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Aluminum 6061 vs 7075

Two of the most popular aluminum alloys for high-strength, low-weight applications are the 6061 aluminum alloy and 7075 aluminum alloy.

When comparing the two on paper, the incredible strength of 7075 aluminum—almost twice that of 6061 aluminum—is often the major difference that jumps off the page.

Additionally, both alloys exhibit good heat dissipation properties, making them suitable for applications where higher thermal conductivity is important.

While 7075 aluminum is one of the highest strength aluminum alloys available, 6061 aluminum is more versatile and heat treatable, allowing for improved properties through heat treatment processes.

Other important differences in 6061 vs 7075 aluminum make them suitable for very different applications in the aerospace and defense industries.

In this post, we’ll compare the chemical composition, manufacturability, and applications of aluminum 6061 vs. 7075 so you can decide which one is best for your project.

Comparing 6061 vs. 7075 Aluminum

Aluminum alloys can have very different properties based on their chemical composition. The main alloying elements of 6061 aluminum are silicon and magnesium, while 7075 is alloyed with zinc, magnesium, and copper.

Strength and Hardness

7075 aluminum alloy has one of the highest strength to weight ratio of any aluminum alloy, so this alloy is primarily used by the aerospace and defense industries.

It is comparable to many grades of steel in tensile strength. It’s also much harder than 6061 aluminum.

However, although the strength of 6061 aluminum alloy is only about half that of 7075, it is still strong enough for many applications in the construction, aerospace, and automotive industries.

Corrosion Resistance

One of the biggest drawbacks of 7075 aluminum compared to 6061 is its inferior corrosion resistance due to the presence of copper as an alloying element.

There is a higher aluminum content in 6061 than in 7075 aluminum alloy, and 6061 also contains less copper, so it forms a more consistent protective oxide layer that protects it against corrosion.

Working with 6061 vs. 7075

While 7075 aluminum is one of the strongest aluminum alloys, 6061 aluminum is much easier to work with. The exceptional tensile strength and hardness of 7075 also make cutting and forming difficult.

Welding

Because of its higher ductility, 6061 is much easier to form and weld than 7075. While 6061 aluminum is easily weldable and can withstand higher temperatures, 7075 is prone to welding defects like heat cracking and is generally considered unweldable.

This is an important consideration if parts will need to be joined, as 7075 can only be joined with rivets or other fasteners.

Machining

Both 6061 and 7075 have good machinability. However, because it’s not as hard, 6061 is more easily machined than 7075 aluminum.

Manufacturers and fabricators consider 6061 the go-to aluminum alloy for most machined parts because of its balance of machinability, strength, and other desirable mechanical properties.

Applications of 6061 Aluminum vs. 7075 Aluminum

Aluminum 6061 is an extremely versatile aluminum alloy and is suitable for a wide range of structural applications. It is particularly useful when:

  • Welding will be required.
  • Corrosion resistance is needed.
  • Cost is an important factor.

However, 7075 aluminum might be a better choice when:

  • A maximum strength-to-weight ratio is needed.
  • Parts will not need to be welded.
  • Cost is less of a concern.

7075 aluminum alloy is extraordinarily strong, but that extra strength comes with a higher price tag. Because of this, it should usually not be used when 6061 has sufficient strength for the application.

However, 7075 aluminum is useful for high-stress structural components like gears and shafts, especially in aircraft where weight is critical.

Mechanical Properties of the 6061 and 7075 Aluminum Alloy

For a quick comparison, the properties of both aluminum 6061 and 7075 aluminum are listed in the table below.

Property Aluminum 6061 Aluminum 7075
Ultimate Tensile Strength 45 ksi 83 ksi
Yield Strength 40 ksi 73 ksi
Shear Strength 31 ksi 48 ksi
Brinell Hardness 95 150
Machinability Good Fair
Formability Good Poor
Weldability Good Poor
Electrical Resistivity 3.99 x 10^-8 Ω·m 5.10 x 10^-8 Ω·m

Where to Buy 6061, 7075, and Other Aluminum Alloys

Industrial Metal Service specializes in supplying 6061, 7075, and a variety of other aluminum alloy options to machine shops, fabricators, and manufacturers in the San Francisco Bay Area. We also ship to a growing number of customers across the U.S. who don’t have the benefit of a local supplier.

We stock an extensive inventory of pure aluminum metal alloys, including 6061 and 7075, and offer customers the option of buying new metal sourced from U.S. mills or verified remnants, which offer considerable savings. We also provide cut-to-size sawing services.

Published by IMS Team

Industrial Metal Service has decades of experience and over 1.1 billion pounds of metal sold and recycled. Our founder, Jeff, has spent his life in the industry and prides himself on offering fair, efficient, trustworthy, knowledgeable, outstanding customer service. We offer metal salesmetal recycling pickup service, and other associated services, such as precise metal sawing, machinery teardown, and warehouse cleanupGive us a call and we’ll get it done.