Alloy or aluminium intercooler
 

I always thought an alloy intercooler is an aluminium intercooler but now I am not so sure.alloy would be a mixture of metals so would be difficult to weld an aluminium bung onto for the IAT sensor. So is there such a thing as an aluminium intercooler or are they all alloy?

most cast aluminum is an "alloy" because it has silicone in it.

There's really no such thing as "pure" aluminum in any industrial context. Nearly all of the aluminum which you encounter in an automotive context is going to be alloyed with some combination of other materials in order to improve its strength, hardness, etc.