New Application of Electromagnetic Vibration Process for Creation of High Potential Metallic Materials
We have developed the new process for refinement of metallic materials during solidification without addition of refiners or without rapid cooling. This process uses electromagnetic body force based on the vibrations caused by simultaneous imposition of direct magnetic field and alternative electric current on the alloy melt during solidification. The vibrations create cavitation in the melt and it breaks out during growth of it. Then explosive force is released toward the surroundings such as the primary solid particles and they are fractured finely. Finally fractured solid particles solidified as very fine grains. This process was applied to hyper- and hypo-eutectic Al-Si alloys, and AZ91D Mg alloys. Primary silicon crystals in Al-17mass%Si alloy decreased the size remarkably by the optimum electromagnetic vibration condition. Primary aluminum dendrites particles in Al-7mass%Si and primary magnesium dendrite particles in AZ91D are also decreased its size markedly. This process has also been applied to create non-equilibrium state metallic materials such as metallic glasses. We have succeeded to obtain metallic glasses in Mg-Y-Cu alloy system and Fe-Co-Si-B-Nb alloy system. These alloys solidified as fully crystals in this cooling rate without electromagnetic vibrations. These glasses are bulky and are used as structural material.
T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran
K. Miwa et al., "New Application of Electromagnetic Vibration Process for Creation of High Potential Metallic Materials", Materials Science Forum, Vols. 539-543, pp. 323-328, 2007