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A Complete Comparison of Aluminum 6061 VS 7075

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Aluminum alloys are known for their improved strength, which is comparable to steel’s. Among other things, both aluminum 6061 and 7075 offer strong, hard and corrosion-resistant properties that make them suitable for many industries. However, some differences are crucial to what these alloys have to offer, e.g. differences in strength, which are important to know before purchase. 


But are you unsure about their differences and applications? Do not worry, we are here for you. This article will take you in a deep dive into the world of aluminum 6061 and 7075.

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What is an Alloy? 

You may have thought of this question before. A metal alloy includes a mixture of two or more metals.

After creating an alloy, the final product is stronger, more resistant and durable than pure metal. So, for instance, an aluminum alloy is thirty times stronger than pure alumnium metal. 


What are Aluminum 6061 and 7075?

First and foremost, they are both aluminum alloys. 

6061 is one of the many alloys in the 6xxx series. This series is differentiated from the others by its usage of magnesium and silicon as the primary components when creating an alloy. 

On the other hand, 6061 is a part of the 7xxx series, where zinc and copper are the primary metals used. 


Chemical Differences 

Both of these alloys contain different metals that make up their composition. They have some metals in common, but the amount/ quantity used is different.


Aluminum 7075

Aluminum 6061

  • 90% aluminum 

  • 1.6% copper 

  • 0.23% chromium 

  • 2.5% magnesium

  • 5.6% zinc 

  • NIL

  • 97.9% aluminum 

  • 0.28% copper 

  • 0.2% chromium 

  • 1.0% magnesium

  • NIL

  • 0.6% silicone 


Mechanical Properties 


Property 

Aluminum 7075 

Aluminum 6061 

Yield strength (MPa)

490

276

Thermal conductivity (W/m-k)

130

167

Modulus of Elasticity (GPa)

71.7

68.9

Hardness (Brinell hardness number)

95-105

150-180

Melting Point (C/F)

477-635°C/ 890 – 1175°F

582 – 652°C/1080 – 1205°F

Shear Strength (MPa)

290

180-200

Ductility (%)

10-12

15-20

Machinability 

Fair 

Good

Mechanical_Properties.jpg


Aluminum 6061 VS Aluminum 7075 

Aluminum 7075 

Aluminum 7075 is one of the strongest metal alloys and is often known as the “aircraft grade” due to its strength, offering almost the same strength as many steels. It has better strength and a high strength-to-weight ratio, which means it is perfect for any project that requires a light body but great strength. It also has a greater yield strength than 6061, meaning it will not permanently deform. However, that does not mean 6061 will yield either.

 It is just less strong.


Aluminum 7075 is also highly corrosive-resistant, which allows it to be used in naval crafts, and has a comparatively low melting temperature, resulting in faster processing times.

You will find the use of aluminum 7075 in the aircraft industry (as previously mentioned), transportation industry and military-grade rifle receivers, among many others. 


It is also harder than and has a T6 strength that is 1.5 times more than aluminum 6061 and reacts well to anodisation, but if the zinc content is too much, it can lead to a brownish color.



Aluminum 6061

Aluminum 6061 may not be as strong or hard as aluminum 7075, but it is relatively more malleable. Therefore, it is perfect if your project requires a lot of custom aluminum plate cutting or milling. 

Another reason for its malleability comes from its lower zinc content. The lower zinc content in aluminum 6061 means that this alloy can be formed and welded more easily than aluminum 7075. 


When it comes to corrosive resistance, it is slightly less resistant thanks to its high copper content. It is also cheaper than aluminum 7075 and can be anodised. You will find its usage in construction, automotive and many consumer goods. 


From the table above, you can see that 6061 has a greater thermal conductivity. This means that 6061 can conduct heat better, making it great for electronic heat sink and exchangers. However, that does not mean that 7075 is terrible for conducting heat. It is still quite good though less than 6061.



Which Should You Use?

It hugely depends on what you are going to make and what your product needs, e.g. does it require a lot of extrusion forming and sheet metal welding services, or does it have to be really strong? 

Here is an overview of their similarities and differences to help you choose for aluminium deep drawing:


Aluminum 7075

Aluminum 6061

  • Stronger 

  • Harder and therefore not so malleable

  • Not fit for forming and welding 

  • More corrosion resistant 

  • Reacts well to anodisation unless the zinc is too high.

  • More expensive

  • Density of 2.81g/cm^3

  • Lower melting temperature than aluminum 6061

  • Relatively less strong

  • More malleable 

  • Can be formed and welded 

  • Less corrosion resistance due to copper 

  • Reacts well to anodisation.

  • Cheaper 

  • Density of 2.7g/cm^3. Almost the same as pure aluminum.


Aluminum_7075.jpg


Industries They are Used In

We have previously mentioned some of the industries in which both of these alloys are used in sheet metal custom fabrication, Now, we will take a look at some others to give you an idea of which you should use:

Aluminum 7075

Besides all the other qualities of aluminum 7075, we have mentioned, one that we have left behind is its ability to endure high stress. This ability allows it to be used in many industries, such as:

  • Sporting goods: e.g. bicycles and skis that need to be lightweight but also have a lot of strength and can withstand stress.

  • Molding and tooling can be very helpful in injection cores.

Aluminum 6061

Aluminum 6061 is definitely more versatile than 7075; therefore, you will see it being used in many everyday and all-purpose things. Some of these include:

  • Electrical components: e.g. busbars and deep drawn aluminum enclosures.

  • Marine: thanks to its corrosive resistance, it can be used as boat hulls and masts, among many other things. 

  • Structural materials: they are the backbone of construction.


Conclusion 

We hope this article helped you choose between aluminum 7075 and 6061. Both of these alloys are similar and useful, though with varying qualities. One of them is not relatively better than the other, but instead both are fit for being used in different industries. 


FAQs

Which aluminum is the strongest?

Aluminum 7075 from the 7xxx series is the strongest aluminum alloy and is even comparable to many types of steel, usually types of mild steel. 

What is the highest quality of aluminum?

Aluminum 5052 is the highest quality of aluminum as it provides a comparatively higher fatigue strength, along with corrosive resistance, high weldability, etc. 

What is the cheapest aluminum alloy?

Aluminum 6061 is the cheapest since the production costs to produce it are low. So, you get a lot of benefits, such as versatility and malleability, at a very cheap rate. 

Which aluminum is better?

There is no easy answer to this. Aluminum alloys are not all the same since they have different amounts of various metals. Therefore, each series, e.g. 7xxx series, comes with its own advantages and disadvantages depending on which metals are the primary ones in the alloy.



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