7075 Aluminum: Get to Know its Properties and Uses

by | Aluminum Alloys, Aluminum Extrusion Design, Aluminum Extrusions, Blog

Alloy selection is important for extrusion projects, and in the aerospace industry, the 7075 aluminum alloy is commonly used.

With zinc as it’s primary alloying element, it is exceptionally strong. A member of the 7000 series, it is one of the strongest alloys available and is comparable to many types of steel. Although it has high strength, it has lower corrosion resistance than other common aluminum alloys and does not offer the same levels of machinability or weldability.

Due to its high strength, it is often used in applications where it will come under high stress such as aircraft wing spar and ground support equipment.

Here are Some General Characteristics of 7075

This alloy features high strength, with average corrosion resistance, poor weldability and workability. It is also fairly machinable. Download a PDF of its characteristics and material properties.

CharacteristicAppraisal
StrengthHigh
Corrosion ResistanceAverage
Weldability & BrazabilityPoor
WorkabilityPoor
MachinabilityFair

This alloy is generally solution heat treated to further enhance its high-strength properties.

Material Properties of 7075-O, 7075-T6, 7075-T73 Aluminum

Some of the most common tempering options for this alloy are O, T6, and T73.

Physical Properties of 7075 Aluminum

Here we can see the density of the alloy. Note that there is no difference in density between the different tempers.

Property7075-O7075-T6, -T6517075-T73, -T7351
Density2.81 g/cc | 0.102 lb/in³2.81 g/cc | 0.102 lb/in³2.81 g/cc | 0.102 lb/in³

Mechanical Properties of 7075 Aluminum

Here we can see the tensile strength, yield strength, and modulus of elasticity for the alloy in the -O, -T6, and -T73 conditions.

Property7075-O7075-T6, -T6517075-T73, -T7351
Tensile Strength228 MPa | 33000 psi572 MPa | 83000 psi505 MPa| 73200 psi
Yield Strength103 MPa | 15000 psi503 MPa | 73000 psi435 MPa | 63100 psi
Modulus of Elasticity71.7 GPa | 10400 ksi71.7 GPa | 10400 ksi72.0 GPa | 10400 ksi

Thermal Properties of 7075 Aluminum

Here we can see some thermal properties of the alloy including the coefficient of thermal expansion and thermal conductivity. The Annealed, T6, and T73 conditions are included.

Property7075-O7075-T6, -T6517075-T73, -T7351
Coefficient of Thermal Expansion @ 20.0 - 100 °C Temp23.4 µm/m-°C | 13.0 µin/in-°F23.4 µm/m-°C | 13.0 µin/in-°F23.4 µm/m-°C | 13.0 µin/in-°F
Thermal Conductivity173 W/m-K | 1200 BTU-in/hr-ft²-°F0.960 J/g-°C | 0.229 BTU/lb-°F155 W/m-K | 1080 BTU-in/hr-ft²-°F

Note: The material properties above have been pulled from Matweb, here, here, and here. Please note that they cannot be 100% verified.

Now, you may be wondering about the composition of the 7075 alloy.

Chemical Composition of 7075 Aluminum

This alloy is part of the 7000 series of alloys. As such, its major alloying element is zinc. Zinc is added to increase strength. It also contains chromium and copper. Here we can see the guidelines for the chemical composition of 7075 aluminum.

ElementMinimum %Maximum %
SiliconNo Min0.4
IronNo Min0.5
Copper1.22
ManganeseNo Min0.3
Magnesium2.12.9
Chromium0.182
Zinc5.16.1
TitaniumNo Min0.2
Other ElementsNo Min0.05 each
0.15 in total

Now that we’ve seen the chemical composition of 7075, let’s talk about how the alloy compares to some other key options.

Comparing 7075 Aluminum to Other Alloys

The 7075 alloy is often chosen for applications that require high strength, but you may be considering other options for your particular application. Below are some other common alloys that are often considered as alternatives.

7075 vs 2024

Airplane Flying From Nose ViewMuch like the 7075 alloy, 2024 aluminum is commonly used in aerospace applications. In particular, it is often used in aircraft wings and fuselages. It’s high strength lends well to these applications. 2024 is suited to applications where high cyclic fatigue resistance is required. Whereas, 7075 is suited to applications that require high stress/strain resistance.

Both of these alloys offer similar weldability. Spot or flash welding can be used, but arc and gas welding are not recommended. They also both offer similar machinability. 2024 has slightly better workability, while 7075 has slightly better corrosion resistance.

7075 vs 6061

Round Aluminum Tube6061 aluminum is commonly referred to as “structural” aluminum. It is often used in construction and is commonly used to extrude aluminum bars, pipes, rods, and tubes. It is also highly versatile, being used for bicycle frames, electrical fittings, and heat sinks. It has better general characteristics than 7075, with higher corrosion resistance, weldability, and machinability. But it does not have the same high strength that 7075 aluminum has. Where strength is the most important consideration, 7075 can be the optimal choice.

Summary

The most important benefit of 7075 aluminum is its high strength. While it does not have the same level of corrosion resistance or weldability that other common alloys due, its resistance to stress and strain makes it highly useful in aerospace applications where it allows for weight savings over steel.

Download our PDF on 7075 aluminum properties to keep as a reference. And if you need an aluminum extrusion supplier in Asia, learn more about our capabilities.

Looking for an Aluminum Extrusion Supplier in Asia?

We help OEMs save costs by producing quality extrusions in Asia.

Take a look at our aluminum extrusions page to learn more about our partner facilities in India. We offer high quality, on-time delivery, and great service.

Get High-Quality Extrusions for Your OEM Project