Experimental Analysis of Making Pb-Sn Alloy by Using Directional Solidification Under Magnetic Fields

摘要

Of all the processing techniques used in the manufacturing materials, solidification is probably the most important. Solidification affects the morphology control of microstructures. The microstructures of materials, which directly influence the mechanical and physical properties. The directional solidification process enables grain orientation to put in order along a specific direction, with this process, will decrease grain boundary (G.B.), which could improve mechanical properties of materials. The electromagnetic solidification process means the solidification process with the magnetic field or electric fields, the electromagnetic solidification is a new research field. In our study of sand mold casting and directional solidification, lead-tin (Sn-10wt%Pb) alloy is used as the casting material. Neodymium magnets are used to make magnetic fields. We used metallographic observation, including macrostructure, microstructure with optical microscope, and calculate grain size with linear intercept method, those are our materials analysis methods. According to the experimental results, casting process with a water-cooling copper chills, it can desired temperature gradient make the purpose of directional solidification. The microstructure of directional solidification process is affected by magnetic fields with experimental results. With linear magnetic field, has the thinner columnar structures than those of the one without magnetic field and with cyclic magnetic field, has the coarser columnar structures than those of the one without magnetic field.