What's the chemical reaction called that happens when you strike aluminum and rusted iron together?

Question

I know it forms molted iron for a split second and they used it to weld railroad stakes together, but what's it called?

Answer 1

Thermite

Fe2O3 + 2Al --> 2Fe + Al2O3 + lots of heat  

Answer 2

It is called the Thermite reaction, but it doesn't happen with just aluminium and iron oxide (rust) at ambient temperature. It needs a heat source to start the reaction. A common simple way to initiate a Thermite reaction is to use burning magnesium metal, magnesium ribbon for instance. The ribbon is inserted into the powdered aluminium and iron oxide and ignited (with a match or lighter). The burning magnesium generates a lot of heat and starts the reaction. The reaction generates Al2O3, molten Fe and MgO. Of course Thermite grenades would have a more sophisticated ingnition mechanism.

Answer 3

It is called the thermite reaction.  Do a search at Youtube.  There are some interesting videos.

http://en.wikipedia.org/wiki/Thermite