Papers by Keyword: Inert Gas Condensation

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Authors: M. Nagashima, Tadachika Nakayama, S. Yamanaka, M. Fujikane, T. Sawada, Yamato Hayashi, Tohru Sekino, Takafumi Kusunose, Koichi Niihara
Authors: Yulia Ivanisenko, Hans Jorg Fecht
Abstract: We suggest a simple method to study the mechanical behaviour of nanocrystalline (nc) samples in compression-torsion mode. High applied pressure prevents the fracture of sample, and quantitative parameters of sample response during torsion test can be compared with developed microstructure. Here we present and discuss the results of systematic investigation of mechanical behaviour of nc Pd with a mean grain size of 12 nm in a wide range of shear strains (0<γ<200) and at strain rates γ& = 3 10-1 s-1 and 3 10-2 s-1. We show that in the studied shear strain range the notable changes in the microstructure, namely a strain induced grain growth occurs, and that controls the relevant deformation mechanisms. For lower strains when the grain size is still small enough, the plastic flow governs by twinning and probably grain boundary sliding. The flow stresses are lower as compared with the later stages of deformation, when the grain size becomes larger and deformation is controlled exceptionally by dislocation glide. Finally, a steady stage is achieved, when the grain size, dislocation density and flow stress are saturated.
Authors: M. Yandouzi, B. Pauwels, D. Schryvers, Helena Van Swygenhoven, Gustaaf Van Tendeloo
Authors: Tadachika Nakayama, T.A. Yamamoto, Yong Ho Choa, Koichi Niihara
Authors: Francesco Delogu, Elisabetta Arca, Igor V. Shvets
Abstract: The present chapter deals with the difficult task of giving a brief survey of the synthetic routes employed to prepare materials with characteristic features on the nanometer scale. Definitions and general concepts regarding nanostructured and nanometer-sized materials are shortly tackled in the introductory part, which is followed by an overview of the most important approaches developed to synthesize such materials. No attempt is made to create a comprehensive and detailed synopsis of the experimental methods currently available. Rather, attention is focused on a selected number of general methodologies, the choice of which can be usually motivated by a mix of historical perspective, scientific significance and technological potential. So-called “top-down” approaches are discussed first, whereas the second part of the chapter is devoted to “bottom-up” ones. The former group includes mechanical processing, melt quenching, and de-vitrification methods. Sonochemistry, pulsed laser ablation, wet chemical synthesis, sol-gel processing, microwave processing, spray pyrolysis, flame synthesis, inert gas condensation, vapor deposition, and vapor-liquid-solid growth form instead the latter group.
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