1. Composition
Purity: Primarily composed of aluminum atoms (typically 99%+ pure in commercial forms).
Elements: May contain trace impurities (e.g., silicon, iron) from the refining process, but no intentional alloying elements.
Mixture: Aluminum combined with other elements (e.g., copper, magnesium, silicon, zinc, manganese) to enhance specific properties.
2. Mechanical Properties
3. Corrosion Resistance
Forms a thin, protective aluminum oxide layer (Al₂O₃) that resists corrosion in most environments.
Excellent for outdoor or corrosive applications (e.g., packaging, construction).
Corrosion resistance varies widely:
High resistance: Alloys like 5xxx (magnesium-based) or 6xxx (used in marine applications).
Lower resistance: Alloys with copper (e.g., 2xxx series) are more prone to corrosion and may require surface treatments (e.g., anodizing).
4. Thermal and Electrical Conductivity
High thermal and electrical conductivity (second only to copper among common metals).
Used in electrical wiring, heat sinks, and cooking utensils.
Conductivity is reduced by alloying elements (e.g., copper, zinc):
Alloys with high silicon/magnesium (e.g., 6xxx) have moderate conductivity.
High-strength alloys (e.g., 7xxx) are less conductive and rarely used for electrical applications.
5. Applications
Packaging: Foil, cans (due to corrosion resistance and malleability).
Electrical: Wire, capacitors.
Reflective surfaces: Mirrors, insulation.
Chemical equipment: Resistance to corrosion from certain acids.
Aerospace: Aircraft frames (2xxx, 7xxx series for strength).
Automotive: Engine components, wheels (6xxx for lightweight strength).
Construction: Windows, doors, structural beams (6063 for extrudability).
Consumer goods: Bicycle frames, cookware (hard-anodized alloys).
6. Manufacturing and Processing
Easy to cast, form, and weld due to low melting point (~660°C) and high ductility.
Processing depends on the alloy:
Heat-treatable alloys : Can be strengthened via heat treatment (solution annealing, quenching, aging).
Non-heat-treatable alloys: Strengthened through cold working or solid solution hardening.
Some alloys (e.g., 7xxx) are more difficult to weld and require specialized techniques.
