QE22A (AMS 4418) Magnesium Alloy,E FOUR

### **QE22A Magnesium Alloy (AMS 4418)** **Product Overview** QE22A is a premium high-strength magnesium-silver-rare earth-zirconium casting alloy that represents the pinnacle of magnesium technology for elevated temperature applications. As specified in AMS 4418, this alloy offers an exceptional combination of high room temperature strength, excellent creep resistance, and superior performance at temperatures up to 250°C (482°F). The addition of silver significantly enhances the age-hardening response, making QE22A one of the strongest magnesium casting alloys available for aerospace applications. This alloy is typically supplied as sand castings and investment castings, with optimal mechanical properties achieved through T6 heat treatment (solution heat treated and aged). --- #### **1. Chemical Composition** QE22A features a sophisticated silver-rare earth system designed for maximum strength and high-temperature performance. | Element | Composition (% by Weight) | | :---------------- | :-------------------------------- | | **Silver (Ag)** | 2.0 - 3.0 % | | **Rare Earths (RE)*** | 1.8 - 2.5 % | | **Zirconium (Zr)** | 0.4 - 1.0 % | | **Zinc (Zn)** | ≤ 0.2 % | | **Manganese (Mn)** | ≤ 0.3 % | | **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" typically include neodymium and gadolinium. **Silver** is a critical alloying element that significantly enhances the age-hardening response, leading to high strength and improved creep resistance. **Zirconium** provides essential grain refinement, while **rare earths** contribute to elevated temperature stability. --- #### **2. Physical & Mechanical Properties** QE22A exhibits outstanding mechanical properties, particularly after T6 heat treatment. **Physical Properties:** * **Density:** 1.82 g/cm³ (0.066 lb/in³) * **Melting Range:** 545 - 640 °C (1013 - 1184 °F) * **Coefficient of Thermal Expansion:** 26.5 μm/m·°C (20-200°C) * **Thermal Conductivity:** 51 W/m·K * **Specific Heat Capacity:** 1050 J/kg·K **Typical Mechanical Properties (T6 Temper):** * **Ultimate Tensile Strength (UTS):** 250 - 265 MPa (36 - 38 ksi) * **Tensile Yield Strength (TYS):** 185 - 200 MPa (27 - 29 ksi) * **Elongation:** 2 - 5% * **Compressive Yield Strength:** 185 - 200 MPa (27 - 29 ksi) * **Shear Strength:** 125 - 140 MPa (18 - 20 ksi) * **Fatigue Strength:** 120 - 140 MPa (17 - 20 ksi) * **Hardness:** 70 - 80 HBW * **Modulus of Elasticity:** 45 GPa (6.5 × 10³ ksi) **Elevated Temperature Performance:** * **Excellent creep resistance up to 250°C (482°F)** * **Superior strength retention at 200°C** * **Stable mechanical properties after prolonged thermal exposure** * **Maintains high strength at elevated temperatures better than most Mg alloys** --- #### **3. International Standards & Specifications** QE22A is recognized by major international standards organizations. * **Aerospace Material Specification:** **AMS 4418** (Primary governing specification) * **ASTM International:** **ASTM B80** (Standard Specification for Magnesium-Alloy Sand Castings) * **SAE International:** **SAE J465** * **UNS Designation:** **UNS M18220** * **Federal Standard:** **QQ-M-56** * **ISO Standards:** **ISO 16220** * **European Standards:** **EN 1753** --- #### **4. Product Applications** QE22A is predominantly used in high-performance aerospace and defense applications where maximum strength and elevated temperature capability are required. * **Aerospace & Gas Turbine Engines:** * **Compressor Casings and Housings** * **Gearbox and Transmission Housings** * **Engine Accessory Drive Housings** * **Turbine Engine Components** * **Aircraft Auxiliary Power Unit (APU) Casings** * **Helicopter Applications:** * **Main Transmission Housings** * **Tail Rotor Gearboxes** * **Engine Mounting Structures** * **Rotor Hub Components** * **Defense & Military:** * **Missile Guidance System Housings** * **Weapon System Components** * **Military Aircraft Structural Parts** * **Radar and Avionics Housings** * **High-Performance Applications:** * **Racing Transmission Cases** * **High-Performance Engine Components** * **Aerospace-Grade Automotive Parts** * **Specialized Industrial Equipment** --- #### **5. Manufacturing Characteristics** **Casting Performance:** * Good castability with proper foundry techniques * Requires careful control of silver content * Suitable for complex casting geometries * Good dimensional stability * Responsive to heat treatment **Secondary Processing:** * Good machinability with proper techniques * Excellent response to T6 heat treatment * Requires appropriate corrosion protection * Good surface finish characteristics * Weldable with specialized procedures --- **Summary** **QE22A Magnesium Alloy (AMS 4418)** represents a premium high-strength magnesium casting alloy that has set performance standards in the aerospace industry for decades. Its unique **silver-rare earth chemistry** provides an exceptional combination of **high tensile and yield strength** at room temperature, coupled with **excellent creep resistance** up to **250°C**. The addition of **silver** significantly enhances the age-hardening response, resulting in mechanical properties that surpass most other magnesium casting alloys. Certification to **AMS 4418** ensures its reliability for critical aerospace components in gas turbine engines and other high-stress applications. While the alloy's cost is higher due to its silver content, its exceptional performance characteristics make it the material of choice for applications where maximum strength-to-weight ratio and reliability under demanding conditions are paramount. QE22A continues to be specified for critical components where its proven track record and superior mechanical properties justify its premium cost, particularly in applications where weight reduction is critical and performance cannot be compromised.

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 3439 gallon liquid totes Special package is available on request.