I think he got it cofused sith Magnesium that does degrade with age.
Most classic race/sport car owners who own cars with magnesium wheels know this very well and are forced to retire wheelsets on their cars after they get a certain number of years old so they can still drive/race their cars safely. My uncle had to change out the Halibrand magnesium wheels on his 1965 427 Cobra a couple of years ago because of this.

Chombi