Various industries rely on aluminum alloys because they possess the right blend of strength, weight, and resistance to corrosion. In the world of aluminum, two commonly compared alloys are Aluminium 6061 and 7075. Knowing what sets them apart is important when choosing materials.
What is 6061 aluminum alloy?
Aluminum in the series 6000, specifically Aluminium 6061 is widely known for its versatility as well as balance between strength-to-weight ratio and workability. Its main alloying elements include magnesium and silicon which give it these properties. It can be referred to as a ‘structural’ aluminium due to its ability of being used in structures where high strengths are required.
What is 7075 aluminum alloy?
Aluminium 7075 stands out in the 7000 series as one of the highest-strength alloys available, primarily attributed to its zinc as the primary alloying element. This alloy is renowned for its excellent mechanical properties, particularly its high strength and toughness, making it a preferred choice for high-performance applications. Aluminium 7075 is also known for its use in applications requiring high stress and strain resistance.
6061 Vs 7075 aluminum: Chemical Composition
Here is a comparison table summarizing the chemical composition differences between Aluminum 6061 and 7075.
| Chemical Elements | 6061 Aluminum | 7075 Aluminum |
|---|---|---|
| Magnesium | 0.8-1.2% | 2.1-2.9% |
| Silicon | 0.4-0.8% | Max 0.4% |
| Iron | Max 0.7% | Max 0.5% |
| Copper | 0.15-0.4% | 1.2-2.0% |
| Manganese | Max 0.15% | Max 0.3% |
| Chromium | 0.04-0.35% | 0.18-0.28% |
| Zinc | Max 0.25% | 5.1-6.1% |
| Titanium | 0.15% | 0.16% |
| Aluminum | Remainder | Remainder |
Mechanical Properties
| Property | Aluminum 6061 | Aluminum 7075 |
|---|---|---|
| Tensile Strength | 18,000 to 35,000 psi | 33,000 to 78,000 psi |
| Yield Strength | 8,000 to 30,000 psi | 23,000 to 73,000 psi |
| Hardness (Brinell) | 95 HB | 150 HB |
| Elongation | 10-15% in 2” | 9-18% in 2” |
| Density | 2.7 g/cm³ | 2.81 g/cm³ |
| Thermal Conductivity | 167 W/m-K | 130 W/m-K |
| Melting Point | 582-652°C (1080-1205°F) | 475-635°C (890-1175°F) |
- Strength:Aluminum 7075 is significantly stronger than 6061, both in terms of tensile and yield strength, primarily due to its higher zinc, magnesium, and copper content.
- Hardness:With a Brinell hardness value significantly higher, 7075 is harder than 6061, making it more resistant to wear and tear.
- Elongation:Both alloys show good ductility, but the specific elongation can vary depending on the temper and processing.
- Thermal Conductivity:Aluminum 6061 has higher thermal conductivity than 7075, making it better suited for applications requiring efficient heat dissipation.
- Density:There is a slight difference in density, with 7075 being a bit denser due to its higher content of alloying elements like zinc and copper.
- Melting Point:The melting point of 6061 is generally higher, indicating different thermal stability under high temperatures.
Physical Properties
To complete the comparison, we’ll now focus on the physical properties of Aluminum 6061 and 7075. These properties include aspects such as weldability, corrosion resistance, formability, and machinability. Here’s how the two types of aluminum compare.
| Property | Aluminum 6061 | Aluminum 7075 |
|---|---|---|
| Weldability | Excellent | Fair to Good |
| Corrosion Resistance | Good | Good, but less than 6061 |
| Formability | Excellent | Good, but less than 6061 |
| Machinability | Good | Good |
| Conductivity | Good electrical conductivity | Lower than 6061 |
| Coating/Finish Quality | Excellent (clear anodic coatings) | Good (can be more susceptible to stress corrosion cracking) |
- Weldability:Aluminum 6061 is known for its excellent weldability, making it ideal for applications involving welding. On the other hand, 7075 is weldable but requires more care and may not perform as well under the same conditions due to its higher susceptibility to cracking.
- Corrosion Resistance:While both materials have good corrosion resistance, 6061 has a slight edge, especially in environments that are wet or corrosive. This makes 6061 a better choice for marine applications.
- Formability:6061 is easier to form into complex shapes and is ideal for projects requiring extensive machining or forming. Although 7075 can also be formed, it is generally considered less formable compared to 6061.
- Machinability:Both alloys are considered to have good machinability, but the specific cutting conditions may vary due to the differences in their hardness and strength.
- Conductivity: 6061 typically has better electrical conductivity, which can be advantageous in electrical and electronic applications.
- Coating/Finish Quality:Aluminum 6061 typically achieves a better surface finish in anodizing processes, making it suitable for applications where aesthetics are important. While 7075 can also be anodized, it may be more prone to cosmetic flaws and stress corrosion cracking.
Applications of 7075 Aluminum vs 6061 Aluminum
Applications of both 7075 and 6061 aluminum alloys vary significantly due to their differing physical properties.
Applications of 6061 Aluminum
– General Fabrication: Because it can easily be joined by welding or formed into complex shapes, this commonly occurs during general fabrication processes such as making frames brackets etcetera used widely within various sectors like construction industry among others.
– Auto Parts: It is used on car parts where the ratio of good strength to weight and resistance to corrosion such as wheels or chassis components.
– Building for Ships: Its anticorrosive nature makes it appropriate for such things as boat hulls, ramps and other marine structures.
– Electrical Items: The fact that it has good electrical conductivity means aluminium can be employed within electric fittings, connectors etc., found throughout electrical systems and devices
– Construction: Due to its high tensile strength-to-weight ratio along with excellent durability and aesthetics; aluminum 6061 is utilized in building construction materials like window frames, doors, roofing systems as well as architectural trims.
Applications of 7075 Aluminum
–Aerospace Components: Wing spars, fuselage frames, and other parts subjected to heavy loads in aircraft structures are some of the areas where 7075’s high strength and low weight are useful.
–Sporting Equipment: Bicycle frames, climbing gear like carabiners or anchors, and baseball bats could benefit from its high strength-to-weight ratio that enables better performance.
–Military Applications: Military applications such as armored vehicles or military grade weapons systems employ it for its high strength properties
–Tooling and Mold Making: Molds, tooling etc where wear resistance is required will do well with this material because of its hardness and strength qualities.
–High-Stress Applications: Any application which needs good balance between high-strength and lightness but ignores formability or weldability can gain from using 7075.
Tips for choosing 6061 or 7075 aluminum alloys
To choose between 6061 and 7075 aluminum alloys you must first evaluate your project’s specific requirements; then consider factors like weldability, formability, corrosion resistance among others.
- Use 7075 Aluminum if you need high strength for your project even at the expense of some formability. Choose 6061 Aluminium when medium strength will suffice however it should be more malleable than hard grades.
- If there are many welds or complex shapes involved in manufacturing processes; use 6061 because it has excellent weldability as well as being highly formable. On the other hand if abrasion resistance is required during the production process due to less number of welded parts then select 7075
- For applications exposed to corrosive environments like marine applications where corrosion resistance is important; go for 6061 that has better corrosion resistant properties over time compared with those found on materials like 7075 which only offer temporary protection against rust formation.If corrosion resistance is not mandatory or achievable through coatings & treatments;then consider taking advantage of higher strengths available in alloys such as those based on copper & magnesium besides zinc.
We at EASIAHOME have over 17 years of experience in machining different metals including aluminum. We are ISO9001 certified and can help guide you through the process of material selection that best suits your needs. If you require any professional services regarding CNC machining 6061 or 7075 aluminum please contact us.
