In the aerospace industry, where safety, strength, and weight efficiency are equally vital, materials must meet the most demanding performance requirements. Every structural component — from fuselage frames to landing gear — must endure high stress, vibration, and extreme environmental conditions while maintaining a minimal weight profile. Among all aluminum alloys designed for aerospace use, the Aircraft Grade Aluminum 7175 Sheet stands out for its exceptional strength, fatigue resistance, and toughness.
Developed as part of the high-strength 7000 series aluminum alloys, Aluminum 7175 offers an outstanding balance between mechanical durability and weight reduction, making it one of the most reliable materials for high-stress aircraft structures. This alloy is widely used in commercial aviation, defense systems, and space vehicles, where precision and long-term performance are non-negotiable.
In this article, we explore why Aircraft Grade Aluminum 7175 Sheet excels in high-stress aerospace applications, discussing its composition, mechanical properties, manufacturing processes, and performance advantages — and how SASAALUMINUM provides aerospace-quality materials that meet the world’s highest standards.
Introduction to Aluminum 7175
Aluminum Alloy 7175 is a heat-treatable aluminum-zinc-magnesium-copper (Al-Zn-Mg-Cu) alloy belonging to the 7000 series. It was specifically engineered for critical aerospace components that require maximum strength with minimum weight.
Compared to standard alloys such as 7075, 7175 offers enhanced fracture toughness, better stress corrosion resistance, and superior fatigue life, especially in the T7351 temper condition. These improvements make it ideal for parts that are constantly subjected to tensile and compressive stresses, thermal cycling, and high vibration loads.
The secret behind 7175’s performance lies in its fine-grain structure and controlled heat treatment, which together deliver high static and dynamic strength without compromising toughness or machinability.
Chemical Composition of Aircraft Grade Aluminum 7175
| Element | Content (%) | Function |
|---|---|---|
| Zinc (Zn) | 5.6 – 6.1 | Main strengthening element through precipitation hardening |
| Magnesium (Mg) | 2.3 – 2.9 | Improves hardness and tensile strength |
| Copper (Cu) | 1.2 – 1.9 | Enhances machinability and stress corrosion resistance |
| Chromium (Cr) | 0.18 – 0.28 | Prevents grain boundary corrosion and refines grain size |
| Iron (Fe) | ≤ 0.20 | Controlled impurity |
| Silicon (Si) | ≤ 0.10 | Controlled impurity to maintain toughness |
| Manganese (Mn) | ≤ 0.10 | Improves ductility and toughness |
| Titanium (Ti) | ≤ 0.06 | Refines grains during casting |
| Aluminum (Al) | Balance | Provides low density and natural corrosion resistance |
The optimized combination of zinc, magnesium, and copper ensures that Aircraft Grade Aluminum 7175 Sheet delivers an exceptional blend of lightweight performance, mechanical strength, and long-term reliability.
Mechanical Properties of Aluminum 7175 Sheet
| Property | Typical Value (T7351 Condition) |
|---|---|
| Tensile Strength | 510 – 570 MPa |
| Yield Strength | 440 – 500 MPa |
| Elongation | 7 – 11% |
| Density | 2.81 g/cm³ |
| Hardness | 155 – 170 HB |
| Fatigue Strength | 160 – 180 MPa |
| Modulus of Elasticity | 71 GPa |
| Operating Temperature Range | -50°C to 120°C |
These properties enable Aluminum 7175 Sheet to sustain extreme mechanical loads while maintaining excellent structural integrity. Its strength-to-weight ratio surpasses that of many conventional materials, including carbon steels and titanium alloys, making it ideal for aerospace load-bearing structures.
Why Aluminum 7175 Excels in High-Stress Aerospace Applications
1. Exceptional Strength-to-Weight Ratio
One of the greatest advantages of Aircraft Grade Aluminum 7175 Sheet is its high strength at low density. Weighing only 2.81 g/cm³, it provides nearly three times the strength of pure aluminum and comparable tensile strength to low-alloy steels — while being about 60% lighter.
This remarkable strength-to-weight ratio directly translates into:
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Increased fuel efficiency and payload capacity
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Reduced takeoff weight and improved flight range
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Enhanced structural efficiency for critical components
In aerospace design, every kilogram saved contributes to significant performance and economic benefits, making 7175 aluminum an invaluable material choice.
2. Superior Fatigue Resistance for Cyclic Loading
Aircraft structures experience millions of cyclic stresses during flight operations — from takeoff and landing to atmospheric pressure changes. Fatigue resistance determines how long a material can withstand repeated loading before cracks initiate.
Aluminum 7175 Sheet, with its fine-grain microstructure and homogeneous precipitation of MgZn₂ particles, exhibits superior fatigue strength compared to traditional alloys.
Advantages include:
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Reduced crack initiation rate
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Higher endurance limit under fluctuating stress
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Greater reliability in pressurized cabin structures and wing joints
This makes 7175 aluminum the preferred alloy for wing spars, fuselage joints, and landing gear fittings where fatigue performance is critical.
3. High Fracture Toughness and Damage Tolerance
Fracture toughness defines how well a material can resist crack propagation once a flaw forms. In aircraft components, this is vital for maintaining safety margins even under localized damage.
Thanks to its controlled grain structure refinement and optimized heat treatment (T7351), Aluminum 7175 offers significantly higher fracture toughness than 7075, ensuring better crack resistance under stress concentrations.
This allows for damage-tolerant design, extending service life and reducing maintenance costs for aircraft operators.
4. Excellent Stress Corrosion Resistance
Stress corrosion cracking (SCC) is one of the leading causes of material degradation in aluminum alloys exposed to moisture and mechanical stress. 7175 aluminum, especially in the T7351 temper, is engineered for superior SCC resistance.
The precise balance of chromium and copper minimizes the risk of intergranular corrosion, ensuring structural stability even in humid, coastal, or fuel-rich environments. This makes the alloy suitable for use in airframe skins, fuselage structures, and aerospace fasteners that face both mechanical and chemical challenges.
5. Stable Performance Under Temperature Variations
Aircraft materials must maintain performance under both cryogenic cold (high-altitude flight) and high thermal stress (engine proximity). Aircraft Grade Aluminum 7175 Sheet maintains its strength and toughness across a wide temperature range from -50°C to 120°C without distortion or loss of ductility.
Its thermal stability and low thermal expansion rate allow it to resist fatigue cracking during temperature fluctuations, making it ideal for structural parts exposed to thermal gradients.
6. Outstanding Machinability and Formability
Despite its high strength, 7175 aluminum sheet offers excellent machinability, allowing engineers to achieve precise dimensions and tight tolerances for complex aerospace geometries.
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Suitable for CNC machining, milling, and precision forming
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Compatible with friction stir welding (FSW) and riveting
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Minimal distortion during processing due to stable microstructure
These qualities reduce fabrication time and cost while maintaining structural consistency, ensuring components meet aerospace-grade specifications.
Comparison: Aluminum 7175 vs. Other Aerospace Alloys
| Property | Aluminum 7175 | Aluminum 7075 | Aluminum 7050 |
|---|---|---|---|
| Strength | Very High | High | Very High |
| Fracture Toughness | Excellent | Moderate | Excellent |
| Stress Corrosion Resistance | Outstanding | Good | Excellent |
| Fatigue Resistance | Excellent | Very Good | Excellent |
| Density (g/cm³) | 2.81 | 2.81 | 2.83 |
| Common Temper | T7351 | T651 | T7451 |
| Applications | Landing gear, wing spars, fuselage joints | Aircraft fittings | Structural forgings |
Aluminum 7175 provides a superior balance of strength, toughness, and corrosion resistance, outperforming 7075 in high-stress environments and offering comparable or improved performance over 7050 in fatigue-critical applications.
Applications of Aircraft Grade Aluminum 7175 Sheet
Given its unique combination of properties, Aircraft Grade Aluminum 7175 Sheet is used in numerous aerospace and defense applications, including:
Aerospace Structural Components
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Wing spars, fuselage frames, and bulkheads
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Landing gear fittings and engine mounts
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Control system parts requiring precision and load-bearing capability
Defense and Military Equipment
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Missile and rocket structures exposed to extreme dynamic loads
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Lightweight armor plating and aircraft carrier components
Spacecraft and Satellite Systems
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Pressure vessels, structural supports, and fuel tank panels where weight reduction is critical
High-Performance Automotive and Industrial Fields
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Suspension systems, robotic arms, and high-stress frames in lightweight engineering
In all these sectors, 7175 aluminum demonstrates long-term performance, structural stability, and fatigue resistance — essential for mission-critical components.
Advantages of Aircraft Grade Aluminum 7175 Sheet
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High Strength with Low Weight – Perfect for aerospace load-bearing parts.
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Exceptional Fatigue and Creep Resistance – Maintains durability under cyclic loads.
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Excellent Corrosion Protection – Ideal for moisture-rich and fuel-contact areas.
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High Machinability and Dimensional Precision – Enables precision aerospace fabrication.
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Superior Thermal Stability – Retains strength across temperature extremes.
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Cost Efficiency Compared to Titanium – Offers high performance at lower production costs.
Why Choose SASAALUMINUM for Aluminum 7175 Sheets
At SASAALUMINUM, we specialize in manufacturing and supplying Aircraft Grade Aluminum 7175 Sheets that meet international aerospace standards such as AMS 4048, ASTM B209, and MIL-DTL-46027.
Our products are produced using advanced melting, rolling, and heat treatment technologies, ensuring superior flatness, microstructural uniformity, and mechanical consistency. Every batch undergoes strict quality inspections, including tensile testing, hardness evaluation, ultrasonic flaw detection, and chemical analysis, to ensure flawless performance under demanding aerospace conditions.
Whether for airframe structures, engine components, or military applications, SASAALUMINUM provides 7175 aluminum sheets engineered for maximum strength, reliability, and lightweight performance.
By partnering with SASAALUMINUM, you gain access to an experienced supplier dedicated to precision, quality, and technological excellence in every stage of production.
Conclusion
The Aircraft Grade Aluminum 7175 Sheet represents the pinnacle of high-strength aerospace materials. Its outstanding mechanical properties, lightweight nature, and resistance to fatigue and corrosion make it a key component in modern aircraft and defense systems. Designed to perform under extreme mechanical stress, 7175 aluminum enables engineers to achieve the perfect balance between strength, durability, and efficiency.
From landing gear and fuselage frames to space vehicle structures, this alloy continues to define the standard for high-stress aerospace applications worldwide.
At SASAALUMINUM, we take pride in supplying premium 7175 aluminum sheets that meet the most demanding specifications, ensuring that every aircraft and system built with our materials delivers exceptional performance and long-term reliability.
Post time: Oct-31-2025