7075-T6 Aluminum vs. 7475 Aluminum
The two alloys are very similar in terms of general composition and thermal properties, but 7475 may have slight advantages in fatigue resistance, elongation, and thermal diffusivity in certain aspects, making it more versatile in high-performance or high-stress applications. On the other hand, 7075-T6 is typically used in structural applications requiring high strength and resistance to deformation.
Both 7075-T6 and 7475 aluminum alloys belong to the high-strength aluminum alloy series and are widely used in aerospace, military, and high-performance structural applications. They have many similarities in chemical composition, thermal properties, and mechanical performance, but there are some key differences that determine their advantages in different applications.
| Performance/Properties | 7075-T6 | 7475 |
| Tensile Strength | Higher, around 572 MPa (83 ksi) | Lower, around 515 MPa (75 ksi) |
| Fatigue Strength | Lower, suitable for low-cycle loading | Higher, suitable for high-cycle loading and repeated loads |
| Elongation at Break | Lower, around 11% | Higher, around 14% |
| Thermal Conductivity | Lower, around 130 W/m·K | Higher, around 135 W/m·K |
| Maximum Operating Temperature | High, around 400°F (204°C) | Lower, around 350°F (177°C) |
| Suitable Fields | High-strength structures, static load environments | High fatigue strength, dynamic load environments |
- 7075-T6 is an extremely strong aluminum alloy, suitable for applications that withstand static or single high loads, such as high-strength aerospace structures and military equipment, but its fatigue strength and ductility are relatively poor.
- 7475 offers better fatigue strength and elongation, making it ideal for applications subjected to high-cycle stress and high-fatigue demands, especially in aerospace and high-performance structures, despite its slightly lower tensile strength.
Depending on the specific application requirements (such as strength, fatigue durability, operating temperature, etc.), choosing the right aluminum alloy will help optimize component performance and lifespan.
7075-T6 Aluminum vs. 7475 Aluminum Alloy Composition
The main elements include zinc (Zn), magnesium (Mg), copper (Cu), and small amounts of silicon (Si), manganese (Mn), etc. Zinc is the primary alloying element, providing extremely high strength.
7075-T6 is an aluminum alloy that has been heat-treated to the T6 condition, with its high strength coming from solid solution strengthening and aging hardening of the alloying elements.
7475 is an aluminum alloy similar to 7075, mainly consisting of zinc (Zn), magnesium (Mg), and a small amount of copper (Cu), but with a relatively lower copper content in 7475.
The alloy design of 7475 allows it to maintain high strength while offering better fatigue resistance and higher elongation at break.
| Element | 7075-T6 Aluminum | 7475 Aluminum |
| Aluminum (Al), % | 86.9 to 91.4 | 88.6 to 91.6 |
| Chromium (Cr), % | 0.18 to 0.28 | 0.18 to 0.25 |
| Copper (Cu), % | 1.2 to 2.0 | 1.2 to 1.9 |
| Iron (Fe), % | 0 to 0.5 | 0 to 0.12 |
| Magnesium (Mg), % | 2.1 to 2.9 | 1.9 to 2.6 |
| Manganese (Mn), % | 0 to 0.3 | 0 to 0.060 |
| Silicon (Si), % | 0 to 0.4 | 0 to 0.1 |
| Titanium (Ti), % | 0 to 0.2 | 0 to 0.060 |
| Zinc (Zn), % | 5.1 to 6.1 | 5.1 to 6.2 |
| Zirconium (Zr), % | 0 to 0.25 | 0 |
| Residuals, % | 0 | 0 to 0.15 |
7075-T6 Aluminum vs. 7475 Aluminum Mechanical Properties
Tensile Strength (UTS)
7075-T6: 7075-T6 offers extremely high tensile strength, typically around 572 MPa (approximately 83 ksi), making it one of the strongest aluminum alloys available.
7475: The tensile strength of 7475 is slightly lower than that of 7075-T6, typically around 515 MPa (approximately 75 ksi). Despite its lower tensile strength, its excellent fatigue resistance and ductility make it suitable for other applications.
Fatigue Strength
7075-T6: 7075-T6 has lower fatigue strength, especially when subjected to cyclic stresses. It is prone to fatigue fracture under high stress conditions.
7475: Compared to 7075-T6, 7475 has a broader fatigue strength range, maintaining a longer service life under higher cyclic loads. This makes 7475 more suitable for applications subjected to repeated or fluctuating loads, such as aircraft wings, landing gears, etc.
Elongation (Elongation at Break)
7075-T6: The elongation at break is typically lower, around 11%, meaning it stretches less before breaking in a tensile test.
7475: The elongation at break for 7475 is higher, typically over 14%, meaning it can stretch better than 7075-T6, providing more plastic deformation and reducing the risk of brittle fracture.
| Property | 7075-T6 Aluminum | 7475 Aluminum |
| Elastic Modulus (x 10⁶ psi) | 10 | 10 |
| Elongation at Break (%) | 7.9 | 10 to 12 |
| Fatigue Strength (x 10³ psi) | 23 | 28 to 31 |
| Poisson's Ratio | 0.32 | 0.32 |
| Shear Modulus (x 10⁶ psi) | 3.8 | 3.8 |
| Shear Strength (x 10³ psi) | 48 | 46 to 51 |
| Tensile Strength: Ultimate (UTS) (x 10³ psi) | 81 | 76 to 85 |
| Tensile Strength: Yield (Proof) (x 10³ psi) | 69 | 64 to 75 |
7075-T6 Aluminum vs. 7475 Aluminum Thermal Properties
Thermal Conductivity
7075-T6: The thermal conductivity is relatively low, around 130 W/m·K. The lower thermal conductivity means it does not perform as well in heat conduction as 7475.
7475: The thermal conductivity of 7475 is slightly higher, around 135 W/m·K. The higher thermal conductivity makes it more stable in high-temperature operating environments and allows it to dissipate heat more effectively.
Maximum Mechanical Temperature
7075-T6: The maximum operating temperature of 7075-T6 is relatively high, typically capable of withstanding temperatures up to 400°F (approximately 204°C). This makes it suitable for more demanding high-temperature environments.
7475: The maximum operating temperature of 7475 is slightly lower, around 350°F (approximately 177°C). While its temperature range is narrower, it is still suitable for most conventional high-strength applications.
| Property | 7075-T6 Aluminum | 7475 Aluminum |
| Latent Heat of Fusion (J/g) | 380 | 380 |
| Maximum Temperature: Mechanical (°F) | 400 | 350 |
| Melting Completion (Liquidus) (°F) | 1180 | 1180 |
| Melting Onset (Solidus) (°F) | 890 | 890 |
| Specific Heat Capacity (BTU/lb-°F) | 0.21 | 0.21 |
| Thermal Conductivity (BTU/h-ft-°F) | 75 | 80 to 94 |
| Thermal Expansion (µm/m-K) | 23 | 23 |
7075-T6 Aluminum vs. 7475 Aluminum Applications
7075-T6 Aluminum
Due to its extremely high tensile strength, 7075-T6 is widely used in structural applications that require strength and resistance to deformation, such as aircraft frames, missiles, military equipment, race cars, and heavy machinery in aerospace.
It is suitable for components that bear high static loads, such as wing beams, fuselage frames, landing gear components, etc.
7475 Aluminum
7475, with its better fatigue resistance and higher elongation at break, is ideal for applications subject to high-cycle stresses, such as wing ribs, landing gears, and critical components of aircraft structures.
In applications that endure long-term vibrations and dynamic loads, 7475 is more ideal, particularly in high-performance aerospace structures and components in high-stress environments.
7075-T6 Aluminum vs. 7475 Aluminum Electrical Properties
| Property | 7075-T6 Aluminum | 7475 Aluminum |
| Electrical Conductivity: Equal Volume (% IACS) | 33 | 33 to 42 |
| Electrical Conductivity: Equal Weight (% IACS) | 98 | 98 to 120 |
Otherwise Unclassified Properties
| Property | 7075-T6 Aluminum | 7475 Aluminum |
| Base Metal Price (% relative) | 10 | 10 |
| Density (lb/ft³) | 190 | 190 |
| Embodied Carbon (kg CO₂/kg material) | 8.3 | 8.2 |
| Embodied Energy (x 10³ BTU/lb) | 64 | 63 |
| Embodied Water (gal/lb) | 130 | 130 |
Common Calculations
| Property | 7075-T6 Aluminum | 7475 Aluminum |
| Resilience: Ultimate (MJ/m³) | 42 | 53 to 68 |
| Resilience: Unit (kJ/m³) | 1630 | 1390 to 1920 |
| Stiffness to Weight: Axial (points) | 13 | 13 |
| Stiffness to Weight: Bending (points) | 46 | 46 |
| Strength to Weight: Axial (points) | 51 | 49 to 55 |
| Strength to Weight: Bending (points) | 50 | 48 to 52 |
| Thermal Diffusivity (mm²/s) | 50 | 53 to 63 |
| Thermal Shock Resistance (points) | 24 | 23 to 26 |
