Aluminium-silicon-strontium Master Alloy，Aluminium silicon strontium Alloy，AlSiSr Alloy，E FORU

**Product Datasheet: Aluminium-Silicon-Strontium Master Alloy (Al-Si-Sr Alloy)** **Version:** 1.0 | **Date:** 2025-04-02 --- ### **1. General Overview** Aluminium-Silicon-Strontium Master Alloy (Al-Si-Sr Alloy) is a premium eutectic modification alloy specifically designed for superior modification of aluminium-silicon casting alloys. Strontium serves as an extremely effective modifier that transforms the acicular eutectic silicon structure into a fine fibrous morphology, significantly enhancing mechanical properties, particularly ductility and impact strength. This master alloy represents the industry standard for high-quality aluminium casting modification. --- ### **2. International Standards** Al-Si-Sr master alloys are specified in numerous international standards: - **ASTM:** ASTM B179 (Standard Specification for Aluminum Alloys in Ingot and Molten Forms) - **ISO:** ISO 209-1 (Wrought aluminium and aluminium alloys) - **EN:** EN 1676 (Aluminium and aluminium alloys - Master alloys) - **GB/T:** GB/T 8734 (Aluminium alloy master alloys) - **JIS:** JIS H 2118 (Aluminium alloy master alloys) - **Typical Master Alloy Grades:** Al-10Si-10Sr, Al-15Si-10Sr, Al-20Si-10Sr, Al-10Si-5Sr --- ### **3. Chemical Composition (Weight %)** Typical composition ranges for Al-Si-Sr master alloy: | Element | Content (%) | Role & Remarks | |---------------------|-------------------|------------------------------------------| | Silicon (Si) | 8.0 – 20.0 | Primary alloying element | | Strontium (Sr) | 3.0 – 15.0 | Eutectic modification element | | Iron (Fe) | ≤ 0.25 | Impurity control | | Calcium (Ca) | ≤ 0.05 | Critical impurity control | | Barium (Ba) | ≤ 0.02 | Impurity control | | Magnesium (Mg) | 0 – 0.10 | Controlled for specific applications | | Other Impurities | ≤ 0.10 total | — | | Aluminium (Al) | Balance | Base metal | --- ### **4. Physical Properties** | Property | Value / Range | |---------------------------|-----------------------------------| | Density | 2.7 – 3.0 g/cm³ | | Melting Range | 580 – 800°C | | Intermetallic Phases | Al₄Sr, Al₂Si₂Sr, AlSiSr | | Thermal Conductivity | 100 – 150 W/m·K | | Electrical Conductivity | 30 – 45 % IACS | | Vickers Hardness | 60 – 120 HV | | Coefficient of Thermal Expansion | 20–23 × 10⁻⁶/K | --- ### **5. Key Characteristics & Advantages** - **Superior Eutectic Modification:** Transforms silicon from acicular to fibrous morphology - **Excellent Ductility Improvement:** Increases elongation by 100–200% - **Long Modification Life:** Effective for extended holding periods (8+ hours) - **Minimal Gas Pickup:** Lower hydrogen absorption compared to sodium - **Consistent Performance:** Reliable and reproducible modification results - **Improved Mechanical Properties:** Enhanced tensile strength and impact resistance --- ### **6. Product Applications** - **Automotive Castings:** Cylinder heads, engine blocks, transmission cases - **Aerospace Components:** Structural castings, brackets, housings - **Pressure-Tight Castings:** Pump housings, valve bodies, hydraulic components - **Architectural Castings:** Decorative elements, structural components - **Consumer Products:** High-quality cookware, machinery parts - **Electrical Components:** Motor housings, transformer cases - **Military Applications:** High-reliability structural components --- ### **7. Available Forms** - **Master Alloy:** Ingots, notch bars, waffle plates - **Special Forms:** Rods, cones for precise addition - **Standard Sizes:** 5–15 kg ingots - **Waffle Plates:** Designed for controlled dissolution --- ### **8. Technical Guidelines for Use** - **Addition Rate:** 0.1–0.3% Sr to the melt (typically 0.01–0.03% effective Sr) - **Melt Temperature:** 720–760°C - **Holding Time:** 30–60 minutes for complete modification - **Stirring:** Gentle mechanical stirring recommended - **Treatment Window:** Effective for 6–10 hours after addition - **Over-modification Avoidance:** Monitor to prevent excessive Sr content (>0.03%) --- ### **9. Modification Performance Comparison** | Modification Element | Modification Efficiency | Duration | Gas Pickup | Cost | |---------------------|------------------------|----------|------------|------| | **Strontium (Sr)** | Excellent | Long | Low | Medium | | **Sodium (Na)** | Excellent | Short | High | Low | | **Antimony (Sb)** | Good | Permanent | Low | Medium | | **Calcium (Ca)** | Fair | Medium | Medium | Low | --- ### **10. Mechanical Property Enhancement** | Property | Unmodified | Sr-Modified | Improvement | |----------|------------|-------------|-------------| | **Tensile Strength (MPa)** | 180–220 | 200–240 | 10–15% | | **Elongation (%)** | 2–4 | 6–12 | 150–200% | | **Impact Strength (J)** | 4–8 | 10–18 | 100–150% | | **Quality Index** | 200–250 | 280–350 | 30–40% | --- ### **11. Quality Control Parameters** - Strontium content consistency (±0.2%) - Critical impurity control (Ca, Ba, Na) - Modification efficiency testing - Microstructural evaluation - Chemical composition certification --- ### **12. Health, Safety & Handling** - **Pyrophoric Nature:** Fine particles may be pyrophoric - handle with care - **Moisture Sensitivity:** Store in dry conditions to prevent hydrolysis - **Personal Protection:** Wear gloves, safety glasses, and protective clothing - **Ventilation:** Adequate fume extraction during addition - **Fire Safety:** Class D fire extinguisher required - **Storage:** Sealed containers in dry, well-ventilated areas --- ### **13. Microstructural Characteristics** - **Modified Structure:** Fine fibrous silicon network - **Intermetallic Phases:** Al₄Sr, Al₂Si₂Sr compounds - **Grain Structure:** Refined eutectic colonies - **Phase Distribution:** Homogeneous silicon particle distribution --- ### **14. Economic Considerations** - **Cost Efficiency:** Higher initial cost but better overall economics - **Process Savings:** Reduced scrap and improved yield - **Quality Benefits:** Superior mechanical properties justify premium cost - **Recycling Compatibility:** Can be used in recycled alloy systems --- ### **15. Research & Development Trends** - **Optimized Compositions:** Development of multi-element modification systems - **Nanoscale Effects:** Understanding modification mechanisms at atomic level - **Additive Manufacturing:** Modification of Al-Si powders for 3D printing - **Environmental Aspects:** Development of more environmentally friendly alternatives - **Process Control:** Advanced monitoring of modification efficiency --- ### **Disclaimer** This information is provided for technical reference only. Properties and performance may vary based on specific application conditions, processing parameters, and base alloy composition. Strontium modification requires careful control to avoid over-modification and gas pickup. Users are advised to conduct thorough testing to determine optimal addition rates and processing parameters for their specific applications. Always follow strict safety guidelines due to strontium's reactive nature, particularly in fine particulate form. Consult with materials engineering specialists for critical applications in automotive and aerospace industries.

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 2312 gallon liquid totes Special package is available on request.