Microstructural evolution in rapidly solidified Al-Fe alloys: An alternative explanation

The solidification sequences in aluminum containing 8 and 16 wt pct iron are described in terms of the formation of metastable and stable primary intermetallic phases. These alloys were studied in the chill-cast and splat-quenched conditions, and marked differences in microstructure due to the different cooling rates were observed. Contrary to previous work, it is proposed that the 50-nm intercellular particles observed in the “zone A” regions of the splat-quenched alloys are primary in nature; this may account, in part, for their remarkable thermal stability.