Plasticity and structural instability in a bulk metallic glass deformed in the supercooled liquid region

The deformation behavior of a bulk amorphous Zr–10Al–5Ti–17.9Cu–14.6Ni alloy was characterized in the supercooled liquid region. The alloy was observed to exhibit Newtonian behavior at low strain rates but to become non-Newtonian at high strain rates. Structures of the amorphous material, both befor...

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Bibliographic Details
Published in:Acta materialia 2001-09, Vol.49 (15), p.2887-2896
Main Authors: Nieh, T.G., Wadsworth, J., Liu, C.T., Ohkubo, T., Hirotsu, Y.
Format: Article
Language:English
Subjects:
Amorphous materials
Applied sciences
Condensed matter: structure, mechanical and thermal properties
DEFORMATION
Exact sciences and technology
Fatigue, brittleness, fracture, and cracks
INSTABILITY
MATERIALS SCIENCE
Mechanical and acoustical properties of condensed matter
Mechanical properties of solids
METALLIC GLASSES
Metals. Metallurgy
MICROSTRUCTURE
Physics
PLASTICITY
Superplasticity
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Summary:The deformation behavior of a bulk amorphous Zr–10Al–5Ti–17.9Cu–14.6Ni alloy was characterized in the supercooled liquid region. The alloy was observed to exhibit Newtonian behavior at low strain rates but to become non-Newtonian at high strain rates. Structures of the amorphous material, both before and after deformation, were examined using X-ray diffraction and high-resolution electron microscopy. Experimental results showed the presence of nanocrystallites in the deformed samples, suggesting that the non-Newtonian behavior was associated with the concurrent crystallization of the amorphous structure during deformation; that is, a mixed crystalline-plus-amorphous structure was being tested. A mechanistic model based upon structural evolution has been developed to interpret the observed non-Newtonian behavior.
ISSN:1359-6454
1873-2453
DOI:10.1016/S1359-6454(01)00218-X