Magnesium ZH62A-T5, UNS M16620;,E FOUR

### **Product Datasheet: Magnesium ZH62A-T5 (UNS M16620)** **High-Strength Rare Earth Magnesium Casting Alloy with Thorium Addition** --- #### **1. Overview** Magnesium ZH62A-T5 (UNS M16620) is a high-strength sand casting alloy that combines zinc and rare earth elements with thorium to achieve enhanced elevated temperature properties. In the T5 temper (artificially aged after casting), this alloy offers a balanced combination of room temperature strength, creep resistance at elevated temperatures, and good castability. Originally developed for aerospace applications requiring performance at temperatures up to 350°C (662°F), ZH62A-T5 provides a cost-effective solution for components operating in demanding thermal environments. --- #### **2. Key Features & Advantages** - **Excellent Elevated Temperature Strength:** Good mechanical properties retention up to 350°C (662°F) - **Superior Creep Resistance:** Maintains dimensional stability under sustained load at high temperatures - **Good Castability:** Rare earth elements improve fluidity and feeding characteristics - **Good Corrosion Resistance:** Comparable to other magnesium-rare earth alloys - **Cost-Effective:** Provides high-temperature capability without silver additions - **Good Machinability:** Can be precision machined with standard equipment --- #### **3. Chemical Composition (Weight %)** | Element | Mg (Balance) | Zn | Rare Earth (RE) | Th | Zr | Other (max) | |---------------|--------------|------------|-----------------|------------|------------|-------------| | **Content (%)** | - | 5.0-6.0 | 1.5-2.5 | 1.5-2.5 | 0.4-1.0 | 0.30 total | *Note: Thorium provides solid solution strengthening and enhances high-temperature stability, while rare earth elements improve castability and corrosion resistance. Zinc contributes to room temperature strength.* --- #### **4. Typical Physical & Mechanical Properties (T5 Temper)** | Property | Value | Condition / Remarks | |---------------------------|------------------------------|---------------------| | **Density** | 1.86 g/cm³ (0.067 lb/in³) | | | **Melting Range** | 540-640°C (1004-1184°F) | | | **Thermal Conductivity** | 108 W/m·K | At 25°C | | **Specific Heat Capacity**| 1040 J/kg·K | At 25°C | | **Coefficient of Thermal Expansion** | 25.5 × 10⁻⁶/°C | 20-200°C | | **Ultimate Tensile Strength** | 240 MPa (35 ksi) | Room Temperature | | **Tensile Yield Strength**| 170 MPa (25 ksi) | 0.2% offset, RT | | **Elevated Temperature YS** | 140 MPa (20 ksi) | At 300°C (572°F) | | **Elongation** | 4-7% | In 2 inches, RT | | **Compressive Yield Strength** | 170 MPa (25 ksi) | | | **Shear Strength** | 140 MPa (20 ksi) | | | **Fatigue Strength** | 100 MPa (15 ksi) | 10⁷ cycles, RT | | **Elastic Modulus** | 45 GPa (6.5×10⁶ psi) | | | **Hardness** | 70-80 HB | | --- #### **5. International Standards** ZH62A-T5 is specified in the following standards: - **ASTM B80:** Standard Specification for Magnesium-Alloy Sand Castings - **ASTM B199:** Specification for Magnesium-Alloy Permanent Mold Castings - **UNS M16620:** Unified Numbering System designation - **AMS 4416:** Aerospace Material Specification for Castings - **MIL-M-46062:** Military Specification (Historical) --- #### **6. Applications** - **Aerospace Components:** - Jet engine compressor casings - Accessory gearbox housings - Missile body sections and wings - Engine mounting brackets - Helicopter transmission components - **Defense Applications:** - Rocket motor components - Military radar housings - Weapon system components - **High-Temperature Industrial:** - Compressor and pump housings - High-temperature instrumentation - Specialized engine components - **Racing & High-Performance:** - Turbocharger housings - Engine components - Transmission cases --- #### **7. Heat Treatment & Processing** - **Artificial Aging (T5):** 325°C ± 5°C (617°F ± 9°F) for 4-8 hours - **Casting Methods:** - Sand casting (primary application) - Permanent mold casting - Investment casting for complex components - **Machining:** Good machinability with proper cooling and chip management - **Joining:** Weldable using TIG methods with compatible filler materials - **Surface Treatment:** Requires standard magnesium protection schemes --- #### **8. Special Considerations** - **Thorium Content:** Requires special handling and disposal due to low-level radioactivity - **Temperature Capability:** Suitable for sustained operation up to 350°C (662°F) - **Corrosion Protection:** Needs appropriate coatings for harsh environments - **Regulatory Compliance:** Subject to nuclear material regulations for thorium content - **Modern Alternatives:** Being replaced by thorium-free alloys like WE43 and WE54 --- **Disclaimer** This technical data is for informational purposes only. The thorium content in ZH62A necessitates special handling, disposal, and regulatory compliance. Users must consult current safety regulations and material specifications before selection and use. Properties may vary based on casting parameters, section size, and aging conditions. Modern thorium-free alloys should be considered for new applications due to regulatory and environmental concerns.

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 3364 gallon liquid totes Special package is available on request.