To solve the macrosegregation of Al-Bi-Sn immiscible alloys

the effects of higher cooling rate and Ti addition on the microstructure of Al

70

Bi

15

Sn

15

alloys were investigated

and the morphology

dimension as well as macrosegregation of Bi-Sn-rich dispersed phase were analyzed. The results indicate that the dimension of Bi-Sn-rich dispersed phase is refined and the macrosegregation is decreased with the increase of cooling rate. After Ti addition

the rod-shaped metallic compound of Al

3

Ti is in-situ generated and presents staggered distribution

which retards the collision and inhibits the growth of Bi-Sn dispersed phase droplets. The droplets are refined

and transformed from elliptic shape to round shape. Moreover

Ti addition also reduces solidification temperature of Bi-Sn eutectic structure. Meanwhile

the hardness of Al-Bi-Sn alloy is improved substantially by the dispersed hard compound of Al

3

Ti.