Why aluminum 7075 is used in aircraft industry?
7075 Aluminum Alloy: An Ideal Choice for Aerospace Applications
In modern industries, aluminum alloys are highly sought after due to their lightweight, high strength, and excellent corrosion resistance. Among them, 7075 aluminum alloy, a high-strength cold-treated forged alloy, has become an essential material in the aerospace sector due to its outstanding properties.
Firstly, in terms of chemical composition, the primary alloying element in 7075 aluminum is zinc, along with moderate amounts of magnesium, copper, and chromium. The zinc content ranges from 5.1% to 6.1%, and magnesium content ranges from 2.1% to 2.9%. The addition of these elements enables the formation of the MgZn₂ phase during heat treatment, significantly enhancing the material's tensile strength. Specifically, 7075 aluminum alloy exhibits a tensile strength of up to 524 MPa, a yield strength of 455 MPa, a hardness of 150 HB, and a density of 2.81 g/cm³. These exceptional mechanical properties allow 7075 aluminum to outperform standard steel in strength while meeting the aerospace industry's stringent requirements for high strength and low weight materials.
Secondly, 7075 aluminum alloy boasts excellent physical characteristics. In addition to its superior mechanical properties, it offers good corrosion resistance and anodizing performance. Its fine grain structure improves performance in deep-hole drilling and enhances tool wear resistance. Moreover, through appropriate heat treatment processes, such as T6 tempering, the strength of 7075 aluminum can be further improved, meeting the needs of complex structural components. These features make 7075 aluminum an outstanding choice for manufacturing aircraft structures and other high-stress components.
In terms of machinability, 7075 aluminum alloy demonstrates excellent processability. Although it belongs to the high-strength aluminum category and has relatively poor weldability, advanced welding techniques such as friction stir welding (FSW) can effectively address issues such as solidification cracks in the weld metal and liquation cracks in the heat-affected zone. This ensures high-quality connections for complex structures in aerospace applications.
application of 7075 aluminum in aerospace
It is used to manufacture key components like aircraft frames, landing gears, and high-strength fittings. Due to its high strength and excellent corrosion resistance, 7075 aluminum significantly enhances the structural strength and safety of aircraft while reducing overall weight and fuel consumption.
7075 aluminum alloy is used in the production of spacecraft components, such as satellite frames and rocket parts. These applications underscore the exceptional performance and critical importance of 7075 aluminum in the aerospace field.
How to Choose Between T6, T651, T73, and T7351 Tempers of 7075 Aluminum Alloy
Each temper of 7075 aluminum alloy has unique characteristics and application scenarios.
T6 Temper: The T6 temper is achieved through solution heat treatment and artificial aging. In this state, the alloy reaches its highest strength but has relatively poor stress corrosion resistance. With a hardness of 150 HB, it is widely used in applications requiring high strength and hardness, such as aircraft structural components, molds, and high-strength mechanical parts.
T651 Temper: The T651 temper is obtained by stretching the material in the T6 state. This process improves stress corrosion resistance while maintaining high strength. 7075 aluminum alloy in the T651 temper is widely used in aerospace for manufacturing critical components such as aircraft fuselages and engine parts.
T73 Temper: The T73 temper is achieved through over-aging treatment, which significantly improves the alloy's resistance to stress corrosion cracking, though it sacrifices some strength. 7075 aluminum in the T73 temper is suitable for applications with high corrosion resistance requirements, such as marine environments or chemical industry equipment.
T7351 Temper: The T7351 temper is an improved version of the T6 temper, achieved through specific heat treatment processes. In this state, the alloy has better stress corrosion resistance than T6 while maintaining high strength. 7075 aluminum in the T7351 temper is commonly used for components requiring high strength and corrosion resistance, such as armaments and high-end mechanical equipment.