Formation of novel microstructures in quenched Al[sbnd]Cu alloys in steady magnetic field

Abstract

The formation of the microstructures in the hypo- and hypereutectic AlCu alloys in the steady magnetic field (SMF) was investigated using the conventional quenching technique. In comparison with quenched structures without the SMF, the additional bulky phases, i.e. θ-Al2Cu phase and the supersaturated α solid solution, were found to form in the Al-26 wt%Cu and Al-45 wt%Cu alloys quenched in the SMF, respectively. The temperature measurements showed that the maximum cooling rate of the quenched sample in the SMF was markedly higher than that without the SMF and thus a larger undercooling was obtained in the SMF. The microstructure formation in the SMF can be rationalized using the AlAl2Cu phase diagram with metastable extensions and the coupled growth zone.