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The microstructural formation of the semi-solid AlSi7Mg alloy stirred by electromagnetic field is investigated together withthe tempeatre field of the stirred melt at continuously cooling. A impoat kinetic factor for primny a-Al nucleation is proposed. It isfound that a low temperatUre gradient exists in the electromagnetic stirred melt. This is why the first dendritic arms and secondary de-ndritic arms are refmed. Experimefltal results also show that the root remelting of secontw dendritic arms is an twortat mechanismfor the primary α-Al refmement. Strong electromagnetic stirring greatly reduces the composition supercooling in the melt and eliminatesprefedrig growth of the first dendritic arms. Therefore, many rosettes or spherical Primary α-Al phase particles form finally.
The microstructural formation of the semi-solid AlSi7Mg alloy stirred by electromagnetic field is investigated together with the temperate field of the stirred melt at continuously cooling. A impoat kinetic factor for primny a-Al nucleation is proposed. It is found that a low temperaturre gradient exists in the electromagnetic stirred melt. This is why the first dendritic arms and secondary de-ndritic arms are refmed. Experimefltal results also show that the root remelting of secontw dendritic arms is an twortat mechanism for the primary α-Al refmement. Composition supercooling in the melt and eliminatesprefedrig growth of the first dendritic arms. Thus, many rosettes or spherical Primary α-Al phase particles form finally.