Aluminium Essay

Physically and chemically Aluminium is a metal much like others such as; steel, copper and titanium. I can occur as a solid, a liquid or a gas and the state at which aluminium occurs depends on its condition, temperature and pressure. Aluminium is a very light weight metal at 2.7 grams per 〖cm〗^3, which is approximately one third the weight of steel. (HIGGINS, 1972) It naturally forms a protective oxide coating which protects it from corrosion; this oxide coating is thin but very dense and can be made harder through a natural or imitated treatment called Anodising. Aluminium can be further protected with treatments such as coating through lacquering and painting. It is an excellent heat and electricity conductor. It has a low melting point and is very ductile. And finally aluminium is completely recyclable without a reduction in quality.

Aluminium Alloys

Aluminium in its most pure form is not suitable for use in aircraft as it is soft and lacks strength. In this condition it only has a tensile strength of 90N/〖mm〗^2. For aircraft and other applications aluminium is alloyed or mixed with other additive metals to increase its strength and rigidity. It is possible to create a high strength aluminium alloy with strength greater than 600N/〖mm〗^2 with the correct additives and treatment (HIGGINS, 1972). Below are some examples of aluminium alloys. Aluminium alloys are specified or designated with a number. This number gives us the chemical composition of the alloy.

1000 series: this type of aluminium is used for construction and contains less than one percent additives. It is used to make sheet metal and foil and is not heat treatable but can be strengthened through work hardening. A process of beating, stretching and bending to inc...

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...l have been absorbed by the aluminium solution at approximately 300 degrees Celsius but to ensure all of the compound is dissolved into the solution the solution is heated further to increase the absorption. This is like salt in hot water.

At approximately 548 degrees Celsius all of the compound has been absorb by the solution (this is a recognised appropriate temperature in chemistry).

At this point the desirable crystalline structure of the metal has been reached but it must not be allowed to be heated further as the solution will begin to melt.

The alloy is then quenched in water to trap or hold the alloy at this desired structure.

Once the alloy has been quenched in this condition it is now stronger because all of the 4% of Copper has been dissolved into the solution and ductile because the brittle crystals of the Cu〖Al〗_2 compound are now absent.