Ulrich Herr

TL;DR: In this paper, the interference function of nanometer-sized crystalline iron (6-nm crystal size) was measured by x-ray diffraction and the measured interference function can only be matched by the computed one if the interfacial component is assumed to have no short- or long-range order.

TL;DR: In this paper, a two-component Mossbauer spectrum of a nanocrystalline material is investigated, consisting of a crystalline component and an interfacial component, formed by the atoms located either in the crystals or in the interfacial regions between them.

TL;DR: In this article, a single phase europium doped yttria was synthesized using a chemical vapor technique and the powder was characterized by x-ray diffraction, transmission electron microscopy, and ultraviolet spectroscopy.

TL;DR: In this article, the results were discussed in terms of competing mixing and de-mixing reaction rates, which is attributed to a first-order kinetic process involving non-equilibrium vacancies.

Abstract: The mechanical alloying process in the immiscible Ni–Ag system with a positive heat of mixing was investigated by x‐ray diffraction and differential scanning calorimetry. High energy ball milling of mixed elemental powders, with nominal composition NixAg100−x (x=95, 90, 70, 50, and 30), results in the formation of mixtures of supersaturated, nanocrystalline Ni‐rich and Ag‐rich solid solutions. The solubilities and final grain sizes of these phases depend on the nominal composition of the powder. The maximum solubilities were determined using Vegard’s law to be 4.3 at. % Ni in Ag and 6.6 at. % Ag in Ni for samples milled at room temperature. The effect of milling temperature on mechanical alloying was examined in the range −195 to 250 °C. Lower temperature milling leads to a larger solubility of Ni in the Ag‐rich samples, up to 7.1 at. % for the Ni30Ag70 composition. Indications for the existence of a concentrated solid solution (Ni36Ag64‐Ni44Ag56) were also found. Milling at higher temperatures leads to l...