The Research Of Viscosities Of Metal Melts Under The Magnetic Field

The viscosity of melt is a sensitive physical parameter. The viscosity of melt is close related to its structure. It is significant for the fundamental science and technological applications to study the viscosity property of liquid metals and alloys.Al, In, Sn, Bi and their alloys are important industrial metallic materials, and they play important roles in the modern industry. In the present work, the dynamic viscosities of Al, In, Sn, and Bi melts under different magnetic field intensities have been investigated by using a torsional oscillation viscometer. The relationship between the viscosity and the intensity of the magnetic field was probed. The effects of liquid metal structure on the viscosity were analyzed, which laid the experimental foundation for the research of the liquid structure.The present research shows that the viscosity curves of the pure metal melts under the magnetic field well. The viscosities of all melts increase under the horizontal magnetic field. That’s because the melt consists of metallic cations and free electron gas. At the high temperature, there are thermal moved cations across the magnetic induction line, the Lorentz force will be obtained. The force will change the state of motion, and make the viscosity of melt increase. At the same superheated temperature, the stronger intensity the magnetic field is, the larger the viscosity the melt is. The viscosity change rate of the lightest element Al is the largest in the samples. The viscosity change rate of Sn is obviously smaller than that of Al, because it possesses covalent bonds and could not change into metallic cations. In addition, the activation energy of the whole melts increases with the intensity of the magnetic field increases.The viscosities of Al-Si alloy and Al-Co alloy, which has the same atomic ratio, increase with decreasing temperature and fit Arrhenius equation well without the magnetic field. Moreover, the viscosity curves for the melt under the magnetic field fits Arrhenius equation well, too. The viscosities of alloys increase with the increasing intensity of magnetic field. Without or under low intensity of magnetic field, the viscosity of Al-Si alloy is smaller than that of Al-Co alloy. However, under the strong intensity of magnetic field, the viscosity of Al-Si alloy is larger than that of Al-Co alloy. That’s because the viscosities of melts under the low intensity of magnetic field are depended on the temperature and the character of element, but under the higher intensity of magnetic field-e, the melt consists of metallic cations and free electron gas, which will obtain the Lorentz force across the magnetic lines, and the state of motion changes. The atomic weight of Si is lighter than that of Co. Thus, the viscosity of Al-Si melt increases much more obviously.The effects of magnetic field on the viscosity of Al-Si alloy melt were larger than those of Al-Co alloy melt. Meanwhile, the pre-exponential Arrhenius equation and the activation energy of melt both increase under the magnetic field. It shows the effects of magnetic field on the melt on the other side.