>>28591245
Aluminum has literally no fatigue limit. It's like plastic. No matter how strong the alloy is at the start, it's on the clock the moment it leaves the forge and enters service, accumulating microfractures and losing strength until eventual failure. (CFC's are technically like this as well.)
It is most useful in non-load bearing components where its low density and high corrosion resistance make it useful as a bulk material.
In the second war of internationalist aggression, aircraft manufacturers all used aluminum alloys in airframes for several reasons. One being that the runs of high specific strength steel alloys were already earmarked for production of ships, tanks, and other equipment likely to see battle damage. An other being that theoretical long term service life years in the future is not much of a concern if you lose the war, and most warplanes going into the line of fire were going end up shot down at one point or another and replaced by new production anyways, and so they were perfectly willing to trade on that for better performance in the today.
Of course, this had the side-effect of creating a huge technical debt in the form of a massive logistical industrial network that was built for producing craft using aluminum, so the aerospace industry as it existed basically just, like, kept doing that anyways, even if the 'market conditions' that made it make sense at first had changed.
