Refinement Effect and Mechanism of AZ31 Magnesium Alloy by Electromagnetic Stirring under the Effect of Grain-refiner

摘要

The effects of electromagnetic stirring and Al_4C_3 grain refiner on the grain refinement of semi-continuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al_4C_3 grain refiner. Electromagnetic stirring can "activate" the Al_4C_3 particles, resulting in more heterogeneous nucleation sites for the primary α-Mg grains. But, longer holding time can "inactivate" the Al_4C_3 particles, and the optimal experimental holding time is 60 min in the present investigation. The activated rate of the electromagnetic under the experimental condition ρ_2=1.65%.