Microstructure of supersaturated fcc Al-Fe alloys: A comparison of rapidly quenched and mechanically alloyed Al98Fe2

Abstract

Alloys of the composition Al98Fe2 have been prepared by rapid quenching from the melt and mechanical alloying methods and have been studied by X‐ray diffraction techniques and room temperature 57Fe Mossbauer effect methods. Results may be summarized as follows: The rapidly quenched sample is a single phase supersaturated fcc Al–Fe alloy. Mossbauer effect spectra indicate the presence of a substantially greater degree of Fe clustering than is expected for a random distribution of atoms on the lattice sites. Mechanically alloyed samples have been studied as a function of milling time and show the initial formation of a supersaturated fcc phase with microstructural properties which are quite similar to those of the rapidly quenched sample. Further milling results in the reduction of the average grain size and the formation of an amorphous phase. Mossbauer studies and previously reported phase diagrams suggest that a substantial fraction of the Fe resides in this phase.