Identification of precipitate phases in a mechanically alloyed rapidly solidified Al-Fe-Ce alloy

The stable and metastable precipitate phases which form during mechanical alloying of a rapidly solidified (RS) Al-8.4Fe-3.4Ce alloy have been unambiguously identified using X-ray diffraction, transmission electron microscopy (TEM), and energy dispersive spectroscopy techniques. The metastable Al₁₀Fe₂Ce and stable Al₁₃Fe₃Ce and Al₁₃Fe⁴ intermetallic phases, with crystal structures and lattice parameters as reported in the literature, have been identified. It is shown that the metastable Al₁₀Fe₂Ce intermetallic phase particles have elongated shapes and their sizes range between 100 and 200 nm and are free of any localized faults, whereas the equilibrium Al₁₃Fe₃Ce and Al₁₃Fe₄ intermetallic phases 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 equilibrium Al₁₃Fe₃Ce phase.