Hợp kim nhôm trong ngành hàng không - Tính chất và ứng dụng

# Hợp Kim Nhôm Trong Ngành Hàng Không - Tính Chất Và Ứng Dụng Aluminum alloys là vật liệu chủ đạo trong ngành aerospace nhờ tỷ lệ strength-to-weight tuyệt vời. ## Các Series Hợp Kim Nhôm ### 2xxx Series (Al-Cu): **Đại diện**: 2024, 2014, 2219 **Đặc điểm**: - **High strength** (up to 470 MPa) - **Good** machinability - **Poor** corrosion resistance - **Heat treatable** **Ứng dụng**: - Aircraft structures - Fuselage frames - Wing spars - Landing gear ### 6xxx Series (Al-Mg-Si): **Đại diện**: 6061, 6082, 6063 **Đặc điểm**: - **Medium strength** (up to 310 MPa) - **Excellent** corrosion resistance - **Good** weldability - **Extrudable** **Ứng dụng**: - Aircraft panels - Interior structures - Non-critical components ### 7xxx Series (Al-Zn): **Đại diện**: 7075, 7050, 7150 **Đặc điểm**: - **Highest strength** (up to 570 MPa) - **Excellent** fatigue resistance - **Good** machinability - **Premium** applications **Ứng dụng**: - Wing structures - Fuselage frames - Landing gear - High-stress components ## Chi Tiết 7075-T6 ### Composition: ``` Aluminum: 87.1-91.4% Zinc: 5.1-6.1% Magnesium: 2.1-2.9% Copper: 1.2-2.0% Chromium: 0.18-0.28% ``` ### Mechanical Properties: ``` Tensile Strength: 572 MPa Yield Strength: 503 MPa Elongation: 11% Hardness: 150 HB Density: 2.81 g/cm³ ``` ### Heat Treatment: ``` Solution: 465-482°C, 1-2 hours Quench: Water, <15 seconds Age: 121°C, 24 hours (T6) ``` ## Manufacturing Processes ### Machining: **Cutting Parameters**: ``` Speed: 200-400 m/min Feed: 0.1-0.3 mm/rev Depth: 1-5 mm Coolant: Flood recommended ``` **Tool Selection**: - **Carbide** inserts - **Sharp** cutting edges - **Positive** rake angles - **Polished** surfaces ### Welding: **TIG Welding**: ``` Current: 80-150A AC Electrode: 2% Thoriated Filler: ER4043 or ER5356 Gas: Argon, 15-20 L/min ``` **Challenges**: - **Hot cracking** susceptibility - **Porosity** issues - **Strength** reduction in HAZ ### Forming: **Bend Radius**: ``` 2024-T3: 2.5t minimum 6061-T6: 1.5t minimum 7075-T6: 4.0t minimum ``` ## Corrosion Protection ### Anodizing: **Type II** (Sulfuric Acid): - **Thickness**: 5-25 μm - **Colors**: Natural, Black, etc. - **Corrosion** resistance improved **Type III** (Hard Anodizing): - **Thickness**: 25-100 μm - **Hardness**: 300-500 HV - **Wear** resistance excellent ### Chemical Conversion: **Alodine/Chromate**: - **Thin** coating (0.5-3 μm) - **Paint** adhesion improved - **Electrical** conductivity maintained ### Primers: - **Zinc Chromate** (traditional) - **Zinc Phosphate** (modern) - **Epoxy** based systems ## Quality Standards ### Aerospace Standards: - **AMS**: Aerospace Material Specifications - **ASTM**: American Society for Testing - **EN**: European Norms - **JIS**: Japanese Industrial Standards ### Testing Requirements: ``` Tensile Testing: ASTM E8 Hardness: ASTM E18 (Rockwell) Corrosion: ASTM B117 (Salt spray) Fatigue: ASTM D7791 ``` ## Cost Considerations ### Material Costs (per kg): ``` 6061-T6: $3-4 2024-T3: $5-7 7075-T6: $8-12 ``` ### Processing Costs: - **Machining**: High (work hardening) - **Welding**: Medium (skill required) - **Forming**: Medium (springback) - **Finishing**: Low-Medium ## Future Trends ### Advanced Alloys: - **Al-Li** alloys (lighter) - **Al-Sc** alloys (stronger) - **MMCs** (Metal Matrix Composites) ### Manufacturing: - **Additive** manufacturing - **Friction** stir welding - **Superplastic** forming ## Environmental Impact ### Recycling: - **95%** energy savings vs primary - **Infinite** recyclability - **Closed loop** systems ### Sustainability: - **Lightweight** = fuel savings - **Corrosion** resistance = longevity - **Recyclable** = circular economy Ai đã làm việc với aluminum alloys? Share kinh nghiệm nhé!