Is 7075 aluminum stronger than 6061?

Yes, 7075 aluminum is generally stronger than 6061 aluminum.

7075 aluminum is known for its high strength-to-weight ratio and is typically used in applications that require high strength, such as aerospace and military applications. It has a higher tensile strength, depending on the specific temper.
6061 aluminum is more versatile and has good mechanical properties, but its strength is not as high as 7075.

If strength is the primary consideration, 7075 aluminum is the better choice. However, 6061 aluminum has good corrosion resistance and weldability, making it suitable for a variety of applications where strength is not the primary requirement.

There are many different types of aluminum alloys, each with unique characteristics and performance based on specific application needs. When selecting an alloy, factors such as electrical conductivity, corrosion resistance, and strength need to be considered. Among aluminum alloys, 7075 and 6061 are two of the most common types, widely used in various fields. As expected, there are several differences between these two alloys. Next, we will compare the two.

6061 vs. 7075 Aluminum Alloys Chemical Composition

7075 aluminum alloy belongs to the 7XXX series, with its main alloying elements being copper and zinc. On the other hand, 6061 aluminum alloy belongs to the 6XXX series, with its main alloying elements being silicon and magnesium. Below is the detailed chemical composition of these two alloys:

Chemical Composition	7075 Aluminium	6061 Aluminium
Aluminium (%)		97.9%
Zinc (%)	5.6%	___
Magnesium (%)	2.5%	0.1%
Chromium (%)	0.23%	0.2%
Copper (%)	1.6%	0.28
Silicon (%)	___	0.6%

6061 vs. 7075 Aluminum Alloys Differences in Characteristics

Below is a comparison table between 7075 T6 aluminum alloy and 6061 T6 aluminum alloy, covering aspects such as strength, machinability, formability, weldability, and corrosion resistance:

Property	7075 T6 Aluminum Alloy	6061 T6 Aluminum Alloy
Tensile Strength	Almost twice that of 6061 T6	Lower than 7075 T6
Shear Strength	About 1.5 times that of 6061 T6	Lower than 7075 T6
Hardness	Generally higher than 6061 T6	Lower than 7075 T6
Machinability	Good, suitable for most machining needs	Better, commonly used in applications requiring machining
Formability	Poor, requires annealing for forming	Excellent, suitable for various forming processes
Weldability	Poor, requires annealing for welding	Excellent, suitable for welding
Corrosion Resistance	Better, has good corrosion resistance	Slightly lower than 7075, but can be enhanced with coatings

This table summarizes the comparison of 7075 T6 and 6061 T6 aluminum alloys across different properties, making it easier to understand their respective strengths and weaknesses.

Machinability

Machinability refers to the material's performance during processes like cutting, drilling, and milling. While both 7075 and 6061 aluminum alloys have good machinability, 6061 is often chosen for applications requiring precise machining due to its superior machinability. Although 7075 is slightly less machinable, it is still suitable for most machining needs.

Formability and Weldability

Due to its composition of silicon and magnesium, 6061 aluminum alloy has excellent formability and weldability, making it suitable for various manufacturing processes. In contrast, 7075 aluminum alloy contains a higher amount of zinc, making it harder and less suitable for direct forming or welding unless it undergoes annealing. In its annealed state, 7075 is easier to form, and it can be welded after subsequent heat treatment.

Corrosion Resistance

Both alloys perform well in terms of corrosion resistance, as aluminum materials naturally form a protective oxide layer when exposed to air or water, effectively preventing further corrosion. However, 6061 aluminum alloy contains copper, which slightly reduces its corrosion resistance compared to 7075 aluminum alloy. Nevertheless, the corrosion resistance of 6061 can be enhanced with surface coatings.

6061 vs. 7075 Aluminum Alloys Mechanical Properties

Mechanical Properties	Type 6061 Aluminium		Type 7075 Aluminium
Mechanical Properties	Metric	English	Metric	English
Yield strength	276 MPa	40,000 psi	503 MPa	73,000 psi
Modulus elasticity	68.9 GPa	10,000ksi	71.7GPa	10,400ksi
Thermal conductivity	167 W/m-K	1160 BTU-in/hr-ft^2_0F	130 W/m-K	900 BTU-in/hr-ft^2_0F
Melting point	1080-1205⁰F	582 - 652⁰C	890-1175⁰F	477-635⁰C
Electrical resistivity	3.99 x 10^-6 ohm-cm		5.15 x 10^-6 ohm-cm
Hardness (Brinell)	95		150
Machinability	Good		Fair

6061 vs. 7075 Aluminum Alloys Applications

7075 is commonly used in aerospace, military, and high-performance applications where strength is a critical factor, such as aircraft structures, military equipment, and high-stress components.

6061 is more often used in structural components, piping, and frames, where a balance of strength, corrosion resistance, and ease of manufacturability is required.

6061 Aluminum Alloy	7075 Aluminum Alloy
Building products	Aircraft wings and fuselages
Electrical products	Missile parts
Piping	Gears and shafts
Bicycle frames	Worm gears
Furniture	Regulating valves
Automotive parts	Fuse parts

6061 vs. 7075 Aluminum Alloys Density

The density of aluminum is an important physical property, but it varies due to the inclusion of other metallic elements with different densities in the alloy. Density is one of the key factors to consider when comparing the physical properties of metals.

The density of 7075 aluminum alloy is 2.81 g/cm³, which is significantly higher than that of pure aluminum. This is because 7075 contains a higher proportion of elements like zinc and magnesium, and the alloy can be strengthened through heat treatment, with the most common temper being 7075-T6.

In contrast, the density of 6061 aluminum alloy is 2.7 g/cm³, which is closer to that of pure aluminum. This is because 6061 has a higher aluminum content, with relatively lower proportions of other alloying elements like silicon and magnesium.