Mixing at micrometric and nanometric scale in mechanically alloyed Fe60Cr40

Mechanical alloying (MA) of iron and chromium powder mixtures was performed from 0 to 190h. SEM, transmission electron microscopy with energy-dispersive X-ray analyses and Mossbauer spectrometry were used to study the mixing at micrometric and nanometric scale. At the stationary mixing state (approximate to 20h of milling), MA of Fe60Cr40 powder mixtures gives particles of several micrometers consisting of magnetic nanograin cores characteristic of crystalline Fe60Cr40 alloy surrounded by a disordered paramagnetic grain surface (at 300 K), which increases during milling. At 85 h, the nanograins are totally disordered. For a longer time of milling, a de-mixing occurs by partial recrystallization of this disordered structure. (C) 2002 Elsevier Science B.V. All rights reserved.