Solidification paths for an icosahedral quasicrystalline phase in cast Al62Cu25.5Fe12.5 and Al55Cu25.5Fe12.5Be7 alloys

Abstract The solidification behavior of the icosahedral (i) phase in (Al 62− x Be x )Cu 25.5 Fe 12.5 ( x =0,7) alloys has been investigated using a conventional casting technique. It was observed that the addition of beryllium (Be) modified the i-phase formation mechanism from peritectic reaction to primary solidification compared to as-cast Al 62 Cu 25.5 Fe 12.5 alloy. The establishment of the new solidification path is attributed to the narrowing of the freezing range resulting from the beryllium addition. However, the resolidification at a slow cooling rate could result in the formation of the i-phase by peritectic reaction. The conversion of the initial solidification path to the peritectic solidification was attributed to a cooling rate effect resulting from the elaboration process. A new decomposition process of the bulk single i-phase in the Be-containing alloy is also proposed in the present paper.