Aluminum has different grades and alloy variants suitable for vast applications. However, the alloying elements tend to modify some of the innate properties of this metal. While some grades may experience better corrosion resistance, others may exhibit increased strength, among other features.
This article explores the relationship between two main types of aluminum alloys: 6061 vs 7075. We give a detailed review of each aluminum grade, including specific differences between 6061 and 7075 aluminum, which will prove effective when deciding on the one that best suits your projects.
What is 6061 Aluminum?
6061 aluminum is one of the most used aluminum alloys for various manufacturing purposes. It is a prominent member of the 6000 aluminum alloy series because of its high tensile strength, versatility, and excellent mechanical properties. Magnesium and silicon are the main alloying elements essential for its improved properties.
However, it also contains other elements like iron, zinc, and copper, enhancing its machining and welding properties, fatigue, and corrosion resistance. In addition, aluminum 6061 is a precipitation-hardened alloy, suggesting enhanced strength through heat treatments. This process accounts for most of this alloy’s enhanced physical and chemical properties.
Besides its excellent machining purposes, 6061 alloy also possesses easy workability, making it suitable for extrusion and machining projects. Another thing to note is that this alloy has different tempered variations: the pre-tempered 6061-O and tempered variants 6061-T651 and 6061-T6 aluminum.
Characteristics of 6061 Aluminum
We already emphasized the excellent mechanical properties of aluminum 6061. Below, let’s drive home the point as we discuss other essential characteristics of this alloy.
Strength-to-Weight Ratio: Like other aluminum alloys, 6061 aluminum is a low-density metal with considerable strength, making it a good choice for lightweight fabrication with high strength specifications.
- Excellent Machinability: Like standard aluminum, the alloy 6061 has excellent machining properties. The relative softness of the metal affords it easy workability. Therefore, it is popular for precision machining and various industrial applications.
- Heat Resistance: Remember, this alloy forms from heat precipitation, enhancing its heat resistance overall mechanical properties and making it more flexible for vast designs and manufacturing needs.
- Surface Features: The 6061 aluminum alloy possesses excellent appearance and surface properties, such that they commonly require less need for finishing operations, particularly after using a precise manufacturing technique like CNC aluminum machining.
Advantages of 6061 Aluminum
The advantages of this aluminum alloy are its excellent mechanical and chemical properties. Below are some of the benefits of using this alloy.
- Good corrosion and heat resistance
- Low density with high considerable strength
- Recyclability
- Excellent machinability and weldability
- Highly versatile for various manufacturing processes
- Cost-effective
Applications of 6061 Aluminum
This alloy is the go-to aluminum for various manufacturing purposes, including the following industries:
- Aerospace – for structural and aircraft fittings;
- Automotive – manufacture of vehicle frames, chassis, and engine parts;
- Consumer goods manufacturing – bicycle frames, camera parts;
- Medical products and devices;
- Electronic parts and gadgets.
What is 7075 Aluminum?
Like 6061 aluminum, 7075 is another aluminum alloy, but as the name suggests, it belongs to the 7000 series. It is a popular choice among its group because of its exceptional strength it is one of the strongest aluminum alloys for manufacturing. This feature makes it a go-to metal for defense and aerospace applications.
Besides the base metal aluminum, the main elements of 7075 aluminum include zinc, magnesium, and copper, providing robust mechanical features. Other elements like iron, chromium, manganese, silicon, and titanium also exist in minute portions.
Similar to the aluminum alloy 6061, the 7075 aluminum also exists in different temperature variations, including 7075-0, 7075-T651, 7075-0, and 7075 T6 aluminum. Each possesses similar characteristics but slightly varying strength, depending on the effect of the heat treatments.
Characteristics of 7075 Aluminum
The 7075 aluminum alloys possess similar features to other aluminum alloys, but these are more pronounced in this alloy.
- High Tensile Strength: The 7075 aluminum is one of the strongest aluminum alloys, making it most suitable for lightweight parts that require high structural integrity.
- Hardness and Toughness: This alloy exhibits high hardness and toughness, ensuring its durability and wear resistance compared to other aluminum variants.
- Heat Treatments: AL 7075 is a good conductor of heat, a feature that allows it to respond excellently to heat treatment. This also proves effective for reinforcing the mechanical properties of products designed from this alloy.
Besides the characteristics we discussed, it also possesses similar features to all aluminum metals. For example, it exhibits good ductility and is an excellent conductor of heat and electricity, including aluminum’s silvery, shiny appearance.
Advantages of 7075 Aluminum
- Enhanced Strength-to-Weight Ratio: As emphasized, this alloy possesses superior strength to most aluminum alloys, even though the densities are comparable. Consequently, it’s a good choice for making structural components.
- Good Machining Properties: Even with its increased strength, the 7075 still exhibits good machining properties, making it suitable for precision manufacturing.
- Durability: The combination of its high strength, toughness, and corrosion resistance makes it a durable material.
Applications of 7075 Aluminum
Its applications are similar to those of 6061 and other aluminum variants. However, because of its increased strength, it may be a better choice for structural parts. The alloy is used in the following industries.
- Defense and military for weaponry and protective components;
- Automotive, particularly for high-end car parts;
- Aerospace for structural and engine components;
- General industrial manufacturing for high-stress structural parts.
6061 vs 7075 Aluminum: A Detailed Comparison of the Two Metal
We have already examined a detailed overview of these two prominent aluminum alloys. This section will explore a detailed comparison of the differences between 6061 and 7075 aluminum.
1. Material Properties Differences Between 6061 and 7075 Aluminum
Both metals are aluminum alloys, containing other alloying elements – metals and nonmetals – in different percentages. Adding these elements is responsible for their improved properties compared to the standard aluminum metal.
1.1 Element Composition
The main alloying elements in 6061 aluminum include magnesium and silicon, while those of 7075 aluminum are mainly zinc, magnesium, and copper. However, both share similarities in the trace elements composition. AL 6061 contains chromium, copper, iron, manganese, and zinc, while the 7075 variant contains magnesium and chromium in trace quantities.
The chart below showcases the alloying elements for these two aluminum alloys, indicating their quantities.
| Element | Aluminum 6061 | Aluminum 7075 |
| Aluminum | 0.979 | 0.9 |
| Magnesium | 0.01 | 0.025 |
| Silicon | 0.006 | – |
| Copper | 0.15 to 0.4 % | 0.016 |
| Zinc | 0 to 0.25 % | 0.056 |
| Titanium | 0 to 0.15 % | 0 to 0.2 % |
| Chromium | 0.04 to 0.35 % | 0 to 0.2 % |
1.2 Corrosion Resistance
Standard aluminum metal exhibits decent corrosion resistance. This future is present in most of its alloys, with 6061 aluminum showing good resistance, making it suitable for fabrication in harsh environmental conditions. Compared to metals like iron, the 7075 aluminum alloy also exhibits good resistance to corrosion. However, because of its significant copper content, it can react better with moisture and atmospheric gasses. Therefore, the 6061 aluminum is more resistant to corrosion.
1.3 Melting Point
You are probably thinking since aluminum 7075 is harder, it melts at a higher temperature. That is not the case; in fact, AL 7075 has a significantly lower onset melting point than AL 6063. However, they finish melting about the same time, though the latter still edges it.
Aluminum 6061 melts at 580 to 650°C (1076 to 1,202°F), and AL 7075 melts at a higher temperature of around 480 to 640°C (896 to 1,1184°F). The higher melting point of the former accounts suggests increased thermal resistance.
1.4 Weldability
Regarding weldability, the 6061 aluminum alloy takes the crown on this. It possesses excellent weldability, while the 7075 variant has limited weldability and may require special care and expertise for welding purposes.
2. Strength Differences Between 6061 and 7075 Aluminum
We have already reiterated that aluminum alloys exhibit a significant strength-to-weight ratio. However, certain variations in their strengths exist depending on the alloying elements. Here, we compare the strengths of Al 6071 and 7075.
2.1 Tensile Strength
As mentioned earlier, aluminum 7075 is one of the strongest aluminum variants, with an approximate tensile strength of about 83,000 psi. On the other hand, the tensile strength of 6061 aluminum is almost half that at 40,000 psi.
2.2 Yield Strength
The yield strength of a material refers to when that material becomes permanently deformed, forming plastic without any increase in load. That said, the yield strength of these two alloys follow similar patterns, with 6061 aluminum exhibiting a lower yield strength of about 35,000 psi.
On the other hand, Al 7075 shows a significantly higher yield strength of up to 73,000 psi, further reinforcing its use in high-stress conditions.
3. Formability Differences Between 6061 and 7075 Aluminum
Like typical aluminum, the two alloys have easy formability, reinforcing their choice as used in parts manufacturing and aluminum prototyping. However, it is more challenging to work with because of the increased strength and toughness of 7075 aluminum.
In addition, aluminum 6061 exhibits good formability, making it a more suitable alloy choice for forming complex, intricate shapes and designs, including for bending, extrusion, and forging applications.
4. Appearance and Touch Differences Between 6061 and 7075 Aluminum
Both alloys possess the silvery, light gray, shiny appearance of aluminum. However, 6061 aluminum exhibits a smoother surface finish, making it a better choice for aesthetic applications. 7075 aluminum tends to have a more textured appearance with a denser feel.
5. Machinability and Challenges Differences Between 6061 and 7075 Aluminum
Generally, aluminum alloys exhibit excellent machining properties. However, the differences in either alloy composition account for the slight variations in 6061 and 7075 aluminum machining features.
Remember that the 6061 variant is slightly softer and easy to work with. These features enhanced its machinability, making it more tenable and compatible with various machining processes, mainly milling, turning, and drilling. On the other hand, aluminum 7075 is slightly less machinable due to the increased hardness and toughness.
However, it is still more readily machinable than other metals and alloys like carbon steel and titanium.
6. Pricing and Options Differences Between 6061 and 7075 Aluminum
Aluminum 6061 is generally more available than the 7075 variant. Therefore, it is more cost-effective and often one of the go-to aluminum alloys for machining parts.
In fact, suppliers are likely to deliver 6061 aluminum over the 7075 version, especially if you do not specify the aluminum alloy you need for your project. The 7075 aluminum variant is often used for specific applications, mainly when high strength is required.
Therefore, you may not need to spend so much on aluminum 7075 if your increased strength is not a significant specification for your machining project. Remember, AL 6061 also possesses excellent mechanical features that suit your intended uses.
A Brief Table for Differences Between 6061 and 7075 Aluminum
The table below gives a summary of the differences between the properties of aluminum 6061 and the 7075 alloy.
| Characteristics | 6061 Aluminum | 7075 Aluminum |
| Alloying Elements | Mainly magnesium and silicon | Mainly zinc and magnesium |
| Corrosion Resistance | Good resistance | Lower than 6061 aluminum |
| Weldability | Good weldability | Limited weldability |
| Melting Point | High | High |
| Strength | Good strength-to-weight ratio | Higher strength |
| Formability | Easy to work with | More challenging to work with |
| Machinability | Excellent machinability | Good machining features |
| Hardness and Toughness | Less hard and tough | One of the hardest aluminum alloys. |
| Conductivity | An excellent conductor of heat and electricity | Good conductor of heat and electricity. |
| Costs | Cost-effective | More expensive |
6061 vs 7075 Aluminum: Which One to Choose?
Regardless of the variation in the properties of aluminum alloys, they remain one of the most used metals in manufacturing because of their excellent mechanical and chemical properties. However, you must understand that alloys of the same metal will exhibit different properties.
Therefore, understanding the distinctive properties of the different alloys will prove effective for selecting the best one that suits your manufacturing needs. Below are reasons to choose the 6061 aluminum variant over the 7075 version.
Choose 6061 Aluminum
- AL 6061 is more suitable for fabrication that requires extensive machining;
- It’s more suitable for projects that require corrosion resistance specifications;
- It’s a better choice when aesthetics is a significant factor to consider;
- If the project requires more welding;
- If you are on a start budget.
Choose 7075 Aluminum
On the other hand, below are reasons to select the 7075 aluminum over the 6061 version.
- The applications require an enhanced strength-to-weight ratio;
- Used in complex and harsh environments;
- Cost is not a primary concern;
- AL 7075 is a better choice when the product will go through post-processing operations, such as surface and heat treatments.
XinCheng: Your Reliable Choice for Metal Parts Manufacturing and Prototyping
Understanding the detailed characteristics of a material before selecting it for your project is highly beneficial. However, partnering with an expert manufacturer is a more reasonable way of guaranteeing a successful project.
XinCheng is the expert your project requires. We offer comprehensive services in CNC machining, die casting, sheet metal fabrication, aluminum extrusion, and other related surface treatments. Whether your project requires custom part machining or manufacturing rare and complex structures, we will meet your machining requirements with cost-effective and high standards.
Conclusion
Aluminum is the most used metal for manufacturing purposes. AL 6061 and 7075 are two of the most used aluminum alloys for industrial manufacturing. However, they differ in some specific properties. Therefore, it is important to understand these distinctions to select the one that best suits your project.
FAQs
Which is the better aluminum alloy between 6061 and 7075 aluminum?
Both alloys are variants of aluminum with top-notch mechanical and chemical properties. Therefore, we cannot just select one as being the better alloy. Instead, the better choice depends on your manufacturing needs. For example, the 7075 is stronger, but the 601 variant has superior machining properties and is more cost-effective.
Which aluminum alloy is stronger: 6061 or 7075 aluminum?
7075 aluminum is more robust and tougher than the 6061 variants. It has a higher tensile and yield stress than the 6061, making it more suitable for high-stress purposes. The 7075 aluminum can withstand more impact and high-pressure conditions with less decoration than the 6061.
Which is easier to machine between 6061 and 7075 aluminum?
Because of the higher strength and toughness of the 7075 aluminum alloy, it is less workable than the 6061 variant. Therefore, the 6061 aluminum alloy responds better to machining, welding, bending, and other manufacturing processes than the 7075 aluminum.
