Effect of electromagnetic vibrations on Fe-Co-B-Si-Nb bulk metallic glasses

Abstract

It is known that cooling rate from the liquid state is an important factor for producing the bulk metallic glasses. However, almost no other factors such as electric and/or magnetic fields were investigated. The present authors have reported that a new method for producing Mg-Cu-Y bulk metallic glasses by using electromagnetic vibrations is effective in forming the metallic glass phase. Moreover, the present authors have reported that the glass-forming ability of Fe-Co-B-Si-Nb alloys also is enhanced with increasing the electromagnetic vibration force. Thus, this study aims to investigate effects of the electromagnetic vibrations on Fe-Co-B-Si-Nb bulk metallic glasses in order to investigate further. Half round lines which consist of fine crystal particles in a glassy phase were observed in the boundary part of the molybdenum electrode for the alloy with the electromagnetic vibrations. It was considered that the reactants of the molybdenum electrode which were solid at 1573 K were moved into the sample by the electromagnetic vibrations and caused the nuclei of crystal particles which composed the half round lines. If tungsten was used as the electrodes, there was no influence of electrodes in the center of the samples. When molybdenum or tungsten was used as the electrodes, the effect of the electromagnetic vibrations was found to be the same, namely the electromagnetic vibrations act on decreasing the number of crystal nuclei. © 2007 The Japan Institute of Metals.