Abstract: The effect of melt over-heating on the morphology of Al9FeNi phase in 2618 aluminumalloy with high contents of Fe and Ni and 0.22wt.% zirconium has been investigatedby optical microscopy, SEM and TEM. The mechanical properties of 2618 aluminumalloy after hot extrusion and quenching/aging have been tested. The results show:melt over-heating treatment of 2618 alloy with high contents of Fe and Ni at 960° Cled to finer and better-distributed needle-like Al9FeNi phase in cast microstructureand fine Al9FeNi particles after hot extrusion; the grain size of the alloy after hotextrusion could also be refined evidently by alloying of zirconium; the ambient andhigh temperature tensile strength and elongation of 2618 alloy have been apparentlyenhanced due to fine Al9FeNi particles and dispersed Al3Zr as well as fine grain size.

Key words: melt over-heating, 2618 alloy, zirconium alloying,