Aircraft Grade Aluminum 7175 Sheet: Preferred Material for High-Strength Designs

In modern aerospace and defense industries, the demand for lightweight yet high-strength materials continues to shape aircraft design and manufacturing. Engineers are constantly searching for alloys that can deliver exceptional tensile strength, fatigue resistance, and corrosion protection while maintaining low density for fuel efficiency and performance. One such material that meets and exceeds these expectations is the Aircraft Grade Aluminum 7175 Sheet.

Renowned for its excellent mechanical properties and reliability, Aluminum Alloy 7175 has become the preferred choice for high-strength aerospace designs, particularly in airframes, wings, landing gear, and structural reinforcements. Developed as an improvement over the classic 7075 alloy, 7175 offers enhanced toughness and superior resistance to stress-corrosion cracking, making it ideal for critical load-bearing structures.

In this article, we will explore why Aircraft Grade Aluminum 7175 Sheet has become the material of choice for modern aerospace engineering and how SASAALUMINUM continues to supply world-class aluminum materials for high-performance aircraft applications.

1. Understanding Aircraft Grade Aluminum 7175

Aluminum Alloy 7175 is a high-strength, heat-treatable alloy within the aluminum-zinc-magnesium-copper (7xxx series) family. It is primarily used in the aerospace industry, where both light weight and superior strength are essential.

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 alloy’s optimized heat treatment process provides an improved balance between strength and fracture toughness, ensuring consistent performance in high-stress environments. This makes the Aircraft Grade Aluminum 7175 Sheet a cornerstone material in high-performance aerospace designs.

2. Key Mechanical Properties

The mechanical characteristics of 7175 aluminum make it a superior alternative to many traditional materials in terms of both performance and weight efficiency.

Typical Mechanical Properties (T7351 Temper):

• Tensile Strength: 540–580 MPa

• Yield Strength: 460–510 MPa

• Elongation: 8–11%

• Hardness: 150–160 HB

• Fatigue Strength: 230–250 MPa

• Density: 2.81 g/cm³

This outstanding combination of high strength and low density allows aircraft manufacturers to reduce structural weight while maintaining the required load-bearing capability for safe flight performance.

3. Why 7175 Aluminum Is Preferred for High-Strength Designs

Aerospace engineers select Aluminum 7175 because it provides the ideal balance of mechanical power, corrosion protection, and processing stability—attributes critical to advanced aircraft design.

3.1 Superior Strength-to-Weight Ratio

7175 aluminum delivers steel-like strength at only one-third of the weight, making it a perfect material for components requiring high structural integrity without sacrificing fuel efficiency or range.

3.2 Excellent Fatigue and Fracture Resistance

Aircraft components are exposed to constant cyclic stress. The fine-grained structure of 7175 aluminum provides outstanding fatigue resistance and fracture toughness, preventing failure under repeated loading.

3.3 Enhanced Stress-Corrosion Resistance

Compared to 7075 alloy, 7175 in the T7351 temper offers excellent stress-corrosion cracking (SCC) resistance, ensuring safe performance in humid or saline environments—essential for long-haul and coastal aircraft.

3.4 Dimensional Stability and Thermal Performance

7175 aluminum maintains stability under temperature fluctuations, ensuring reliable operation across wide temperature ranges—from freezing altitudes to high-heat engine zones.

3.5 Superior Machinability and Finish

Its ability to be precisely machined into complex forms with excellent surface quality makes it ideal for aerodynamic parts, precision fittings, and high-tolerance structures.

4. Applications in Aerospace Structures

The Aircraft Grade Aluminum 7175 Sheet plays a critical role in high-strength, weight-sensitive parts of modern aircraft structures. Below are some of the major applications:

4.1 Fuselage Frames and Reinforcements

Fuselage structures require exceptional load-bearing capacity to handle cabin pressurization and aerodynamic forces. 7175 aluminum provides rigidity, toughness, and lightweight efficiency, making it perfect for fuselage frames, reinforcements, and panels.

4.2 Wing Spars and Ribs

Aircraft wings experience both bending and torsional loads during flight. The high strength and fatigue resistance of 7175 aluminum make it ideal for wing spars, ribs, and brackets, ensuring long-term durability.

4.3 Landing Gear Components

Landing gear systems face extreme compression and impact forces. 7175 aluminum’s toughness and fatigue performance allow it to be used in struts, supports, and actuator housings that endure repetitive landing cycles.

4.4 Engine Mounts and Pylon Structures

The alloy’s heat and corrosion resistance make it suitable for engine support frames and pylons, where mechanical vibration and high temperatures demand consistent reliability.

4.5 Secondary Aerospace Components

7175 aluminum is also used in seat tracks, structural brackets, and interior reinforcement plates, contributing to overall aircraft strength without adding unnecessary weight.

5. Comparison: 7175 vs 7075 Aluminum

While both belong to the 7000 series, 7175 aluminum offers significant advantages over 7075, especially for critical aerospace applications.