Semi-solid A356 alloy slurry was prepared by adding RE element（Er）and weak electromagnetic stirring method.Microstructure of the prepared samples was investigated by OM（optical microscope）

SEM（scanning electron microscope）

TEM（transmission electron microscope）and EDS（energy dispersive spectrometer）

and microstructure evolution was discussed.The results show that with 0.05% Er addition

primary α phase is converted from rosette structure into spherical ones.Grain size in the prepared alloy containing Er can be further refined with weak electromagnetic stirring at 625 ℃

obtaining the required semi-solid slurry.