Formation of microstructures of an Al-10 wt.% Sr alloy prepared by electrolysis and mixing

In this work, the microstructures of an Al-10 wt.% Sr alloy prepared by molten salts electrolysis and direct mixing method have been investigated using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). It has been found that the microstructure of the deeply etched Al-10 wt.% Sr alloy prepared by electrolysis is markedly different from that prepared by direct mixing method. The primary Al4Sr phase is dendritic in the electrolysis-prepared Al-10 wt.% Sr alloy but slablike in the mixing-prepared alloy. The eutectic Al4Sr phase in the electrolysis-prepared alloy is much finer and more complex in morphology than that in the mixing-prepared alloy. It can be speculated that the intensive current and electromagnetic field in the electrolysis process have a significant effect on the liquid structure of the Al-Sr melt and the subsequent solidification process and the microstructure. (C) 2002 Elsevier Science B.V. All rights reserved.