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Influence of yttrium and gadolinium additions on thermal

Domenii publicaţii > Stiinte ingineresti + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: I. V. STASI, G. NEDELCU, C. GHEORGHIEŞ, N. MATTERN, J. ECKERT

Editorial: inoe, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 10, No. 11, November 2008,, p.p. 2963 - , 2008.

Rezumat:

Interest in finding binary alloys that can form bulk metallic glasses (BMGs) has stimulated recent work on the Cu-Zr system,
which is know to show glass formation over a wide composition range. The thermal and structural behaviour of rapidly
quenched Cu-Zr alloys were analyzed. The ribbons of Cu50Zr50-xMex (Me=Y,Gd; x=5,10,15,20,25) were produced by Melt
Spinning method and investigated by using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy
and transmission electron microscopy techniques. The characterization of Cu-Zr alloys using DSC related that the reforming
activity was strongly correlated with the endothermic heat during the glass state of alloys. Furthermore, the Y or Gd content
in Cu-Zr alloys affected the endothermic heat. DSC analyses have confirmed the existence of glass transition, followed by
supercooled liquid region in all the composition, in one or two steps. X-ray diffraction patterns of the ribbons before DSC
showed that some are amorphous and other partial amorphous. X-ray diffraction patterns recorded for the ribbons heated
up to 973 K in DSC using a rate of 20 K min-1 under a flow of purified argon showed that the samples crystallized. SEM and
TEM demonstrated that the microstructural evolution depends on the amount of Y or Gd. The precipitating phases were
determined by SEM, TEM and XRD. Finally, crystallization processes of the samples were summarized. In the future the
study will be focus to interpret all obtained dates. Therefore, these types of BMGs are very promising for the further
development of Cu-Zr-based alloys as engineering materials.

Cuvinte cheie: Bulk metallic glasses, Cu-Zr alloys, Y,Gd addition, XRD, DSC, TEM, SEM // Bulk metallic glasses, Cu-Zr alloys, Y,Gd addition, XRD, DSC, TEM, SEM