Aluminum alloy is an extremely complex structure, often comprising between six to nine different metal elements. In a molten state, during alloy production, some elements are dissolved in others (like cream in coffee) and some are not (like oil in water). As the molten alloy begins to cool a point will be reached when solidification begins. At that point “crystals” begin to form and, as cooling continues, more crystals develop, building on the first to form a metallic grain structure. Other compounds may also form within the alloy as it cools, some dissolved within the grain structure and others between the grains, along grain boundaries. The malleability, ductility and strength of the alloy are all dependent on the nature of the final alloy grain structure.