It's trivially easy to improve most aluminum alloys, especially in the 7000-series, with the addition of a little bit of Zr and sometimes a bit of mischmetal or Ce/Er/whatever. We're talking on the order 0.1% Zr and 0.3% Er, so it's not expensive. You get way better strength, better fatigue performance, and at no penalty to ductility.
Why is this not more commonly done?!?!
Why does something like 7075 still exist, when 7068 is better in every way, and 7068+Er would be better still? Yet 7068 is not only uncommon, it's practically impossible to find.
It's trivially easy to improve most aluminum alloys, especially in the 7000-series, with the addition of a little bit of Zr and sometimes a bit of mischmetal or Ce/Er/whatever. We're talking on the order 0.1% Zr and 0.3% Er, so it's not expensive. You get way better strength, better fatigue performance, and at no penalty to ductility.
Why is this not more commonly done?!?!
Why does something like 7075 still exist, when 7068 is better in every way, and 7068+Er would be better still? Yet 7068 is not only uncommon, it's practically impossible to find.
I honestly don't get it.