Magnesium QH21A-T6,E FOUR

### **Product Datasheet: Magnesium QH21A-T6** **High-Temperature Magnesium Casting Alloy with Superior Creep Resistance** --- #### **1. Overview** Magnesium QH21A-T6 is a premium heat-treatable casting alloy specifically engineered for exceptional high-temperature performance and creep resistance. Utilizing thorium and rare earth element additions, this alloy maintains significant mechanical strength at temperatures up to 350°C (660°F), outperforming most conventional magnesium alloys. The T6 temper (solution heat-treated and artificially aged) provides optimal strength characteristics for demanding aerospace and military applications where weight savings and elevated temperature performance are critical. --- #### **2. Key Features & Advantages** - **Exceptional High-Temperature Strength:** Maintains properties up to 350°C (660°F) - **Superior Creep Resistance:** Excellent long-term stability under sustained load at elevated temperatures - **Good Castability:** Suitable for sand and permanent mold casting processes - **Excellent Damping Capacity:** Effective vibration absorption characteristics - **Good Weldability:** Can be repaired using TIG welding methods - **Outstanding Strength-to-Weight Ratio:** Ideal for weight-critical applications --- #### **3. Chemical Composition (Weight %)** | Element | Mg (Balance) | Th | Rare Earth (RE) | Zn | Mn (max) | Other (max) | |---------------|--------------|------------|-----------------|------------|------------|-------------| | **Content (%)** | - | 1.5-2.5 | 0.6-1.5 | 0.4-1.0 | 0.15 | 0.30 total | *Note: The thorium content provides solid solution strengthening and enhances high-temperature stability, while rare earth elements improve castability and corrosion resistance.* --- #### **4. Typical Physical & Mechanical Properties (T6 Temper)** | Property | Value | Condition / Remarks | |---------------------------|------------------------------|---------------------| | **Density** | 1.82 g/cm³ (0.066 lb/in³) | | | **Melting Range** | 590-645°C (1094-1193°F) | | | **Thermal Conductivity** | 105 W/m·K | At 25°C | | **Coefficient of Thermal Expansion** | 25.8 × 10⁻⁶/°C | 20-200°C | | **Ultimate Tensile Strength** | 235 MPa (34 ksi) | Room Temperature | | **Tensile Yield Strength**| 175 MPa (25 ksi) | 0.2% offset, RT | | **Elevated Temperature YS** | 150 MPa (22 ksi) | At 260°C (500°F) | | **Elongation** | 3-5% | In 2 inches, RT | | **Compressive Yield Strength** | 175 MPa (25 ksi) | | | **Shear Strength** | 140 MPa (20 ksi) | | | **Fatigue Strength** | 90 MPa (13 ksi) | 5×10⁸ cycles, RT | | **Elastic Modulus** | 45 GPa (6.5×10⁶ psi) | | | **Hardness** | 65-75 HB | | --- #### **5. International Standards** QH21A-T6 conforms to the following specifications: - **ASTM B80:** Standard Specification for Magnesium-Alloy Sand Castings - **AMS 4419:** Aerospace Material Specification for Castings - **MIL-M-46062:** Military Specification (Historical) - **Proprietary Specifications:** Often supplied to customer-specific requirements --- #### **6. Applications** - **Aerospace Components:** - Jet engine compressor casings and housings - Gearbox assemblies - Missile body sections and wings - Helicopter transmission housings - **Defense Systems:** - Military radar housings - Rocket motor components - Avionics enclosures - **High-Temperature Industrial:** - Engine test equipment - Specialized pump housings - High-temperature instrumentation cases --- #### **7. Heat Treatment & Processing** - **Solution Treatment:** 530°C (986°F) for 4-10 hours followed by rapid quenching - **Artificial Aging:** 200°C (392°F) for 8-16 hours (T6 temper) - **Casting Considerations:** - Suitable for sand and permanent mold casting - Requires controlled cooling rates - Good pressure tightness characteristics - **Machining:** Good machinability with proper techniques and cooling - **Joining:** Reparable using TIG welding with compatible filler rods --- #### **8. Special Considerations** - **Thorium Handling:** Requires special precautions due to low-level radioactivity - **Corrosion Protection:** Needs appropriate surface treatments for harsh environments - **Quality Control:** Requires rigorous inspection for aerospace applications - **Temperature Limitations:** Avoid prolonged exposure above 400°C (750°F) --- **Disclaimer** This technical data is provided for informational purposes only. The thorium content in QH21A 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 heat treatment details. Appropriate testing should be conducted to verify suitability for specific applications.

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 3351 gallon liquid totes Special package is available on request.