Crystal alignment of Sn-Pb alloy by controlled imposition of a static magnetic field and an alternating electric current during solidification

In this study, a new process for a crystal alignment of an alloy during solidification has been proposed in which the imposing periods of a static magnetic field and an alternating current are controlled. In the initial stage of the solidification both the magnetic and electric fields are imposed on the alloy to break dendrites into pieces and to spread them to the whole area of the sample. In the next stage, only the static magnetic field was applied for the sample. The function of the static magnetic field in this stage is not only the rotation of the crystals to magnetically stable direction but also the suppression of the disturbance such as liquid motion. The principle of this process was experimentally confirmed by using a Sn-10mass%Pb alloy. In the X-ray diffraction pattern of the sample solidified without the static magnetic field, the first and second highest peaks were (101)-plane and (200)-plane. That is, the crystal direction is random. On the other hand, only the peaks corresponding to a,b-plane were observed in the sample solidified under the imposition of the controlled electromagnetic field. Therefore, this process is useful for the crystal alignment of alloy.