High-volume fraction SiCp/Mg composites with different particle sizes were fabricated by vacuum-pressure infiltration technology

and the effects of SiC particle size on thermal expansion behavior of SiCp/Mg composites were examined.The results indicate that the particle size has the significant effect on the coefficient of thermal expansion（CTE）

and at the same volume fraction conditions

the CTE of the composites is decreased with the decrease of the particle size.In addition

the CTE of the composites with different volume fraction is inversely proportional to the interfacial area of the composites.CTE of the composites can be effectively decreased by decreasing the particle size and increasing the volume fraction of particle.The effect of particle size on thermal expansion behavior of the SiCp/Mg composites is attributed to acting on interfacial area

relative density of the composites as well as dislocation density of AZ91D alloy.