Density of aluminum: the key parameter behind lightweight metals

Among many industrial metals, there are not many elements as widely used as aluminum. In particular, aluminum alloys are widely used in aviation, automobiles, construction and other fields due to their good ductility, strength，lightweight and corrosion resistance. The "density of aluminum" as one of the basic parameters for evaluating material properties is an important reason why aluminum is favored.

What is the density of aluminum? What is the density of pure aluminum?

Aluminum usually exists in pure form in nature and is used in pure aluminum form in many practical applications. Its standard density has been standardized by the Aluminum Association of America -

In the International System of Units (SI): 2700 kg/m³

In centimeter-gram-second (CGS) units: 2.70 g/cm³

In imperial units: about 0.1 pounds/cubic inches

Density is essentially the mass of a substance contained in a unit volume, expressed as:

Density = mass / volume

This definition provides a basis for us to evaluate the performance of materials in structural design and quality control.

Density variation range of aluminum alloys

Although the density of pure aluminum is relatively fixed (about 2.70 g/cm³), when aluminum forms an alloy with other elements, its density will change to a certain extent. These differences depend on the type of alloying elements added and their proportions. For example:

The aluminum content in the 1xxx series alloys is as high as 99%, and the density is close to that of pure aluminum, usually between 2.70~2.71 g/cm³. Typical grades are 1050 and 1060, which are often used for conductive materials and decorative panels.

The 2xxx series alloys contain a higher proportion of copper elements, and the density is usually between 2.77~2.84 g/cm³, such as 2024, 2011, etc., with high strength but slightly increased density, and are mostly used for aviation structural parts.

The 3xxx series alloys use manganese as the main alloying element, with a density of about 2.72~2.73 g/cm³, such as 3003, 3105, etc., which maintain a lower density while improving corrosion resistance, and are suitable for daily necessities such as roof panels and storage tanks.

The 4xxx series alloys mainly add silicon, and their density is usually lower than that of pure aluminum, generally between 2.66 and 2.69 g/cm³, such as 4032 and 4045, which are often used in automobile engine parts and welding materials.

The 5xxx series alloys mainly contain magnesium, with a density range of about 2.64 to 2.69 g/cm³, such as 5052, 5083, 5754, etc., which are typical lightweight corrosion-resistant alloys and are widely used in ships, transportation equipment and tanks.

The 6xxx series alloys are mainly magnesium and silicon, with a density of about 2.70 to 2.72 g/cm³, such as 6061, 6063, 6082, etc., with a density close to pure aluminum, suitable for medium-strength scenes such as structural parts, frames, and rails.

Because the 7xxx series alloys contain zinc and magnesium, the density can reach 2.80 to 2.90 g/cm³, such as 7075 and 7050, which are typical materials with high strength requirements and are used in key parts such as aviation and military industry.

The 8xxx series alloys are complex in composition and are mostly functional alloys. Their density is usually between 2.70 and 2.80 g/cm³. For example, 8011 is used for aluminum foil and 8079 is used for packaging layers. Their density is slightly higher but does not affect their flexibility and processing performance.

This small but important density change will affect the application scenarios of the material. For example, aircraft structures need to balance strength and lightness, and high-density and high-strength alloys such as 2024 and 7075 are often used; while automobile chassis and rail profiles tend to prefer 6061 and 5083 with moderate density and balanced comprehensive performance; for lightweight packaging materials, 1xxx and 8xxx series are given priority to achieve the optimization between weight control and ductility.

Density comparison table of different aluminum alloys

The following are the density parameters of common aluminum alloys for quick reference:

Series	Alloy	Density (kg/m³)	Density (g/cm³)	Density (lb/in³)
1xxx (High - Purity Aluminum)	1050	2705	2.705	0.0977
	1060	2705	2.705	0.0977
	1070	2700	2.700	0.0975
	1100	2710	2.710	0.0979
	1350	2700	2.700	0.0975
	1235	2705	2.705	0.0977
2xxx (Al - Cu Alloy)	2011	2830	2.830	0.1022
	2014	2800	2.800	0.1012
	2024	2780	2.780	0.1004
	2618	2760	2.760	0.0997
	2219	2840	2.840	0.1026
3xxx (Al - Mn Alloy)	3003	2730	2.730	0.0986
	3004	2720	2.720	0.0983
	3005	2730	2.730	0.0986
	3105	2720	2.720	0.0983
4xxx (Al - Si Alloy)	4032	2680	2.680	0.0968
	4045	2670	2.670	0.0965
	4047	2660	2.660	0.0961
	4343	2680	2.680	0.0968
5xxx (Al - Mg Alloy)	5005	2700	2.700	0.0975
	5052	2680	2.680	0.0968
	5056	2640	2.640	0.0954
	5083	2660	2.660	0.0961
	5182	2670	2.670	0.0965
	5754	2665	2.665	0.0963
	5454	2690	2.690	0.0972
	5154	2660	2.660	0.0961
6xxx (Al - Mg - Si Alloy)	6005	2700	2.700	0.0975
	6060	2700	2.700	0.0975
	6061	2700	2.700	0.0975
	6063	2700	2.700	0.0975
	6082	2700	2.700	0.0975
	6101	2700	2.700	0.0975
	6262	2720	2.720	0.0983
7xxx (Al - Zn Alloy)	7005	2780	2.780	0.1004
	7049	2840	2.840	0.1026
	7050	2830	2.830	0.1022
	7075	2810	2.810	0.1015
	7475	2810	2.810	0.1015
8xxx (Special Alloy)	8011	2710	2.710	0.0979
	8021	2700	2.700	0.0975
	8079	2700	2.700	0.0975
	8176	2710	2.710	0.0979
Cast Aluminum Alloys (Common Die - Casting/Sand - Casting Materials)	A356	2690	2.690	0.0972
	A319	2685	2.685	0.0969
	A380	2770	2.770	0.1001
	A413	2660	2.660	0.0961
	319	2680	2.680	0.0968

The significance and advantages of low density of aluminum

(1) The preferred material for lightweight design

Currently, the density of all aluminum alloys is less than 3 g/cm³, making it extremely competitive in weight-sensitive fields such as aviation, automobiles, and rail transportation. The lighter the weight, the higher the fuel efficiency and the lower the system load.

(2) Strong structural substitutability

Aluminum alloys can replace heavier steel for structural design with their good strength-to-weight ratio, especially for frames, shells, connectors and other parts.

(3) Excellent corrosion resistance

Many aluminum alloys naturally form a dense oxide film on their surface, which greatly improves their antioxidant capacity. Compared with pure aluminum, alloys perform better in maintaining corrosion resistance.

(4) Good recyclability, energy saving and environmental protection

Compared with high-density metals, aluminum has a lower melting point and requires less energy for remelting, and has good recyclability and environmental protection value.

(5) High conductivity

Although aluminum is not as conductive as copper, it has a low density and light weight. Its conductivity per unit weight is even twice that of copper, making it suitable for transmission lines, cables and other fields.

Summary