Progress in dispersoids distribution precipitating during homogenising Zr-containing Al–Cu–Li and Al–Zn–Mg alloys

Retaining elongated grain microstructure during thermo-mechanical processes would be attractive for obtaining high-strength aluminium alloys with good toughness. A small Zr addition promotes the formation of Al₃Zr dispersoids to inhibit the recrystallisation. Since the dispersoids precipitate directly from castings, their inhomogeneous distribution reduces the effectiveness on the recrystallisation resistance. This paper systematically summarised the theoretical and experimental contributions to optimise the distribution of dispersoids in the Zr-containing aerospace Al alloys including Al–Cu–Li and Al–Zn–Mg alloys. It is concluded that improving the distribution of dispersoids across a grain can be effectively realised by refining the homogenisation conditions such as lowering ramp heating rate, two-step homogenisation, etc., and by controlling the concentrations of the dispersoid-forming elements such as Zr, Mn, Sc, etc.