Study On Micro Structure Evolution Of Solidification Structure Of Al-In Monotectic Alloy

Al-In monotectic alloy is an alloy with good soft magnetic properties,and its low coercivity makes it widely used in the batteries of original equipment such as industrial motors and transformers.However,the excellent structural properties of the material are only manifested in the solidified structure in which the dispersed phase is evenly distributed,and the monocrystalline alloy is decomposed into two insoluble liquid phases when it is solidified to the difficult miscible interval of the component,which is extremely easy to cause.The phenomenon of severe segregation and even two-phase delamination of the monocrystalline alloy greatly limits the research and development of such a heteromorphic alloy.In this paper,Al-In monotectic alloy is selected as the research object,and the simulation and partial experimental research on the solidification process of monocrystalline alloy under the conditions of no gravity,normal gravity,steady magnetic field,rotating magnetic field and different components are studied.A new way to uniformly solidify monocrystalline alloys.In this paper,the Euler-Eulerian method is used to describe the complex physical processes such as dispersive phase nucleation,diffusion growth,Ostwald ripening,Marangoni migration,steady magnetic field and rotating magnetic field in the inhomogeneous zone of Al-In monotectic alloy.Based on the mathematical model,a mathematical model of macroscopic energy transfer is established based on the conservation equation.The partial differential equations that can describe the solidification process of the monotectic alloy are established by the source term,the unsteady phase,the diffusion phase and the convection.Based on the CFD computational fluid dynamics commercial software,the double-precision coupling solution of the equation is realized in the C++language compiled operation program.The effects of various conditions on the uniformity of solidification microstructure of the monotectic alloy were analyzed by the simulation of the solidification process of the matrix phase,the dispersion phase velocity field,the volume fraction field and the droplet diameter distribution.In this paper,the simulation experiment of Al-In monotectic alloy under normal gravity conditions was carried out,and the microstructure of the monotectic alloy under gravity was obtained and analyzed.The simulation results show that under the condition of no gravity,the Marangoni force caused by the temperature gradient plays a major role in the solidification process of the monotectic alloy.When gravity exists,the convection intensity due to gravity is greater than the convection generated by the Marangoni force.Therefore,gravity becomes the main cause of macrosegregation of the solidification structure of the monotectic alloy.When the 1T steady magnetic field is applied,the effect of gravity convection is obviously inhibited.Under the action of the magnetic field,the maximum velocity of the droplets in the dispersed phase is only 14.4%under the condition of gravity;the maximum diameter of the droplets in the dispersed phase is only the gravity.In the case of 2.2?m reduction,it can be seen that under the action of the magnetic field,the migration rate of the dispersed phase droplets is suppressed,and the convection between the two phases of the monocrystalline alloy is alleviated,so that the solidified tissue distribution is more uniform.The Lorentz force of the change between the rotating magnetic field and the molten metal under the condition of a rotating magnetic field with a strength of 1T and a rotating frequency of 36 Hz serves to fully agitate and hinder the convection of the droplet,so that the temperature field of the matrix phase is more stable than the steady magnetic field.Uniform,more favorable for uniform solidification structure formation.The solidification experiment of Al-5%In monotectic alloy was carried out.The results show that the microstructure of the Al-In monotectic alloy under normal gravity produces obvious segregation.Along the direction of gravity,the sample showed obvious upper and lower delamination,resulting in uneven distribution of solidification structure of the monocrystalline alloy.The simulation results under gravity conditions are basically consistent with the experimental results from the quantitative relationship to the trend,verifying the accuracy of the established simulation model and the simulation method used.