Under energetic ion bombardment, amorphous materials deform plastically in the form of anisotropic growth. At medium electronic stopping power (5 to 30 keV/nm) this phenomenon starts only after a certain incubation dose depending on values of the electronic stopping power and temperature. This delay is modeled on the basis of the assumption of a drastic irradiation induced viscosity reduction, ...

The devitrification of initially amorphous Ni80B20 has been studied by x-ray-absorption spectroscopy as a function of the annealing temperature. It is found that the full width at half maximum ~FWHM! of the main absorption peak at '850 eV is sensitive to the degree of amorphization of the specimen. The initial FWHM of 2.51 eV for the homogeneous amorphous Ni80B20 decreases to a value of 2.12 eV...

Although amorphous structures have been widely obtained in various multi-component metallic alloys, amorphization in pure metals has seldom been observed and remains a long-standing scientific curiosity and technological interest. Here we present experimental evidence of localized solid-state amorphization in bulk nanocrystalline nickel introduced by quasi-static compression at room temperature...

In recent years, co-milling of active pharmaceutical ingredients (APIs) with excipients is being investigated as a promising technique to improve desired properties such as solubility and dissolution profiles, bioavailability, aerosolization and physical stability. Traditionally, excipients are simply blended into a drug formulation to improve the manufacturability or product quality, e.g. to i...

Usually metals and alloys are in a crystalline state. However, metallic glasses ( amorphous metals ) can be obtained from certain alloys with the right composition, when they are quenched from the liquid state at a high enough cooling rate. Since their discovery in 1960, amorphous metals or metallic glasses have been developed from binary systems of micron size (ribbons and powders) to multi-co...

The melting of zircon and the amorphous state produced by quenching from the melt were simulated by molecular dynamics using a partial charge model combined with the Ziegler-Biersack-Littmark potential. The model has been established for the description of the crystalline and aperiodic structures of zircon in order to be used for the simulation of displacement cascades. It provides an excellent...

Revealing the essential structural features of metallic glasses (MGs) will enhance the understanding of glass-forming mechanisms. In this work, a feasible scheme is provided where we performed the state-of-the-art synchrotron-radiation based experiments combined with simulations to investigate the microstructures of ZrCu amorphous compositions. It is revealed that in order to stabilize the amor...

Heidarian Höckerfelt, M. 2015. On the chemical and processing stability of pharmaceutical solids. Solid form dependent water presenting capacity and process induced solid form transformation. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy 203. 57 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9325-7. There is a need for improving our knowledg...

A partial monolayer of approximately 20 000 uniform spherical steel beads, vibrated vertically on a flat plate, shows remarkable ordering transitions and cooperative behavior just below 1g maximum acceleration. We study the stability of a quiescent disordered or "amorphous" state formed when the acceleration is switched off in the excited "gaseous" state. The transition from the amorphous state...

Using a combination of theory and molecular dynamics simulations, we show how solid behaviour emerges in amorphous materials from microscopic considerations. The effect on the systems response to a sudden change in strain, upon entering the history dependent glass state, is focused on. An important symmetry that is always present in a fluid state, is shown to be broken for a simulated history d...