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Structural changes of amorphous Pd80Si20 with neutron irradiation, with an interpretation in terms of the imperfections in the structure of amorphous solids

1979; Elsevier BV; Volume: 34; Issue: 3 Linguagem: Inglês

10.1016/0022-3093(79)90026-7

1873-4812

Kenji Doi, Tetsuo Ayano, Kazutaka Kawamura,

Material Dynamics and Properties

Wide and small-angle X-ray scattering measurements were made, as well as differential scanning calorimetry, for amorphous Pd80Si20 before and after irradiation by neutrons (5 × 1020 neutrons/cm2, > 1 Mev), and the structural changes thereby produced are described. Before irradiation the structure is well assimilated with a dense random packing (DRP) structure except that the coherence between neighboring Pd atoms extends farther than expected from the DRP structure, the coherent length estimated from the X-ray scattering being about 8 Å. With irradiation the coherent regions of 8 Å diameter get separated from each other by a mean distance of 20 Å, thus producing structural inhomogeneities which do not exist at all before irradiation. The glass transition temperature is found to be increased by about 10 K after irradiation. The effects of irradiation are interpreted as being due to the structural imperfections produced by particle bombardment. The DPR structure is adopted as a model structure for the perfect amorphous solids.