Effect of electromagnetic stirring on solidification structure of clad ingots

The solid-liquid compound method was used to prepare 3003/4004 and 5056/AZ91 clad ingots.The optical microscope and XRD were used to analyze the effect of electromagnetic stirring on the modification of solidification structure.The results show that,with electromagnetic stirring,the interface morphology of solidification structure obviously changes.For 3003/4004 clad ingot,without electromagnetic stirring,the solidification structure of 4004 aluminum alloy near the interface is coarse dendrite,when electromagnetic stirring is used,the solidification structure of 4004 aluminum alloy changes into non-dendrite crystal.For 5056/AZ91 clad ingot,without electromagnetic stirring,the of intermetallic compounds congregate on the interface,which closing to 5056 side and AZ91 side are Mg2Al3 and Mg17Al12.When electromagnetic stirring is used,the forced convection in AZ91 melt caused by Lorentz force washes against 5056 solidification shell to remelting,a great quantity of Al element involves in the core of the ingot and mixed with magnesium alloy melt,so that Mg2Al3 is generated from the interface to the core.