The alloying element common to all 2xxx
alloys is copper. Several common alloys also contain
magnesium and/or manganese. These alloys
are precipitation hardened. After final fabrication,
the alloys are solution heat treated and quenched.
They are then frequently used in the as-quenched
and naturally aged (room temperature) condition
(T3 or T4 tempers) or artificially aged to increase
strength via formation of Al-Cu(-Mg) strengthening
precipitates (T6 or T8 tempers).