If you are meticulus about protecting aluminum it's a good material that will last a long time and will likely hold up better in the event of iceberg derbies. Allow a dissimilar material situaiton and it will fail very quickly. That can be as simple as dropping a coin or nut into a hidden area of the bilge
or having a stray current
isn't prone to corrosion
but it is more brittle. Assuming you are going for a heavily built solid hull
for cruising, it can take quite a bit of abuse before it will crack. If it's lightly built performance oriented design and you are running into solid objects, the aluminum holds the advantage.
In either case, I would prefer to avoid hitting solid things.
My question back is how much experience do you have that you are thinking of arcitc sailing and aren't familiar with the material differences? If it's just a vague someday I might want to go beyond the easy warm weather
cruising, I suggest ignoring the arctic qualities and when you get enough experience and actualy are ready to head
to the arctic, then get a boat for that purpose as the prefered designs will be different.