Magnesium HM31A-T5，UNS M13312; ,E FOUR

Product Datasheet: Magnesium Alloy HM31A-T5 (UNS M13312)** **A High-Strength, Elevated Temperature Wrought Magnesium Alloy** --- #### **Overview** Magnesium Alloy HM31A-T5 (UNS M13312) is a high-strength, heat-treatable wrought magnesium alloy specifically engineered for applications requiring excellent strength and creep resistance at elevated temperatures. Its superior mechanical properties, combined with the low density inherent to magnesium, make it an ideal choice for weight-critical components in the aerospace and racing industries. The "T5" temper designation indicates that the alloy has been artificially aged after an elevated temperature fabrication process, such as extrusion, to achieve its peak strength properties. --- #### **Key Features & Benefits** * **High Strength-to-Weight Ratio:** Offers exceptional mechanical strength while minimizing component weight. * **Excellent Creep Resistance:** Maintains dimensional stability and strength under sustained loads at elevated temperatures (up to approximately 300°C / 570°F). * **Good Thermal Stability:** Retains properties after prolonged exposure to high temperatures. * **Machinability:** Exhibits excellent machinability, allowing for high-speed operations and good surface finishes. --- #### **Chemical Composition (Weight %)** The nominal composition of HM31A alloy is as follows: | Element | Magnesium (Mg) | Thorium (Th) | Manganese (Mn) | Others (Total) | | :--- | :--- | :--- | :--- | :--- | | **Content %** | Balance | 2.5 - 3.5 | 0.45 - 0.80 | ≤ 0.30 | *Note: The presence of Thorium (a low-level radioactive element) necessitates special handling, disposal considerations, and export controls, which has limited its use in modern commercial applications.* --- #### **Physical & Mechanical Properties (Typical for T5 Temper)** The following values are typical and can vary based on the specific form (e.g., extrusion thickness, forging size) and processing parameters. | Property | Value | Condition / Note | | :--- | :--- | :--- | | **Density** | 1.78 g/cm³ (0.064 lb/in³) | At 20°C | | **Melting Range** | ~ 645°C (1195°F) | | | **Ultimate Tensile Strength (UTS)** | 255 MPa (37,000 psi) | Room Temperature | | **Tensile Yield Strength (TYS)** | 200 MPa (29,000 psi) | Room Temperature | | **Compressive Yield Strength (CYS)** | 110 MPa (16,000 psi) | Room Temperature | | **Elongation** | 7% | In 2 inches (50 mm) | | **Modulus of Elasticity** | 45 GPa (6.5 x 10⁶ psi) | | | **Hardness** | 55 HB | | **Elevated Temperature Performance:** HM31A retains a significant portion of its room-temperature strength at elevated temperatures, which is its key advantage. For example, at 315°C (600°F), it can maintain a tensile yield strength of approximately 125 MPa (18,000 psi). --- #### **International Standards & Cross-References** HM31A is specified under various international standards. The most common equivalents are: * **ASTM:** **ASTM B107 / B107M** - Specification for Magnesium-Alloy Extruded Bars, Rods, Profiles, Tubes, and Wire. * **AMS:** **AMS 4382** - Sheet and Plate, Magnesium Alloy HM31A-T5. * **UNS:** **M13312** * **Common Name:** **HM31A-T5** --- #### **Product Applications** HM31A-T5 is primarily used in high-performance, weight-sensitive applications where elevated temperature performance is critical. * **Aerospace & Defense:** * Missile and rocket body skins and components * Engine access doors and cowlings * Aircraft gearbox housings * Auxiliary power unit (APU) components * **High-Performance Automotive:** * Pistons, connecting rods, and other engine components for racing * Gearbox cases * **Nuclear Industry:** * Specialized components (utilizing its neutron moderation properties and high-temperature stability). --- #### **Processing & Handling** * **Heat Treatment:** The T5 temper is achieved by artificially aging the material after a hot-working process. * **Fabrication:** Suitable for extrusion and forging. It can be welded using gas tungsten arc welding (GTAW/TIG) methods. * **Corrosion Protection:** Like most magnesium alloys, HM31A requires protective coatings or finishes (e.g., anodizing, chromate conversion coatings, paint) for service in corrosive environments. --- **Disclaimer:** This information is provided for reference purposes only. Material properties can vary based on manufacturing process, lot, and specific product form. Users should consult the relevant material standards and conduct their own testing to verify suitability for a specific application. Special attention must be paid to the handling and regulatory requirements due to the Thorium content.

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 3342 gallon liquid totes Special package is available on request.