I don't think it would melt. It might lose it's strength however.

I've both done and seen this experiment before but not with aluminum. I think I should share this with the ETS community because now that I think about it, this tidbit of knowledge might come in handy.

What you need: Paper cup (Dixie bathroom cup works great), Water, Fire

If my memory serves me correctly the paper cup will not burn if it is holding water. The upper edge might burn because you probably won't fill it up to the brim. What I did on a camping trip way back in the day was to catch crawdads in a stream and put them in the boiling water in the paper cup which was in the fire. It cooked the crawdads and BAM! (emeril type) instant mini-lobster meat lol. I haven't seen this method done in a long time and I may be missing a step but it's not all that complicated. Bringing this back to the aluminum foil, I'd say the metal stands a greater chance become more pliable (sp?) when it's hot but it shouldn't melt if it's holding water.