Density of Aluminum

The density of aluminum is about 0.098–0.101 lb/in³ (≈ 2.66–2.81 g/cm³ or 2660–2810 kg/m³) depending on the alloy. Most wrought aluminum alloys are within ±5% of 2.70 g/cm³ (2700 kg/m³). This is roughly one-third the density of carbon and stainless steels.

Density is the weighted average of the alloy’s elemental constituents. Series 5xxx and 6xxx tend to be lighter (Mg, Si). Wrought products are close to nominal density; castings are typically 95–100% of theoretical due to porosity.

What is Aluminum?

Aluminum is a lightweight, corrosion-resistant structural material that can be strengthened through alloying and, depending on composition, further strengthened by heat treatment and/or cold working. Advantages include low density, high strength-to-weight ratio, good corrosion resistance, ease of fabrication and diverse forms.

What is the Aluminum Alloy Designation System?

A four-digit system identifies wrought aluminum alloys; the first digit denotes the major alloying element:

• Aluminum ≥ 99.00%: 1xxx
• Copper: 2xxx
• Manganese: 3xxx
• Silicon: 4xxx
• Magnesium: 5xxx
• Magnesium & silicon: 6xxx
• Zinc: 7xxx
• Other element: 8xxx

The last two digits identify the alloy or its purity; the second digit indicates a modification of the original alloy.

Cast aluminum alloys use a similar scheme with a decimal point indicating product form (casting vs. ingot):

• Copper: 2xx.x
• Silicon (with Cu and/or Mg): 3xx.x
• Silicon: 4xx.x
• Magnesium: 5xx.x
• Zinc: 7xx.x
• Tin: 8xx.x
• Other element: 9xx.x

Material Properties of Aluminum

• Linear Thermal Expansion Coefficient of Aluminum
• Specific Heat of Aluminum
• Young's Modulus of Aluminum
• Yield and Tensile Strength of Aluminum

Reference

• Callister, W. D., Jr. (2007). Materials Science and Engineering: An Introduction. 7th ed., John Wiley & Sons, Inc.
• Kissell, J. L., Ferry, R. L. (2002). Aluminum Structures: A Guide to Their Specifications and Design. 2nd ed., John Wiley & Sons, Inc.