7068-T6; 7068-T651 Aluminum alloy,Aluminum 7068-T6; 7068-T651 alloy，E FORU

### **7068-T6 / 7068-T651 Aluminum Alloy: Ultra-High Strength Structural Alloy** **7068 Aluminum Alloy** is one of the strongest commercially available aluminum alloys, belonging to the Al-Zn-Mg-Cu (7xxx) series. In the T6 and T651 tempers, this alloy achieves exceptional strength levels while maintaining good toughness and fatigue resistance, making it suitable for the most demanding structural applications. --- #### **1. Chemical Composition** | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 7.3 - 8.3 | Primary strengthening element through formation of MgZn₂ precipitates | | **Magnesium (Mg)** | 2.0 - 3.0 | Enhances strength and work hardening characteristics | | **Copper (Cu)** | 1.6 - 2.4 | Improves strength and stress corrosion cracking resistance | | **Zirconium (Zr)** | 0.05 - 0.15 | Controls grain structure and inhibits recrystallization | | **Iron (Fe)** | ≤ 0.15 | Impurity - controlled for improved toughness | | **Silicon (Si)** | ≤ 0.12 | Impurity - controlled for improved ductility | | **Manganese (Mn)** | ≤ 0.10 | - | | **Chromium (Cr)** | ≤ 0.05 | - | | **Titanium (Ti)** | ≤ 0.10 | - | | **Other Elements** | ≤ 0.05 each; ≤ 0.15 total | - | | **Aluminum (Al)** | Balance | Base metal | --- #### **2. Understanding the T6 and T651 Tempers** **T6 Temper:** - Solution heat-treated and artificially aged to peak strength - Provides maximum strength and hardness - May contain residual stresses from quenching **T651 Temper:** - Solution heat-treated, stress-relieved by stretching (1-3%), and artificially aged - Maintains high strength while reducing residual stresses - Improved dimensional stability for machining - Better for complex components requiring precise machining --- #### **3. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 2.85 g/cm³ (0.103 lb/in³) | | **Melting Range** | 475°C - 635°C (887°F - 1175°F) | | **Electrical Conductivity** | 35-40% IACS | | **Thermal Conductivity** | 115-130 W/m·K | | **Coefficient of Thermal Expansion** | 23.5 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 71 GPa (10.3 × 10⁶ psi) | --- #### **4. Mechanical Properties (Typical)** | Property | T6 Temper | T651 Temper | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 610 - 650 MPa (88 - 94 ksi) | 600 - 640 MPa (87 - 93 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 560 - 600 MPa (81 - 87 ksi) | 550 - 590 MPa (80 - 86 ksi) | | **Elongation** | 8-11% | 9-12% | | **Compression Yield Strength** | 550 - 590 MPa (80 - 86 ksi) | 540 - 580 MPa (78 - 84 ksi) | | **Shear Strength** | 340 - 370 MPa (49 - 54 ksi) | 330 - 360 MPa (48 - 52 ksi) | | **Fatigue Strength** | 180 - 200 MPa (26 - 29 ksi) | 175 - 195 MPa (25 - 28 ksi) | | **Brinell Hardness** | 155 - 170 HB | 150 - 165 HB | --- #### **5. Product Applications** **7068-T6/T651** is used in ultra-high strength applications: * **Aerospace & Defense:** * Aircraft landing gear components * Missile and rocket components * Military vehicle armor components * Helicopter transmission parts * **High-Performance Automotive:** * Racing suspension components * High-performance brake calipers * * Chassis components * Drive train components * **Industrial Applications:** * High-strength fasteners * Machinery components * Material handling equipment * Robotics and automation components * **Sports Equipment:** * High-performance bicycle frames * Mountain bike components * Competition sports equipment --- #### **6. International Standards** | Standard Body | Designation | Specification | | :--- | :--- | :--- | | **Aluminum Association** | 7068-T6 / 7068-T651 | AA Teal Sheets | | **ASTM International** | 7068-T6 / 7068-T651 | ASTM B209 / B221 | | **Aerospace (AMS)** | 7068 | AMS 4338 | | **European Norm** | EN AW-7068 T6 / T651 | EN 485-2 / EN 755-2 | | **Unified Numbering System** | A97068 | UNS Registry | --- #### **7. Key Characteristics** **Advantages:** - **Ultra-high strength** - among the strongest aluminum alloys available - Excellent strength-to-weight ratio - Good fatigue resistance - Good machinability in heat-treated condition - Good wear resistance **Limitations:** - Lower corrosion resistance than other 7xxx series alloys - Requires stress relief (T651) for complex machining - Limited formability in aged condition - Higher cost - Requires careful handling due to high strength --- #### **8. Manufacturing Considerations** * **Machining:** Requires carbide tooling; T651 preferred for complex machining * **Forming:** Must be formed in annealed condition * **Welding:** Not generally recommended; requires specialized techniques * **Heat Treatment:** Requires precise temperature control * **Corrosion Protection:** Requires appropriate surface protection --- #### **9. Special Notes** **7068-T6/T651** represents the pinnacle of aluminum alloy strength development. While it offers exceptional mechanical properties, designers should consider: - The T651 temper is generally preferred for critical components due to its reduced residual stresses - Corrosion protection is essential for applications in aggressive environments - Proper tool selection is crucial for machining operations - The alloy responds well to various surface treatments and coatings This alloy fills an important niche where the strength of steel is desired but weight constraints require aluminum, making it particularly valuable in aerospace, defense, and high-performance automotive applications where every kilogram saved translates directly into improved performance.

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 2159 gallon liquid totes Special package is available on request.