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Sub-nanometer open volume regions in a bulk metallic glass investigated by positron annihilation

✍ Scribed by K.M. Flores; E. Sherer; A. Bharathula; H. Chen; Y.C. Jean


Publisher
Elsevier Science
Year
2007
Tongue
English
Weight
412 KB
Volume
55
Category
Article
ISSN
1359-6454

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✦ Synopsis


The size distribution of open volume regions in a Zr-based bulk metallic glass is investigated by positron annihilation lifetime spectroscopy. Three lifetime components are identified, indicating the presence of three distinct size ranges for open volume defects in the glass. The first two components compare favorably with literature values for bulk and vacancy annihilation in crystalline Zr, and are assigned to annihilation in the densely packed bulk and loosely packed flow defects within the glass. The third lifetime component corresponds to the annihilation of ortho-Positronium in a very low concentration of voids with radii 2.1-2.7 A ˚. The sizes of all three defects decrease with inhomogeneous deformation, while the concentrations of flow defects and voids increase.