Aluminum has become a popular choice across various industries thanks to its lightweight, high strength, and versatility. Among the many aluminum alloys available, 6061 and 7075 are two of the most commonly compared options. But which one is lighter? And what are the key differences between them? In this guide, we’ll break down their features to help you make the best choice for your project.

6061 Aluminum vs 7075 Aluminum，Which Is Lighter？

6061 aluminum is lighter than 7075 aluminum. 6061 aluminum is mainly alloyed with magnesium and silicon, while 7075 aluminum is mainly alloyed with zinc. 7075 aluminum contains higher levels of zinc and other metals, resulting in greater density and weight.

7075 contains more zinc and copper for strength, making it denser and heavier than 6061, which has more magnesium and silicon.

If weight is your top priority, 6061 is lighter. However, if strength is critical, 7075 is better despite its slightly higher weight.

Comparing 7075 Aluminum vs 6061

When selecting an aluminum alloy for your project, it’s essential to consider the specific properties required—whether it’s strength, corrosion resistance, the intended application, or a combination of these factors. Among the most commonly used alloys in the industry, 7075 and 6061 aluminum are frequently compared and worth a closer look.

What is the Chemical Composition of  7075 Aluminum & 6061？

The difference between 6061 and 7075 aluminum alloys can be traced back to their numerical designations. 6061 belongs to the 6XXX series, while 7075 falls under the 7XXX series. This distinction reflects their differences in chemical composition.

7075 aluminum alloy

The main alloying element is zinc, with a content of about 5.1%~6.1%;

Other important elements include magnesium (2.1%~2.9%), copper (1.2%~2.0%), and chromium (0.18%~0.28%);

Contains silicon (0.40%), iron (0.50%), manganese (0.30%), titanium (0.20%) and other elements, as well as residual aluminum and other trace elements.

6061 aluminum alloy

The main alloying elements are magnesium and silicon, with magnesium content of about 0.8%-1.2% and silicon content of about 0.4%-0.8%;

Other elements include chromium (0.04%-0.35%), copper (0.15%-0.4%), and the balance of aluminum and other trace elements.

Strength

7075 Aluminum Alloy:Known for its exceptionally high strength, 7075 can achieve tensile strengths exceeding 700 MPa in some cases. Other sources report tensile strengths around 524 MPa to 560 MPa, depending on the specific temper. It also offers high hardness, though its toughness is relatively lower.

6061 Aluminum Alloy:Offers moderate strength, with typical tensile strengths ranging from 240 MPa to 310 MPa. Some sources also indicate a minimum tensile strength of around 180 MPa. It has medium hardness but generally provides better toughness compared to 7075.

Machinability

7075 Aluminum Alloy: Offers poor weldability due to its high and complex alloying content, which can cause issues during welding. It has good machinability, but its high hardness requires proper tooling and cutting parameters. However, its formability is limited, making it less suitable for complex bending or deep drawing processes.

6061 Aluminum Alloy: Known for its excellent weldability, it is compatible with various welding methods. It also has good machinability and can be easily processed into different shapes. Additionally, it boasts excellent formability, allowing for a wide range of bending, stretching, and stamping applications.

Corrosion resistance

Compared with 6061 aluminum , 7075 aluminum  has poorer corrosion resistance, especially in marine environment. 6061 aluminum  has better corrosion resistance and is suitable for most environments. Its good corrosion resistance makes it widely used in construction, transportation and other fields.

Heat Treatment

The solution heat treatment temperature for 6061 aluminum alloy is typically around 527°C, while for 7075 aluminum alloy, it is generally around 530°C.

The aging (heat treatment) time for 6061 aluminum alloy usually ranges from 1 to 18 hours, depending on factors such as the size, shape, and intended use of the workpiece. In contrast, 7075 aluminum alloy requires a shorter aging time, typically 1 to 4 hours, due to its faster age-hardening response.

Machinability

Machinability refers to how well a material responds to processes such as cutting, drilling, milling and casting. Both 7075 and 6061 aluminum  have good machinability. However, for applications that require extensive machining, 6061 aluminum alloy is generally considered a better choice. Even so, 7075 aluminum is still rated as having moderate machinability.

Cost Comparison

6061 aluminum is widely recognized as a common commercial-grade material due to its easy availability and overall low cost. With relatively simple manufacturing processes and ample market supply, it is more affordable in various forms. In contrast, 7075 aluminum commands a higher price because of its superior strength and the addition of alloying elements such as copper and zinc. Its more complex processing and suitability for high-performance applications further drive up the overall cost.

Applications of 6061 vs 7075

Due to its high strength and hardness, 7075 aluminum is suitable for fields that require high performance, such as aerospace (for aircraft structures, wing beams, etc.), mold manufacturing (for high-strength molds), and mechanical equipment (for parts that require high strength and hardness).

Due to its good weldability and corrosion resistance, 6061 aluminum is suitable for construction (for doors, windows, frames, etc.), transportation (for cars, bicycles, ships, etc.), and industrial structural parts (for various parts that require good weldability and corrosion resistance).

Conclusion

There are significant differences between 7075 and 6061 aluminum in terms of chemical composition, mechanical properties, processing properties, corrosion resistance, application areas and price. The choice of aluminum alloy material depends on the specific application needs and performance requirements. You can carefully consider these factors and choose the most suitable aluminum alloy for your project to ensure the best performance and cost-effectiveness.

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