The Applications of Aluminum and Aluminum Alloys

This article was updated on the 11th September 2019.

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In this article, we discuss the various applications of aluminum and aluminum alloys, which are very versatile engineering materials.

Electrical Conductors

Conductors in either the 1000 or 6000 series alloys are sensible technical alternatives to copper for all electrical conductors, even in domestic wiring.

The majority of overhead, high voltage power lines utilize aluminum rather than copper as the conductor as it is lighter and more economical to use. The relatively low strength of these grades requires that they are reinforced by including a galvanized or aluminum-coated high tensile steel wire in each strand.

Aluminum alloys have a conductivity averaging 62% of the International Annealed Copper Standard (IACS) but, because of its lower density, it can carry more than twice as much electricity as an equivalent weight of copper.

Transport

Aluminum and its alloys have been the prime material of construction for the aircraft industry throughout most of its history. Even today, when titanium and composites are growing in use, 70% of commercial civil aircraft airframes are made from aluminum alloys, and without aluminum civil aviation would not be economically viable.

Aluminum’s combination of acceptable cost, low component mass (derived from its low density), appropriate mechanical properties, structural integrity and ease of fabrication are also attractive in other areas of transport. There are now many examples of its use in commercial vehicles, both passenger and freight rail cars, marine hulls and superstructures and military vehicles.

Volume car production now uses aluminum for engine castings, wheels, radiators and increasingly for body parts. For general production, the 5000 and 6000 series alloys provide adequate strength combined with good corrosion resistance, high toughness and ease of welding. In aircrafts, the very strong 2000, 7000 and 8000 series alloys are preferred, and in military vehicles, the weldable 7000 series alloys can provide ballistic properties to match steel armor.

Packaging

The successful use of the 1000 series alloys as foil for food wrapping and containers utilizes their good corrosion resistance and ability to act as a barrier against UV light, moisture and odor. Aluminum foil can be readily formed, attractively decorated and can be usefully combined with paper and plastic if required.

The most significant use of aluminum in packaging has been in the production of beverage cans with a pull tab or ring pull in the lid. This has rapidly grown to 15% of all aluminum consumption, with one hundred billion cans being produced a year.

Cans for some food products – particularly fish – which also employ the easy opening facilities of aluminum, have been used for over sixty years. From a technical point of view, there is no reason why more use should not be made of aluminum as a food packaging material, costs seem to be the restraining factor at present. This may become less important in the future, see the section on recycling.

Building and Architecture

Aluminum is used in buildings for a wide array of applications. These include roofing for factories which incorporate foil vapor barriers; windows and pre-formed sheet cladding features; doors, canopies and fronts for shops and prestigious buildings; architectural hardware and fittings; rainwater goods; and replacement windows.

Aluminum structures and cladding are also used to refurbish many of the concrete structures built in the 1950s and 1960s which are now showing signs of deterioration and spoilage.

In building applications, the durability of aluminum is of paramount importance. There are several good examples of the durability of aluminum which may be familiar to the reader. This includes the statue of Eros in Piccadilly Circus, London, erected in 1893 and the clad dome of the church of San Gioacchino in Rome, installed in 1887. More recently, the oil and gas industry has employed aluminum widely in offshore structures.

The 1000, 3000, 5000 and 6000 wrought series alloys will perform without protection even in industrial and marine environments, with no reduction of strength. They may, however, suffer some deterioration in their appearance, and protection by painting or anodizing can be advisable.

Anodised films may be clear to preserve the natural aluminum finish or in a limited range of colors. Painting offers a wider range of colors and an appearance similar to other painted metals.

These finishing operations may also, of course, be used for purely decorative effects.

Miscellaneous Applications

The applications outlined above account for approximately 85% of global aluminum consumption. The remaining 15% consists mainly of the following applications.

High Pressure Gas Cylinders

Compressed gas cylinders of up to fifty liters are used for the storage and transportation of carbon dioxide, air, oxygen and special gases. The 6000 series alloys combine light weight, good corrosion resistance, compatibility with the gas to be contained and mechanical toughness, making them a good choice for gas cylinders.

Machined Components

High tolerance components can be machined from the 2000 and 6000 series alloys. These alloys have additions of lead and bismuth which gives them machinability that approaches that of the free machining brasses.

Ladders and Access Equipment

Aluminum alloys are highly suited to ladders and access equipment due to their light weight, corrosion resistance and toughness. The 6000 series extrusions in particular are used both industrially and domestically.

Sporting Goods

The 2000 and 7000 series alloys are used for golf clubs and trolleys, racquets for many sports, snooker and pool cues, and ski poles, often employing spin-off technologies from the aerospace industry.

Road Barriers and Signs

The 2000 and 7000 series alloys are used for golf clubs and trolleys, racquets for many sports, snooker and pool cues, and ski poles, often employing spin-off technologies from the aerospace industry.

Domestic and Office Furniture

The complexity and surface finish of extrusions in the 6000 series alloys coupled with the range of shapes from castings and the use of superplastically formed sheets allows designers an almost unlimited scope when working with aluminum and aluminum alloys.

Lithographic Plates

The complexity and surface finish of extrusions in the 6000 series alloys coupled with the range of shapes from castings and the use of superplastically formed sheets allows designers an almost unlimited scope when working with aluminum and aluminum alloys.

Primary author: Roy Woodward
Source: Materials Information Service edited by Stephen Harmer.
For more information on Materials Information Service please visit The Institute of Materials Minerals and Mining.

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