Ordliste
Aluminium — definition
A light metal with a density of 2.7 g/cm³ — roughly a third of steel — melting at 660 °C, which can be anodised and heat treated.
Aluminium is chosen when weight matters. It resists corrosion because it forms a dense oxide layer in air, it conducts heat well, and it can be recycled indefinitely without loss of quality.
Here it is cast at 680–700 °C. That high temperature wears the tool faster than zinc does, which shortens tool life.
The alloys divide into two groups: those that can be heat treated and those that cannot. That choice has to be made early, because it also decides whether the part will be die cast or gravity cast.