Magnesium EA55RS-T4,E FOUR

### **Technical Datasheet: Magnesium Alloy EA55RS-T4** --- #### **1. Material Overview** EA55RS-T4 is a specialized rare-earth containing magnesium alloy supplied in the solution heat-treated condition. The **"T4"** temper indicates the material has undergone **solution heat treatment followed by natural aging**, providing an optimal combination of ductility, toughness, and corrosion resistance. The "RS" designation indicates a specific rare-earth element composition optimized for improved casting characteristics and mechanical properties. --- #### **2. Key Features** - **Excellent ductility and impact toughness** - **Superior corrosion resistance** - **Good castability with reduced hot tearing** - **Enhanced fatigue performance** - **Good weldability and repairability** - **Stable mechanical properties** --- #### **3. Chemical Composition (Weight %)** | Element | Composition (%) | |---------|-----------------| | **Rare Earths (RE)** | 4.8–5.5% | | **Silver (Ag)** | 2.0–3.0% | | **Zirconium (Zr)** | 0.4–1.0% | | **Zinc (Zn)** | ≤ 0.30% | | **Manganese (Mn)** | ≤ 0.20% | | **Silicon (Si)** | ≤ 0.05% | | **Copper (Cu)** | ≤ 0.05% | | **Iron (Fe)** | ≤ 0.01% | | **Nickel (Ni)** | ≤ 0.005% | | **Other Elements** | ≤ 0.30% | | **Magnesium (Mg)** | Balance | *Note: The specific combination of rare earths (typically including yttrium and heavy rare earths) with silver provides unique strengthening mechanisms and improved corrosion resistance.* --- #### **4. Mechanical Properties (T4 Temper)** | Property | Value (Metric) | Value (Imperial) | |----------|----------------|------------------| | **Ultimate Tensile Strength** | 240–280 MPa | 35–41 ksi | | **Tensile Yield Strength (0.2%)** | 140–170 MPa | 20–25 ksi | | **Elongation (% in 50mm)** | 10–15% | 10–15% | | **Compressive Yield Strength** | 140–170 MPa | 20–25 ksi | | **Hardness (Brinell)** | 65–75 HB | 65–75 HB | | **Shear Strength** | 140–160 MPa | 20–23 ksi | | **Fatigue Strength** | 110–130 MPa | 16–19 ksi | | **Impact Toughness (Charpy)** | 12–18 J | 9–13 ft-lb | | **Modulus of Elasticity** | 44 GPa | 6.4×10⁶ psi | --- #### **5. Physical Properties** | Property | Value | |----------|-------| | **Density** | 1.83 g/cm³ | | **Melting Range** | 550–645°C | | **Specific Heat** | 1.02 kJ/kg·K | | **Thermal Conductivity** | 98 W/m·K | | **Coefficient of Thermal Expansion** | 26.5 μm/m·K | | **Electrical Resistivity** | 80 nΩ·m | --- #### **6. Heat Treatment Cycle (T4)** - **Solution Treatment:** 520°C ± 5°C for 8–16 hours - **Quenching:** Hot water (60–90°C) or forced air - **Natural Aging:** Room temperature for 30+ days - **Microstructure:** Supersaturated solid solution with minimal precipitation --- #### **7. Applicable Standards** - **ASTM International:** - **ASTM B80** – Magnesium-Alloy Sand Castings - **ASTM B199** – Magnesium-Alloy Permanent Mold Castings - **Aerospace Standards:** - **AMS 4427** – Magnesium Alloy Castings - **BAC 5731** – Boeing Material Specification - **European Standards:** - **EN 1753** – Magnesium and magnesium alloys - **Proprietary Specifications:** - Aerospace OEM specifications (Airbus, Boeing, etc.) --- #### **8. Manufacturing Characteristics** - **Casting Methods:** Sand casting, permanent mold casting, investment casting - **Pouring Temperature:** 710–760°C - **Fluidity:** Excellent - **Hot Tearing Resistance:** Very good - **Machinability:** Excellent - **Weldability:** Very good (TIG recommended) --- #### **9. Applications** - **Aerospace Structures:** - Aircraft gearbox components - Structural brackets and fittings - Helicopter transmission parts - Spacecraft components - **Defense Applications:** - Lightweight armor components - Military vehicle parts - Portable equipment housings - **High-Performance Automotive:** - Racing engine components - Suspension parts - High-stress brackets - **Specialized Industrial:** - Nuclear industry components - Medical equipment housings - Precision instrument frames --- #### **10. Corrosion Performance & Protection** - **Salt Spray Resistance:** >600 hours to initial corrosion - **Stress Corrosion Cracking:** Excellent resistance - **Galvanic Corrosion:** Requires isolation from dissimilar metals - **Recommended Coatings:** Chemical conversion, anodizing, paint systems --- #### **11. Design Guidelines** - **Maximum Service Temperature:** 200°C continuous - **Section Thickness Range:** 3–100 mm - **Stress Analysis:** Consider high ductility in design - **Fatigue Design:** Excellent for cyclic loading applications --- #### **12. Comparison with Similar Alloys** - **vs. EA55RS-T6:** Higher ductility, lower strength - **vs. WE43-T4:** Better corrosion resistance, similar mechanical properties - **vs. Conventional Mg Alloys:** Superior combination of strength and corrosion resistance --- **Note:** EA55RS-T4 offers an exceptional balance of mechanical properties and corrosion resistance, making it suitable for demanding applications where both performance and reliability are critical. The T4 condition provides maximum toughness and damage tolerance, which is particularly valuable in aerospace and defense applications. Always consult with materials engineers for specific application requirements and conduct appropriate testing for critical 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 3327 gallon liquid totes Special package is available on request.