ZA27 alloy was prepared by controlled diffusion solidification

and effects of precursor alloy composition on microstructure of the ZA27 alloy prepared were investigated.The results show that the grain size of ZA27 alloy can be refined

and the microstructure morphology is improved by controlled diffusion solidification.With increasing in Zn content in precursor alloy 2（Al-Zn-Cu-Mg alloy）

the chilling and forced convection of precursor alloy 1（Pure Zn）on precursor alloy 2are weakened

so the effect of controlled diffusion solidification on ZA27 alloy microstructure was decreased.When the content of Zn in precursor alloy 2is 0

the grain size with irregular particle structure is 95.9μm.When the content of Zn in precursor alloy 2reaches 10%

the grain size is increased to 103.8μm

and a part of equiaxed grain can be observed.Whereas it reaches 30%

the grain size is increased to 137.3μm

slightly less than 145.6μm of ones produced by traditional casting

and the dendritic morphology can be observed.After the content of Zn in precursor alloy 2is increased to 40%

the grain size of ZA27 alloy prepared reaches 145.4μm

which reveals that the effect of controlled diffusion solidification on microstructure of ZA27 alloy almost disappear.