The virtually pure series of aluminum alloy – 99% or higher purity – is referred to as the 1xxx series. This series of aluminum alloy possesses excellent workability and corrosion resistance in addition to high electrical and thermal conductivity. For this reason, the 1xxx series is used commonly for power grid in transmission purposes – in other words, the electrical lines that connect the national electric grid across the U.S. Some common alloy designations in this series are 1100 for food packaging trays and 1350 for electrical applications.
Aluminum has properties that include workability, density, electrical conductivity, corrosion resistance, and strength that can be enhanced by the addition of certain elements. This leads us to a discussion of other aluminum alloys as opposed to standard aluminum or 99% pure aluminum as mentioned above.
Aluminum Alloys (2xxx-7xxx Series)
An aluminum alloy is a combination of mostly aluminum combined with other elements added. When these elements are mixed in with aluminum and a molten (liquid) condition, the resulting composition cools, forming a homogeneous solid solution. The other elements can comprise as much as 15% of the resulting alloy in terms of mass. Some of the elements that may be added to form the owl include copper, iron, zinc, silicon, and magnesium. Alloys are given a four digit number. The first digit signifies the series or general class of the alloy, characterizing its major alloying elements.
Aluminum alloys tend to have characteristics that include corrosion resistance and a high strength to weight ratio. They also often possess improved characteristics involving workability, electrical conductivity, strength, and corrosion resistance compared to the pure aluminum metallic element.
The strength of aluminum alloys can be increased through cold working or heat treatment. The resulting attributes of a particular alloy are determined by the elements added to the pure aluminum and any treatment applied to the alloy.
For instance, when manganese is added to aluminum, the resulting alloy possesses greater strength, with exceptional corrosion resistance, and workability.
Aluminum Alloy Classification
Two major categories of aluminum alloy are casting alloy and wrought alloy. Each group of alloys is divided into two categories – heat treatable and non-heat treatable. Wrought alloys utilize about 85% of aluminum. Cast alloys are on the inexpensive side to produce due to the fact they have a low melting point. The tensile strengths of cast aluminum alloys also tend to be lower than the tensile strength possessed by wrought alloys.
