The Ultimate Guide to Aluminum Alloy Al 7075

As a manufacturing factory specializing in custom Al 7075 parts, we recognize the importance and wide-ranging applications of this material in mechanical design. Aluminum alloy Al 7075 is a top choice among many mechanical designers due to its outstanding mechanical properties and versatility.

Al 7075 boasts an excellent strength-to-weight ratio, making it ideal for lightweight and high-strength applications. With a tensile strength of up to 560 MPa, it is suitable for industries requiring stringent part strength and durability, such as aerospace, automotive manufacturing, and sports equipment.

Additionally, aluminum alloy Al 7075 exhibits excellent machinability and can be shaped using various processes including milling, drilling, turning, and welding to create complex structures and shapes. It also demonstrates superb corrosion resistance, particularly in harsh environments like seawater and chloride.

In this blog post, we will delve into the unique properties and application areas of aluminum alloy Al 7075, sharing real-world examples and success stories to provide valuable insights and inspiration for mechanical designers. Let’s explore the advantages and innovative uses of Al 7075 together, contributing our experience and expertise to the advancement of mechanical design.

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What is 7075 aluminium alloy?

Aluminum alloy Al 7075 is known for its strength, light weight, and corrosion resistance. It’s a top choice in mechanical design for its exceptional performance.

In the world of engineering, Al 7075 is popular because it offers high strength while being lightweight. This makes it perfect for applications where durability and weight are critical factors.

Its corrosion resistance is also a big plus, especially in challenging environments like marine settings or areas with high chloride exposure.

Overall, Al 7075 is prized for its ability to combine strength, lightness, and durability, making it indispensable in mechanical design.

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Al 7075: Exceptional Mechanical Performance

Aluminum alloy Al 7075 exhibits excellent mechanical properties, making it highly desirable for various mechanical applications. With a tensile strength of approximately 570 MPa (83,000 psi) and a yield strength of around 505 MPa (73,000 psi), Al 7075 offers exceptional strength comparable to many steels but at a much lower weight. This high strength-to-weight ratio makes Al 7075 ideal for applications where both strength and weight are critical considerations, such as aerospace components, automotive parts, and sporting equipment. Additionally, Al 7075 maintains good toughness and fatigue strength, ensuring reliable performance under demanding conditions. Its combination of strength, lightness, and durability contributes to its widespread use and popularity in mechanical design.

Hardness, and Corrosion Resistance

Aluminum alloy Al 7075 is renowned for its impressive mechanical properties, characterized by high strength, excellent hardness, and notable corrosion resistance. With a typical tensile strength of approximately 570 MPa (83,000 psi) and a yield strength of around 505 MPa (73,000 psi), Al 7075 exhibits exceptional strength-to-weight ratio, making it suitable for lightweight structural applications. In terms of hardness, Al 7075 typically achieves a hardness of 150 HB (Brinell Hardness), demonstrating its ability to withstand wear and deformation. Moreover, Al 7075 possesses good corrosion resistance, particularly in environments where it may be exposed to moisture, saltwater, or chloride. This combination of mechanical properties makes Aluminum Alloy Al 7075 a preferred choice for industries requiring high-performance materials with resistance to corrosion and wear.

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Mechanical properties

The mechanical properties of Aluminum Alloy 7075 vary significantly based on the tempering process applied to the material.

7075-O
Untreated 7075 (in the 7075-O temper) exhibits a maximum tensile strength of up to 280 MPa (40,000 psi) and a maximum yield strength of around 140 MPa (21,000 psi). The material can stretch or elongate by 9–10% before reaching ultimate failure. Similar to other 7075 aluminum alloys, 7075-O offers high corrosion resistance along with a generally acceptable strength profile.

7075-T6
7075-T6 temper demonstrates an ultimate tensile strength ranging from 510 to 540 MPa (74,000–78,000 psi) and a yield strength of at least 430–480 MPa (63,000–69,000 psi). It shows a failure elongation of 5–11%.

Achieving the T6 temper involves homogenizing the cast 7075 at 450 °C for several hours, followed by quenching and ageing at 120 °C for 24 hours. This process results in the peak strength of the 7075 alloys, mainly attributed to finely dispersed eta and eta’ precipitates within and along the grain boundaries.

7075-T651
In the T651 temper, 7075 has an ultimate tensile strength of 570 MPa (83,000 psi) and a yield strength of 500 MPa (73,000 psi), with a failure elongation of 3–9%. These properties can vary depending on the specific form of the material used, with thicker plates potentially exhibiting lower strengths and elongation compared to the listed values.

7075-T7
7075-T7 temper offers an ultimate tensile strength of 505 MPa (73,200 psi) and a yield strength of 435 MPa (63,100 psi), along with a failure elongation of 13%. The T7 temper involves overaging the material (aging past peak hardness), typically at temperatures between 100–120 °C for several hours followed by further aging at 160–180 °C for 24 hours or more. This process results in a microstructure predominantly composed of eta precipitates, which are larger and preferentially grow along grain boundaries, reducing susceptibility to stress corrosion cracking.

7075-RRA
The retrogression and reage (RRA) temper is a multistage heat treatment process. Starting with a sheet in the T6 temper, RRA involves overaging past peak hardness (similar to T7 temper), followed by reaging at 120 °C for 24 hours to restore hardness and strength levels close to or equivalent to the T6 temper.

RRA treatments can be conducted using various procedures, typically involving retrogressing between 180 and 240 °C for 15 minutes and 10 seconds.

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Al 7075 VS Common Aluminum Alloys

Aluminum alloy Al 7075 stands out among other commonly used aluminum alloys due to its exceptional mechanical properties. Let’s compare Al 7075 with some typical aluminum alloys:

  1. Tensile Strength:
    • Al 7075: Approximately 570 MPa (83,000 psi)
    • Al 6061: Approximately 310 MPa (45,000 psi)
    • Al 6063: Approximately 210 MPa (30,000 psi)
  2. Yield Strength:
    • Al 7075: Approximately 505 MPa (73,000 psi)
    • Al 6061: Approximately 275 MPa (40,000 psi)
    • Al 6063: Approximately 170 MPa (25,000 psi)
  3. Hardness (Brinell Hardness):
    • Al 7075: Typically around 150 HB
    • Al 6061: Typically around 95 HB
    • Al 6063: Typically around 60 HB
  4. Corrosion Resistance:
    • Al 7075: Good corrosion resistance, especially in marine and chloride-rich environments.
    • Al 6061: Moderate corrosion resistance.
    • Al 6063: Moderate corrosion resistance, suitable for architectural applications.

From these comparisons, it’s evident that Aluminum Alloy Al 7075 surpasses other common aluminum alloys in terms of strength, hardness, and corrosion resistance. Its significantly higher tensile and yield strengths make it ideal for applications requiring lightweight yet durable components, such as aerospace structures, automotive parts, and sporting equipment. The enhanced mechanical properties of Al 7075 contribute to its widespread use and preference in demanding engineering applications.

CNC turning of 7075 aluminum

Aluminum Alloy Al 7075: Enhancing Automotive Prototypes

As a manufacturing company, we collaborated with a European automotive manufacturer on a prototype project, customizing aluminum alloy Al 7075 components to showcase their practical application and effectiveness.

This project lasted approximately three months, from initial design confirmation to the delivery of components. We worked closely with the automotive manufacturer’s engineering team to define the design and specification requirements of the parts. Al 7075 was chosen as the preferred material due to its ability to meet lightweight and high-strength requirements, suitable for automotive prototype design and manufacturing.

During the machining process, we utilized advanced CNC machining equipment with multi-axis cutting technology to precisely machine Al 7075 material. This included milling, drilling, and turning processes to achieve precise shaping of complex parts. We paid particular attention to dimensional accuracy and surface quality to meet the client’s high standards.

Ultimately, we successfully manufactured and delivered the Al 7075 components according to schedule. Upon receiving the parts, the client highly praised their quality and performance, particularly impressed by the strength and lightweight characteristics of Al 7075 material. These components were successfully integrated into their prototype vehicle, showcasing the superior performance and practical application of the material.

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Applications

Through this project, we gained a deep appreciation for the importance of aluminum alloy Al 7075 in automotive design and manufacturing, as well as its value and potential in practical projects. This outstanding material brings additional possibilities and innovations to the automotive industry, driving the entire sector towards lighter and more efficient solutions.

Aluminum alloy Al 7075 is a high-strength, lightweight material widely used in mechanical design across various industries. Here are common application areas:

  1. Aerospace Industry:
    • Al 7075 is extensively used in aircraft structures and components such as fuselage shells, wings, landing gear, and engine parts. Its high strength-to-weight ratio improves aircraft performance and fuel efficiency.
  2. Automotive Industry:
    • In automotive manufacturing, Al 7075 is employed to fabricate critical components like car wheel hubs, body structures, and suspension parts. It reduces vehicle weight, enhances performance, and offers excellent corrosion resistance.
  3. Sports Equipment:
    • Al 7075 is commonly used for manufacturing sports equipment such as bicycle frames, golf clubs, and scooter parts. Its high strength and durability make these equipment lighter, stronger, and provide superior performance.
  4. Defense and Military Applications:
    • Due to its exceptional mechanical properties and durability, Al 7075 finds extensive use in defense and military applications, including aircraft, helicopters, artillery, missiles, and armored vehicles.

7075 aluminum parts machining

Al 7075 in Mechanical Design: Principles and Best Practices

Aluminum alloy Al 7075 is a commonly used high-strength alloy in mechanical design for applications requiring lightweight construction and high strength. Here is a discussion on the principles and best practices for maximizing the use of Al 7075, as well as its suitability, limitations, and key considerations in design:

1. Advantages and Suitability of Al 7075:

  • High Strength: Al 7075 offers high tensile strength and hardness compared to many common aluminum alloys like Al 6061, making it suitable for applications subjected to high loads or stress.
  • Lightweight: With a lower density compared to many other metals, aluminum alloy Al 7075 is beneficial for designs where weight reduction is critical, such as in aerospace and automotive industries.
  • Corrosion Resistance: Al 7075 exhibits good corrosion resistance and performs well in most industrial environments, especially in contact with saltwater or other corrosive liquids.

2. Limitations and Considerations with Al 7075:

  • Weldability: Al 7075 has poor weldability and is prone to hot cracking, necessitating the consideration of alternative joining methods like riveting or mechanical fastening in designs.
  • Stress Corrosion Cracking: Under certain stress environments, Al 7075 may experience stress corrosion cracking, requiring avoidance in parts susceptible to stress concentration or prolonged high stress.
  • Surface Treatment: Due to its lower surface hardness, Al 7075 is susceptible to wear and scratches, necessitating the consideration of surface coatings or other enhancement measures in design.

3. Key Factors to Consider in Design:

  • Stress Analysis: Conduct thorough stress analysis to ensure that the designed structure and thickness can meet the required loads and stress requirements.
  • Process and Manufacturing: Consider the machinability of Al 7075 and associated manufacturing costs, selecting appropriate machining processes and equipment.
  • Geometry: Avoid overly complex geometries or stress concentration points in design, striving for uniform structural features.
  • Environment and Conditions of Use: Consider the operating environment and conditions for the designed component, including temperature, humidity, and chemical exposure, to ensure material selection and design durability.
  • Material Properties: Understand the material properties of Al 7075, including strength, hardness, thermal expansion coefficient, etc., for informed design and material selection decisions.
  • Joining Methods: Select suitable joining methods based on Al 7075’s welding characteristics, such as riveting, bolting, or mechanical fastening.
  • Surface Treatments: Consider the need for surface treatments on Al 7075, such as anodizing, coatings, or finishes, to enhance wear resistance, corrosion resistance, and aesthetics.

7075 aluminum alloy machining

Manufacturing and Machining Methods for Al 7075

As a professional factory specializing in manufacturing Al 7075 parts, we employ advanced techniques and expertise in machining this high-strength aluminum alloy. Here is a discussion on machining methods and considerations for working with aluminum alloy Al 7075, including milling, turning, welding, and key tips for successful processing:

Machining Methods and Techniques:

1. Milling:

  • Tool Selection: Use carbide or high-speed steel (HSS) tools with sharp cutting edges to reduce tool wear.
  • Cutting Parameters: Optimize cutting speed and feed rates to minimize heat generation and achieve smooth surface finishes.
  • Coolant Use: Apply adequate coolant or cutting fluid to dissipate heat and improve chip evacuation.

2. Turning:

  • Tool Geometry: Utilize sharp cutting tools with positive rake angles for efficient chip removal.
  • Cutting Speed: Maintain appropriate cutting speeds to prevent work hardening of Al 7075.
  • Chip Control: Implement proper chip control techniques to avoid built-up edge (BUE) and ensure dimensional accuracy.

3. Welding:

  • Preparation: Clean surfaces thoroughly to remove oxide layers and contaminants before welding.
  • Welding Techniques: Use TIG (Tungsten Inert Gas) or MIG (Metal Inert Gas) welding for Al 7075, with proper shielding gases (e.g., argon) to prevent oxidation.
  • Post-Weld Treatment: Apply appropriate heat treatments (e.g., T6 tempering) to restore mechanical properties after welding.

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Considerations and Tips for Processing Al 7075:

  • Avoid Excessive Heat: Al 7075 is sensitive to high temperatures, which can lead to work hardening and reduced machinability. Employ techniques to control heat generation during machining.
  • Tool Selection: Choose cutting tools specifically designed for aluminum alloys, considering material hardness and abrasiveness.
  • Workholding: Ensure secure and rigid workholding to minimize vibrations and maintain dimensional accuracy.
  • Chip Management: Implement effective chip evacuation strategies to prevent chip re-cutting and tool damage.
  • Surface Finish: Use appropriate feeds and speeds to achieve desired surface finishes without compromising tool life or part integrity.

Yes, 7075 aluminum is stronger than many types of steel, including some lower-grade steels. It has a high tensile strength comparable to certain steel alloys.

Among commonly used aluminum alloys, 7075 is one of the strongest. It exhibits excellent strength-to-weight ratio and is often considered the strongest aluminum alloy available for commercial use.

The choice between 6061 and 7075 aluminum depends on the specific application. Generally, 7075 offers higher strength but is more difficult to machine and more expensive compared to 6061, which has good machinability and moderate strength.

Welding 7075 aluminum is challenging due to its high strength and susceptibility to cracking during welding. It tends to crack under heat stress, making alternative joining methods like riveting or adhesive bonding preferable.

Yes, 7075 aluminum is considered difficult to machine due to its high strength and tendency to generate heat during cutting. Specialized cutting tools and techniques are required to achieve optimal results.

7075 aluminum has limited formability and is not particularly suited for bending operations compared to softer aluminum alloys like 6061. It may crack or fracture when subjected to severe bending without proper precautions.

No, aluminum does not rust like iron or steel. However, 7075 aluminum can corrode over time when exposed to certain environments, particularly in the presence of moisture and salts. Proper surface treatments and coatings can enhance corrosion resistance.

Since its establishment in 2005, Modo Rapid has been a leader in the custom aluminum parts industry. Whether it’s prototypes, small batches, or large-scale production, we offer manufacturing services to assist product developers in gaining deeper insights into materials and processes, supporting their growth every step of the way. We look forward to addressing your needs and providing solutions.

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