Action of constant magnetic field on refractory phase inclusions during solidification of the monotectic system alloy with composition of the lower liquidus zone
Alloys of monotectic systems are perspective as cast metallic special alloys,foremost those,based on a less refractory component.Alloys properties are provided,in particular,by structure in forming between temperatures of monotectic and eutectic.A row of such alloys properties increased by decreasing refractory phases sizes.The research aim was to establish,in making casts in insignificant and developed convection,possibilities of application of constant magnetic field with small flux density for forming of dispersed structural constituents in the monotectic systems alloys,with compositions of the lower liquidus zone.The low temperature Bi-Zn alloy was selected as research object-the eutectic point and boundary between the lower liquidus and the immiscibility zone correspond to 3wt.%Zn,temperature 255℃ and 15wt.%Zn,monotectic temperature 416℃.It was defined,that increasing melt cooling rate from 2.5 to 1.7 ·103℃/s led to raising quantity(q)of Zn inclusions in 4.5 times.Inclusions with length(l)250 and thickness(b)15 μm prevailed in 2.5℃/s.Speed-up cooling decreased l to 120 and b to 6 μm.Imposition of magnetic field of 1 T in slow cooling increased q in two times.Process of branching of the inclusions and their disorientation from heat transfer direction began.Magnetic field in speed-up cooling substantially did not change q and l.Tendency of thickness increasing of most of the inclusions and their branching appeared.Probably,in increased cooling time of structure forming was not enough for effective influence of magnetic field.Melt stirring in cooling~1℃/s decreased l to 10-60,b to 1-10 μm and increased their amount(in 11 times more,than in static conditions).Imposition of magnetic field of 1 T,(parameter of magnetohydrodynamic interaction~6)in casting increased q(almost in 13 times higher,than without stirring),due to appearance of the inclusions with (l) 1-10 μm.The results used for determination of parameters for treatment of industrial aluminum alloys with refractory second phases by constant magnetic field.Treatment in the rational regimes in cooling and solidification of the bearing alloy(Al-6wt.%Fe)by magnetic field led,on comparison with the alloys produced without constant magnetic field,to increasing twice of quantity,compactness and equitability distribution of the refractory phase inclusions.As result alloy wear resistance increased in 6 times.
cast alloy monotectic system lower liquidus solidification constant magnetic field structure
V.A.Seredenko V.I.Dubodelov E.V.Seredenko
Department of Magnetic Hydrodynamics,Physico-Technological Institute of Metals and Alloys of the National Academy of Sciences of Ukraine,Vernadsky ave. 34/1,Kyiv-142,03680,Ukraine
国际会议
The 7th International Conference on Electromagnetic Processing of Materials(第七届冶金与材料电磁过程国际大会)
北京
英文
1-4
2012-10-22（万方平台首次上网日期，不代表论文的发表时间）