The composites of Al-50 Si

Al-60 Si and Al-70 Si alloy were prepared by hot pressing to understand effect of Si content on the microstructure and physical properties of the composites prepared.The results show that the Si content has a great influence on powder metallurgy aluminum-silicon composites.When the Si content is 50%

the Al matrix forms a continuous network structure in the composites prepared

however a large number of fine pores can be observed.When the Si content is increased to 60%

the Al matrix is distributed in a continuous network and the internal pores are reduced obviously.When the Si content reaches 70%

the probability of Si particles growing apart from each other presents more obvious

and the Si phase size is significantly increased.The Al-60 Si composites has the desirable performance with thermal conductivity of 128.0 W/（m·K）

and the thermal expansion coefficient is 9.92×10

-6

℃

-1

from room temperature to 150℃

and the density reaches up to2.462 g/cm

3

.