be formed in the annealed condition and subsequently heat treated
Due to its high strength, springback during forming is greater than that of many other aluminium alloys
If forming difficulties arise in the annealed state, formability can be improved by heating the material to 95–120°C (200–250°F).
7075-T6 Aluminium Mechanical Properties
Brinell Hardness: 150
Elastic (Young's) Modulus: 70 GPa
Ultimate Tensile Strength (UTS): 560 MPa
Yield Strength: 480 MPa
Elongation at Break: 7.9%
Fatigue Strength: 160 MPa
Poisson's Ratio: 0.32
Shear Modulus: 26 GPa
Shear Strength: 330 MPa
7075-T6 Aluminium Thermal Properties
Melting Onset (Solidus): 480 °C (890 °F)
Specific Heat Capacity: 870 J/kg·K (0.21 BTU/lb·°F)
Thermal Conductivity: 130 W/m·K (75 BTU/h·ft·°F)
Thermal Expansion: 23 µm/m·K
7075-T6 Aluminium Electrical Properties
Electrical Conductivity (Equal Volume): 33% IACS
Electrical Conductivity (Equal Weight): 98% IACS
