Research output: Contribution to journal › Article › peer-review
Cluster structure in amorphous Ti-Ni-Cu alloys subjected to high-pressure torsion deformation. / Gunderov, D. V.; Boltynjuk, E. V.; Ubyivovk, E. V.; Lukyanov, A. V.; Churakova, A. A.; Kilmametov, A. R.; Zamula, Yu S.; Valiev, R. Z.
In: Journal of Alloys and Compounds, Vol. 749, 15.06.2018, p. 612-619.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Cluster structure in amorphous Ti-Ni-Cu alloys subjected to high-pressure torsion deformation
AU - Gunderov, D. V.
AU - Boltynjuk, E. V.
AU - Ubyivovk, E. V.
AU - Lukyanov, A. V.
AU - Churakova, A. A.
AU - Kilmametov, A. R.
AU - Zamula, Yu S.
AU - Valiev, R. Z.
N1 - Категории Scopus: Materials Chemistry, Mechanical Engineering, Mechanics of Materials, Metals and Alloys Категории Web of Science: Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering
PY - 2018/6/15
Y1 - 2018/6/15
N2 - The features of the internal structure's evolution of melt-spun (MS) amorphous Ti50Ni25Cu25 alloy samples subjected to high-pressure torsion (HPT) at 20 and 150 °C were revealed by TEM and STEM – in the planar direction and the cross-sectional direction of the HPT-processed disc-shaped samples. In STEM HAADF observations in the planar direction, areas with brightness contrast with a size of 20 nm are revealed. We assume them to be “amorphous nanoclusters”. In dark-field TEM images, in many areas nanocrystals (with sizes about 5 nm) are revealed, resulting from strain-induced nanocrystallization. In STEM HAADF images, there can be seen nanoclusters (with sizes about 20 nm) separated by bright boundaries. Groups of shear bands (SBs) are revealed on the cross-sectional directions on lamellae cut from the HPT-processed samples. Nanocrystals form directly in the shear bands as a result of strain-induced nanocrystallization. Amorphous nanoclusters are also observed in the amorphous phase surrounding the SBs. Formation of the amorphous nanocluster in the areas surrounding the shear bands has been discovered for the first time. Atomic force microscopy (AFM) was used to study the surface morphology of foils prepared by ion polishing from the initial amorphous ribbons and HPT-processed samples. A hollows-like surface morphology in the HPT-processed state is revealed by AFM, which is reflected as nanocluster contrast in TEM images. The hollows-like surface morphology could be explained by the specifics of etching processes in the HPT-processed state. Brittle fracture of melt-spun Ti50Ni25Cu25 in the as-cast state and after HPT processing is determined during tensile tests. However, observable changes in the fracture surfaces correspond to an increased local ductility in samples subjected to HPT, in comparison with the initial state.
AB - The features of the internal structure's evolution of melt-spun (MS) amorphous Ti50Ni25Cu25 alloy samples subjected to high-pressure torsion (HPT) at 20 and 150 °C were revealed by TEM and STEM – in the planar direction and the cross-sectional direction of the HPT-processed disc-shaped samples. In STEM HAADF observations in the planar direction, areas with brightness contrast with a size of 20 nm are revealed. We assume them to be “amorphous nanoclusters”. In dark-field TEM images, in many areas nanocrystals (with sizes about 5 nm) are revealed, resulting from strain-induced nanocrystallization. In STEM HAADF images, there can be seen nanoclusters (with sizes about 20 nm) separated by bright boundaries. Groups of shear bands (SBs) are revealed on the cross-sectional directions on lamellae cut from the HPT-processed samples. Nanocrystals form directly in the shear bands as a result of strain-induced nanocrystallization. Amorphous nanoclusters are also observed in the amorphous phase surrounding the SBs. Formation of the amorphous nanocluster in the areas surrounding the shear bands has been discovered for the first time. Atomic force microscopy (AFM) was used to study the surface morphology of foils prepared by ion polishing from the initial amorphous ribbons and HPT-processed samples. A hollows-like surface morphology in the HPT-processed state is revealed by AFM, which is reflected as nanocluster contrast in TEM images. The hollows-like surface morphology could be explained by the specifics of etching processes in the HPT-processed state. Brittle fracture of melt-spun Ti50Ni25Cu25 in the as-cast state and after HPT processing is determined during tensile tests. However, observable changes in the fracture surfaces correspond to an increased local ductility in samples subjected to HPT, in comparison with the initial state.
KW - Amorphous metals
KW - Clusters
KW - Glass transition and crystallization
KW - Severe plastic deformation
KW - TI50NI25CU25 ALLOY
KW - STATE
KW - SPUN ND9FE85B6 ALLOY
KW - EVOLUTION
KW - SEVERE PLASTIC-DEFORMATION
KW - BULK METALLIC GLASSES
KW - SHEAR BANDS
KW - DUCTILITY
KW - MICROSTRUCTURE
KW - Amorphous metals
KW - Clusters
KW - Glass transition and crystallization
KW - Severe plastic deformation
UR - http://www.scopus.com/inward/record.url?scp=85044591239&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2018.03.357
DO - 10.1016/j.jallcom.2018.03.357
M3 - статья
AN - SCOPUS:85044591239
VL - 749
SP - 612
EP - 619
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
ER -
ID: 25677308