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001-es BibID:	BIBFORM008865
Első szerző:	Bernardini, Jean
Cím:	Grain boundary diffusion and segregation in nanolayered materials / Bernardini, J., Girardeaux, C., Erdelyi, Z., Lexcellent, C.
Dátum:	2004
ISSN:	1422-6375
Megjegyzések:	Grain boundary (GB) diffusion and segregation in nanostructured materials is analysed taking into account the low thermal stability and the large portion of atoms presented in short circuits. Since two other chapters of this book are devoted to the bulk nanocrystalline as well as to the compacted and sintered nanocrystalline alloys, we mainly focused on measurements performed in nanolayered materials of which potential application is in effect in the area of high temperature applications. Important features relative to the theoretical background of GB diffusion were first developed; then we sketched different experimental requirements to measure GB diffusion. Finally we detailed what are the parameters obtained using the Hwang-Balluffi accumulation technique especially well adapted to measurements in nanolayered materials and discussed the existing data in the literature.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Metastable and Nanocrystalline Materials. - 19 (2004), p. 35-54. -
További szerzők:	Girardeaux, Christophe Erdélyi Zoltán (1974-) (fizikus) Lexcellent, Christian
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001-es BibID:	BIBFORM086068
Első szerző:	Katona Gábor (fizikus)
Cím:	Formation and stability of metastable Pd(Zr) solid solution developed during ball milling and/or heat treatment of Pd3Zr / G. L. Katona, M. Kis-Varga, D. L. Beke
Dátum:	2002
ISSN:	1422-6375 2297-6620
Megjegyzések:	Formation of nanocrystalline solid solution induced by ball milling and/or subsequent annealing of the Pd3Zr intermetallic compound was studied. The single phase initial compound was milled in a medium energy vibrating mill under vacuum for various time periods. The structural characterization was made by X-ray diffraction with monochromatic CuK?1 radiation. After a short milling time (46 h) the Pd3Zr compound transformed to nanocrystalline one without disordering. By annealing this ball milled material, the formation of Pd(Zr) solid solution was observed by X-ray diffraction. During heat treatment at increasing temperatures the phase fraction of Pd(Zr) reached a maximum between 800 and 900 ?C, then it decreased and finally the reflections of disordered phase disappeared from XRD spectrum at 1330 ?C indicating the return to the single phase ordered state. However, while the above results are in accordance with that of Weissmüller and Ehrhardt [1], we also observed that ball milling of Pd3Zr for longer periods resulted in direct transformation of increasing fraction of the ordered phase to nanocrystalline Pd(Zr) solid solution. The amount of this phase increased with milling time and with annealing temperature, and the disordered state proved to be metastable even at high temperatures. The stabilization of solid solution phase is explained by the segregation at grain boundaries of the nanocrystalline material and by oxidation at interfaces/grain boundaries during the preparation and annealing processes.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Ball milling Heat treatment Order-disorder transition Segregation
Megjelenés:	Journal of Metastable and Nanocrystalline Materials. - 13 (2002), p. 193-198. -
További szerzők:	Kis-Varga Miklós Beke Dezső László (1945-) (fizikus)
Pályázati támogatás:	T025485 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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