7075-T73; 7075-T735x Aluminum alloy,Aluminum 7075-T73; 7075-T735x alloy，E FORU

### **7075-T73 / 7075-T735x Aluminum Alloy: High-Strength with Superior Corrosion Resistance** **7075-T73 and 7075-T735x** are over-aged tempers of the high-strength 7075 aluminum alloy, specifically developed to provide excellent resistance to stress corrosion cracking (SCC) and exfoliation corrosion while maintaining high strength levels. These tempers represent an optimal balance between mechanical properties and environmental durability for critical aerospace applications. --- #### **1. Chemical Composition** | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 5.1 - 6.1 | Primary strengthening element through formation of MgZn₂ precipitates | | **Magnesium (Mg)** | 2.1 - 2.9 | Enhances strength and work hardening characteristics | | **Copper (Cu)** | 1.2 - 2.0 | Improves strength and stress corrosion cracking resistance | | **Chromium (Cr)** | 0.18 - 0.28 | Controls grain structure and inhibits recrystallization | | **Iron (Fe)** | ≤ 0.50 | Impurity - controlled for improved consistency | | **Silicon (Si)** | ≤ 0.40 | Impurity - controlled for improved ductility | | **Manganese (Mn)** | ≤ 0.30 | - | | **Titanium (Ti)** | ≤ 0.20 | - | | **Other Elements** | ≤ 0.05 each; ≤ 0.15 total | - | | **Aluminum (Al)** | Balance | Base metal | --- #### **2. Understanding the T73 and T735x Tempers** **T73 Temper:** - Solution heat-treated and artificially over-aged using a two-step aging process - Optimized for maximum stress corrosion cracking resistance - Slightly lower strength than T6 temper but superior corrosion resistance **T735x Tempers:** - **T7351**: Plate, stress-relieved by stretching - **T7352**: Die forgings, stress-relieved by compressing - Solution heat-treated, stress-relieved, and over-aged - Improved dimensional stability for machining **Key Characteristics:** - Excellent exfoliation corrosion resistance - Superior stress corrosion cracking resistance - Good strength-to-weight ratio - Improved dimensional stability --- #### **3. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 2.81 g/cm³ (0.101 lb/in³) | | **Melting Range** | 477°C - 638°C (890°F - 1180°F) | | **Electrical Conductivity** | 38-42% IACS | | **Thermal Conductivity** | 135-155 W/m·K | | **Coefficient of Thermal Expansion** | 23.6 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 71 GPa (10.3 × 10⁶ psi) | --- #### **4. Mechanical Properties (Typical)** | Property | T73 Temper | T7351 Temper | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 470 - 520 MPa (68 - 75 ksi) | 460 - 510 MPa (67 - 74 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 390 - 450 MPa (57 - 65 ksi) | 380 - 440 MPa (55 - 64 ksi) | | **Elongation** | 7-13% | 8-14% | | **Compression Yield Strength** | 390 - 450 MPa (57 - 65 ksi) | 380 - 440 MPa (55 - 64 ksi) | | **Shear Strength** | 270 - 310 MPa (39 - 45 ksi) | 260 - 300 MPa (38 - 44 ksi) | | **Fatigue Strength** | 140 - 170 MPa (20 - 25 ksi) | 135 - 165 MPa (20 - 24 ksi) | | **Brinell Hardness** | 125 - 140 HB | 120 - 135 HB | --- #### **5. Product Applications** **7075-T73/T735x** is used in applications requiring both high strength and superior corrosion resistance: * **Aerospace Structures:** * Aircraft wing skins and planks * Fuselage frames and bulkheads * Upper wing components * Helicopter rotor components * Spacecraft structures * **Marine Applications:** * Marine aircraft components * Ship and boat structures * Offshore platform components * **Defense Applications:** * Military aircraft structural components * Naval aircraft components * Missile components * **High-Performance Applications:** * Racing components for marine environments * High-stress components in corrosive environments --- #### **6. International Standards** | Standard Body | Designation | Specification | | :--- | :--- | :--- | | **Aluminum Association** | 7075-T73 / 7075-T7351 | AA Teal Sheets | | **ASTM International** | 7075-T73 / 7075-T7351 | ASTM B209 / B211 | | **Aerospace (AMS)** | 7075-T73 | AMS 4048 | | **Aerospace (AMS)** | 7075-T7351 | AMS 4051 | | **European Norm** | EN AW-7075 T73 / T7351 | EN 485-2 / EN 754-2 | | **Unified Numbering System** | A97075 | UNS Registry | --- #### **7. Key Characteristics** **Advantages:** - **Excellent stress corrosion cracking resistance** - **Superior exfoliation corrosion resistance** - High strength-to-weight ratio - Good fatigue performance - Improved dimensional stability (T735x tempers) - Proven reliability in corrosive environments **Limitations:** - Lower strength than T6 temper (approximately 10-15% reduction) - Higher cost due to complex heat treatment - Limited formability in aged condition - Requires specialized heat treatment facilities --- #### **8. Manufacturing Considerations** * **Machining:** Good machinability with proper tooling * **Forming:** Must be formed in annealed condition then heat-treated * **Welding:** Not generally recommended; requires specialized techniques * **Heat Treatment:** Complex two-step aging process required * **Surface Treatment:** Excellent for anodizing and coating --- #### **9. Special Features** **7075-T73/T735x** offers unique advantages: * **Corrosion Performance:** Dramatically improved over T6 temper * **Heat Treatment Process:** Two-step aging for optimal precipitation * **Environmental Durability:** Suitable for marine and industrial environments * **Reliability:** Proven performance in critical aerospace applications **Comparison with T6 Temper:** - 10-15% lower strength but significantly better corrosion resistance - Superior performance in humid and saltwater environments - Better long-term reliability in corrosive conditions - Preferred for thick sections where stress corrosion is a concern --- #### **10. Performance Characteristics** - **Stress Corrosion Cracking:** Excellent resistance in all directions - **Exfoliation Corrosion:** High resistance to layered corrosion - **Fatigue Strength:** Maintains good fatigue performance - **Fracture Toughness:** Good for high-strength aluminum alloy **7075-T73/T735x Aluminum Alloy** represents the optimal choice for applications requiring the high strength of 7075 aluminum combined with superior corrosion resistance. The over-aging process sacrifices a small amount of strength to achieve dramatic improvements in environmental durability, making these tempers particularly valuable for aerospace, marine, and defense applications where long-term reliability in corrosive environments is essential.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2170 gallon liquid totes Special package is available on request.