Microstructure evolution in nanocrystalline NiTi alloy produced by HPT

R. Singh; S. V. Divinski; H. Rösner; E. A. Prokofiev; R. Z. Valiev; G. Wilde

doi:10.1016/j.jallcom.2011.01.206

Microstructure evolution in nanocrystalline NiTi alloy produced by HPT

R. Singh^*, S. V. Divinski, H. Rösner, E. A. Prokofiev, R. Z. Valiev, G. Wilde

^*Corresponding author for this work

Physics

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

A slightly Ni-rich nano-NiTi alloy, deformed by high-pressure torsion (HPT) was investigated. By HPT, almost complete amorphization of initial B2 NiTi is obtained. Crystallization and microstructure evolution during isothermal treatment were investigated by differential scanning calorimetry (DSC) and transmission electron microscopy. The DSC signals observed during continuous heating experiments indicate an unusually large separation between the crystallization and the growth stages. A detailed analysis of the evolution of the enthalpy release upon annealing reveals reproducibly non-monotonous trends with annealing time that cannot be explained solely by growth of crystalline volume fractions. The size of nanocrystals increases dramatically after annealing for 5 h. The effective activation enthalpies for stress relaxation (along with crystallization) and grain growth were estimated at 115 and 289 kJ/mol, respectively. The results are discussed with respect to the intricate interdependencies between synthesis and thermal processing pathways and the evolution of the nanoscale microstructure.

Original language	English
Pages (from-to)	S290-S293
Journal	Journal of Alloys and Compounds
Volume	509
Issue number	SUPPL. 1
DOIs	https://doi.org/10.1016/j.jallcom.2011.01.206
Publication status	Published - Jul 14 2011

Keywords

Crystallization
High pressure torsion
Nanocrystalline
NiTi
Relaxation

ASJC Scopus subject areas

Mechanics of Materials
Mechanical Engineering
Metals and Alloys
Materials Chemistry

Access to Document

10.1016/j.jallcom.2011.01.206

Cite this

@article{135194319e814a7aa5eba1ac13451d4b,

title = "Microstructure evolution in nanocrystalline NiTi alloy produced by HPT",

abstract = "A slightly Ni-rich nano-NiTi alloy, deformed by high-pressure torsion (HPT) was investigated. By HPT, almost complete amorphization of initial B2 NiTi is obtained. Crystallization and microstructure evolution during isothermal treatment were investigated by differential scanning calorimetry (DSC) and transmission electron microscopy. The DSC signals observed during continuous heating experiments indicate an unusually large separation between the crystallization and the growth stages. A detailed analysis of the evolution of the enthalpy release upon annealing reveals reproducibly non-monotonous trends with annealing time that cannot be explained solely by growth of crystalline volume fractions. The size of nanocrystals increases dramatically after annealing for 5 h. The effective activation enthalpies for stress relaxation (along with crystallization) and grain growth were estimated at 115 and 289 kJ/mol, respectively. The results are discussed with respect to the intricate interdependencies between synthesis and thermal processing pathways and the evolution of the nanoscale microstructure.",

keywords = "Crystallization, High pressure torsion, Nanocrystalline, NiTi, Relaxation",

author = "R. Singh and Divinski, {S. V.} and H. R{\"o}sner and Prokofiev, {E. A.} and Valiev, {R. Z.} and G. Wilde",

note = "Funding Information: Financial support by the Deutsche Forschungsgemeinschft (DFG) is gratefully acknowledged. The authors also acknowledge the support from the Russian Foundation for Basic Research (the project number 08-02-91955).",

year = "2011",

month = jul,

day = "14",

doi = "10.1016/j.jallcom.2011.01.206",

language = "English",

volume = "509",

pages = "S290--S293",

journal = "Journal of Alloys and Compounds",

issn = "0925-8388",

publisher = "Elsevier BV",

number = "SUPPL. 1",

}

TY - JOUR

T1 - Microstructure evolution in nanocrystalline NiTi alloy produced by HPT

AU - Singh, R.

AU - Divinski, S. V.

AU - Rösner, H.

AU - Prokofiev, E. A.

AU - Valiev, R. Z.

AU - Wilde, G.

N1 - Funding Information: Financial support by the Deutsche Forschungsgemeinschft (DFG) is gratefully acknowledged. The authors also acknowledge the support from the Russian Foundation for Basic Research (the project number 08-02-91955).

PY - 2011/7/14

Y1 - 2011/7/14

N2 - A slightly Ni-rich nano-NiTi alloy, deformed by high-pressure torsion (HPT) was investigated. By HPT, almost complete amorphization of initial B2 NiTi is obtained. Crystallization and microstructure evolution during isothermal treatment were investigated by differential scanning calorimetry (DSC) and transmission electron microscopy. The DSC signals observed during continuous heating experiments indicate an unusually large separation between the crystallization and the growth stages. A detailed analysis of the evolution of the enthalpy release upon annealing reveals reproducibly non-monotonous trends with annealing time that cannot be explained solely by growth of crystalline volume fractions. The size of nanocrystals increases dramatically after annealing for 5 h. The effective activation enthalpies for stress relaxation (along with crystallization) and grain growth were estimated at 115 and 289 kJ/mol, respectively. The results are discussed with respect to the intricate interdependencies between synthesis and thermal processing pathways and the evolution of the nanoscale microstructure.

AB - A slightly Ni-rich nano-NiTi alloy, deformed by high-pressure torsion (HPT) was investigated. By HPT, almost complete amorphization of initial B2 NiTi is obtained. Crystallization and microstructure evolution during isothermal treatment were investigated by differential scanning calorimetry (DSC) and transmission electron microscopy. The DSC signals observed during continuous heating experiments indicate an unusually large separation between the crystallization and the growth stages. A detailed analysis of the evolution of the enthalpy release upon annealing reveals reproducibly non-monotonous trends with annealing time that cannot be explained solely by growth of crystalline volume fractions. The size of nanocrystals increases dramatically after annealing for 5 h. The effective activation enthalpies for stress relaxation (along with crystallization) and grain growth were estimated at 115 and 289 kJ/mol, respectively. The results are discussed with respect to the intricate interdependencies between synthesis and thermal processing pathways and the evolution of the nanoscale microstructure.

KW - Crystallization

KW - High pressure torsion

KW - Nanocrystalline

KW - NiTi

KW - Relaxation

UR - http://www.scopus.com/inward/record.url?scp=79958132582&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79958132582&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2011.01.206

DO - 10.1016/j.jallcom.2011.01.206

M3 - Article

AN - SCOPUS:79958132582

SN - 0925-8388

VL - 509

SP - S290-S293

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

IS - SUPPL. 1

ER -

Microstructure evolution in nanocrystalline NiTi alloy produced by HPT

Abstract

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this