Effect of Purity and Superheating on the Glass-Forming Ability of Mg-Cu-Y Alloys by an Electromagnetic Vibration Method

抄録

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 the glass-forming ability of Mg-Cu-Y and Fe-Co-B-Si-Nb alloys is enhanced with increasing electromagnetic vibration force. The electromagnetic vibrations affect the increase of the cooling rate and the decrease in the number of crystal nuclei directly, but don’t affect the crystal growing rate. However, effects of the electromagnetic vibrations are not fully investigated so far. Thus, this study aims to investigate effect of the purity and superheating on the glass-forming ability of Mg-Cu-Y alloys by the electromagnetic vibration method. It was found that the glass-forming ability of Mg-Cu-Y alloys is sensitive to the purity of an Ar atmosphere under which the mother alloy is prepared. However, the glass-forming ability was enhanced by the electromagnetic vibrations even if the mother alloy was prepared under low purity Ar. The enhancement of the glass-forming ability by the electromagnetic vibrations in the liquid state was decreased with the increase of superheating. These results support the presumption that disappearance or decrement of the clusters by the electromagnetic vibrations applied to the liquid state causes suppression of crystal nucleation.