Roentgenometry of the Zr–2.5Nb alloy under cyclic loads

Research output: Contribution to journalArticle

Abstract

Studies were carried out in this work to establish the influence of thermal cyclic and mechanical cyclic loads that simulated the factors of operational impact on structural stability and crystal lattice dilatation of zirconium alloys. It is shown that during cold cyclic deformation at the first moment of loading the Zr–2.5Nb alloy is characterized by significant instantaneous deformation. The effect of anomalous thermal deformations of the zirconium alloy crystal lattices, which are typical for phase transitions of type I and type II, was detected in the operating temperature range (250–350 °C). The absence of phase transformation in this temperature range allows us to suggest the existence of a causal relationship between the anomalous thermal expansion effects of zirconium crystal lattices with orientation changes and phase transformations in grain boundaries. The performed calculations showed the presence of an anomalous change in the crystallite size distribution at a given temperature. The coincidence that temperatures were correlated with size effects and phenomena such as blistering and flecking has been established. The hypothesis of grain-boundary transformations is indirectly confirmed by the results of the second thermal cycle, during which a second jump of the crystal lattice thermal deformations, not related to structural phase transitions, was detected in the range of 550–650 °C.

Original languageEnglish
Pages (from-to)381-389
Number of pages9
JournalInternational Journal of Fatigue
Volume126
DOIs
Publication statusPublished - 1 Sep 2019

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Cyclic loads
Crystal lattices
Crystal
Phase transitions
Thermal Deformation
Anomalous
Zirconium alloys
Phase Transformation
Grain Boundary
Grain boundaries
Phase Transition
Range of data
Temperature
Structural Stability
Dilatation
Thermal Expansion
Size Effect
Crystallite size
Coincidence
Zirconium

Keywords

  • Fuel rod
  • Micro X-ray dilatometry
  • Process channel
  • Thermal cycling
  • Zirconium alloy

ASJC Scopus subject areas

  • Modelling and Simulation
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

Cite this

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title = "Roentgenometry of the Zr–2.5Nb alloy under cyclic loads",
abstract = "Studies were carried out in this work to establish the influence of thermal cyclic and mechanical cyclic loads that simulated the factors of operational impact on structural stability and crystal lattice dilatation of zirconium alloys. It is shown that during cold cyclic deformation at the first moment of loading the Zr–2.5Nb alloy is characterized by significant instantaneous deformation. The effect of anomalous thermal deformations of the zirconium alloy crystal lattices, which are typical for phase transitions of type I and type II, was detected in the operating temperature range (250–350 °C). The absence of phase transformation in this temperature range allows us to suggest the existence of a causal relationship between the anomalous thermal expansion effects of zirconium crystal lattices with orientation changes and phase transformations in grain boundaries. The performed calculations showed the presence of an anomalous change in the crystallite size distribution at a given temperature. The coincidence that temperatures were correlated with size effects and phenomena such as blistering and flecking has been established. The hypothesis of grain-boundary transformations is indirectly confirmed by the results of the second thermal cycle, during which a second jump of the crystal lattice thermal deformations, not related to structural phase transitions, was detected in the range of 550–650 °C.",
keywords = "Fuel rod, Micro X-ray dilatometry, Process channel, Thermal cycling, Zirconium alloy",
author = "Lyubimova, {Lyudmila L.} and Tashlykov, {Alexander A.} and Buvakov, {Konstantin V.}",
year = "2019",
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AU - Lyubimova, Lyudmila L.

AU - Tashlykov, Alexander A.

AU - Buvakov, Konstantin V.

PY - 2019/9/1

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N2 - Studies were carried out in this work to establish the influence of thermal cyclic and mechanical cyclic loads that simulated the factors of operational impact on structural stability and crystal lattice dilatation of zirconium alloys. It is shown that during cold cyclic deformation at the first moment of loading the Zr–2.5Nb alloy is characterized by significant instantaneous deformation. The effect of anomalous thermal deformations of the zirconium alloy crystal lattices, which are typical for phase transitions of type I and type II, was detected in the operating temperature range (250–350 °C). The absence of phase transformation in this temperature range allows us to suggest the existence of a causal relationship between the anomalous thermal expansion effects of zirconium crystal lattices with orientation changes and phase transformations in grain boundaries. The performed calculations showed the presence of an anomalous change in the crystallite size distribution at a given temperature. The coincidence that temperatures were correlated with size effects and phenomena such as blistering and flecking has been established. The hypothesis of grain-boundary transformations is indirectly confirmed by the results of the second thermal cycle, during which a second jump of the crystal lattice thermal deformations, not related to structural phase transitions, was detected in the range of 550–650 °C.

AB - Studies were carried out in this work to establish the influence of thermal cyclic and mechanical cyclic loads that simulated the factors of operational impact on structural stability and crystal lattice dilatation of zirconium alloys. It is shown that during cold cyclic deformation at the first moment of loading the Zr–2.5Nb alloy is characterized by significant instantaneous deformation. The effect of anomalous thermal deformations of the zirconium alloy crystal lattices, which are typical for phase transitions of type I and type II, was detected in the operating temperature range (250–350 °C). The absence of phase transformation in this temperature range allows us to suggest the existence of a causal relationship between the anomalous thermal expansion effects of zirconium crystal lattices with orientation changes and phase transformations in grain boundaries. The performed calculations showed the presence of an anomalous change in the crystallite size distribution at a given temperature. The coincidence that temperatures were correlated with size effects and phenomena such as blistering and flecking has been established. The hypothesis of grain-boundary transformations is indirectly confirmed by the results of the second thermal cycle, during which a second jump of the crystal lattice thermal deformations, not related to structural phase transitions, was detected in the range of 550–650 °C.

KW - Fuel rod

KW - Micro X-ray dilatometry

KW - Process channel

KW - Thermal cycling

KW - Zirconium alloy

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