Aluminum wire was used for a time to
distribute electricity in
US homes. After a few years it was de-certified, and now
copper is the only acceptable wiring for structures.
There are two problems with aluminum wiring. The first is that it is harder than copper, so when you install it, it does not flatten slightly. This allows the wiring to become loosened, causing non-functional outlets. The other (more important) problem is that if you run too much current through an aluminum wire, it literally explodes. Copper does not have this shortfall.
Aluminum was originally chosen because it is very inexpensive. Some folks still use aluminum wire for a lightning ground because it is easily routed (and still cheap). The only problem you have to consider is that you cannot allow the wire to enter the structure because exploding aluminum can cause a fire. Also, make sure you use gradual curves instead of sharp bends, since lightning can use the bend as a jumping-off point to your structure.