Hyperfine Interactions 130: 45–70, 2000.  2000 Kluwer Academic Publishers. Printed in the Netherlands. Mixing of iron with various metals by high-energy ball milling of elemental powder mixtures G. Le Caër a,∗ , T. Ziller a , P. Delcroix a and C. Bellouard b a Laboratoire de Science et Génie des Matériaux Métalliques, CNRS UMR 7584, École des Mines, F-54042 Nancy Cedex, France b Laboratoire de Physique des Matériaux, CNRS UMR 7556, Université Henri Poincaré-Nancy I, BP 239, F-54506 Vandoeuvre-les-Nancy Cedex, France The alloying of Fe with T = V, Cr and Mn by high-energy ball milling of elemental pow- der mixtures has been studied from the scale of a powder particle down to the atomic scale using X-ray and neutron diffraction, Mössbauer spectrometry and magnetic measurements for Fe 1−x T x alloys with x = 0.50, 0.65 for T = V, x = 0.50, 0.70 for T = Cr and x = 0.72 for T = Mn. Different alloying behaviours are observed according to T once powder particles have the final composition. The rather fast mechanical alloying of Fe with Mn reflects the statistical nature of the milling process in contrast to the slow mixing of Fe with V and of Fe with Cr. Hyperfine magnetic field distributions remain stationary in shape in the last milling stage at room temperature both for T = V and T = Cr. Magnetic measurements evidence the persistence with milling time of a large population of nanometer-sized Fe–Cr zones that are superparamagnetic at room temperature and at 400 K. By contrast, room-temperature Möss- bauer spectra show only a single line for long milling times. The unmixed stationary state of milled p-Fe 0.7 Cr 0.3 is discussed in the light of a recent model of systems driven by competing dynamics. Keywords: mechanical alloying, Mössbauer spectroscopy, iron–chromium alloys, superpara- magnetism 1. Generalities on mechanical alloying and high-energy ball-milling Advanced methods most often spring to mind when thinking of means of mixing and combining elements in the solid state down to the atomic scale at moderate tem- peratures. Surprisingly, milling, one of the earliest activities of man which was and still is mainly used for reducing the sizes of particles of various materials, is a possible method for that purpose when used in appropriate conditions, notably conditions of en- ergy transfer to milled powders. Powders of the materials to be mixed are introduced in the required proportions in a vial together with balls usually made of hardened steel. The vial is generally sealed in a glove box in argon atmosphere. A “high-energy” mill is then used to shake the vial vigorously to trap powder particles repeatedly between colliding balls or between vial and balls with impact speeds of the order of some m/s and shock ∗ Corresponding author. E-mail: lecaer@mines.u-nancy.fr