Effects of Sb and Te compound modification on microstructure and mechanical properties of A357 alloy were investigated by using OM （optical microscopy）

SEM （scanning electron microscopy）

EDS （energy dispersive spectrometer） and tensile test. The results show that with the increase of Te addition

the tensile strength and elongation of the alloy are increased

and the size of the α -Al phase becomes much finer. In addition the morphology of the eutectic Si is changed from flake

needlelike shape to fine fibre shape and finally to granular shape. With 0.2%Te addition

the tensile strength and elongation reach the maximum value

and the morphology of the eutectic Si becomes granular shape with finer size of the α -Al phase. However

with Te addition more than 0.2%

the mechanical properties of the alloy are deteriorated

where the tensile strength and elongation are decreased

and the size of the α -Al phase and Si phase are coarsened.