Münster 1999 – wissenschaftliches Programm

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M: Metallphysik

M 26: Postersitzung

M 26.38: Poster

Donnerstag, 25. März 1999, 15:00–19:00, Aula

Mechanical hydrogen relaxation spectra in amorphous, quasicrystalline and crystalline phases of the Zr-Cu-Ni-Al system. — •Roberto Scarfone and Hans-Reiner Sinning — Institut für Werkstoffe der TU, Langer Kamp 8, 38106 Braunschweig

The metallic glass with nominal composition

Zr_69,5Cu₁₂Ni₁₁Al_7,5, belonging to the zirconium

based amorphous alloys with a wide undercooled melt range, has

been investigated using the vibrating reed technique.

The change of the Young modulus upon heating, reflecting the

phase transformations of the material, has been observed and the

results have been compared with TEM and DSC measurements

confirming the development, in the undercooled melt range, of a

metastable quasicrystalline state.

The hydrogen induced damping peaks in the different phases of the

material have been then studied for increasing hydrogen

concentration, showing characteristics which are sensitive to the

structure of the samples. Particularly interesting is the

observation of such peaks in the quasicrystalline phase. The

marked hydrogen concentration dependence of these peaks, as well

as the temperature at which they can be seen (200-300 K), suggest

that grain boundary damping effects can be excluded and that the

microscopic hydrogen reorientation processes can indeed be

located in the quasicrystals.

Gefördert in Rahmen des DFG-SPP Ünterkühlte Metallschmelzen.