Aluminum 6061 VS 7075: Definition and Differences

Aluminum alloys are widely used in different machining process due to its lightweight, easy to be machined properties. Aluminum 6061 and Aluminum 7075 are mostly used in precision machining. but what are difference between these two aluminum alloys? how to choose when you design a product? In this blog, we will anwser these questions for you.

What Is 6061 Aluminum Grade?

Aluminum grade 6061 is the most commonly used aluminum alloy. it is the most famous member of the 6000 series of aluminum alloys. Due to its strength, 6061 aluminum alloy is referred as structural aluminum. it is Composed primarily of aluminum(97.9%) and also magnesium, silicon, copper, chromium, and a tiny amount of other elements.

What Is 7075 Aluminum Grade?

Aluminum 7075 is a heat-treatable aluminum alloy with high strength used for highly stressed structural parts. it is a member of the 7000 series aluminum alloys. as a primarily zinc-based aluminum alloy, It contains 5.6% zinc, 2.1% magnesium, 1.2% copper.

Key Differences between Aluminum 6061 and 7075

6061 vs. 7075 Aluminum: Chemical Composition Comparison

Below is table to show the Chemical Composition of both materials and you will find how each Chemical affect the performance of the materials.

Element	Property Affected	Aluminum 6061 Composition (%)	Aluminum 7075 Composition (%)
Aluminum (Al)	Strength, Hardness	Approximately 97.9	Balance (Over 90%)
Silicon (Si)	Machinability	0.4 – 0.8	0.4
Magnesium (Mg)	Strength, Corrosion Resistance	0.8 – 1.2	2.1 – 2.9
Zinc (Zn)	Strength	0.25	5.1 – 6.1
Copper (Cu)	Corrosion Resistance., Strength	0.15 – 0.4	1.2 – 2.0
Iron (Fe)	Strength	0.7	0.5
Manganese (Mn)	Strength, Machinability	0.15	0.3
Chromium (Cr)	Corrosion Resistance	0.04 – 0.35	0.18 – 0.28
Titanium (Ti)		0.15	0.2

6061 vs. 7075 Aluminum: mechanical properties comparison

A comparison table as below for mechanical properties of both materials.

Property	Aluminum 6061	Aluminum 7075
Tensile Strength (MPa)	276	572
Yield Strength (MPa)	241	503
Hardness (Brinell HB)	95	150
Fatigue Strength (MPa)	96	159
Shear Strength (MPa)	207	331
Young’s Modulus (GPa)	69	71
Poisson’s Ratio	0.33	0.33
Thermal Conductivity (W/m·K)	167	130
Electrical Resistivity (Ω·mm²/m)	0.036	0.0003
Elasticity	Good	Good
Temperature Resistance	Up to 300°C	Up to 160°C
Corrosion Resistance	Good	Average

This property measures a material’s resistance to a longitudinal pulling force. Aluminum 7075 is very good in this aspect, making it ideal for applications where high strength is critical, such as aerospace components.

Yield strength indicates the point at which a material begins to deform plastically. Aluminum 7075 have a higher yield strength compared to 6061, means its superior ability to withstand deformation.

Hardness means a material’s resistance to surface indentation or abrasion. Aluminum 7075’s hardness is higher than that of aluminum 6061, making it more resistant to wear and damage.

Elongation measures how far a material can stretch before breaking. Aluminum 6061 is more ductile in this aspect, meaning it can deform significantly before reaching its breaking point compared to 7075.

This property defines a material’s stiffness and its ability to return to its original shape after deformation. Both alloys have similar values, but 6061 is slightly more elastic, making it better suited for applications requiring flexibility.

It means how efficiently a material conducts heat. Aluminum 6061 has higher thermal conductivity, making it suitable for heat dissipation applications like heat sinks.

This property quantifies a material’s opposition to electrical current flow. 7075 has slightly lower electrical resistivity, making it better for electrical conductivity applications.

Elasticity reflects a material’s ability to deform and regain its original shape under applied stress. Aluminum 6061 has higher elasticity, allowing it to flex more without permanent deformation.

This property indicates how well a material can withstand elevated temperatures. Aluminum 7075 is better in high-temperature environments due to its higher melting point.

It shows a material’s ability to withstand deterioration when exposed to corrosive substances. Both alloys have good corrosion resistance, but aluminum 6061 is better.

6061 vs. 7075 Aluminum: machinability comparison

Here’s a table that includes both the machinability factors and additional machining characteristics of Aluminum 6061 and Aluminum 7075.

machinability Property / Aspect	Aluminum 6061	Aluminum 7075
CNC Machinability	Excellent	Good
Weldability	Good	Fair
Bending	Good	Fair
Sawing	Good	Fair
Grinding	Good	Fair
EDM (Electrical Discharge Machining)	Good	Fair
Plating/Coating	Good	Fair
Chip Formation	Longer, continuous chips	Shorter, segmented chips
Tool Wear	Low to moderate	Moderate to high
Surface Finish	Generally smooth	May require post-processing
Machining Precision	High	Requires careful setup

Aluminum 6061 is easy to be machined, used for producing longer, continuous chips during CNC Aluminum machining. On the other hand, Aluminum 7075 is also machinable, but it generates shorter, segmented chips.

In terms of weldability, Aluminum 6061 is better. It is adaptable for various welding techniques, including TIG and MIG welding with a good result. Although Aluminum 7075 is weldable, it demands more expertise and carefully control of welding parameters.

For bending operations, Aluminum 6061 is highly formable and can be bent to various angles without the risk of cracking or distortion. In contrast, Aluminum 7075 is less ductile and possible to crack during bending.

Both alloys can be cut effectively, but Aluminum 6061 is more easier to be cut. Standard sawing equipment can easily cut 6061, ensuring precise and clean cuts. Aluminum 7075 require specialized sawing equipment for optimal cutting results.

Aluminum 6061 is highly suitable for grinding processes, providing a smooth surface finish. Aluminum 7075 require more effort due to its hardness.

While EDM is not commonly used on Aluminum 6061 due to its excellent machinability using conventional methods. For Aluminum 7075, EDM is a viable option, especially in cases demanding high-precision components.

Both Aluminum 6061 and Aluminum 7075 is ok for plating or coating processes. However, proper surface preparation is needed, particularly for 7075 due to its hardness.

Aluminum 6061 tends to produce longer, continuous chips. Aluminum 7075 generates shorter, segmented chips.

Tool wear is a key consideration during machining. Aluminum 6061 shows low tool wear. Aluminum 7075, while still machinable have high tool wear due to its high hardness.

Aluminum 6061 generally delivers a smooth surface finish, making it an excellent choice when aesthetics is important. Aluminum 7075 can also achieve a satisfactory surface finish, but it may require more effort due to its high hardness.

Machining precision is the ability to achieve accurate and consistent dimensions during machining operations. Aluminum 6061 can be machined to meet tight tolerances and dimensional requirements. Aluminum 7075 allows for high machining precision. but require skilled machining techniques.

Aluminum 6061 VS 7075, how to choose?

With the answer to following three questions , you will know how to choose.

Which One is Stronger: 6061 or 7075 Aluminum?

7075 aluminum alloy has a higher yield strength compared to 6061 aluminum, So it can withstand impacts better than 6061.

Which One is Easier to Machine: 6061 or 7075 Aluminum?

6061 aluminum has lower tensile strength and hardness compared to 7075 aluminum. So, 6061 aluminum is more easier to be machined and shaped.

Which One is More Cost-Effective?

The raw material cost and machining expenses for 7075 are higher. So Aluminum 6061 is more cost-effective.

Application for 6061 Aluminum Alloy

Aluminum 6061 can be considered to use in following situations:

When parts require a lot of welding process.
When there’s a high demand for corrosion resistance.
When a lower cost is priority.

6061 aluminum alloy is commonly used in the production of the following components:

Building products
Automotive parts
Electrical products
Bicycle frames
Pipelines

Application for 7075 Aluminum Alloy

7075 aluminum is more suitable for the following situation:

When achieving a high strength-to-weight ratio is needed.
When parts need to withstand high temperatures.
When parts will be subjected to high stress.
When the budget allows for higher material costs.

Some typical applications of 7075 aluminum include:

Missile components
Aircraft parts
Gears and axles
Fuse components
Regulating valves

Conclusion

Aluminum alloys are the most widely used metal materials in machining processes such as CNC aluminum, Aluminum die casting ,aluminum extrusion, Aluminum sheet fabrication. KUSLA is a manufacture with precision aluminum alloy machining in China. Feel free to get in touch with us for your aluminum machining projects.