Accueil >
Production scientifique
Etude des propriétés structurales, électroniques et vibrationnelles des verres et des nanostructures par simulation ab-initio
(18) Production(s) de l'année 2017
|
|
Raman spectra of indented pristine and irradiated sodium borosilicate glasses 
Auteur(s): Kilymis D., Faivre A., Michel T., Peuget Sylvain, Delaye Jean-Marc, Delrieu Julien, Ramonda Michel, Ispas S.
(Article) Publié:
Journal Of Non-Crystalline Solids, vol. 464 p.5-13 (2017)
Ref HAL: hal-01562695_v1
DOI: 10.1016/j.jnoncrysol.2017.03.012
WoS: WOS:000404205100002
Exporter : BibTex | endNote
8 Citations
Résumé: In this work we have carried out variable-load indentation testing on three sodium borosilicate glassesand characterized the indentation imprints using Raman spectroscopy. The resulting analysis of thespectra helps describe the relative amount of densification and shear ow appearing in each glass, as wellas the different microstructural mechanisms that take place during deformation. Additionally, we showthat the two glasses that are relatively poor in sodium exhibit enhanced mixing of the silicate and borateunits after indentation. For the indentations performed using the highest load, we also acquired spectraby focusing at various depths below the imprint, in order to characterize the deformed region of theglasses and estimate its size. Similar experiments have been also carried out for one of the three glassesafter neutron irradiation, in order to study the effects of mechanical deformation on its depolymerizedand swollen structure.
|
|
|
|
Hard X-rays as pump and probe of atomic motion in oxide glasses
Auteur(s): Ruta Beatrice, Zotone F, Chushkin Y., Baldi G., Pintori G., Monaco G., Ruffle B., Kob W.
(Article) Publié:
Scientific Reports, vol. 7 p.3962 (2017)
Texte intégral en Openaccess : 
Ref HAL: hal-01548255_v1
DOI: 10.1038/s41598-017-04271-x
Exporter : BibTex | endNote
Résumé: Nowadays powerful X-ray sources like synchrotrons and free-electron lasers are considered as ultimate tools for probing microscopic properties in materials. However, the correct interpretation of such experiments requires a good understanding on how the beam affects the properties of the sample, knowledge that is currently lacking for intense X-rays. Here we use X-ray photon correlation spectroscopy to probe static and dynamic properties of oxide and metallic glasses. We find that although the structure does not depend on the flux, strong fluxes do induce a non-trivial microscopic motion in oxide glasses, whereas no such dependence is found for metallic glasses. These results show that high fluxes can alter dynamical properties in hard materials, an effect that needs to be considered in the analysis of X-ray data but which also gives novel possibilities to study materials properties since the beam can not only be used to probe the dynamics but also to pump it.
|
|
|
|
Origin of Noncubic Scaling Law in Disordered Granular Packing
Auteur(s): Xia Chengjie, Li Jindong, Kou Binquan, Cao Yixin, Li Zhifeng, Xiao Xianghui, Fu Yanan, Xiao Tiqiao, Hong Liang, Zhang Jie, Kob W., Wang Yujie
(Article) Publié:
Physical Review Letters, vol. 118 p.238002 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01536101_v1
DOI: 10.1103/PhysRevLett.118.238002
WoS: 000402979400019
Exporter : BibTex | endNote
6 Citations
Résumé: Recent diffraction experiments on metallic glasses have unveiled an unexpected non-cubic scaling 14 law between density and average interatomic distance, which lead to the speculations on the presence of 15 fractal glass order. Using X-ray tomography we identify here a similar non-cubic scaling law in 16 disordered granular packing of spherical particles. We find that the scaling law is directly related to the 17 contact neighbors within first nearest neighbor shell, and therefore is closely connected to the 18 phenomenon of jamming. The seemingly universal scaling exponent around 2.5 arises due to the isostatic 19 condition with contact number around 6, and we argue that the exponent should not be universal. .
|
