When it comes to high-performance engineering materials, 7075 aluminum often stands out as one of the strongest alloys ever developed. It is widely used in aerospace, defense, and automotive industries where strength, durability, and lightweight construction are essential.
A common question that engineers and designers ask is: “Is 7075 aluminum stronger than steel?”
The short answer is — in some cases, yes. Although aluminum is typically lighter and softer than steel, the 7075 alloy has been engineered to achieve strength levels comparable to, or even exceeding, certain types of mild and structural steels, while weighing only about one-third as much.
In this detailed guide, SASAALUMINUM explores the mechanical properties, advantages, and limitations of 7075 aluminum compared with different types of steel, helping you understand when aluminum can be the superior choice.
1. What Is 7075 Aluminum
7075 aluminum is a high-strength, heat-treatable alloy that belongs to the 7xxx series — a group of aluminum alloys primarily composed of zinc (Zn) as the main alloying element, along with magnesium, copper, and chromium.
It was originally developed by the Japanese company Sumitomo Metal in the 1940s for the Mitsubishi Zero fighter aircraft, marking a major breakthrough in lightweight aerospace engineering.
Typical Chemical Composition (Weight Percent)
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Zinc (Zn): 5.6–6.1
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Magnesium (Mg): 2.1–2.5
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Copper (Cu): 1.2–1.6
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Chromium (Cr): 0.18–0.28
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Iron (Fe): ≤ 0.5
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Silicon (Si): ≤ 0.4
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Aluminum (Al): Balance
This optimized combination of elements provides exceptional tensile strength and fatigue resistance, making 7075 aluminum one of the most powerful non-ferrous alloys available today.
2. Key Properties of 7075 Aluminum
7075 aluminum is known for its high strength-to-weight ratio, making it ideal for applications where every gram matters.
Mechanical Properties (T6 Temper)
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Tensile Strength: 510–570 MPa
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Yield Strength: 430–500 MPa
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Elongation: 10–12 percent
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Hardness: 150 HB (Brinell)
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Density: 2.81 g/cm³
The most common tempers are T6 (solution heat-treated and artificially aged) and T73 (overaged for improved stress corrosion resistance).
In the T6 condition, 7075 aluminum achieves mechanical strength comparable to medium-carbon steel — while being nearly three times lighter.
3. Strength Comparison: 7075 Aluminum vs Steel
To understand whether 7075 aluminum is stronger than steel, we must compare it with various types of steel, since “steel” covers a wide range of alloys with very different mechanical properties.
A. 7075 Aluminum vs Mild Steel (AISI 1018)
| Property | 7075-T6 Aluminum | AISI 1018 Steel |
|---|---|---|
| Tensile Strength | ~570 MPa | ~440 MPa |
| Yield Strength | ~500 MPa | ~370 MPa |
| Density | 2.81 g/cm³ | 7.85 g/cm³ |
Result: 7075 aluminum is stronger than mild steel on both tensile and yield strength, while being around 65% lighter. This gives it an outstanding strength-to-weight advantage.
B. 7075 Aluminum vs Structural Steel (A36)
| Property | 7075-T6 Aluminum | ASTM A36 Steel |
|---|---|---|
| Tensile Strength | ~570 MPa | ~400 MPa |
| Yield Strength | ~500 MPa | ~250 MPa |
| Density | 2.81 g/cm³ | 7.85 g/cm³ |
Result: 7075 aluminum again outperforms structural steel in terms of strength per unit weight. This is why it is commonly used in aircraft frames, racing vehicles, and bicycles where minimizing weight is crucial.
C. 7075 Aluminum vs High-Strength Alloy Steel (4340)
| Property | 7075-T6 Aluminum | AISI 4340 Steel |
|---|---|---|
| Tensile Strength | ~570 MPa | ~1100 MPa |
| Yield Strength | ~500 MPa | ~850 MPa |
| Density | 2.81 g/cm³ | 7.85 g/cm³ |
Result: In this case, high-strength alloy steels still outperform 7075 aluminum in absolute strength, but at a significant weight penalty.
When weight is normalized, 7075 aluminum has a superior strength-to-weight ratio, making it the better material for applications where weight reduction is key.
4. Strength-to-Weight Ratio Advantage
One of the main reasons 7075 aluminum is used instead of steel is its exceptionally high strength-to-weight ratio (specific strength).
| Material | Tensile Strength (MPa) | Density (g/cm³) | Specific Strength (MPa per g/cm³) |
|---|---|---|---|
| 7075 Aluminum | 570 | 2.81 | 203 |
| Mild Steel | 440 | 7.85 | 56 |
| 4340 Alloy Steel | 1100 | 7.85 | 140 |
From this comparison, it’s clear that 7075 aluminum provides roughly 3.5 times the strength per unit weight of mild steel, and even exceeds the specific strength of some high-grade alloy steels.
That’s why in industries like aerospace and racing, where every kilogram counts, 7075 aluminum is preferred over steel.
5. Other Key Property Comparisons
Corrosion Resistance
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7075 Aluminum: Excellent natural resistance due to its protective oxide layer; however, slightly less corrosion-resistant than marine-grade alloys like 5052 or 5083.
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Steel: Requires coatings, paints, or galvanization to resist rust.
Verdict: 7075 aluminum offers better corrosion resistance than unprotected steel, especially in humid or marine environments.
Machinability and Formability
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7075 aluminum is easy to machine and can be milled, turned, or drilled with high precision.
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Steel, depending on the grade, can be more difficult to machine and causes more tool wear.
Verdict: 7075 aluminum offers superior machinability for precision components.
Fatigue and Stress Resistance
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7075-T6 exhibits excellent fatigue strength, making it suitable for dynamic load-bearing structures.
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Certain steels can still outperform aluminum under continuous cyclic loading, but at a cost of higher mass.
Verdict: For lightweight fatigue-critical parts, 7075 aluminum is highly effective.
Thermal Conductivity
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7075 aluminum conducts heat roughly three times better than most steels.
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This makes it ideal for components requiring heat dissipation, such as engine parts and molds.
Verdict: 7075 aluminum wins for applications where thermal performance matters.
Cost Comparison
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7075 aluminum is generally more expensive per kilogram than mild steel but cheaper to transport and machine due to its light weight and lower density.
Verdict: For mass production where cost outweighs weight savings, steel may remain the practical option. But for high-performance engineering, 7075 provides better long-term value.
6. Where 7075 Aluminum Is Used Instead of Steel
Because of its outstanding combination of strength, weight reduction, and corrosion resistance, 7075 aluminum is a material of choice in the following industries:
Aerospace and Aviation
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Aircraft fuselage frames, wing spars, landing gear parts
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Helicopter rotor components and fasteners
Automotive and Motorsports
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Racing car chassis and suspension arms
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High-performance motorcycle and bicycle frames
Military and Defense
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Armor plates, weapon components, and rocket casings
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High-stress structural parts in defense vehicles
Industrial and Engineering Applications
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Molds, jigs, and tooling for precision manufacturing
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Hydraulic parts and high-pressure components
In each of these applications, 7075 aluminum replaces steel not because it is universally stronger, but because it offers comparable strength with much lower weight — improving efficiency and performance.
7. Limitations of 7075 Aluminum
While 7075 aluminum is exceptionally strong, it does have some limitations:
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Weldability: Poor weldability due to its zinc content; tends to crack under standard welding processes.
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Corrosion Resistance: Lower than 5xxx-series alloys; requires protective coating in marine environments.
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Cost: More expensive than lower-strength alloys such as 6061 or 5052.
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Ductility: Less flexible than some steels; prone to brittle fracture under extreme stress.
For these reasons, 7075 aluminum is typically reserved for applications where weight savings and strength outweigh these limitations.
8. Real-World Example: Aircraft Structures
To understand the practical comparison, let’s take an example from aerospace manufacturing.
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Traditional steel structural parts can support extreme loads but add significant weight, reducing fuel efficiency.
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7075 aluminum provides similar strength with up to 60 percent weight reduction, allowing better performance and fuel economy.
This is why almost all modern aircraft use aluminum alloys like 7075, 7050, and 2024 for their frames, wings, and landing gear components, while using steel only for the highest-load and heat-exposed parts.
9. Sustainability and Recycling
7075 aluminum is also environmentally friendly, as it can be recycled indefinitely without losing strength.
Recycling aluminum consumes only 5 percent of the energy needed to produce primary metal from ore, making it both cost-effective and eco-friendly.
By comparison, recycling steel also saves energy, but due to its heavier mass, aluminum remains the preferred option for industries focused on sustainability and efficiency.
10. Summary: Strength and Efficiency
| Feature | 7075 Aluminum | Steel |
|---|---|---|
| Tensile Strength | 510–570 MPa | 250–1100 MPa (depending on type) |
| Density | 2.81 g/cm³ | 7.85 g/cm³ |
| Corrosion Resistance | Excellent (with coating) | Moderate (requires coating) |
| Weight | Light | Heavy |
| Machinability | Excellent | Moderate |
| Weldability | Limited | Good |
| Recyclability | Excellent | Excellent |
From this comparison, it’s clear that 7075 aluminum is not universally stronger than all steels, but it offers a better strength-to-weight ratio than nearly any steel grade.
This makes it the superior choice for applications demanding high strength and light weight, such as aircraft, racing vehicles, and defense systems.
11. Why Choose SASAALUMINUM
As a global supplier of premium aluminum alloys, SASAALUMINUM offers certified 7075 plates, bars, rods, and forgings for aerospace, automotive, and high-performance industrial applications.
Our products meet strict international standards such as ASTM B209, AMS 4045, and EN 485, ensuring reliability, traceability, and mechanical integrity.
SASAALUMINUM provides:
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High-quality aluminum alloys with precise composition control
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Customized cutting, CNC machining, and heat treatment
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Full certification (EN 10204 3.1/3.2) for aerospace compliance
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Technical support and fast global delivery
Whether you need lightweight structures for aircraft or high-strength components for defense applications, we supply the materials you can trust.
12. Conclusion
So, is 7075 aluminum stronger than steel?
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In absolute terms: Only compared to mild or structural steels.
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In strength-to-weight ratio: Absolutely yes — it’s one of the strongest and lightest alloys available.
7075 aluminum delivers the strength of steel with only one-third of its weight, along with better corrosion resistance and machinability.
That’s why it remains the alloy of choice for aerospace engineers, automotive designers, and industrial innovators who value performance, efficiency, and precision.
For certified and high-quality 7075 aluminum materials, contact SASAALUMINUM, your trusted global supplier for advanced aluminum alloys engineered for strength and reliability.
Post time: Oct-22-2025