Recently a friend of mine claimed that it’s possible to make a lighter structure of the same strength out of steel by removing some of the metal and holding it together with magnets. And that it isn’t normally done because the amount of energy needed to power a sufficiently effective electromagnet doesn’t make it economical.
This strikes me as an idea that would come up in a poorly researched sci-fi movie (why would metal be lighter just because it’s being held together with magnets). So I thought I’d ask you guys.
Can merely holding metal together with magnets make it stronger, and if not is there some sort of engineering technique using electromagnets (or some other form of energy) to replace part of a structure? If this is the case, why haven’t more people heard of it?