Effect Of Electromagnetic Field On Solidification Structure Of Al-5Ti-1B

The application of aluminum and aluminum alloy is increasingly extensive,and people have stricter requirements on the microstructure and mechanical properties of their products.Equiaxed grain structure is conducive to improving mechanical properties,reducing hot cracking,eliminating shrinkage cavity,uniformly distributing the second phase,and improving the machinability of cast parts.At present,the simplest,economical and effective method to refine grain is to refine aluminum and aluminum alloy by grain refiner.In actual production,the most used refiner is Al-5Ti-1B.However,there are many quality problems in the domestic production of Al-5Ti-1B refiner,so it has become a hot research topic for finding an optimal treatment process.For the optimal production of Al-5Ti-1B refiner,most researchers focus on starting with the raw materials for preparing refiners and producing refiners with excellent quality through different material ratios.The refiner produced by this method has improved the refining effect,but there are often other problems,such as substituting impurity elements into the structure,which affects the properties of the material.We still need to explore the treatment process that can not only eliminate the influence of impurity elements,but also improve the quality of refiner.Electromagnetic field has been widely used in material processing,metallurgy and other fields due to its non-contact transfer of heat energy and kinetic energy.The purpose of refining solidification structure and improving the quality of metal materials can be achieved by interaction between electromagnetic field and metal.In this paper,the effect of electromagnetic field on solidification structure of Al-5Ti-1B master alloy was studied by applying electromagnetic field during remelting casting of Al-5Ti-1B master alloy.The refining test of industrial pure aluminum was carried out with self-made refiner.It is found that applying electromagnetic field treatment during solidification of molten Al-5Ti-1B can obviously improve the morphology and distribution of its second phase structure and improve the quality of ingot.It is shown that the size of TiAl₃ and TiB₂decreases and the distribution is more dispersed.After remelting casting at 660?for 30s,the microstructure optimization effect of Al-5Ti-1B ingot is the best.The average dimensions of TiAl₃ at the center and edge of the ingot are 13?m and 15?m respectively,which are reduced by 41%and 32%respectively compared with the original.The average dimensions of TiB₂ at the center and edge of the ingot are 65nm and 96nm respectively,which are reduced by 73%and 51%respectively compared with the original.Al-5Ti-1B refiner was used to refine industrial pure aluminum.After magnetic field treatment was applied during solidification,the grain size of pure aluminum changed from coarse strip to regular fine block with an average grain size of 218?m,which was 58.7%less than that of the original,and the refining effect was excellent.