Mixing of iron with various metals by high-energy ball milling of elemental powder mixtures

The alloying of Fe with T = V, Cr and Mn by high-energy ball milling of ele mental powder mixtures has been studied from the scale of a powder particle down to the atomic scale using X-ray and neutron diffraction, Mossbauer sp ectrometry and magnetic measurements for Fe1-xTx 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 al loying behaviours are observed according to T once powder particles have th e final composition. The rather fast mechanical alloying of Fe with Mn refl ects 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 distributio ns 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 Mossbauer spectra show only a single line for long milling time s. The unmixed stationary state of milled p-Fe0.7Cr0.3 is discussed in the light of a recent model of systems driven by competing dynamics.