Zirconium aluminum alloy is added in some 7000 series alloys in order to reduce the susceptibility of corrosion by tension.
The addition of Zr (in order to reach a 0.1 to 0.3% rate) is performed to form a thin precipitate of intermetallic particles which suppresses the recovery and the recrystallization. In other alloys, Zr is used to increase the recrystallization temperature and the control of grain structure in cast products.