https://www.youtube.com/watch?v=2SY6PlbJz0Q
My guess, he's not so much folding it as reshaping and mixing the metal under intense pressure in much the same way you might work dough ... (yeah, bad analogy... )
No its a good one. Reminds me of how they made "Damascus" Steele by pounding different layers together.
Too bad aluminum is too soft for this technique to provide any advantages.
...or perhaps that should actually be tested. Would this kind of processing change the mechanical properties of aluminum in any significant way?