IDENTIFICATION OF PRECIPITATE PHASES IN A MECHANICALLY ALLOYED RAPIDLY SOLIDIFIED AL-FE-CE ALLOY

The stable and metastable precipitate phases which form during mechani cal alloying of a rapidly solidified (RS) Al-8.4Fe-3.4Ce alloy have be en unambiguously identified using X-ray diffraction, transmission elec tron microscopy (TEM), and energy dispersive spectroscopy techniques. The metastable Al10Fe2Ce and stable Al13Fe3Ce and Al13Fe4 intermetalli c phases, with crystal structures and lattice parameters as reported i n the literature, have been identified. It is shown that the metastabl e Al10Fe2Ce intermetallic phase particles have elongated shapes and th eir sizes range between 100 and 200 nm and are free of any localized f aults, whereas the equilibrium Al13Fe3Ce and Al13Fe4 intermetallic pha ses are equiaxed in shape and have particle sizes ranging from 200 to 500 nm. It is suggested that the presence of the metastable Al10Fe2Ce in this material is due to its incomplete transformation to the equili brium Al13Fe3Ce phase.