Aircraft Grade Aluminum 7175 Sheet for Fuselage, Wing, and Landing Gear Components

In the highly advanced aerospace industry, the selection of structural materials plays a vital role in ensuring safety, performance, and efficiency. Modern aircraft demand materials that are not only strong and lightweight but also capable of withstanding high stress, fatigue, and corrosion over long service lifespans. Among the many aluminum alloys available, the Aircraft Grade Aluminum 7175 Sheet has emerged as a superior choice for critical components such as the fuselage, wings, and landing gear structures.

Developed as an improvement over the 7075 alloy, Aluminum Alloy 7175 offers enhanced fracture toughness, excellent mechanical strength, and exceptional fatigue resistance, making it ideal for aircraft assemblies exposed to demanding flight conditions.

This article explores the properties, advantages, and specific applications of Aircraft Grade Aluminum 7175 Sheet in aerospace structures and highlights why SASAALUMINUM remains a trusted supplier to global aircraft manufacturers.

1. Overview of Aircraft Grade Aluminum 7175

Aluminum Alloy 7175 is a heat-treatable aluminum-zinc-magnesium-copper alloy designed primarily for aerospace structural applications. It is closely related to the well-known 7075 alloy but features a more refined microstructure, which results in better toughness and uniform mechanical properties.

Typical Chemical Composition (%):

• Zinc (Zn): 5.6–6.1

• Magnesium (Mg): 2.4–2.9

• Copper (Cu): 1.2–1.6

• Chromium (Cr): 0.18–0.28

• Aluminum (Al): Balance

The addition of zinc and magnesium gives the alloy its superior strength, while copper and chromium improve heat-treating response and corrosion resistance. As a result, Aircraft Grade Aluminum 7175 Sheet provides both lightweight efficiency and high structural integrity—key attributes in modern aircraft design.

2. Key Mechanical Properties

The performance of 7175 aluminum is enhanced through heat treatment and precise processing, making it one of the most robust aluminum alloys used in aviation.

Typical Mechanical Properties (T7351 Temper):

• Tensile Strength: 540–580 MPa

• Yield Strength: 460–510 MPa

• Elongation: 8–11%

• Hardness: 150–160 HB

• Density: 2.81 g/cm³

• Fatigue Strength: 230–250 MPa

These values highlight 7175 aluminum’s outstanding strength-to-weight ratio, which is essential for reducing aircraft mass while maintaining rigidity and safety.

3. Advantages of Aluminum 7175 in Aerospace Engineering

The Aircraft Grade Aluminum 7175 Sheet delivers several distinct advantages that make it highly suitable for airframe and landing gear components:

3.1 Superior Strength-to-Weight Ratio

7175 aluminum offers near-steel strength at only one-third of the weight, making it ideal for reducing aircraft mass without sacrificing performance or durability.

3.2 Excellent Fatigue and Fracture Resistance

With improved fracture toughness and fatigue performance over 7075, 7175 can endure the repetitive loading cycles experienced by wings and fuselage during flight operations.

3.3 High Corrosion and Stress-Corrosion Resistance

In the T7351 condition, 7175 aluminum exhibits superior stress-corrosion cracking (SCC) resistance, essential for components exposed to moisture, hydraulic fluids, and temperature variations.

3.4 Stable Thermal Performance

The alloy maintains consistent mechanical properties under both low and elevated temperatures, ensuring structural integrity in changing flight conditions.

3.5 Excellent Machinability and Surface Finish

Aircraft Grade Aluminum 7175 Sheet machines cleanly and produces precise components with excellent surface finish—important for tight-fitting assemblies and aerodynamic surfaces.

4. Applications in Fuselage Structures

The fuselage serves as the main structural body of an aircraft, housing passengers, cargo, and critical systems. To ensure strength, rigidity, and weight reduction, 7175 aluminum sheets are widely used in several fuselage components.

4.1 Frame Assemblies and Bulkheads

7175 aluminum provides the high compressive strength required for fuselage frames and bulkheads, absorbing flight loads while maintaining low mass.

4.2 Skin Reinforcements and Stringers

Lightweight yet strong, 7175 sheets are used in skin reinforcements, stringers, and stiffeners, contributing to the fuselage’s ability to resist pressurization and vibration fatigue.

4.3 Door Surrounds and Cargo Sections

The alloy’s superior corrosion resistance ensures longevity in areas frequently exposed to humidity and pressure cycles, such as door frames and cargo compartments.

4.4 Pressure Vessel Sections

Its fracture toughness and fatigue strength make it ideal for pressure-resistant areas of the fuselage, maintaining safety during rapid altitude changes.

5. Applications in Wing Structures

Aircraft wings must endure aerodynamic loads, vibration, and temperature fluctuations throughout every flight. Aluminum 7175 excels in these demanding applications.

5.1 Wing Spars and Ribs

Wing spars act as the “backbone” of the wing. 7175’s strength and fatigue resistance enable the spars and ribs to carry bending moments and shear loads efficiently.

5.2 Wing Skins and Panels

The smooth machinability and high surface quality of 7175 aluminum make it suitable for wing skin panels, ensuring excellent aerodynamics and corrosion protection.

5.3 Flap and Aileron Fittings

Precision components such as flap tracks, hinges, and aileron brackets benefit from 7175’s combination of toughness and lightweight performance.

5.4 Attachment Points and Mounting Plates

The alloy’s hardness and wear resistance make it ideal for mounting interfaces where components are bolted or riveted under high stress.

6. Applications in Landing Gear Components

The landing gear experiences some of the most extreme loads in aircraft operation. Components must withstand impact, torsion, and corrosion—conditions that Aircraft Grade Aluminum 7175 Sheet is designed to handle effectively.

6.1 Struts and Braces

Landing gear struts made from 7175 alloy combine high compressive strength and toughness, ensuring safety during takeoff and landing impacts.

6.2 Fittings and Actuator Mounts

The alloy’s high yield strength allows it to resist deformation in actuator fittings, trunnions, and brackets under heavy landing loads.

6.3 Support Frames and Housing Sections

Corrosion resistance ensures reliability even when the landing gear is exposed to rain, de-icing fluids, or salt spray during airport operations.

6.4 Fastening and Connection Hardware

Fasteners and brackets fabricated from 7175 aluminum retain strength while keeping the overall structure lightweight and stable.

7. Comparison: 7175 Aluminum vs 7075 Aluminum

While both alloys belong to the high-strength 7000 series, 7175 aluminum offers improved reliability in critical aerospace structures.