Hey liz!
I use alot of aluminum type furniture on my deck! Currently, I have a dining table with 4 chairs, and a swing on the opposite end made of all aluminum. ( Except for the cushions of course!!

) I like using those because it doesn't harm the wood, and if they get wet or anything from rain being blown into the deck its not going to harm them as much as it would metal.
Do you currently have any furniture on your deck?