Aluminum (Al)
Aluminum is the most abundant metallic element in Earth's crust and the second most-used metal after steel. With one-third the density of steel, excellent corrosion resistance, and infinite recyclability, it is indispensable in aerospace, automotive, construction, and packaging. Alloy series (1xxx–8xxx) cover a vast range of properties.
Properties
- Density
- 2,700 kg/m³
- Melting Point
- 660 °C
- Boiling Point
- 2,519 °C
- Thermal Conductivity
- 237 W/(m·K)
- Electrical Resistivity
- 2.65 × 10⁻⁸ Ω·m
- Tensile Strength
- 70–570 MPa
- Yield Strength
- 30–505 MPa
- Hardness
- 15–175 HB
- Elongation
- 5–40%
- Crystal Structure
- FCC
Common Grades
- 6061-T6: The most versatile alloy — good strength, weldability, corrosion resistance. Structural profiles, marine, transport.
- 5083-H321: Marine-grade alloy — highest strength non-heat-treatable. Shipbuilding, pressure vessels, cryogenic.
- 7075-T6: Ultra-high-strength aerospace alloy. Aircraft structures, high-stress components. Not weldable.
- 2024-T3: High-strength aerospace alloy. Fuselage skins, wing structures. Limited corrosion resistance.
- 1050-H14: Commercially pure aluminum (99.5%). Chemical equipment, reflectors, electrical conductors.
- 6082-T6: European structural alloy, slightly stronger than 6061. Bridges, cranes, transport. EN 1090 certified.
- 5052-H32: Excellent formability and corrosion resistance. Sheet metal work, fuel tanks, marine hardware.
Applications
- Aerospace: Fuselage panels, wing structures, landing gear components, satellite frames
- Automotive: Engine blocks, wheels, body panels, heat exchangers, EV battery enclosures
- Construction: Window frames, curtain walls, roofing, structural profiles, facades
- Marine: Hull structures (5083), superstructures, masts, marine hardware
- Packaging: Beverage cans, foil, food containers, pharmaceutical packaging
FAQ
What is the strongest aluminum alloy?
7075-T6 is the strongest common aluminum alloy with tensile strength up to 570 MPa, approaching that of many steels. However, it has poor weldability and corrosion resistance. For structural applications requiring welding, 6061-T6 (310 MPa) is the standard choice.
Can aluminum be welded to steel?
Direct fusion welding of aluminum to steel is not practical due to the formation of brittle intermetallic compounds. Joining methods include friction stir welding, explosion bonding, bimetallic transition inserts, or mechanical fastening with insulation to prevent galvanic corrosion.
Why is aluminum used in aerospace?
Aluminum's low density (2,700 kg/m³ vs. steel's 7,850), good strength-to-weight ratio, and corrosion resistance make it ideal for aerospace. The 2xxx and 7xxx series alloys achieve strength levels comparable to mild steel at one-third the weight.
What does the T6 temper designation mean?
T6 means the alloy was solution heat treated (dissolved alloying elements at ~530°C) and then artificially aged (held at 160–190°C for hours) to precipitate fine strengthening particles. This produces the maximum strength condition. T6 is the most common temper for structural 6xxx and 7xxx alloys.
Is aluminum recyclable?
Yes — aluminum is infinitely recyclable with no quality loss. Recycling uses only 5% of the energy needed for primary production (from bauxite ore). Over 75% of all aluminum ever produced is still in use. Beverage can recycling rates exceed 70% in Europe, with can-to-can recycling in as little as 60 days.