Aluminium 6061 Vs 7075. Which one is suitable for you? 

Aluminium 6061 Vs 7075. Which one is suitable for you? 

Nowadays, aluminium alloys are the top priority for manufacturing different industrial products. Their basic function is to enhance conductivity, strength, corrosion resistance, etc. That is why manufacturers prefer Al alloys for manufacturing aerospace, automobiles, CNC machines, electrical, and sports equipment.

However, when it comes to choosing a suitable alloy for your project, the task becomes pretty tricky. This mostly happens when you’re asked to choose between two aluminium alloys. In such a situation, you need to consider certain parameters for a better decision.

In this article, we’re given two aluminium alloys, Al 6061 and Al 7075. Both these aluminium alloys have many common similarities but still differ at certain points. Let’s compare both of them and see which one suits best for your project needs.

Introduction to 6061 Aluminum Alloy

The 6061 aluminium is one of the types of  6000 aluminium alloy series. Silicon and magnesium act as the primary elements of this alloy. However, the detailed composition of aluminium 6061 is given below;

• 0.2% Cr
• 0.28% Cu
• 1.0% Mg
• 0.6% Si
• 97.9% Al

The copper content in this alloy makes it pretty susceptible to corrosion.

6061 Al alloy is highly versatile as it allows you to use it for any structural component. Moreover, you may roll, extrude, or forge this wrought alloy into a variety of shapes. On the other hand, you’ll find that 6061 aluminium is well-known for its great strength, heat treatability, and easy weldability.

You may get this excellent alloy at a relatively low cost. Many industries prefer this aluminium alloy for extrusion projects due to its superb workability. Generally, you’ll find 6061 aluminium a great choice for piping and manufacturing electrical, aerospace, automotive, consumer products, etc.

Introduction to 7075 Aluminum Alloy

The 7075 aluminium is one of the types of 7000 aluminium alloy series. Zinc acts as the primary alloying element in 7075 Al. Yet, the detailed chemical composition of this aluminium alloy is as follows;

• 5.6% Zn
• 2.5% Mg
• 1.6% Cu
• 0.23% Cr
• 90.0% Al

Here, the high concentration of Copper tends to make Al 7075  exceptionally strong. The increased mechanical strength makes it ideal for aerospace and defence industries. In addition, it can withstand fatigue stress which makes it pretty reliable.

Moreover, it is suitable for applications where you need to expose some parts to high heat and friction. For instance, plastic moulds in die or tool industries.

However, it doesn’t share the high corrosion resistance as compared to other Al alloys due to copper. Further, it possesses poor forming and weldability. Another downside of this Al alloy is its high cost.

Comparison of Aluminum 6061 and Aluminum 7075

Have you ever wondered if both these 6061 and 7075 are aluminium alloys but still different from each other?

Well, the aluminium alloy 6061 and 7075 are pretty common to each other. Usually, the point of difference lies in the following features;

• Chemical compositions
• Alloy series
• Mechanical properties
• Applications
• Fabrication considerations

Now, let’s compare both these alloys on the basis of the above-mentioned factors.

1. Aluminium 6061 Vs 7075: Chemical Composition

While comparing the chemical compositions we may say that Al 6061 mainly consists of silicon while Al 7075 consists of a high amount of zinc. On the other hand, both contain magnesium, yet the amount is a bit higher in Aluminum 7075.

Moreover, Aluminium 7075 includes a higher proportion of copper, which acts as a drawback for this alloy. However, Aluminum 6061 constitutes almost 97.9% Al and Aluminium 7075 constitutes 90.0% Al.

2. Aluminum 6061 Vs 7075: Alloy Series

The aluminum 6061 alloy exists in the following temper grades;

• Annealed 6061-O
• Naturally aged 6061-T4
• Artificially aged 6061-T6
• Artificially aged 6061-T65
• Artificially aged 6061-T6511

In contrast, 7075 aluminum alloy exists in the following tempers; 

• 7075-O
• 7075-T6
• 7075-T651

3. Aluminum 6061 Vs 7075: Mechanical Properties

In order to compare the mechanical properties of Al 6061 and 7075, various factors are considered. So, let’s differentiate these alloys on the basis of different factors.

• Thermal Conductivity

The ability of a material to transfer heat from one place to the other is called thermal conductivity. Generally, aluminium alloys are good conductors of heat so you can’t use them for insulation. Typically, the thermal conductivity of both aluminium alloys is different from each other. This is due to the difference in their heat treatment and chemical compositions.

You will observe slightly higher thermal conductivity in the case of Aluminium 6061 as compared to 7075. Therefore, if you require heat dissipation, you should prefer Aluminium 6061. 

• Yield Strength

Mainly when talking about yield strength it means the ability of a material to resist the pressure without deforming it. While comparing both the aluminium alloys, Al 7075 possesses a higher yield strength. This means Aluminum 7075 is much stronger and can withstand high pressure. Primarily, Zn offers high strength to the Al 7075.

However, you can also not declare aluminium 6061 weak as its yield strength differs slightly as compared to Al 7075.

• The hardness of the material

The chances of indention and penetration are lower in the case of hard materials. In the case of these aluminium alloys, you’ll find both of them enough harder. They can easily withstand the pressures without causing any deformation.

Yet, while talking specifically, aluminum 7075 is harder than aluminum 6061. This difference is mainly due to the chemical composition.

• Electrical Resistivity

The electrical resistivity of a material means how much a material can bear the electricity transfer. Luckily, both these aluminum alloys feature low electrical resistivity. This proves that they are good conductors of electricity.

However, aluminium 6061 features comparatively lower electrical resistivity. Therefore, it is much better for electrical applications as compared to 7075 aluminium.

• Elasticity

You can explain elasticity as the ability of a material to return to its original form after the removal of deformation pressure. After calculating the young’s tensile modulus of both aluminium alloys we come to know that elasticity is almost equal.

Typically, 6061 aluminium has 69 GPa while 7075 aluminium features 70 GPa.

• Corrosion Resistance

While comparing corrosion resistance in both aluminium alloys we found that 6061 aluminium is more resistant to corrosion as compared to Al 7075. This is due to the excess composition of the copper in Al 7075. Copper allows it to react with the environment and cause corrosion.

• Weldability

You may weld Aluminium 6061. However, you need to take good care while selecting the suitable filler metal. On the other hand, Aluminium 7075 is not weldable. It is pretty easy to crack after welding 7075.

4. Aluminum 6061 Vs 7075: Fabrication Considerations

Aluminum 6061 alloy has comparatively lower tensile strength and hardness so boasts of better fabrication. As a result, you can machine it easily. On the contrary, 7075 aluminum doesn’t possess this feature.

Therefore, you may conclude that Aluminum 6061 features better formability than 7075 aluminum alloy.

5. Aluminum 6061 Vs 7075: Applications

When talking about the applications of aluminium alloys, both of them are useful in the production of automotive parts and aerospace components. Yet, the applications may differ in some areas. So, let’s look at some major applications of these alloys separately. 

• 6061 Aluminum Applications

6061Aluminium is well-known for its strength and reasonable cost. That is why it is chiefly used in cars for fuel-efficiency. Additionally, due to its superb machinability, it is perfect for welding aircraft. You may resolve the strength of Al 6061 by heat treatment after welding.

Furthermore, due to its corrosion resistance, you may use it in the marine industry. All you’ll need will be the use of some protective paints. After doing so you may use it for making boat hulls, fishing equipment, docks, mooring, etc.

In addition, the following are some more common applications of Al 6061;

• Automotive industries
• Consumer products, i.e, bicycle frames, fishing reels, utility boats, gangways, and many more.
• Food industries
• Electrical fittings
• Construction industries

• 7075 Aluminum Applications

Aluminium 7075 is the best alternative to steel due to its excellent strength. Therefore, it is ideal for the aviation industry.

Commonly, you may use this aluminum alloy in the following areas;

• Transportation industry
• Camping utensils
• Industrial molding and tooling
• Firearms
• Missile components
• Gears and shafts
• Regulating valves

Which Aluminium alloy is suitable for your project? 

The very important but pretty tricky task is to choose the one between aluminium 6061 and 7075. Undoubtedly, both the alloys possess remarkable qualities but still, you need to choose the most suitable one.

The best way is to go for the features of both aluminium alloys. Like, if your project demands low-weight and high strength materials, you must prefer Al 7075. Also, if you need to deal with a lot of heat and friction again you should go for Al 7075.

On the other hand, if you ought to undergo the parts of the welding process, we’ll highly recommend you to consider Aluminum 6061. Plus, if you want to get the best results at cheap rates, Al 6061 is the best choice. 

Conclusion

No doubt, that both the above-mentioned aluminum alloys are super-efficient in performance. Each has its own specifications and plus points. Therefore, the choice is all yours.

You may choose the one which suffices your project’s requirements completely.