| In order to investigate the microstructures of Al-(0.8, 1.3, 3)wt%Fe alloys, solidification processes were performed with water-cooled mold, air-cooled mold and in furnace. The intermetallic particles of these alloys were analyzed by X-ray diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy. The eutectic structure between Al and Al_6Fe particles was dominant and a few Al₃Fe particles were observed as cooling rate increased. With the increasing Fe contents and cooling rate, the formation of microcellular structures of Al grains largely containing globular or rod-liked Al_6Fe intermetallic precipitates were predominant. The crystallographic orientation relationships between Al matrix and particles were identified as [2(33)￣]_(Al)//[(11)￣0]_(Al₃Fe), ((311)￣)_(Al)//(2(22)￣)_(Al_6Fe), (011￣)_(Al)//(001)_(Al_bFe) and [1￣12]_(Al)//[010]_(Al₃Fe). The Al-Fe alloy exibited goad thermal stability and appreciable strength up to 450℃. The results indicate that high solidification rate is necessary to obtain high temperature strength Al-Fe alloy. |
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