Manufacturers use various aluminum alloys in product machining, with 6061 and 7075 aluminum being two of the most popularly used grades.
While there may be overlaps in their uses, these alloys have some distinguishing properties. Therefore, there is a need to compare 6061 vs. 7075 aluminum.
Understanding the differences between these excellent metal materials allows you to choose the suitable material for your project.
This article explores all you need to know about the difference between 6061 and 7075 aluminum, including how to choose the right one for your project. Let’s dive in!
What Is 6061 Aluminum?
The 6061 aluminum is a popular alloy in the 6000 series, famous for its versatility and excellent mechanical qualities. The 6061 aluminum alloy exhibits great machinability, remarkable tensile strength, and excellent corrosion resistance. Its primary alloying elements include silicon and magnesium.
These alloying elements give the 6061 aluminum a competitive advantage in machining corrosion resistance, even on braided surfaces.
Additionally, its low costs contribute to its usefulness in various industries. Engineers often use this alloy for various extrusion projects due to its easy workability.
Likewise, it is ideal for applications for automotive, electrical, aerospace, and consumer products. It offers a smoother surface finish than other commercial alloys. However, you can anodize the 6061 aluminum for an additional thin layer of protection.
Characteristics of 6061 Aluminum
The main distinctive characteristic of the 6061 aluminum is that it contains less zinc than the 7075. As a result, it is easy to weld and machine. However, this attribute reduces the 6061 aluminum’s strength and resistance to stress. Other properties of the 6061 alloy include the following:
- Tensile strength – 45000 psi
- Yield strength – 40,000 psi
- Brinell Hardness – 95
- Shear strength – 31,000 psi
- Elongation at Break – 12%
- Thermal conductivity – 170 W/m-K
- Strength-to-weight ratio – 115 KN-m/kg
Advantages of 6061 Aluminum
Manufacturers often use the 6061 aluminum alloy for various applications due to its enormous advantages. Here are some of them:
- Superior structural strength and toughness
- High-quality surface finish
- Excellent corrosion resistance
- Good machinability and weldability
Applications of 6061 Aluminum
The 6061 is a structural aluminum alloy with excellent mechanical properties, making it a perfect alloy for several applications.
You can mold the 6061 aluminum in any desired shape. However, you can find the 6061 aluminum in several applications, such as:
- Aerospace industry
- Electrical fittings
- Automotive industry
- Food and beverage industry
- Consumer products (e.g., small utility boats, SCUBA tanks, bicycle frames, dock gangways, etc.)
- Building construction industry (e.g., cover plate, subway platforms, stairs flooring, and more)
What Is 7075 Aluminum?
The 7075 is a top member of the 7000 series, famous for its excellent strength. The defense and aerospace industries adopt the 7075 aluminum in its applications due to its increased mechanical strength. The 7075 alloy has zinc as its primary component.
As a result, it has a higher capability to withstand fatigue stress, making it a perfect choice for several industries.
The 7075 alloy has a higher cost compared to the 6061 alloy. However, it has a remarkable machining level even though it is less weldable.
Characteristics of 7075 Aluminum
The 7075 aluminum comprises more zinc than 6061, resulting in higher strength and a higher strength-to-weight ratio. Here are other properties of the 7075 aluminum:
- Tensile strength – 83, 000 psi
- Shear strength – 48,000 psi
- Brinell Hardness – 150
- Strength-to-weight ratio – 196 KN-m/kg
- Yield strength – 74,000 psi
- Elongation at Break – 10%
- Thermal conductivity – 130 W/m-K
Advantages of 7075 Aluminum
Although the 7075 aluminum offers many advantages when used for suitable applications. The benefits of using 7075 aluminum include the following:
- Higher overall strength and strength-to-weight ratio
- Resistance to stress-corrosion cracking
- Outstanding fatigue strength
- Great machinability
Applications of 7075 Aluminum
The 7075 aluminum is an ideal replacement for steel when your project requires lightweight materials with higher strength.
Likewise, it is a go-to choice for applications where parts are exposed to extreme heat and friction. Its primary applications include:
- Firearms
- Industrial tooling and molding
- Camping utensils
- Automotive industry
- Aviation industry
- Rock climbing and inline skate equipment
6061 vs. 7075 Aluminum: A Detailed Comparison Between the Two Popular Metal Choices
This section discusses the differences between the 6061 and 7075 aluminum alloys.
Material Properties Differences Between 6061 Aluminum and 7075 Aluminum
Element Composition
The 6061 aluminum comprises 95.8 to 98.6 percent aluminum, 0.4 to 0.8% Silicon, and 0.8 to 1.2% magnesium.
Similarly, it contains other elements such as Chromium, Copper, and more. On the other hand, the 7075 aluminum includes 1.2 to 1.6% copper, 2.1 to 2.5% magnesium, and 5.6 to 6.1% zinc.
Other elements in the 7075 aluminum include iron, silicon, titanium, chromium, manganese, and more.
Corrosion Resistance
Regarding 6061 vs. 7075 corrosion resistance, the 6061 possesses higher resistance to corrosion than the 7075 alloys. This is due to the chemical composition of both aluminum alloys. The 7075 alloy contains a higher copper component than the 6061 alloy.
As a result, the 7075 aluminum reacts with the environment leading to corrosion. However, it would be best to consider using the 6061 aluminum for more corrosive-resistant applications.
Durability
Both 6061 and 7075 aluminum are durable aluminum alloy grades. However, the 6061 aluminum has excellent strength and moderate corrosion resistance, making it suitable for various applications.
Additionally, you can heat treat the 6061 aluminum to improve its durability. On the other hand, you can enhance the durability of 7075 aluminum. Nonetheless, it erodes quickly, causing degradation of the alloy.
Weight
When considering the difference in 6061 vs. 7075 aluminum weight, 7075 aluminum possesses a higher strength-to-weight ratio than 6061.
As a result, manufacturers prefer the 7075 aluminum to 6061 aluminum because it enables the creation of lightweight frames for high-quality handling and excellent fight range.
However, the strength-to-weight ratio for 6061 aluminum is 115 KN-m/Kg, while that of 7075 aluminum is 196 KN-m/Kg.
Machinability
The machinability of a material is how it reacts to machining processes like die-casting, milling, cutting, etc. Similarly, you can look at the machinability of a material as its fabrication considerations.
When machining, you can determine/calculate the machinability of a specific alloy using its tooling speed, tool life, and surface finish.
Both aluminum 7075 and 6061 can be machined without complications.
However, 6061 aluminum is more weldable and formable because it has less hardness and lower tensile strength. Consequently, the 6160 aluminum alloy grade responds well to machining.
Weldability
The 6061 aluminum is better for sheet metal fabrication than 7075 aluminum because of its reduced hardness and tensile stress.
More importantly, you should note that you can join both alloys using techniques like adhesive, soldering, or brazing. However, 6061 aluminum is weldable compared to 7075 aluminum.
Although 6061 aluminum is considerably weldable, you must take precautions in choosing the perfect weld filler metal.
However, you may need a post-weld heat treatment to restore the weld to the original “T” designation. On the other hand, the 7075 aluminum is prone to cracking following the welding process.
Strength Differences Between 6061 Aluminum and 7075 Aluminum
This section covers the comparison between the 6061 vs. 7075 aluminum strength:
Tensile Strength
7075 t6 vs. 6061 t6 tensile strength is a distinguishing factor. Although manufacturers use the 7075 t6 less in product development because it is costlier than the 6061 t6, the 7075 t6 aluminum has a tensile strength that is twice the amount of the 6061 t6.
Yield Strength
The 7075 aluminum alloy has better yield strength in contrast to 6061 aluminum. The 7075 can withstand extreme pressure and impact without deformation.
It would help to note that the 7075 aluminum has excellent yield strength due to its chemical composition and heat treatment. However, the 6061 aluminum has a yield strength of 276Mpa which means it isn’t entirely weak.
Ability to Form
Formability
The formability of aluminum alloys is the degree of deformation they can withstand without fracturing. It is one of its valuable characteristics.
Although aluminum can be easily formed, some aluminum grade has excellent formability than others.
In this context, the 6061 aluminum alloy has better formability than the 7075 aluminum because it can be cold-formed at lower temperatures. You can shape it without encountering any thermal shock.
Melting Point
The melting point of a metal means the temperature at which it changes from solid to liquid. However, the difference in the melting points of 6061 and 7075 aluminum alloys helps to determine their temperature resistance.
The 6061 aluminum melts between 1079.6 and 1205.6 ºF, while the 7075 aluminum’s melting point ranges between 890.6 and 117.5 ºF.
The 7075 aluminum melts at a slightly lower temperature even though it is stronger than 6061 aluminum. Nonetheless, know that the 7075 aluminum reacts well to heat treatment and facilitates the better distribution of elements in the metal compared to 6061 aluminum.
Appearance and Touch
Color
Both 6061 and 7075 aluminum have a grey-like color in their original form. However, you can apply any color your project requires when you anodize or paint the surface.
Hardness
The hardness of a material is a crucial measure in material selection. Hard materials are often breakable and can dent easily, while less hard alloys are flexible, allowing them to withstand bending without getting bent under pressure.
A material’s hardness determines its ability to withstand/resist deformation by penetration, indentation, or other ways. Hence, there must be a balance between ductility and hardness.
Both 6061 and 7075 alloys are hard enough to withstand pressure without deforming. Nevertheless, 7075 aluminum is harder when compared to 6061 aluminum.
Conductivity Differences Between 6061 Aluminum and 7075 Aluminum
Electrical Conductivity
6061 aluminum and 7075 aluminum are excellent electrical conductors due to their low electrical resistivity. Hence, both alloys are ideal for electrical applications.
Nevertheless, the 6061 possesses the lowest electrical resistivity, meaning it is a more suitable electrical conductor than the 7075 aluminum alloy.
Thermal Conductivity
Generally, aluminum alloys are outstanding heat/thermal conductors. However, the thermal conductivity of aluminum 6061 vs. 7075 varies due to their heat treatment and chemical composition.
6061 aluminum has a slightly higher thermal conductivity than 7075 alloys. As a result, it is a better option in heat exchangers with heat dissipation as a primary requirement.
Pricing & Options
It is evident that 7075 aluminum costs more than 6061 aluminum when compared. Consequently, manufacturers often use the 7075 aluminum when its high strength is required.
Although the 7075 aluminum has an extensive range of applications, manufacturers in the aircraft industries use it the most. However, you should consider using the 7075 aluminum if your project requires its high strength and lightweight properties.
6061 vs. 7075 Aluminum: Which is Cheaper?
The 6061 aluminum alloy grade is a versatile material that costs less than 7075 aluminum. More importantly, it possesses excellent corrosion resistance and is compatible with various machining processes such as extrusion and welding.
6061 vs. 7075 Aluminum: Which One to Choose?
Before choosing the ideal aluminum alloy for your project between 6061 and 7075 aluminum, you must examine the priorities.
This procedure requires a wide range of expertise and tests to determine the best aluminum alloy for your application. Nonetheless, it would help to note that the 7075 vs. 6061 mechanical properties are suited for various applications.
The 6061 aluminum alloy saves costs, has medium strength, and is easy to work with. However, 7075 aluminum is incredibly strong and has smoother surface finishes but costs more than 6061 aluminum.
Consequentially, engineers often use the 6061 aluminum frequently compared to 7075 aluminum because of the cost difference.
Although most suppliers use the 6061 aluminum as a first choice in aluminum alloy selection, you should consider the 7075 aluminum for desired results if your project requires its properties.
Additionally, the 6061 aluminum is the ideal alloy for welded parts with moderate-to-high tensile strength. However, the 7075 aluminum has excellent strength, perfect for applications that require extremely high tensile strength.
Kemal: Manufacturing Metal Parts and Prototypes for You
Kemal is a reliable manufacturing partner capable of providing the right solutions to all your manufacturing complexities.
We understand the importance of choosing suitable materials for your product machining at Kemal. Therefore, we use our expertise to guide you through the process, as our primary objective is to help you achieve the best-desired result.
We offer a wide array of materials for product manufacturing, providing you with options that best meet your demands. We combine excellent engineering capabilities and manufacturing standards to provide reliable rapid prototyping services.
Conclusion
Choosing between the right materials is crucial to the quality of parts in product development. That being said, aluminum alloys, amongst other materials, are commonly used by engineers in metal fabrication processes.
This article explored the differences between the 6061 and 7075 aluminum based on their specific applications and unique features. More importantly, it would help to carefully consider each material to ensure you choose the perfect one for your products.
