Ben Z.

Nope, not even close. Some heat treating procedures have many, many steps. The temperatures you heat to, cool to, times you hold at each temperature, and the rates that you get there are all important. Heat treating aluminum alloys is generally more complicated than heat treating steels.

Big generalizations:

In (certain) aluminum alloys you generally heat up to a certain temp that dissolves everything in to a solid solution. Then you quench down to a much colder temp. Then you heat up to an intermediate temp that allows small particles to precipitate out of solution (think the solid version of making a slushy). Then you cool back down to lock in that structure.

nine-44

Metal basicly has grain like wood. Cast would be particle board, molocules randomly compressed together. Forged would be hardwood, organized compressed molocules conforming to shape. That's the best I can explain.

Ben Z.

The microstructure of cast metal is generally VERY far from randomly distributed grains like particle board. In fact here is a cool image of the dendrites that form when a metal cools from a liquid to a solid like in a casting (this is a weld):



Now, it is possible that dendrites won't form in a given casting, but it all depends on the temperature gradients and surface energies associated with the interfaces. Also, the local compositions change as dendrites form, all in all it gets really complicated really fast.