Aluminum seems to fatigue faster, but a single bend with a reasonable radius, I think it would be fine. As far as the flat stock is concerned, those are oversized sections, they have one direction to bend where they would bend with minimal stress, and the material would be a lot lighter. Obviously the Blackburn type racks were bent, they were also welded so they were presumably heat treated, Falanx level of complexity, too much for me.

For what it's worth both bows and arrows have been made with aluminium both uses involved repeated bending, though obviously not through yield at least not intentionally. When arrows are bent through yield, they can be re-straitened and reused though it is technically fairly difficult.