7075 T73 Aluminum
What is 7075 T73?
7075 T73 is a high-strength wrought aluminum alloy and an important member of the 7000 series (Al-Zn-Mg-Cu series) ultra-hard aluminum alloy family. It is produced based on standard 7075 aluminum alloy through a special heat treatment process, combining high strength with excellent stress corrosion resistance.
7075 T73 aluminum undergoes a special aging process to reach the T73 temper. This tempering process involves heat treating the material to the T6 condition, followed by further aging.
"T73" represents the specific heat treatment temper of this alloy. Specifically:
- "T" indicates a heat-treated temper (different from F, O, H tempers)
- "7" indicates a stabilized temper after solution heat treatment
- "3" indicates a specific overaging treatment level
Compared with the commonly used 7075-T6 temper, the T73 temper significantly improves the alloy’s resistance to stress corrosion cracking through a special two-stage aging process, while reducing notch sensitivity. This treatment allows the material to maintain relatively high strength while greatly enhancing its corrosion resistance.
7075 T73 Processing Characteristics
- Step aging after solution heat treatment
- Strength slightly lower than T6 temper
- Significantly improved stress corrosion resistance
- Better fracture toughness than T6 temper
7075 T73 Physical Properties
- Density: approximately 2.85 g/cm³
- Melting range: 475–635°C
- Coefficient of thermal expansion (20–100°C): 23.6 μm/m·K
- Thermal conductivity: approximately 125 W/(m·K)
7075 T73 meets the following specifications:
- ASTM-B209
- AMS-4078
- AMS-QQ-A-250/12
Other relevant standards for 7075 T73 aluminum:
- AMS-4124: Standard for cold-finished bars, rods, and wire in 7075-T7351 condition.
- AMS-4166: Standard for extrusions in 7075-T73 condition.
- AMS-4167: Standard for extrusions in 7075-T73511 condition.
- QQ-A-250/13: Standard for Alclad 7075 aluminum alloy sheet and plate.
- MIL-A-22771: Military specification for aluminum and aluminum alloy forgings.
Haomei Aluminum’s 7075 T73 aluminum alloy products fully comply with the above standards, ensuring their quality and performance in various application fields.
Chemistry Informations 7075 T73 Aluminum
| Element | Percentage |
| Al | 90 |
| Cr | 0.18 - 0.28 |
| Cu | 1.2 - 2 |
| Fe | 0.5 max |
| Mg | 2.1 - 2.9 |
| Mn | 0.3 max |
| Si | 0.4 max |
| Ti | 0.2 max |
| Zn | 5.1 - 6.1 |
| Zr+Ti | 0.25 max |
7075 T73 Aluminum Mechanical Properties
| Property | Value |
| Density g/cm^3 | 3 |
| Elongation % in 2 in. | 7 |
| Rockwell Hardness B Scale | 82 |
| Ultimate Tensile Strength KSI | 72 |
| Yield Tensile Strength KSI | 63 |
| Brinell Hardness 500 kg load | 135 |
| Shear Strength KSI | 43 |
| Melting Point °F | 890 - 1180 |
| Machinability % | 70 |
| Electrical Conductivity % IACS | 33 |
7075 T73 Aluminum Thermal and Physical Properties
| Property | Value |
| Melting Range | 480°C - 640°C |
| Density | 2.81 g/cm³ (0.102 lb/in³) |
| Thermal Conductivity & Expansion | Good thermal conductivity and predictable thermal expansion |
7075 T73 Material Properties
Fatigue Properties and Fracture Toughness
The fatigue performance of 7075 T73 is particularly outstanding, which is one of the important characteristics that distinguish it from other aluminum alloys:
- Fatigue strength: In the T73 condition, smooth, notch-free specimens tested in an R.R. Moore-type test for 5×10⁸ cycles can reach a fatigue strength of 159 MPa (23 ksi).
- Improved fatigue resistance: Compared with standard 7075 alloy, the fatigue resistance of the T73 condition is improved by about 30%.
- Fracture toughness: The fracture toughness of the T73 condition is superior to that of the T6 condition, meaning it is less likely to experience sudden fracture in the presence of defects or stress concentrations.
Corrosion Resistance and Environmental Characteristics
One of the main advantages of 7075 T73 is its excellent corrosion resistance, especially its resistance to stress corrosion cracking (SCC):
- Stress corrosion cracking resistance: The T73 condition, through special overaging treatment, greatly improves resistance to stress corrosion cracking — an advantage not present in the T6 condition.
- Resistance to exfoliation corrosion: 7075 T73 alloy also has good resistance to exfoliation corrosion.
- General corrosion resistance: Although not as high as pure aluminum or certain aluminum alloys (such as 6061), 7075 alloy in the T73 condition has sufficient resistance to general atmospheric corrosion, especially when appropriately surface treated.
7075 T73 Aluminum Product Forms and Specifications
Main Product Forms of 7075 T73 Aluminum
Standard 7075 T73 Aluminum Products
- 7075 T73 aluminum plates and sheets
- 7075 T73 aluminum round bars and square bars
- 7075 T73 aluminum tubes
- 7075 T73 aluminum extrusions
- 7075 T73 aluminum wire and rod
- 7075 T73 aluminum forgings
Special 7075 T73 Aluminum Products
- 7075 T73 Alclad (clad aluminum) products
- Pre-stretched plates (T651/T7351)
- 7075 T73 aluminum precision machined parts
- 7075 T73 ultra-thick plates
- 7075 T73 aluminum composite structural materials
Typical Specifications of 7075 T73 Aluminum Products
| Product Form | Main Specifications |
| 7075 T73 aluminum plates and sheets | Thickness: 0.032 mm to 350 mm Width: 1219 mm to 3658 mm Length: customized |
| 7075 T73 aluminum round bars | Diameter: 3.0 mm to 500 mm Length: customized |
| 7075 T73 aluminum tubes | Outer diameter: 6 mm to 387 mm Wall thickness: 0.5 mm to 127 mm Length: customized |
| 7075 T73 aluminum extrusions | Cross-sectional dimensions: various complex profiles customizable Length: customized |
| 7075 T73 aluminum wire | Diameter: 0.1 mm to 20 mm Supplied in coils, lengths up to several hundred meters |
| 7075 T73 aluminum forgings | Dimensions: customizable in various sizes and shapes Weight: from several hundred grams to several hundred kilograms |
7075 T73 Aluminum Applications
Due to its unique high strength, excellent corrosion resistance, and enhanced durability, 7075 T73 aluminum is widely used in:
Aerospace
- Aircraft structural components
- Spacecraft applications
- Aerospace engine components
- Military aircraft structures
Military & Defense
- Armor systems
- Weapon systems
- Military vehicles
- Naval applications
Transportation
- Automotive industry
- Rail vehicles
- Ships and yachts
- Bicycles and sports equipment
Industrial & Consumer Products
- Mold manufacturing
- Machinery manufacturing
- Medical equipment
- Electronics
- Construction and decoration
- Energy sector
| Field | Application | Description |
| Aerospace | Wing spars, landing gear, fuselage components | 7075-T73 is widely used in aerospace applications, especially in wing spars, landing gear, and fuselage components. Due to its high strength and good corrosion resistance, 7075-T73 maintains structural integrity under extreme temperatures and pressure conditions. Its lightweight properties reduce the overall weight of aircraft, thus improving fuel efficiency. Additionally, 7075-T73 has excellent fatigue strength, ensuring the long service life of aerospace components. |
| Military | Armor components, firearm receivers | 7075-T73 is widely used in military applications, particularly in the manufacturing of armor components and firearm receivers. Its high strength effectively resists impact from high-speed bullets or fragments, providing excellent protection. Its low density also allows for lighter equipment while maintaining high strength, making it easier to carry and operate. The use of 7075-T73 in firearm receivers improves the durability and precision of weapons, reducing wear. |
| Automotive | Racing components, suspension systems | 7075-T73 offers indispensable advantages in the automotive industry, particularly in racing components and suspension systems. Due to its high strength and lightweight characteristics, 7075-T73 helps reduce the weight of racing cars, improving acceleration and handling performance. Its use in suspension systems allows it to effectively withstand the high pressures and impacts of high-speed driving while ensuring long-term durability and stability, reducing maintenance needs. |
| Marine and Industrial | High-stress gears, shafts, and structural components | In the marine and industrial fields, 7075-T73 shows outstanding performance as a material for high-stress gears, shafts, and structural components. Its excellent strength and corrosion resistance allow it to maintain a long service life in marine environments, especially under high-stress conditions, such as the extreme loads experienced by gears and bearings. 7075-T73 not only provides excellent corrosion resistance, reducing damage from seawater corrosion but also maintains high strength and stability in complex industrial environments. |
7075 T73 Aluminum Comparison with T6 Temper
| Property | T73 | T6 |
| Strength | Moderate | Maximum |
| Corrosion Resistance | High | Moderate |
| Ductility | Higher | Lower |
| Primary Use | Corrosive environments | High-strength, static loads |
7075 T73 Aluminum Machining and Manufacturing
- Machinability: Rated at approximately 70% of free-machining brass; due to its high hardness, sharp tools are required.
- Weldability: Limited to resistance welding; fusion welding is generally not recommended.
- Formability: Best under annealed conditions, but achievable in T73 with controlled processes.
When an application requires a material that combines the high strength of the 7000 series with better stress corrosion resistance, 7075 T73 aluminum is an excellent choice—this balance makes it particularly valuable in critical structural applications.
7075 T73 Aluminum Purchasing Recommendations and Considerations
- Define technical requirements: Specify standards, specifications, and performance indicators
- Select appropriate suppliers: Evaluate production capacity, quality systems, and after-sales service
- Quality inspection and acceptance: Develop inspection plans and verify key performance
- Contract terms: Clearly define specifications, quality, price, and delivery schedule
- Inventory management: Plan procurement volumes reasonably and consider storage conditions
