What is Aluminium and What are Aluminum Alloys?

In this article we will try to give information about aluminum alloys and aluminium metal.

Aluminum is a chemical element with the symbol Al and the atomic number 13. It is a silvery-white, soft, non-magnetic, and ductile metal that makes up about 8% of the Earth’s crust by mass. These alloys are the most abundant metals in the Earth’s crust and the third most abundant element after oxygen and silicon.

Why are aluminum alloys important?

Aluminum alloys have a wide range of properties that make them useful for various engineering applications. Some of these properties are:

Lightweight

Aluminum has a density of only 2.7 g/cm3, approximately one-third as much as steel (7.83 g/cm3). This means that these alloy products are lighter than steel products of the same size and shape, which can reduce the weight and fuel consumption of vehicles, aircraft, and spacecraft.

High strength

Some al. alloys have tensile strengths exceeding that of structural steel, which means they can withstand high loads and stresses without breaking or deforming. For example, alloy 7075-T6 has a tensile strength of about 570 MPa (83 ksi), while alloy 2024-T3 has a tensile strength of about 470 MPa (68 ksi).

Corrosion resistance

Aluminum forms a thin layer of aluminum oxide on its surface when exposed to air or water, which protects it from further oxidation and corrosion. This layer is colorless, transparent, and self-healing if scratched. These alloys can also resist corrosion by various chemicals and environmental factors by adding appropriate alloying elements or applying surface treatments such as anodizing or painting.

Electrical conductivity

Aluminum alloys have an electrical conductivity of about 37.7 MS/m (62% IACS), which is nearly twice that of copper on an equivalent weight basis. This means that aluminum wires can carry more current than copper wires of the same weight, which can reduce the cost and size of electrical cables and equipment.

Thermal conductivity

Aluminum has a thermal conductivity of about 205 W/mK (142 BTU/h ft °F), which is about 50 to 60% that of copper. This means that the alloy can transfer heat efficiently across its surface or through its body, which is useful for heat exchangers, evaporators, radiators, and other applications that involve heat transfer or dissipation.

Reflectivity

Aluminum alloy surfaces can be highly reflective of radiant energy, visible light, radiant heat, and electromagnetic waves. This can be beneficial for decorative purposes or for applications that require reflecting or redirecting light or energy. For example, aluminum foil can reflect heat and light to keep food warm or cool; mirrors can reflect light for telescopes or solar panels; coatings can reflect radar waves for stealth aircraft or satellites.

What are some examples of these aluminum alloys and their applications?

There are hundreds of aluminum alloys with different compositions, properties, and applications. Here are some examples of common or notable alloys and their uses:

Aluminum Alloys: 1100

This is a commercially pure al. (99% or more) that has excellent corrosion resistance, workability, and weldability. It is used for food and chemical handling equipment, cooking utensils, heat exchangers, and decorative trim.

Aluminum Alloys: 2014

This is a heat-treatable alloy that has high strength and good machinability. It is used for aircraft structures, truck frames, forgings, and fittings.

Aluminum Alloys: 3003

This is a non-heat-treatable alloy that has good corrosion resistance, formability, and weldability. It is used for pressure vessels, cans, roofing, siding, and cooking utensils.

Aluminum Alloys: 5052

This is a non-heat-treatable alloy that has high strength, good corrosion resistance, and good formability. It is used for marine applications, fuel tanks, truck bodies, sheet metal work, and appliances.

Aluminum Alloys: 6061

This is a heat-treatable alloy that has medium to high strength, good corrosion resistance, and good machinability. It is used for structural components, automotive parts, bicycle frames, pipes, fittings, and furniture.

Aluminum Alloys: 7075

This is a heat-treatable alloy that has very high strength but low corrosion resistance. It is used for aircraft structures, gears, shafts, and missile components.

Al-Li

This is a group of alloys that contain lithium as an alloying element to reduce the density and increase the stiffness of aluminum. They are used for aerospace applications such as fuselage panels, wing skins, and propellant tanks.