Cluster structure in amorphous Ti-Ni-Cu alloys subjected to high-pressure torsion deformation

D. V. Gunderov, E. V. Boltynjuk, E. V. Ubyivovk, A. V. Lukyanov, A. A. Churakova, A. R. Kilmametov, Yu S. Zamula, R. Z. Valiev

Research outputpeer-review

5 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)612-619
Number of pages8
JournalJournal of Alloys and Compounds
Volume749
DOIs
Publication statusPublished - 15 Jun 2018

Fingerprint

Torsional stress
Nanoclusters
Shear bands
Nanocrystallization
Surface morphology
Transmission electron microscopy
Nanocrystals
Atomic force microscopy
titanium nickelide
Brittle fracture
Amorphous alloys
Polishing
Metal foil
Ductility
Luminance
Etching
Ions
Direction compound
Processing

Scopus subject areas

  • Materials Chemistry
  • Mechanical Engineering
  • Mechanics of Materials
  • Metals and Alloys

Cite this

@article{1d7fa3316866426baeda7e46f2ad69dd,
title = "Cluster structure in amorphous Ti-Ni-Cu alloys subjected to high-pressure torsion deformation",
abstract = "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.",
keywords = "Amorphous metals, Clusters, Glass transition and crystallization, Severe plastic deformation, TI50NI25CU25 ALLOY, STATE, SPUN ND9FE85B6 ALLOY, EVOLUTION, SEVERE PLASTIC-DEFORMATION, BULK METALLIC GLASSES, SHEAR BANDS, DUCTILITY, MICROSTRUCTURE, Amorphous metals, Clusters, Glass transition and crystallization, Severe plastic deformation",
author = "Gunderov, {D. V.} and Boltynjuk, {E. V.} and Ubyivovk, {E. V.} and Lukyanov, {A. V.} and Churakova, {A. A.} and Kilmametov, {A. R.} and Zamula, {Yu S.} and Valiev, {R. Z.}",
note = "Категории Scopus: Materials Chemistry, Mechanical Engineering, Mechanics of Materials, Metals and Alloys Категории Web of Science: Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering",
year = "2018",
month = "6",
day = "15",
doi = "10.1016/j.jallcom.2018.03.357",
language = "Английский",
volume = "749",
pages = "612--619",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
publisher = "Elsevier",

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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

VL - 749

SP - 612

EP - 619

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -