If you walk down the street, you will see many aluminum alloy products. They are among the most popular materials in the automotive, sports equipment, electrical, construction and aerospace industries due to their excellent strength-to-weight ratio, high relative strength and corrosion resistance. With the wide variety of aluminum alloys available, it can be difficult to choose the right one for your project. This article compares two common aluminum alloys, 6061 and 7075, from several perspectives, including composition, mechanical properties, and cost, and we hope to help you decide which fits your project.
What is 6061 grade aluminum?
If you ask the question: What is the most used aluminum alloy in the world?
The answer is 6061 aluminum, mainly due to its high strength, heat treatability and relative ease of machining and welding. The main alloying elements of 6061 are magnesium and silicon. These elements give it a competitive advantage in maintaining corrosion resistance even when the surface is braided. If that wasn't enough, it can also be anodized in different colors for an additional thin layer of protection.
6061 is available in multiple formats, including extrusion, sheet, and architectural shapes. It is important to note that 6063 aluminum is also a popular choice in the 6000 series. However, its surface finish is much smoother than other commercial alloys. And its strength is about half that of 6061, because although its main alloying elements are magnesium and silicon, it contains much smaller amounts of them. This makes it suitable for applications where strength is not as important, such as non-structural poles and roofs or decorative structures.
What is 7075 grade aluminum?
7075 aluminum is most commonly associated with high-strength applications, particularly in the aerospace and defense industries. It is one of the high-strength aluminum alloys in the world, as its main alloying elements are zinc and copper. It has excellent mechanical properties and exhibits high strength, toughness, good ductility and good fatigue resistance.
7075 aluminum also has average to good ratings for corrosion resistance, anodizing performance, and machinability. Grade 7075 aluminum is easy to machine, but welding is not recommended. While excellent in many ways, it is quite expensive compared to other alloys, which is why it is not as common as 6061 aluminum.
FAQs About 6061 Aluminum and 7075 Aluminum
1. What type of aluminum should I use?
2. Can they be welded and molded?
6061 aluminum is easy to weld and form because magnesium and silicon are the main elements. 7075 aluminum is not as malleable and weldable as a much harder material with higher zinc content. However, when annealed, this type can be shaped and, if necessary, heat treated and welded in place.
3. Which aluminum has better anodizing properties?
The 6xxx series alloys respond excellently to anodizing. 6061 aluminum is a high-strength structural alloy with excellent machinability. When parts must be hard anodized in a wide range of colors, 6061 aluminum is the favorite of many shops. Aluminum 7075 is considered an ultra-high strength alloy and is widely used in the aerospace industry. Depending on the alloy and the anodizing process, they anodize gray, blue-gray and brown-black (spotted).
4. How strong are they?
It is noticeable that the tensile strength of 7075-T6 aluminum is almost twice that of 6061-T6 aluminum when considering both alloys in the “T6” condition. The shear strength of 7075-T6 is estimated to be 1.5 times that of 6061-T6. Therefore, 7075-T6 aluminum is significantly harder than 6061-T6.
Aluminum 6061 vs. Aluminum 7075, tips for choosing
To answer the question “Which aluminum alloy is best for my project?”, we need to weigh priorities. It takes a lot of experience and trial and error to figure out which aluminum alloy is best for your application. Both alloys have excellent mechanical properties and are used in a wide range of applications.
In summary, 6061 aluminum is cheaper, has medium strength and is easy to process, while 7075 aluminum is exceptionally strong, typically has smoother surfaces, but is more expensive.
6061 aluminum is more commonly used compared to 7075 aluminum mainly due to the difference in cost.
When it comes to aluminum alloys, 6061 aluminum is often the first choice of most suppliers. However, if your project requires the properties of 7075 aluminum, you must consider it to achieve the desired result.
