FeCoSiBNbCu bulk metallic glass with large compressive deformability studied by time-resolved synchrotron X-ray diffraction
- IFW Dresden, Institute for Complex Materials, Helmholtzstr. 20, D-01069 Dresden (Germany)
- Deutsches Elektronen-Synchrotron (DESY), FS-PE Group, Notkestr. 85, D-22607 Hamburg (Germany)
By adding 0.5 at. % Cu to the strong but brittle [(Fe{sub 0.5}Co{sub 0.5}){sub 0.75}Si{sub 0.05}B{sub 0.20}]{sub 96}Nb{sub 4} bulk metallic glass, fully amorphous rods with diameters up to 2 mm were obtained. The monolithic samples with 1 mm diameter revealed a fracture strain of 3.80% and a maximum stress of 4143 MPa upon compression, together with a slight work-hardening behavior. SEM micrographs of fractured samples did neither reveal any shear bands on the lateral surface nor the typical vein patterns which characterize ductile fracture. However, some layers appear to have flowed and this phenomenon took place before the brittle final fracture. An estimate of the temperature rise ΔT in the shear plane gives 1039 K, which is large enough to melt a layer of 120 nm. The overall performance and the macroscopic plastic strain depend on the interaction between cleavage-like and viscous flow-like features. Mechanical tests performed in-situ under synchrotron radiation allowed the calculation of the strain tensor components, using the reciprocal-space data and analyzing the shift of the first (the main) and the second broad peak positions in the X-ray diffraction patterns. The results revealed that each atomic shell may have a different stiffness, which may explain the macroscopic compressive plastic deformation. Also, there were no signs of (nano) crystallization induced by the applied stress, but the samples preserve a monolithic amorphous structure until catastrophic failure occurs.
- OSTI ID:
- 22278095
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMORPHOUS STATE
BORON ADDITIONS
COBALT ALLOYS
COMPRESSION
CRYSTALLIZATION
FLEXIBILITY
FRACTURES
IRON ALLOYS
MECHANICAL TESTS
METALLIC GLASSES
NIOBIUM ADDITIONS
PLASTICITY
SCANNING ELECTRON MICROSCOPY
SILICON ADDITIONS
STRAIN HARDENING
STRESSES
SYNCHROTRON RADIATION
TIME RESOLUTION
VISCOUS FLOW
X-RAY DIFFRACTION