Common Aluminum Alloy Types & Uses: 2024, 6061, and 7075 – From the Industry Experts

In industries where durability, reliability, and performance are crucial, your choice of aluminum grade matters. But with several types of aluminum metals to choose from, it can be difficult to know which option is best for your application. Whether you need one that features incredible corrosion resistance or prioritize strength and fatigue resistance, learn about three common aluminum alloy types to determine which will work for your desired use. 

Here, we’ll cover the differences between 2024, 6061, and 7075 aluminum, showcasing each one’s specific chemical composition, key properties, tempers, and ideal applications. 

2024 Aluminum 

Offering high strength and outstanding fatigue resistance, 2024 aluminum is a top choice for many industries. This aluminum alloy type contains a composition of approximately 90–95% aluminum, 3.8–4.9% copper, up to 1.2–1.8% magnesium, up to 0.3–0.9% manganese, and lesser amounts of other elements, such as silicon, iron, and zinc. 

This unique composition lends itself to 2024 aluminum’s key properties, including:

• Excellent strength-to-weight ratio
• Average to good machinability
• Incredible fatigue resistance
• Poor weldability
• Lower corrosion resistance than other aluminum alloys

2024 aluminum can undergo solution heat treating and aging to increase its strength, stability, and tolerability. Here are some examples of temper designations for this type of aluminum alloy, all of which are available in various sizes of all types of cross-fittings:

• CF 2024 ALUM T351: Heat-treated, cold-worked, and naturally aged, then stress-relieved by stretching.
• CF 2024 ALUM T4: Heat-treated and naturally aged. Does not undergo cold work or stress relief after heat treatment, making this temper beneficial for certain fatigue requirements.
• CF 2024 ALUM T851: Heat-treated, cold-worked, and artificially aged (meaning that it uses an accelerated heating process), then stress-relieved by stretching.
• EXT 2024 ALUM T3511: Heat-treated, cold-worked, and naturally aged; stress-relieved by stretching; and undergoes minor straightening to align with standard tolerances.

Because of its lightweight and durable properties, you’ll find 2024 aluminum being used in the aerospace and defense industries, with specific applications such as fittings, gears, pistons, and fastening devices. 

6061 Aluminum

6061 aluminum is a highly versatile, widely used aluminum alloy type composed of approximately 95–98% aluminum, 1.2% magnesium, 0.7% iron, 0.4–0.8% silicon, and only 0.4% copper (among other elements, which contain lesser amounts).

Key properties of this type of aluminum alloy include: 

• Excellent corrosion resistance
• Incredible weldability
• Good machinability
• Good fatigue resistance 
• Lower strength-to-weight ratio than other aluminum alloy types

As with 2024 aluminum, the 6061 alloy can also undergo specific treatments to enhance its properties. The following are its temper designations: 

• CF 6061 ALUM T-6: Heat-treated and artificially aged. 
• CF 6061 ALUM T651: Heat-treated and artificially aged, then stress-relieved by stretching. 
• EXT 6061 ALUM T6511: Heat-treated and artificially aged; stress-relieved by stretching; then undergoes minor straightening to comply with standard tolerances. 
• EXT 6061 ALUM T6: Heat-treated and artificially aged. 

Nearly countless industries have found opportunities for 6061 aluminum applications, from aircraft, automotive, and boat components to bicycle frames, engineering equipment, and more.

7075 Aluminum

Another common aluminum alloy type is 7075 aluminum, which is primarily alloyed with zinc. It’s composed of approximately 87–94% aluminum, 5.1–6.1% zinc, 2.1–2.9% magnesium, 1.2–2% copper, and less than 1% of several other elements. 

This aluminum alloy option features the following properties: 

• High strength
• Incredible performance in high-stress uses
• Excellent strength-to-weight ratio
• Lower corrosion resistance and weldability than other aluminum alloys
• Good machinability

There are several types of temper designations available for 7075 aluminum: 

• CF 7075 ALUM T-6: Heat-treated and artificially aged. 
• CF 7075 ALUM T-651: Heat-treated and artificially aged, then stress-relieved by stretching. 
• CF 7075 ALUM T73: Heat-treated and artificially overaged to enhance stabilization and strength. 
• CF 7075 ALUM T7351: Heat-treated, artificially overaged, then stress-relieved by stretching.
• EXT 7075 ALUM T6511: Heat-treated and artificially aged; stress-relieved by stretching; then undergoes minor straightening. 
• EXT 7075 ALUM T73511: Heat-treated, artificially overaged, then stress-relieved by stretching.
   

7075 aluminum is used in the aerospace, defense, and industrial industries to manufacture high-performance parts, such as aircraft frames and precision machine components. 

How to Select the Right Grade for Your Application

To choose the right grade for your application, it’s important to understand how alloying elements affect aluminum’s properties, such as strength, corrosion, and resistance. All three types—2024, 6061, and 7075—feature different primary alloyed elements. 

• 2024 aluminum properties and uses are affected by the higher amount of copper, which greatly increases strength but reduces corrosion resistance.
• 6061 aluminum has higher amounts of magnesium, silicon, and iron, which lead to generally lower strength than 2024 and 7075 grades but higher corrosion resistance and weldability. 
• 7075 aluminum features zinc, magnesium, and copper, all of which provide incredible strength and fatigue resistance but lower corrosion resistance and weldability. 

With this in mind, choose your aluminum grade based on its key properties: 

• For supreme strength-to-weight ratio, choose 7075. 
• For more general-purpose applications that require high corrosion resistance, select 6061. 
• For excellent fatigue strength and high strength-to-weight ratio, opt for 2024. 

Fry Steel: Your Certified Aluminum Supplier

In the business of serving customers across various industries for over seven decades, Fry Steel is the leading choice for your aluminum needs. We hold ISO 9001, AS 9100, and AS 9120B certifications, giving you peace of mind that we and our suppliers meet global industry standards for quality. We stock all three grades of aluminum alloy types, including 2024, 6061, and 7075, in a wide range of sizes, shapes, and tempers and in both cold-finished and extruded forms. Find a Fry Steel rep in your area today to get started.