Duralumin Sheet Used In The Aviation Industry

Duralumin sheet is an age-hardening aluminum alloy sheet, primarily composed of aluminum, copper, manganese, and magnesium. Due to its excellent strength and lightweight properties, it is widely used in the aviation industry. Although it has been replaced in some modern applications by more advanced alloys, it remains irreplaceable in specific fields.

Composition of duralumin sheet:

Duralumin is a typical representative of heat-treatable aluminum alloys based on the aluminum-copper-magnesium system. Its core components are:

Aluminum (Al): Over 90%, providing a lightweight foundation (density approximately 2.8 g/cm³, only 1/3 that of steel);

Copper (Cu): Approximately 4%, forming the main strengthening phase (such as Al₂CuMg), significantly improving strength;

Magnesium (Mg): 0.5%-1.5%, synergistically strengthening with copper while improving heat resistance;

Manganese (Mn): 0.4%-1.0%, refining grain size and improving toughness.

Key characteristics of duralumin plate:

- High strength:

Tensile strength at room temperature reaches 370-420MPa, yield strength 240-280MPa, comparable to steel;

- Lightweight:

Low density, significantly reducing aircraft structural weight and improving fuel efficiency;

- Heat treatment strengthening:

Hardness is further improved through solution treatment and artificial aging (T6 state), reaching 105-125HB;

- Machining performance:

Supports rolling, extrusion, forging, and other processes, with a superplastic deformation rate exceeding 200% (requires electric field modification).

Common alloy grades of duralumin sheet:

2017-T4 aluminum: Material for aerospace rivets, possessing good machinability and strength.

2024-T3 aluminum: Standard grade for structural plates, used for aircraft skin and wing ribs.

2219-T8 aluminum: Material for welded space propulsion fuel tanks, with a wide temperature range.

7075 Super Hard Aluminum: With added zinc, its strength is 50% higher than the basic type, used for high-stress components.

Duralumin aluminum sheets can be processed through shearing, stamping, welding, and riveting to manufacture parts that meet design requirements. Furthermore, heat treatment (such as aging) can further improve their mechanical properties. To address the limitations of Duralumin (such as poor corrosion resistance and low weldability), the aerospace industry has optimized it through the following methods:

- Surface treatment:

Alclad: Applying a high-purity aluminum layer to the sheet surface significantly improves corrosion resistance;

Anodizing: Forming an oxide film that enhances corrosion and wear resistance; the film thickness can reach 10-25 μm.

- Heat treatment processes:

T4 Temper: Solution treatment + natural aging, suitable for processing scenarios requiring good plasticity;

T6 Temper: Solution treatment + artificial aging, increasing strength by 50%, suitable for high-load-bearing structures.

- Welding improvements:

Using 4043 or 4047 welding wire, preheating to 150-200℃ before welding, and performing T6 treatment after welding to reduce the risk of cracking.

Performance characteristics of duralumin sheet:

- High strength:

Duralumin possesses high strength and good fatigue resistance, with a typical yield strength of approximately 450 MPa, meeting the requirements of aerospace components to withstand high stresses.

- Lightweight and low density:

As an aluminum alloy, Duralumin has a low density, effectively reducing the overall weight of aircraft and improving fuel efficiency.

- Ease of machining:

Duralumin is easy to form and weld, exhibiting excellent machinability. It can be manufactured into complex shapes using various processing techniques to meet the needs of aerospace design.

- Heat treatable strengthening:

Duralumin is a heat-treatable aluminum alloy; its strength and hardness can be further improved through processes such as quenching and aging.

- Corrosion resistance:

Due to its high copper content, Duralumin's corrosion resistance is not as good as some other aluminum alloys. However, its corrosion resistance can be enhanced through surface treatments such as anodizing and cladding.

In the aviation industry, Duralumin sheet is widely used in aircraft structural components such as skins, frames, ribs, and bulkheads. It is also commonly used in the manufacture of rivets, truck wheel hubs, propeller components, and other parts. These components need to be as lightweight as possible while maintaining strength to improve flight performance and economy.

- Skin and panels:

As the aircraft's outer shell, they bear aerodynamic loads and require high strength and lightweight construction.

- Stringers and ribs:

Forming the wing skeleton and supporting the wing surface structure, they require high tensile strength.

- Spacecraft supports:

Used in satellites, rocket fuel tanks, etc., they need to withstand environments ranging from -270°C to 300°C.

- Precision components:

Such as aircraft propellers and high-speed gears, relying on their high strength and wear resistance.

Duralumin sheets, with their lightweight and high-strength properties, have laid the material foundation for the aviation industry. Their applications have expanded from early airship frames to modern passenger aircraft structural components, and their performance limits are continuously being pushed through surface treatment, heat treatment optimization, and composite strengthening technologies.