Structural and microstructural study of nanostructured Fe50Al40Ni10 powders produced by mechanical alloying

A nanostructured Fe50Al40Ni10 mixture was prepared by mechanical alloying of elemental Fe, Al and Ni powders in a planetary ball mill. Structural and microstructural changes during the milling process were followed by X-ray diffraction technique. The patterns so obtained were analyzed using the Maud program. An ordered B2 FeAl phase is formed after 1 h of milling. The observed lattice expansion is related to the production of antisite defects; FeAl and AlFe. During the intermediate stages of milling, the mechanical alloying process gives rise to a mixture of two BCC αi-Fe(Al,Ni) (i = 1,2) structures with the same crystallite size but different lattice parameters, microstrains and proportions. The BCC α2-Fe(Al,Ni) disappeared after 4 h, only the B2 FeAl and BCC α1-Fe(Al,Ni) solid solution persist over prolonged milling times.

Research highlights
► Fe50Al40Ni10 was prepared by MA from Fe, Al and Ni powders in a planetary ball mill.
► B2 FeAl is formed after 1 h of MA. Lattice expansion is related to FeAl and AlFe defects.
► MA gives rise to 2 BCC structures with the same L but different a, <σ2>1/2 and %.