In aerospace engineering, the search for materials that combine lightweight efficiency, superior strength, and long-term durability never stops. Aluminum alloys have been at the heart of this pursuit, particularly the 7000 series, which includes some of the most advanced materials ever developed for aircraft construction. Among them, 7175 aluminum, 7075 aluminum, and 7050 aluminum stand out for their exceptional mechanical properties and reliability in high-stress environments.
These alloys have been widely adopted in aircraft frames, wing spars, fuselage components, and landing gear structures, where strength-to-weight ratio, fatigue resistance, and corrosion performance are critical. While they share many similarities, each alloy offers distinct advantages depending on the specific design and operational requirements.
This article provides an in-depth comparison of 7175 aluminum sheet, 7075 aluminum sheet, and 7050 aluminum sheet, exploring their composition, mechanical properties, heat treatment behavior, and aerospace performance, while highlighting how SASAALUMINUM ensures world-class quality for global aviation standards.
Overview of 7000 Series Aluminum Alloys
The 7000 series of aluminum alloys is based primarily on aluminum-zinc-magnesium-copper (Al-Zn-Mg-Cu) chemistry. These alloys are known for:
-
Very high strength, often exceeding 500 MPa in tensile performance.
-
Excellent fatigue resistance under cyclic loading conditions.
-
Good machinability and heat-treatable characteristics.
However, the key difference among 7075, 7050, and 7175 lies in their metallurgical optimization for toughness, corrosion resistance, and performance consistency at various temperatures and stress levels.
Chemical Composition Comparison
| Element | 7175 (%) | 7075 (%) | 7050 (%) |
|---|---|---|---|
| Zinc (Zn) | 5.6 – 6.1 | 5.1 – 6.1 | 5.7 – 6.7 |
| Magnesium (Mg) | 2.3 – 2.9 | 2.1 – 2.9 | 1.9 – 2.6 |
| Copper (Cu) | 1.2 – 1.9 | 1.2 – 2.0 | 2.0 – 2.6 |
| Chromium (Cr) | 0.18 – 0.28 | 0.18 – 0.28 | ≤ 0.15 |
| Iron (Fe) | ≤ 0.20 | ≤ 0.50 | ≤ 0.15 |
| Silicon (Si) | ≤ 0.10 | ≤ 0.40 | ≤ 0.12 |
| Manganese (Mn) | ≤ 0.10 | ≤ 0.30 | ≤ 0.10 |
| Titanium (Ti) | ≤ 0.06 | ≤ 0.20 | ≤ 0.06 |
| Aluminum (Al) | Balance | Balance | Balance |
Key Observations
-
7175 and 7075 share a similar chemical base but differ in processing and heat treatment control, leading to enhanced fracture toughness in 7175.
-
7050 contains higher copper and slightly lower magnesium, providing improved corrosion resistance and better thermal stability, especially in thicker sections.
Mechanical Properties Comparison
| Property | 7175-T7351 | 7075-T651 | 7050-T7451 |
|---|---|---|---|
| Tensile Strength | 510 – 570 MPa | 480 – 540 MPa | 490 – 540 MPa |
| Yield Strength | 440 – 500 MPa | 410 – 480 MPa | 420 – 470 MPa |
| Elongation | 7 – 11% | 6 – 10% | 8 – 12% |
| Hardness | 155 – 170 HB | 150 – 165 HB | 145 – 160 HB |
| Density | 2.81 g/cm³ | 2.81 g/cm³ | 2.83 g/cm³ |
| Fracture Toughness | Excellent | Moderate | Excellent |
| Fatigue Resistance | Excellent | Very Good | Excellent |
| Stress Corrosion Resistance | Outstanding (T7351) | Good (T651) | Outstanding (T7451) |
Analysis
-
7175 aluminum sheet achieves the best combination of strength, fracture toughness, and corrosion resistance among the three.
-
7075 aluminum sheet offers high strength but is more susceptible to stress corrosion cracking, making it less ideal for long-term high-humidity or fuel-rich environments.
-
7050 aluminum sheet provides superior corrosion resistance and retained strength in thicker sections, commonly used for aircraft forgings and heavy plate structures.
Heat Treatment Behavior
The heat treatment process for these alloys directly affects their final properties by controlling the formation of precipitates (MgZn₂) responsible for hardening.
| Alloy | Typical Tempers | Heat Treatment Notes |
|---|---|---|
| 7175 | T6, T7351 | Precipitation hardened; T7351 offers better toughness and SCC resistance. |
| 7075 | T6, T651 | T6 provides highest strength but lower SCC resistance; T651 adds stress relief. |
| 7050 | T74, T7451 | Over-aged condition improves corrosion resistance and thermal stability. |
Summary
-
7175-T7351 achieves a perfect balance between strength and corrosion resistance, making it ideal for aircraft structures exposed to varying climates.
-
7075-T6 offers maximum strength but requires surface treatments like anodizing to combat corrosion.
-
7050-T7451 maintains excellent mechanical properties after prolonged exposure to elevated temperatures, a key factor in aerospace bulkheads and fuselage frames.
Fatigue and Fracture Toughness
In aerospace applications, fatigue resistance and fracture toughness are critical for ensuring structural longevity under cyclic loads.
7175 aluminum sheet excels in both properties due to its refined grain structure and optimized heat treatment. The controlled over-aging process in T7351 temper reduces internal residual stresses, minimizing crack initiation and propagation.
| Property | 7175 | 7075 | 7050 |
|---|---|---|---|
| Fatigue Strength (MPa) | 160 – 180 | 140 – 160 | 160 – 180 |
| Fracture Toughness (MPa√m) | > 35 | 25 – 30 | > 35 |
| Crack Growth Resistance | Excellent | Moderate | Excellent |
Conclusion
For aircraft subjected to vibration, pressure cycling, and aerodynamic stress, 7175 and 7050 offer superior long-term performance, while 7075 is better suited for secondary or short-duration load-bearing components.
Corrosion Resistance Comparison
| Alloy | Resistance to Stress Corrosion Cracking (SCC) | Pitting Resistance | General Corrosion |
|---|---|---|---|
| 7175 (T7351) | Excellent | Excellent | Excellent |
| 7075 (T651) | Fair | Good | Moderate |
| 7050 (T7451) | Excellent | Excellent | Excellent |
7175 aluminum demonstrates significantly improved SCC resistance over 7075, primarily due to its controlled over-aging during heat treatment. This makes it particularly suitable for humid, marine, and chemically active aerospace environments.
Additionally, 7050 aluminum performs exceptionally well under similar conditions, especially for thick structural components like fuselage frames and landing gear.
Strength-to-Weight Ratio and Structural Efficiency
Weight reduction is one of the most critical factors in aerospace design. With a density of approximately 2.8 g/cm³, all three alloys provide exceptional structural efficiency.
However, 7175 aluminum sheet stands out for maintaining superior tensile strength at minimal weight, giving engineers a higher strength-to-mass ratio that directly translates into:
-
Better fuel efficiency
-
Improved payload capacity
-
Greater flight range and agility
For this reason, Aircraft Grade Aluminum 7175 Sheet is often chosen for wing spars, fuselage joints, and load-bearing assemblies where strength and weight optimization are paramount.
Thermal Stability and High-Temperature Performance
7050 aluminum maintains slightly better thermal stability than 7175 and 7075, retaining mechanical strength even after long exposure at elevated temperatures (~120°C).
However, 7175 also performs exceptionally well in typical aircraft temperature ranges, showing minimal thermal fatigue and excellent dimensional stability, making it suitable for aerospace skins, engine brackets, and structural reinforcements.
Advantages of Aluminum 7175 Sheet Over 7075 and 7050
-
Higher Strength and Fracture Toughness – Outperforms 7075 in both static and fatigue strength.
-
Better Stress Corrosion Resistance – Ideal for humid and chemically exposed conditions.
-
Balanced Thermal Stability – Performs well in both high and low-temperature environments.
-
Excellent Machinability – Easier to process than 7050 for precision aerospace parts.
-
Superior Fatigue Life – Ensures long-term durability under cyclic loading.
-
Lighter Structural Weight – Offers high strength at minimum mass for aircraft efficiency.
Why Choose SASAALUMINUM for 7175 Aluminum Sheet
At SASAALUMINUM, we specialize in producing and supplying Aircraft Grade Aluminum 7175 Sheets that meet the most demanding aerospace standards, including AMS 4048, ASTM B209, and MIL-DTL-46027.
Our products are manufactured using advanced melting, rolling, and heat treatment technologies, ensuring uniform microstructure, tight tolerances, and reliable mechanical properties.
SASAALUMINUM Quality Highlights
-
State-of-the-art heat treatment furnaces for precise temper control.
-
Rigorous chemical composition analysis and ultrasonic testing.
-
Tensile, hardness, and fatigue testing for every production batch.
-
Global supply network supporting aerospace OEMs and defense contractors.
When you choose SASAALUMINUM, you gain a trusted partner dedicated to performance, precision, and reliability in every product delivered.
Conclusion
In the comparison of 7175, 7075, and 7050 aluminum sheets, each alloy has its strengths, but Aircraft Grade Aluminum 7175 Sheet stands out as the most balanced solution for modern aerospace applications.
-
It combines the high strength of 7075 with the corrosion resistance and toughness of 7050.
-
Its T7351 temper provides unmatched fatigue performance and dimensional stability.
-
Its lightweight nature enables higher efficiency in aircraft performance and fuel economy.
Whether for wing spars, fuselage structures, or landing gear, 7175 aluminum sheet delivers dependable performance where strength, safety, and precision matter most.
At SASAALUMINUM, we are proud to supply world-class 7175 aluminum sheets that meet the highest standards of aerospace quality — providing the materials that keep innovation and aviation moving forward.
Post time: Oct-31-2025