This thesis presents for the first time direct structural measurements of both reversible and irreversible structural relaxation and the glass transition in the metal-metalloid glass Pd$ sb{40}$Ni$ sb{40}$P$ sb{20}$. The techniques have been x-ray diffraction and Mossbauer spectroscopy, and a new analysis method for changes of amorphous diffraction patterns was developed. / It is found that irreversible relaxation proceeds by many local shear-type motions involving the metal atoms, and that it is accompanied by a small densification. Reversible relaxation at high annealing temperatures entails the same microscopic processes, but it does not change the density of the glass. The type of atomic processes changes continuously as the annealing temperature is lowered, and at sufficiently low temperatures the distribution of metal atoms remains constant, so that reversible relaxation then proceeds via rearrangement of the metalloid atoms. This rearrangement leads to more ordered, but less isotropic atomic sites. / The second part of the thesis is concerned with the motion of the atoms in a metallic glass below and above the glass transition. Mossbauer spectroscopy allows the direct measurement of vibrational and diffusional motion. The increase of the amplitude of atomic vibration has the same temperature dependence as the increase in volume that marks the glass transition, thus the two processes are governed by the same mechanism. The directly measured diffusional motion is in agreement with macroscopic measurements of diffusion.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74345 |
| Date | January 1990 |
| Creators | Brüning, Ralf |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001073492, proquestno: AAINN63717, Theses scanned by UMI/ProQuest. |
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