Scandium SC thread., page-69

Spot on afewdB, as I posted here a year or so ago, with a lifetime spent in aviation flight testing I know how much the aviation industry needs lightweight, high strength and long life alloys that can be easily fabricated.
(BTW, the opposite extreme is alloys of titanium, the only current material to enable aircraft to fly faster than Mach 2.1 because of impact air temperatures causing aluminium alloy softening. Our Mirages had no placarded Mach limit, just a red light that came on at 130 degC on the wing leading edge. We checked that light on every factory acceptance test.)
But titanium is very difficult to fabricate and too expensive....