Aluminum or Aluminium Alloys

An aluminum alloy is a composition consisting mainly of aluminum to which other elements have been added. The alloy is made by mixing together the elements when aluminum is molten (liquid), which cools to form a homogeneous solid solution. The other elements may make up as much as 15 percent of the alloy by mass. Added elements include iron, copper, magnesium, silicon, and zinc. The addition of elements to the aluminum gives the alloy improved strength, workability, corrosion resistance, electrical conductivity, and/or density, compared with the pure metallic element. Aluminum alloys tend to be lightweight and corrosion resistant.

List of Aluminum Alloys

This is a list of some important aluminum or aluminium alloys.

• AA-8000: used for building wire per the National Electrical Code
• Alclad: aluminum sheet made by bonding high-purity aluminum to a high strength core material
• Al-Li (lithium, sometimes mercury)
• Alnico (aluminum, nickel, copper)
• Birmabright (aluminum, magnesium)
• Duralumin (copper, aluminum)
• Hindalium (aluminum, magnesium, manganese, silicon)
• Magnalium (5% magnesium)
• Magnox (magnesium oxide, aluminum)
• Nambe (aluminum plus seven other unspecified metals)
• Silumin (aluminum, silicon)
• Titanal (aluminum, zinc, magnesium, copper, zirconium)
• Zamak (zinc, aluminum, magnesium, copper)
• Aluminum forms other complex alloys with magnesium, manganese, and platinum

Identifying Aluminum Alloys

Alloys have common names, but they may be identified using a four-digit number. The first digit of the number identifies the class or series of alloy.

1xxx - Commercially pure aluminum also has a four-digit numerical identifier. Series 1xxx alloys are made of 99 percent or higher purity aluminum.

2xxx - The principal alloying element in the 2xxx series is copper. Heat treating these alloys improves their strength. These alloys are strong and tough, but not as corrosion resistant as other aluminum alloys, so they are usually painted or coated for use. The most common aircraft alloy is 2024. Alloy 2024-T351 is among the hardest of the aluminum alloys.

3xxx - The main alloying element in this series is manganese, usually with a smaller amount of magnesium. The most popular alloy from this series is 3003, which is workable and moderately strong. 3003 is used to make cooking utensils. Alloy 3004 is one of the alloys used to make aluminum cans for beverages.

4xxx - Silicon is added to aluminum to make 4xxx alloys. This lowers the melting point of the metal without making it brittle. This series is used to make welding wire. Alloy 4043 is used to make filler alloys for welding cars and structural elements.

5xxx - The principal alloying element in the 5xxx series is magnesium. These alloys are strong, weldable, and resist marine corrosion. The 5xxx alloys are used to make pressure vessels and storage tanks and for various marine applications. Alloy 5182 is used to make the lid of aluminum beverage cans. So, aluminum cans actually consist of at least two alloys!

6xxx - Silicon and magnesium are present in 6xxx alloys. The elements combine to form magnesium silicide. These alloys are formable, weldable, and heat treatable. They have good corrosion resistance and moderate strength. The most common alloy in this series is 6061, which is used to make truck and boat frames. Extrusion products from the 6xxx series are used in architecture and to make the iPhone 6.

7xxx - Zinc is the principal alloying element in the series starting with the number 7. The resulting alloy is heat-treatable and very strong. Important alloys are 7050 and 7075, both used to construct aircraft.

8xxx - These are aluminum alloys made with other elements. Examples include 8500, 8510, and 8520.

9xxx - Presently, the series starting with the number 9 is unused.

What Is the Strongest Aluminum Alloy?

Manganese added to aluminum increases its strength and yields an alloy with excellent workability and corrosion resistance. The highest strength alloy in the non-heat-treatable grade is alloy 5052.

Aluminum Alloy Classification

In general, the two broad categories of aluminum alloys are wrought alloys and casting alloys. Both of these groups are subdivided into heat-treatable and non-heat-treatable types. Around 85% of aluminum is used in wrought alloys. Cast alloys are relatively inexpensive to produce because of their low melting point, but they tend to have lower tensile strengths than their wrought counterparts.

Sources

• Davis, J.R. (2001). "Aluminum and Aluminum Alloys". Alloying: Understanding the Basics. pp. 351–416.
• Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003). Materials and Processes in Manufacturing (9th ed.). Wiley. p. 133. ISBN 0-471-65653-4.
• Kaufman, John Gilbert (2000). "Applications for Aluminium Alloys and Tempers". Introduction to aluminum alloys and tempers. ASM International. pp. 93–94. ISBN 978-0-87170-689-8.