New F150 coming to Detroit auto show

If I'm not mistaken, the hood of the current F 150's are already made of aluminum. If Ford is talking a weight savings of nearly 700 lbs. most of that would be realized from use of an aluminum box. My only question would be how an aluminum bed would hold up to daily use if the owner is throwing more than groceries in it........And, would the bed be subject to cracking from vibration and flex?