Elektron MSR-B Magnesium Casting Alloy, UNS M18220,E FOUR

*Elektron MSR-B Magnesium Casting Alloy (UNS M18220)** **Product Overview** Elektron MSR-B is a high-purity, creep-resistant magnesium casting alloy specifically formulated for elevated temperature service. It belongs to the family of magnesium-strontium (Mg-Sr) alloys and was developed as a modern, environmentally friendly replacement for traditional alloys containing thorium. MSR-B offers an excellent combination of castability, corrosion resistance, and, most notably, good mechanical strength and creep resistance at temperatures up to approximately **200°C (392°F)**. This alloy is designed for use in sand, permanent mold, and investment casting processes to produce complex components for the aerospace and automotive industries where weight reduction and high-temperature performance are critical. --- #### **1. Chemical Composition** The composition of Elektron MSR-B is characterized by a strontium-based system with strict control over impurities to ensure performance and corrosion resistance. | Element | Composition (% by Weight) | | :--- | :--- | | **Strontium (Sr)** | 1.2 - 2.2 % | | **Rare Earths (RE)*** | 1.5 - 2.5 % | | **Manganese (Mn)** | 0.3 - 0.6 % | | **Zinc (Zn)** | ≤ 0.3 % | | **Zirconium (Zr)** | ≤ 0.10 % | | **Copper (Cu)** | ≤ 0.03 % | | **Iron (Fe)** | ≤ 0.03 % | | **Nickel (Ni)** | ≤ 0.003 % | | **Silicon (Si)** | ≤ 0.03 % | | **Other Impurities** | ≤ 0.30 % (each) | | **Magnesium (Mg)** | Balance | *Note:* The "Rare Earths" are typically based on Neodymium (Nd). The key innovation is the use of **Strontium (Sr)** to form stable intermetallic phases that inhibit grain boundary sliding at high temperatures, providing creep resistance without the environmental and health concerns associated with thorium. --- #### **2. Physical & Mechanical Properties** Elektron MSR-B provides a robust balance of room temperature and elevated temperature properties, typically delivered in the T6 temper (solution heat treated and aged). **Physical Properties:** * **Density:** ~1.81 g/cm³ (0.065 lb/in³) - Maintains the exceptional lightweight advantage of magnesium. * **Melting Range:** ~ 550 - 640 °C (1022 - 1184 °F) **Typical Mechanical Properties (at Room Temperature, T6 Condition):** * **Ultimate Tensile Strength (UTS):** 220 - 240 MPa (32 - 35 ksi) * **Tensile Yield Strength (TYS):** 145 - 165 MPa (21 - 24 ksi) * **Elongation:** 3 - 6% * **Shear Strength:** ~ 120 MPa (17 ksi) **Elevated Temperature Performance (Key Feature):** MSR-B is engineered to outperform standard alloys like AZ91 at elevated temperatures. * **Creep Resistance:** Good resistance up to **200°C (392°F)**, making it suitable for many under-hood automotive and lower-temperature aerospace applications. * **Strength Retention:** Maintains a higher percentage of its yield strength at temperatures between 150°C and 200°C compared to aluminum-based common casting alloys. --- #### **3. International Standards & Specifications** Elektron MSR-B is recognized under several key international and proprietary standards. * **Unified Numbering System (UNS):** **UNS M18220** * **Aerospace Material Specification (AMS):** **AMS 4439** (This is the primary specification for sand castings of this alloy) * **ASTM International:** Referenced within AMS and other procurement documents. * **Proprietary Designation:** **Elektron MSR-B** is a registered trademark of Luxfer MEL Technologies. The "MSR" stands for Magnesium-Strontium-Rare Earth. --- #### **4. Product Applications** The primary application of MSR-B is in components that require lightweight characteristics and must withstand sustained operation at elevated temperatures. * **Aerospace:** * **Auxiliary Power Unit (APU) Housings:** Engine casings and components. * **Gearbox Housings:** For transmissions and accessory drives located in hot zones. * **Engine Accessories:** Mounts, brackets, and compressor housings. * **Automotive (High-Performance & Racing):** * **Engine Components:** Timing chain covers, oil pans, and intake manifolds for high-performance engines. * **Transmission Casings:** For motorsport applications where weight and temperature are concerns. * **General Industrial:** * Housings for high-speed machinery and equipment where moving mass reduction is critical. --- **Summary** **Elektron MSR-B (UNS M18220)** represents a significant advancement in environmentally conscious magnesium alloy technology. By utilizing **strontium** as a key alloying element, it delivers reliable **creep resistance up to 200°C** without relying on hazardous elements. Its specification under **AMS 4439** certifies it for demanding aerospace applications, while its good castability and corrosion resistance make it a versatile choice for automotive and industrial sectors. MSR-B effectively bridges the gap between standard alloys like AZ91 and the ultra-high-temperature capabilities of alloys like EQ21, offering a balanced and sustainable solution for elevated temperature service.

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 3391 gallon liquid totes Special package is available on request.