EFFECTS OF FORCED ELECTROMAGNETIC VIBRATIONS DURING THE SOLIDIFICATION OF ALUMINUM-ALLOYS .2. SOLIDIFICATION IN THE PRESENCE OF COLINEAR VARIABLE AND STATIONARY MAGNETIC-FIELDS

The influence on grain refinement of electromagnetic vibrations impose d during solidification of various aluminum alloys has been examined. The vibrations were produced, without any material contact with the so lidifying alloys, by the simultaneous application of a stationary magn etic field B-0 and a periodic magnetic field bit! of 50 Hz frequency. Extensive grain refinement has been observed in both continuous castin g and batch-type mold casting. This investigation shows that the mean grain size obtained by this electromagnetic vibrational method is smal ler than that produced by the variable magnetic field acting alone (el ectromagnetic stirring), particularly when the alloys are characterize d by a narrow freezing range.