AMCIS 2021 Awards and Closing Ceremony

This is a video recording of the AMCIS 2021 Awards and Closing Ceremony

Materials science

Bibliogr.: p. 107-110Université de PoitiersVytauto Didžiojo universiteta

The effects of dynamic structural transformations on hydrogenation properties of Mg and MgNi thin films

Mg capped with Al and Ti thin layers and MgxNi films have been sputter-deposited on quartz substrates and hydrogenated at 600 kPa for 250 °C. A complete fast transformation of metallic into hydride phase is registered for the films, demonstrating the dynamic state of the internal microstructure under hydrogenation. It leads to local and long-range restructuring and the fast hydrogenation rate is attributed to the fast hydrogen uptake and transport along columns and grain boundaries of nanocrystallites. A slow H-loading is observed when the dynamic structural relaxation processes are suppressed by internal and external inhomogeneities such as barrier layers on the surface, new phases in the bulk and impurities. A partial transformation of metallic into hydride phase is registered when the structural formations newly nucleated at the initial stages of hydrogenation suppress dynamic processes and prevent the H-uptakeFizikos katedraLietuvos energetikos institutasVytauto Didžiojo universiteta

Hydrogen storage in the bubbles formed by high-flux ion implantation in thin Al films

The storage of implanted hydrogen in 2-5 mu m thick Al films on stainless steel substrates was investigated in this work. Plasma immersion 1 keV H-2(+) ion implantation was used to load hydrogen into the Al film. The correlation between the effusion of the implanted hydrogen and the evolution of surface morphology was studied by thermal desorption spectroscopy and scanning electron microscopy. It has been found that as-implanted hydrogen at temperatures below 320 K is associated with defects and is chemically bonded at the grain boundaries of nanocrystallites. At higher temperatures, the released hydrogen is accommodated in bubbles. The major part of hydrogen effuses at similar to 630 K and the effusion process is controlled by the migration of hydrogen through the surface oxide layer. (c) 2005 Elsevier B.V. All rights reservedLietuvos energetikos institutas, [email protected] Didžiojo universiteta

Self-formation processes in studies of surface topography under ion irradiation

[6th International Conference on Self-Formation Theory and Applications Vilnius, Lithuania, Nov. 26-28, 2003]. ISBN-13: 978-3-908450-85-6. Formerly Part B of “Diffusion and Defect Data” ISSN 0377-6883Surface atoms are activated as result of replacement collisional sequences in solids by incident ions. In dependence on theirs threshold (displacement) energy and angular distribution they may be sputtered (removed) or laterally relocated on the surface. The relocation length distribution depends on the energy and angular distributions of activated atoms and interaction atom-solid potential. The process of lateral relocation of surface atoms is considered as a sequence of stochastic removal and adsorption processes. The rate equations describing processes of sputtering, relocation and thermal diffusion are built and steady state solutions are presented for multielemental solids. The mechanisms of stochastic mixing of atoms and roughening of surface is discussedVytauto Didžiojo universiteta

Nanocomposites TITN-NI PVD coating (synthesis, structural and mechanical properties)

Des revêtements nanocomposites TiN-Ni ont été élaborés par pulvérisation ionique réactive (PIR) et par pulvérisation magnétron réactive (PMR). Les propriétés structurales et les contraintes résiduelles ont été étudiées principalement en utilisant la diffraction des rayons X. Les propriétés mécaniques - dureté, ténacité, adhérence au substrat et résistance à l usure - ont été évaluées par nanoindentation, test de rayure, indentation à forte charge, tribomètre pion-disque et profilométrie 3D. Les revêtements élaborés par la technique PIR se composent de nanograins (<10 nm) de TiN entourés par une phase métallique amorphe constituée du nickel. Les couches PMR sont formées de nanograins d une solution solide métastable de TiN(Ni) entourés par une phase amorphe de Ti2Ni. La plupart des propriétés sont contrôlées par la l addition du nickel. Quelle que soit la technique d élaboration, une texture est observée, qui évolue vers la texture (200) quand la concentration en Ni augmente. Pour des températures de substrat élevées (200-400C), les contraintes résiduelles diminuent pour les dépôts PIR tandis qu elles augmentent pour les dépôts PMR. Les deux types de dépôts ont une dureté améliorée. Pour les dépôts PIR, une super dureté (~45 GPa) est observée, qui correspond a une taille de grain TiN proche de 8 nm et une couverture par le Ni de 1 monocouche. L addition de nickel améliore la ténacité des revêtements. Comparé à TiN, la résistance à l usure est augmentée d un facteur 20 pour les dépôts présentant une ténacité améliorée. Au contraire, les dépôts présentant une plus grande dureté ont une résistance à l usure identique et même plus faible que TiN.Nanocomposite TiN-Ni coatings were deposited using reactive dual ion beam sputtering (RDIBS) and reactive unbalanced magnetron sputtering (RUBMS). Structural properties and residual stresses have been investigated mainly using X-ray diffraction. Mechanical properties including hardness, toughness adhesion and wear resistance were evaluated using nanoindentation, scratch test, high load indentation and ball on disc tests coupled with 3D profilometry. In RDIBS coatings, the only crystalline phase is TiN with grain size smaller than 10 nm embedded in a 2 monolayers thick Ni tissue at 22 at.% Ni. In RUBMS coatings, Ni containing TiN metastable phase is embedded in a Ti2Ni amorphous layer. Most of structural and mechanical properties are governed by the Ni content. Whatever the deposition technique, a texture is observed which evolves towards the (200) texture with increasing the Ni content. At high substrate temperatures (200-400C), the residual stress decreases for RDIBS coatings when adding Ni while it increases for the RUBMS coatings. This later increase is related to Ni incorporation in the TiN lattice. Both coatings exhibit a hardness enhancement. For the RDIBS coatings, superhardness (~45 GPa) is observed, which corresponds to TiN crystallite size of ~8 nm and Ni coverage of about one monolayer. The addition of Ni improves coating toughness. Compare to the TiN films, an enhancement in wear resistance up to 20 times was observed for the coatings with improved toughness. On the contrary, the superhard coatings exhibited identical or even worse wear resistance than TiN.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Nitruration par faisceau d'ions des aciers austénitiques inoxydables (étude du transport atomique d'azote, des effets de flux et des effets structuraux)

POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Modeling of carbon behavior in tungsten under carbon and hydrogen mixed irradiation

Université de PoitiersVytauto Didžiojo universiteta

Plasma technologies : monography

Santr. anglBibliogr.: p. 94-95Lietuvos energetikos institutas, [email protected]é de PoitiersVytauto Didžiojo universiteta

Hydrogenation of Mg thin films in CH4 + Ar plasmas

Magnesium films were magnetron sputter deposited on AISI 316L stainless steel and hydrogenated at 450 K by the plasma immersion ion implantation technique using CH4 + Ar gases under a pressure of 10 Pa. The goal was to obtain hydrogen separation and formation of hydrides in Mg film thus avoiding a hydrogen gas purification process. The depth profiles of C and H atoms across the Mg film were analyzed by the Nuclear Reaction Analysis and secondary ion mass spectrometry. After 0.5 h of plasma treatment with a 1 kV bias voltage, C atoms remained in the near surface region while H atoms were homogeneously distributed across the entire film thickness. The results are explained on the basis of C and H ion implantation and atomic transport kinetics along the grain boundaries of a nanocrystalline Mg filmFizikos katedraGamtos mokslų fakultetasLietuvos energetikos institutasVytauto Didžiojo universiteta