Alumina particle reinforced aluminum matrix composites were prepared successfully by in-situ reaction in melt after adding SiO

2

powder into aluminum melt via semi-solid mechanical stirring technique.The fabrication of the composites under different squeezing pressures was also investigated.The micro-structure and phase constituent of the composites prepared were analyzed by scanning electron microscope and X-ray diffraction

meanwhile

the tensile properties of the composites were measured.The results reveal that the internal defects of squeeze-casting composites are decreased greatly

and the reinforcement particles are distributed homogeneously into the composites.With the increase of squeezing pressure

the tensile strength

hardness and elongation of both the as-cast and T6heat-treated composites are the higher than those of the matrix ZL109 alloy.Meanwhile

these properties are increased with the increase of squeezing pressure.