The Al-16 Si-7 Ti composite tubes reinforced with in-situ primary particles were prepared by centrifugal casting.Microstructure in the composites prepared was observed and analyzed by SEM

EDS and OM

and the effects of heat treatment on the microstructure and properties of the composites were investigated.The results show that the centrifugal casting of Al-16 Si-7 Ti composites forms three layer structures

the outer layer containing a large number of primary TiAlSi/Si particles（the enhancement phase）

the middle layer of particle free matrix zone

and the inner layer with a very small amount of primary Si particles.After heat treatment

the morphology change of primary TiAlSi phase can be ignored and the sharp corners of the primary Si particles tends to be spherical

and the eutectic structure is dissolved and presents a punctate distribution.The hardness value of the aged alloy reaches HRB 67.5.The wear resistance of the composites after aging treatment is also better than that of the as cast ones

and the volume wear of the aged composite is reduced by 65%.