Research Of High Magnetic Field Effect On Al-Si Alloy Structure And Property

The advancement of the material plays an essential role for the development of the national economy and science, because of the fast improving science and technology; every demand for the new material or techniques is strict and accurate. In material science, it is time to adopt new craft to improve material performance and to develop new technology.Al-Si alloy has many excellent physics and chemical properties, Al-Si alloy is an important metal in the industry field, but primary Si distributes asymmetry in the alloy and it is hard to be refined. So it's difficulty to obtain the ideal alloy in normal condition.High magnetic served as a brightly developing tool for material science; it has been applied in many scopes. Because of the improvement and apply of the superconductivity magnetic field, high magnetic becomes a novelty and important way to improve material property. It has been used not only in the iron alloy but also in other alloys. High magnetic has the ability to refine and re-distribute grains easily.This thesis will summarize some relevant developments and main performance of the high magnetic field applied in the research in the past. It will introduce the methods, which were used to improve Al-Si alloy property before. Then it will forecast the influence on the material science and technology that the high magnetic field will give. Finally it will focus on the magnetic field applying on Al-15%Si alloy, to discuss the results of grain refinement, Al grain alignment and primary Si re-distributing.Result shows:1. High magnetic field increases the free energy of face-center Si and eutectic Al-Si alloy. It will decrease the potential barrier and critical grain radius comparatively. Magnetic field will induce the refinement of primary Si and eutectic Al-Si alloy.2. Under high magnetic field, the appearance of Al-Si long stick structure will change into the structure mix of short stick and thin bar.3. Owing to magnetic force, when Bz ? dBz/dz is positive, Si particle will assemble at the top of the specimen ,when Bz ? dBz/dz is negative,Si particle will assemble at the bottom of the specimen.4.In order to obtain the lowest free energy, under Lorentz force, Si particle will gather at the edge of the sample.5.Because of the magnetic energy, it is found that the magnetic field induced Al grain to orient the (111) crystal face and the orientation degree decreased as the temperature increased.