Effect of Melt Mixing Treatment on Morphologies of Primary Silicon of Al-20%Si Alloy
The influences of temperature and composition of high and low temperature melt on the primary Silicon refinement of Al-20%Si alloy during melt mixing were investigated. The microstructure was studied by optical microscope. The average diameter and nodularization of the primary silicon were measured using image Pro. The results show that by melt mixing,the morphology of primary silicon could be changed effectively. Adopting an appropriate melt mixing condition, which is high temperature melt with 1050 ℃ and low temperature melt with 690 ℃, can obtain the optimal refining effect that the primary silicon size is 34 μm. The larger the difference of Si content between the high and low temperature melts before mixing, the smaller the grain size of primary silicon.