When looking for the ideal basic material, there's no getting around aluminum, because its attributes and qualities are interesting. It has excellent heat conductivity, which is the reason why it is used for CPU coolers. Thanks to its low density of only 2.702 g/cm³, it is considerably lighter than other ferric products (iron: 7.9 g/cm³). In addition, it is less susceptible to corrosion, due to a thin oxide film on the surface. Thus, aluminum surfaces do not require varnishing and can easily be cleaned with a wet cloth.
However, if there weren't any disadvantages, aluminum would have been used much more frequently in the computer sector. Welding aluminum, for example, requires more effort than steel, which is why aluminum cases are riveted for the most part.
Aluminum also carries a hefty price tag. Aluminum is derived in two ways: either from ore or from the recycling of scrap. Due to its low melting point of 660°C (steel: 1535 °C), processing or recycling of aluminum is very easy - although that has not actually helped reduce the high prices for aluminum cases.
On the other hand, extraction from ore has its issues too. It requires that bauxite be turned into an aluminum oxide, and then converted into aluminum using electronlysis.
It takes four tonnes of bauxite to produce two tonnes of aluminum oxide which in turn produces one tonne of aluminum. The main reason for the costly production process is that aluminum oxide is extracted from the raw bauxite by applying high pressure and high temperature during what is called the Bayer process. The Bayer chemical process releases aluminum oxide from bauxite in a caustic soda solution. This is filtered, and the resultant aluminum hydroxide is then precipitated from the soda solution, washed and dried while the soda solution is recycled. After calcination, the end-product, aluminum oxide is a fine grained white powder.
So far we are merely talking about a process of purification, but this already eats up approximately 150 kWh (Kilowatt hours) of energy per kilogram of aluminum.
You can find more information on aluminum here , if you want some background on the material.
Computer case vendors have not embraced aluminum, even though it has very desireable characteristics, such as excellent heat conductivity, and only few manufacturers produce aluminum cases. The reason for this is largely the high dominance and preponderance of steel whose characteristics can be defined by the proportion of carbon making it easier for vendors to deliver competitive products and compete on price. So, it's a Catch-22, the quantities of aluminum cases are low for various reasons, and this in turn hampers competitive pricing.