Phase constituent and microstructure of a new particle reinforced Al matrix composites have been observed by XRD and SEM

which is prepared by molten reaction based on a new developed in-situ Al-K

2

ZrF

6

-KBF

4

system. The results show that there exist ZrB

2

and Al

3

Zr particles with size of 1

4

μm uniformly distributed into the synthesized composites

in which the sectioned morphology of the ZrB

2

particle is similar to regular hexahedron. Tensile testing indicates that tensile strength and yield strength of the （Al

3

Zr+ZrB

2

）p/Al composites can be increased with increasing in reactive additive. With the reactive additive of 20% （weight）

the ultimate tensile strength and yield strength of the composites are 152.3 MPa and 112.3 MPa

respectively

improved by 95.2% and 167.3%

compared with those of the aluminum matrix

78.0MPa and 42.0 MPa.