Effect Of Electromagnetic Field On The Structure And Properties Of Eutectic Al-(Si)-Fe Alloy

Aluminum alloy is widely used in manufacturing of aerospace and vehicle parts due to its advantages of low density,good ductility and corrosion resistance.However,the coarse precipitate phase in aluminum alloy can split the matrix and reduce the properties of the alloy.Therefore,it is important to refine the coarse precipitates in the of Al-Fe and Al-Si-Fe alloys.The effects of rotating magnetic field and pulsed magnetic field on microstructure,tensile strength and elongation of eutectic Al-2%Fe and Al-12.6%Si-0.8%Fe alloys have been studied.The microstructure of alloy was characterized by metallurgical microscope,scanning electron microscope and transmission electron microscope,and the mechanical properties of alloy were measured by electronic testing machine.The result shows:rotating magnetic field and pulsed magnetic field can promote the transformation of columnar and dendritic grains to equiaxed grains in eutectic Al-2%Fe alloy.Optimum 80V rotating magnetic field or a pulsed magnetic field at 430V,equiaxed grains with diameters of about 10μm or 18μm were obtained in the alloy,respectively.Meanwhile,rotating magnetic field will cause the lath Al₃Fe phase in the eutectic Al-2%Fe alloy and the bulk primaryβ-Si phase and lathβ-Al₅Fe Si phase in the eutectic Al-12.6%Si-0.8%Fe alloy segregates at the edge of the ingot;the number of lath Al₃Fe phase and bulk primaryβ-Si phase and lathβ-Al₅Fe Si phase in the top microstructure of eutectic Al-2%Fe alloy and eutectic Al-12.6%Si-0.8%Fe alloy increased by pulsed magnetic field.In the eutectic Al-2%Fe alloy and the eutectic Al-12.6%Si-0.8%Fe alloy,the best refining effect of the rotating magnetic field with the voltage of 80V is obtained,the length of the acicular Al₃Fe phase and the acicularβ-Si phase are 24μm and 30μm,respectively;pulsed magnetic field with 430V plays a good role in refining the acicular phases in two eutectic alloys,under these conditions,the length of acicular Al₃Fe phase and acicularβ-Si phase are 38μm and 34μm,respectively.Under the rotating magnetic field,the tensile strength and elongation of the eutectic Al-2%Fe alloy and the eutectic Al-12.6%Si-0.8%Fe alloy first increase and then decrease,when the voltage intensity of the rotating magnetic field is 80V,the tensile strength and elongation of the two eutectic alloys are the largest,among them:the maximun tensile strength and elongation of the eutectic Al-2%Fe alloy are 94.4 MPa and 13.47%respectively,which are increased by 19.5%and 39.2%respectively;the maximun tensile strength and elongation of the eutectic Al-12.6%Si-0.8%Fe alloy are 119.2MPa and 13.54%,which are increased by 22.3%and 70.7%respectively.Under the pulsed magnetic field with a voltage of 430V,the tensile strength and elongation of the eutectic Al-2%Fe alloy are 83.26 MPa and 10.65%,respectively,which are increased by 5.4%and 10.1%;the tensile strength and elongation of the eutectic Al-12.6%Si-0.8%Fe alloy are 117.1 MPa and 12.63%respectively,which are increased by 20.1%and 59.3%respectively.