Which is better 6061 or 7075 aluminum?

Which is better 6061 or 7075 aluminum?

When it comes to the age-old question of deciding between using 6061 aluminum alloy or 7075 aluminum alloy for a project or task, understanding their differences and application ranges can go a long way and save you the trouble when looking to balance performance with cost. For most general purposes, both alloys may be able to get the job done but the differences in composition, mechanical properties and cost between both alloys can help you determine which of the two is the best choice for your structural needs. In this post, let’s discuss the general similarities and differences between 6061 and 7075 aluminum alloys.

Composition Differences
When it comes to compositional differences between 6061 and 7075 aluminum, the differences aren’t visible at first glance. Sure, both contain the same alloy agents such as magnesium, silicon, copper, iron, zinc, titanium, manganese and chromium, but the biggest distinction isn’t what’s in your aluminum plate or square rod but rather, how much is in your material.

For instance, 6061 aluminum alloy contains less zinc than its 7075 counterpart, meaning that while 6061 alloys provide superior welding abilities and workability over other alloys, it doesn’t boast the same high strength and stress resistance as 7075 offers.

aluminum square materials

Applications for 6061 and 7075 Aluminum Alloy
As is the case with many similar materials, 6061 and 7075 aluminum can be used in many of the same tasks and can often be swapped out when costs and risks are deemed suitable to go with a less expensive option such as 6061. That being said, here are general guidelines for uses for each alloy – when making a decision on your material needs, consider these points as a general overview for applications:

6061 Aluminum Alloy Applications
6061 aluminum is highly versatile and can be used for almost any structural component. Commercial and personal use vehicles utilize 6061 for truck frames and running boards, infrastructural uses include mass transit and subway platforms, steps, flooring, walkways and cover plates, and consumer products such as bicycle frames and components, SCUBA tanks, fishing reels and small utility boats all benefit from the increased weldable nature and its ability to undergo hot forging.


7075 Aluminum Alloy Applications
Because of its high strength-to-weight ratio and improved strength over 6061 alloys, 7075 is largely used in aerospace, marine and transportation industries where strength and light weight properties are critical. High-end bicycle components, molding materials for the plastics and tool industries, glider and hobby-grade airframes and even numerous military applications including assault rifle receivers and precision rifles all benefit from the high polish and improved thermal properties that 7000-series alloys provide.

Mechanical Properties of Aluminum
Generally speaking, aluminum is the second most widely used metal in the world and its physical properties (and its abundance on Earth) explain why. With such traits as low density/low weight, high strength, easier machining and malleability, superb resistance to corrosion and ideal electrical and thermal conductivity, it’s easy to see why aluminum is in demand for metalworkers and numerous industrial applications. While there are numerous alloys and even more temper options available, let’s compare 6061 and 7075 aluminum alloys of the T651 temper variety for a quick side by side:

General Mechanical Properties of 6061 Aluminum (T651 Bare)
Tensile Strength – 45,000 psi
Yield Point – 40,000 psi
Brinell Hardness – 95
Elongation at Break – 12%
Shear Strength – 31,000 psi
Thermal Conductivity – 170 W/m-K
Strength to Weight Ratio: 115 kN-m/kg

General Mechanical Properties of 7075 Aluminum (T651)
Tensile Strength – 83,000 psi
Yield Point – 74,000 psi
Brinell Hardness – 150
Elongation at Break – 10%
Shear Strength – 48,000 psi
Thermal Conductivity – 130 W/m-K
Strength to Weight Ratio: 196 kN-m/kg

Summary – 6061 vs 7075 Aluminum Alloy
In general, when looking to compare 6061 versus 7075 aluminum alloys, 6061 is considered by many to be highly versatile for a wide variety of general purpose mechanical applications. 7075 is one of the strongest aluminum alloys available and while its increased cost and tougher workability may come across as obstacles, 7075 alloys are worth their price tag when it comes to applications in which its increased strength and toughness are crucial.