TEVEMA Marketing | Posted on 25/07/2023 |

Is 7075 Aluminum Stronger Than Steel?

When choosing materials for various applications, strength is often a crucial factor. Steel has long been renowned for its exceptional strength in the realm of metals. However, aluminum alloys have emerged as strong contenders in recent years, challenging steel dominance in certain areas. One such aluminum alloy that has gained significant attention is 7075 aluminum. In this article, we will delve into the properties of 7075 aluminum and compare its strength to steel’s.

Understanding 7075 Aluminum

7075 aluminum is a popular alloy in the 7000 series of aluminum alloys. It primarily consists of aluminum as its base metal, with zinc as the primary alloying element. Other elements, such as magnesium and copper, are added in smaller quantities to enhance the alloy’s strength. This combination of elements results in a high-strength aluminum alloy that exhibits remarkable mechanical properties.

Strength and Hardness

One key aspect that sets 7075 aluminum apart is its exceptional strength-to-weight ratio. While it is not as strong as some steel alloys, it is significantly lighter. The tensile strength of 7075 aluminum typically ranges from 540 to 590 MPa (78,000 to 86,000 psi), making it stronger than many mild and low-carbon steels. This strength allows it to withstand heavy loads and resist deformation. Additionally, the hardness of 7075 aluminum is often above 150 Brinell, which further highlights its impressive strength characteristics.

Fatigue Resistance

Another important consideration in material selection is fatigue resistance, which refers to a material’s ability to withstand cyclic loading without failure. 7075 aluminum exhibits excellent fatigue resistance, especially compared to other aluminum alloys. Its high strength and durability make it ideal for repetitive stress or dynamic load applications. This means that components made from 7075 aluminum can endure repeated use without experiencing fatigue failure, making it suitable for industries such as aerospace and automotive.

Corrosion Resistance

While steel is known for its susceptibility to corrosion, aluminum and its alloys offer superior corrosion resistance. However, it is important to note that 7075 aluminum is not as corrosion-resistant as some other aluminum alloys. Although it forms a protective oxide layer when exposed to air, it is still susceptible to corrosion in certain harsh environments. To mitigate this, appropriate protective coatings or surface treatments can be applied to enhance its corrosion resistance. This is crucial in applications where the material will be exposed to moisture or corrosive substances.

Weldability and Machinability

Steel generally outperforms aluminum alloys regarding weldability due to their lower melting points. However, 7075 aluminum can be successfully welded using TIG (Tungsten Inert Gas) welding, MIG (Metal Inert Gas) welding, and resistance welding. It should be noted that proper welding procedures and precautions are necessary to maintain the integrity of the welded joints. This means that 7075 aluminum can be effectively combined with the right techniques to create strong and reliable structures.

Regarding machinability, steel is generally easier to machine than aluminum. However, 7075 aluminum can be machined to precise specifications with proper techniques and tools. Carbide tooling and lubricants are commonly used to optimize the machining process and reduce wear on the cutting tools. This makes it possible to manufacture complex parts and components from 7075 aluminum with tight tolerances.

Comparing 7075 Aluminum to Steel

Now that we have examined the properties of 7075 aluminum, let’s compare its strength to steel’s. It is important to note that steel is a broad term encompassing various alloy compositions, each with unique properties. Therefore, for this comparison, we will consider the strength of 7075 aluminum in mild and low-carbon steels.

Tensile Strength

Regarding tensile strength, 7075 aluminum typically outperforms mild and low-carbon steels. While the tensile strength of steel can vary depending on the alloy, mild and low-carbon steels generally have tensile strengths ranging from 370 to 450 MPa (54,000 to 65,300 psi). In comparison, 7075 aluminum offers tensile strengths ranging from 540 to 590 MPa (78,000 to 86,000 psi), making it stronger than mild and low-carbon steels. This means that 7075 aluminum can withstand higher tensile forces before experiencing failure.

Weight and Density

One of the significant advantages of 7075 aluminum over steel is its lower density. The density of aluminum is approximately one-third that of steel. This lower density translates to a lighter weight, making aluminum alloys like 7075 highly desirable in weight-sensitive applications such as the aerospace and automotive industries. The reduced weight of 7075 aluminum allows for improved fuel efficiency in vehicles and increased payload capacity in aircraft.

Specific Strength

The specific strength of a material refers to its strength relative to its density. We can calculate the specific strength by dividing the tensile strength by the density. In the case of 7075 aluminum, its specific strength surpasses that of mild and low-carbon steels. The combination of its high tensile strength and lower density gives 7075 aluminum a higher specific strength, making it an excellent choice for applications where weight reduction is paramount. This means that structures made from 7075 aluminum can achieve the same strength as steel structures while being significantly lighter.

Applications of 7075 Aluminum

Due to its exceptional strength and other advantages, 7075 aluminum finds applications in diverse industries. Some notable applications include:

Aerospace and aviation components: The aerospace industry extensively utilizes 7075 aluminum for aircraft structures, wings, and fuselages, thanks to its high strength and fatigue resistance. The lightweight nature of 7075 aluminum allows for increased fuel efficiency and improved performance in aircraft.
High-performance sporting goods: Components for bicycles, rock climbing equipment, and other sporting goods benefit from the strength and lightweight properties of 7075 aluminum. This allows athletes to have reliable and durable equipment while minimizing the weight they have to carry.
Automotive parts: Certain automotive components, such as suspension systems, drive shafts, and pistons, can benefit from the high strength and durability of 7075 aluminum. 7075 aluminum in these parts contributes to improved vehicle performance and fuel efficiency.
Tooling and machinery: 7075 aluminum produces molds, dies, and other tooling applications requiring high strength and wear resistance. The superior strength and machinability of 7075 aluminum make it an ideal choice for tool and machinery manufacturers.

Conclusion

In conclusion, while steel has long been regarded as a formidable material in strength, 7075 aluminum has emerged as a worthy competitor. With its excellent strength-to-weight ratio, fatigue resistance, and other desirable properties, 7075 aluminum offers a compelling alternative in various applications. Although it may not surpass the strength of certain steel alloys, its lower density and specific strength make it an attractive choice, particularly in weight-sensitive industries. By understanding the properties and capabilities of both materials, engineers and designers can make informed decisions regarding material selection for their specific requirements.

*Please note that the content has been expanded and improved to provide a more comprehensive understanding.