Simulation Study On Flow And Solidfication Characteristics Of Cu-Ag Alloy Prepared By Electromagnetic

With the rapid development of science and technology,most traditional materials cannot well meet the needs of daily production and life.For pure copper,it cannot have both good electrical conductivity and strength at the same time,so research a high-strength,high-conductivity performance of the copper-based alloy is very necessary,and it has also been widely concerned by related researchers.For Cu-Ag,Cu-Zn,Cu-Al and other copper-based binary alloys,due to the relatively simple preparation process of Cu-Ag alloys and its excellent electrical and thermal conductivity,it can be applied to electronic technology,new materials,lead frames of integrated circuits,and conductor materials.Because the microstructure of the material determines its physical properties,the study of the solidification process is particularly important for the material.During the solidification process of the alloy,it is always accompanied by segregation,which is an inevitable solidification defect that seriously affects the quality of products.In order to study the segregation phenomenon of Cu-6%Ag alloy during solidification,a three-dimensional mathematical model of fluid flow,heat transfer and solute transmission coupling of Cu-6%Ag alloy Solidification was established.The experimental results are used.On the basis of verification,the solidification transport process of Cu-6%Ag alloy was simulated,and the results show that:(1)The influence of the mold size on the solidification of the ingot is studied.With the same cooling conditions and pouring temperature,the quality of the Φ40 mm ingot is better than that of the Φ160 mm ingot.The Φ40 mm ingot size is small and the solute distribution is uniform.On the contrary,the solidification time of the Φ160 mm ingot is long,and the solute Ag does not have enough time to diffuse,so it is necessary to propose a measure to improve the segregation phenomenon of the large-sized ingot.(2)The solidification rule of Φ160 mm large section ingot under different cooling conditions was studied With the increase of the heat transfer coefficient of the mold wall,the convection of the alloy liquid is accelerated,which helps to enhance the fluid flow in the liquid zone and accelerates the mixing of solutes in the liquid zone,as a results,the ingot segregation decreases.In the process of preparing large-size ingots,the mold wall with strong heat exchange capacity should be selected for pouring.(3)The solidification laws of Φ160 mm large cross-section ingots at different pouring temeratures are studied.When the pouring temperature is low,the flow of the alloy liquid is slower and a strong positive segregation zone is formed in the center of the ingot.When the casting temperature is too high,the ingot will produce negative segregation zone.There should be a suitable pouring temperature.In this article,the pouring temperature is 1353.54 K.(4)The study of the solidification and transport process of small-size ingots under electromagnetic stirring found that,regardless of whether the solute buoyancy is considered,from the perspective of temperature gradient and solute distribution,electromagnetic stirring is not suitable for small-size ingots.(5)The segregation law of different stirring methods on the internal solute transport in large-size ingots is studied.Electromagnetic stirring can reduce the temperature gradient of the alloy liquid in the ingot and accelerate the heat dissipation.The ingot solidification time is the shortest under the action of linear stirring,so for large cross-sections,the effect of linear agitation to weaken the segregation will be better.(6)The stirring effect under three kinds of magnetic induction intensity(0.018 T,0.036 T,0.06 T)under linear stirring action was studied.The comparison results of solute segregation under the three conditions showed that the segregation situation was weak when the magnetic induction intensity was 0.036 T.(7)The comparison of solute segregation at three current frequencies(4 Hz,8 Hz,12 Hz)under linear stirring action shows that the segregation is weaker when the current frequency is 4-8 Hz.