Alloy 6061 in Review
A member of the 6000 series, 6061 aluminum’s main alloying elements are magnesium and silicon, and it’s a great example of a jack of all trades. The alloy is somewhat universal, seeing some exposure in structural and building products as well as the aerospace and recreation industries.

Alloy 6061 displays good tensile strength, which can be improved by temper treatment, and good corrosion resistance, weldability, and workability. Its workability makes it the right choice for many extrusion projects, as it is easy to form.

The alloy is widely available at a relatively low cost and is a great option to produce varied and precise components in different shapes. Although alloy 6061 doesn’t rank first in any aluminum properties tier list, it’s a great and reliable all-around aluminum alloy to work with.
Alloy 7075 in Review
Aluminum 7075 is a member of the 7000 series, which has zinc as its main alloying component and is well known for its extraordinarily high strength. Tempering treatment can then further enhance its high mechanical strength. This property makes alloy 7075 very popular in the aerospace and defense industries.

Its strength is comparable to that of many types of steel, but it has a much lower density. The alloy is an excellent substitute to steel in high-stress applications. It also excels in withstanding fatigue stress, rendering it very reliable, a quality much sought after in the industries mentioned above.

Alloy 7075 offers only average corrosion resistance, an outcome of the small amount of copper included in its chemical composition. It also features reasonable machinability and poor forming and weldability. Another drawback of this alloy is that it has a comparatively high cost relative to other aluminum alloys due to its exceptionally high strength.

Applications of the 7075 and 6061 aluminum alloys differ significantly due to their unique physical properties.

Applications of 6061 Aluminum

General Fabrication: Due to its ability to be easily welded or shaped, this material is often used in general fabrication processes, such as creating frames, brackets, and other components widely used in various sectors, including the construction industry.
Auto Parts: It is used in car parts where good strength-to-weight ratio and resistance to corrosion are essential, such as wheels or chassis components.
Electrical Items: The good electrical conductivity of aluminium allows its use in electric fittings and connectors found throughout electrical systems and devices.
Building for Ships: Its anticorrosive properties make it suitable for boat hulls, ramps, and other marine structures.
Construction: Aluminum 6061 is used in building construction due to its high tensile strength-to-weight ratio, excellent durability, and appealing aesthetics. It is commonly found in materials such as window frames, doors, roofing systems, and architectural trims.

Applications of 7075 Aluminum

Aerospace Components: Wing spars, fuselage frames, and other components subject to heavy loads in aircraft structures demonstrate the significant advantages of 7075’s high strength and low weight.
Tooling and Mold Making: Molds and tooling where wear resistance is required perform well with this material due to its hardness and strength qualities.
Military Applications: Military applications, such as armored vehicles and military-grade weapon systems, utilize it for its high-strength properties.
Sporting Equipment: Bicycle frames, climbing gear such as carabiners or anchors, and baseball bats can benefit from their high strength-to-weight ratio, which enhances performance.
High-Stress Applications: Any application that requires a strong yet lightweight material while maintaining formability and weldability can benefit from using 7075.
Cost Considerations
Cost is an important factor to consider when choosing between 6061 and 7075 aluminum. Generally, 6061 is more cost-effective due to its easier production and versatility. In contrast, 7075, known for its superior strength, tends to be more expensive. Your budget constraints will significantly influence your decision.

6061 vs. 7075 Aluminum: Which One to Choose?

Choosing between aluminum alloys for CNC machining can be challenging. Both alloy grades possess high strength-to-weight ratios, making them excellent choices for various manufacturing applications and structural metal fabrication.
However, as with many other manufacturing considerations, your choice will depend on several factors. One major factor to consider is the intended application of the final product. Additional factors include budget and manufacturing conditions.
6061 aluminum alloy is highly versatile, making it suitable for various structural applications. It is the ideal choice when machining, welding, or forming is required.
If corrosion is a concern in outdoor applications, 6061 aluminum is the better choice between the two. Additionally, extruding complex shapes from aluminum is more effectively done with 6061, especially when working with a limited budget.
On the other hand, a key characteristic of aluminum 7075 is its increased strength. As a result, it is a better choice when you require a material with very high tensile strength. This strength is complemented by excellent wear resistance and a high strength-to-weight ratio.
Choosing the 7075 alloy is the best option if you need to expose the component to heat or if there is significant friction involved. If cost is not a primary concern, this would be the ideal choice.
Conclusion
Ultimately, the choice between Aluminum 6061 and 7075 is up to the specific requirements of your project. To determine which alloy is best suited for your needs, consider factors such as composition, strength, machinability, applications, cost, and yield strength. Both alloys have unique strengths, and by evaluating the demands of your project, you can make a wise decision that will help to your success in the chosen application.