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Struktur und Dynamik Poster: Mi., 14:00–16:30 M-P146
Amorphization of Quasicrystalline Zr-Ti-Ni-Cu
Stefan Mechler 1 , Gerhard Schumacher 1 , Siegfried Klaumünzer 1 , Thomas
Zumkley 1 , Nelia Wanderka 1 , Michael-Peter Macht 1 , Christian Abromeit 1
1 Hahn-Meitner-Institut Berlin, Glienicker Straße 100, D-14109 Berlin
Au, Xe and Kr ions in the energetic range of 300-600 MeV were used to study the
stability of quasicrystalline Zr-Ti-Ni-Cu under irradiation with swift heavy ions. Irradiation
experiments have been performed at room temperature and at liquid nitrogen
temperature at ISL. Prior to irradiation and after each fluence step the structure of
the material was analyzed by means of X-ray diffraction. The X-ray measurements
have been performed at room temperature under Bragg-Brentano geometry. Some
specimens have also been analyzed by conventional and High Resolution Electron Microscopy
(TEM and HRTEM, respectively) in the non-irradiated condition and after
irradiation to moderate fluence steps. The structure of the specimens was completely
quasicrystalline prior to irradiation. The relative decrease of the relative amount of
the quasicrystalline phase under irradiation was determined by measuring the relative
changes in X-ray peak intensity.
Irradiation with 600 MeV Au ions lead to complete amorphization of the specimens
already at fluence of 1x10 13 cm −2 . At lower fluences amorphous tracks inside the
quasicrystals were visualized by the use of HRTEM. The track diameter near the surface
determined by HREM was 12 nm. This value is in agreement with the value determined
from X-ray diffraction measurements. Amorphization induced by 350 MeV Au ions
and 600 MeV Au ions was assigned to the electronic energy loss while amorphization
by 300 MeV Kr ions is predominantly due to the nuclear energy loss. Within the
experimental uncertainty, there was no difference in amorphization between 350 MeV
Au ions and 600 MeV Au ions. Irradiation at liquid nitrogen temperature results in
slower amorphization compared to room-temperature irradiation. This result is in
qualitative agreement with predictions of thermal spike models.