Structural aspects of elastic deformation of a metallic glass
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218-2681 (United States)
We report the use of high-energy x-ray scattering to measure strain in a Zr{sub 57}Ti{sub 5}Cu{sub 20}Ni{sub 8}Al{sub 10} bulk metallic glass in situ during uniaxial compression in the elastic regime up to stresses of approximately 60% of the yield stress. The strains extracted in two ways--directly from the normalized scattering data and from the pair correlation functions--are in good agreement with each other for length scales greater than 4 A. The elastic modulus calculated on the basis of this strain is in good agreement with that reported for closely related amorphous alloys based on macroscopic measurements. The strain measured for atoms in the nearest-neighbor shell, however, is smaller than that for more distant shells, and the effective elastic modulus calculated from the strain on this scale is therefore larger, comparable to crystalline alloys of similar composition. These observations are in agreement with previously proposed models in which the nominally elastic deformation of a metallic glass has a significant anelastic component due to atomic rearrangements in topologically unstable regions of the structure. We also observe that the distribution of the atomic-level stresses in the glass becomes more uniform during loading. This implies that the stiffness of metallic glasses may have an entropic contribution, analogous to the entropic contribution in rubber elasticity.
- OSTI ID:
- 20787897
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 73, Issue 6; Other Information: DOI: 10.1103/PhysRevB.73.064204; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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