Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu-Al-Be shape memory alloy

Lajos Daróczi, Tarek El Rasasi, Dezso L. Beke

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Thermoelasic martensitic transformations are controlled by the local equilibrium of chemical and non-chemical free energy contributions (D and E being the dissipative and elastic energies, respectively). The derivatives of non-chemical free energies (∂D/∂ξ=d(ξ),∂E/∂ξ= e(ξ) as a function of the transformed martensite fraction (ξ) can be expressed from the experimental data obtained from the temperature-elongation, temperature-resistance, etc hysteresis loops. This method, developed in our laboratory, was used for the investigation of non complete, partial thermoelastic transformation cycles. In the first set of experiments the subsequent cycles were started below the Mf temperature and the maximum temperature was decreased gradually from a value above Af (series U). In the second (L) set the cycles were started above the Af and the minimum temperature was gradually increased from a value below Mf. In the third (UL) set the minor loops were positioned into the centre of the two phase region (i.e. the cycling was made with an increasing ΔT temperature interval with ΔTf-Mf). From the minor hysteresis loops the d(ξ) and e(ξ) functions were evaluated as the function of ξ. The ξ dependence of the elastic energy contribution, e(ξ), is nearly identical in all subcycles (showing moderate downward as well as upward branches around the end points, for the U and L branches, respectively). In the UL set the downward and upward branches appear for ξ>0.5 and ξ

Original languageEnglish
Title of host publicationMaterials Science Forum
Pages38-45
Number of pages8
Volume738-739
DOIs
Publication statusPublished - 2013
Event9th European Symposium on Martensitic Transformations, ESOMAT 2012 - Saint-Petersburg, Russian Federation
Duration: Sep 9 2012Sep 16 2012

Publication series

NameMaterials Science Forum
Volume738-739
ISSN (Print)02555476

Other

Other9th European Symposium on Martensitic Transformations, ESOMAT 2012
CountryRussian Federation
CitySaint-Petersburg
Period9/9/129/16/12

Fingerprint

shape memory alloys
Shape memory effect
Free energy
free energy
cycles
Hysteresis loops
Temperature
temperature
hysteresis
Martensitic transformations
martensitic transformation
martensite
Martensite
elongation
Hot Temperature
Elongation
Derivatives
intervals
energy
Experiments

Keywords

  • Free energy contributions
  • Hysteretic behaviour
  • Shape memory alloys
  • Thermal cycles

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

Cite this

Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu-Al-Be shape memory alloy. / Daróczi, Lajos; El Rasasi, Tarek; Beke, Dezso L.

Materials Science Forum. Vol. 738-739 2013. p. 38-45 (Materials Science Forum; Vol. 738-739).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Daróczi, L, El Rasasi, T & Beke, DL 2013, Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu-Al-Be shape memory alloy. in Materials Science Forum. vol. 738-739, Materials Science Forum, vol. 738-739, pp. 38-45, 9th European Symposium on Martensitic Transformations, ESOMAT 2012, Saint-Petersburg, Russian Federation, 9/9/12. https://doi.org/10.4028/www.scientific.net/MSF.738-739.38
Daróczi, Lajos ; El Rasasi, Tarek ; Beke, Dezso L. / Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu-Al-Be shape memory alloy. Materials Science Forum. Vol. 738-739 2013. pp. 38-45 (Materials Science Forum).
@inproceedings{55a2fa8c019d43979a66d809dae30aca,
title = "Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu-Al-Be shape memory alloy",
abstract = "Thermoelasic martensitic transformations are controlled by the local equilibrium of chemical and non-chemical free energy contributions (D and E being the dissipative and elastic energies, respectively). The derivatives of non-chemical free energies (∂D/∂ξ=d(ξ),∂E/∂ξ= e(ξ) as a function of the transformed martensite fraction (ξ) can be expressed from the experimental data obtained from the temperature-elongation, temperature-resistance, etc hysteresis loops. This method, developed in our laboratory, was used for the investigation of non complete, partial thermoelastic transformation cycles. In the first set of experiments the subsequent cycles were started below the Mf temperature and the maximum temperature was decreased gradually from a value above Af (series U). In the second (L) set the cycles were started above the Af and the minimum temperature was gradually increased from a value below Mf. In the third (UL) set the minor loops were positioned into the centre of the two phase region (i.e. the cycling was made with an increasing ΔT temperature interval with ΔTf-Mf). From the minor hysteresis loops the d(ξ) and e(ξ) functions were evaluated as the function of ξ. The ξ dependence of the elastic energy contribution, e(ξ), is nearly identical in all subcycles (showing moderate downward as well as upward branches around the end points, for the U and L branches, respectively). In the UL set the downward and upward branches appear for ξ>0.5 and ξ",
keywords = "Free energy contributions, Hysteretic behaviour, Shape memory alloys, Thermal cycles",
author = "Lajos Dar{\'o}czi and {El Rasasi}, Tarek and Beke, {Dezso L.}",
year = "2013",
doi = "10.4028/www.scientific.net/MSF.738-739.38",
language = "English",
isbn = "9783037856109",
volume = "738-739",
series = "Materials Science Forum",
pages = "38--45",
booktitle = "Materials Science Forum",

}

TY - GEN

T1 - Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu-Al-Be shape memory alloy

AU - Daróczi, Lajos

AU - El Rasasi, Tarek

AU - Beke, Dezso L.

PY - 2013

Y1 - 2013

N2 - Thermoelasic martensitic transformations are controlled by the local equilibrium of chemical and non-chemical free energy contributions (D and E being the dissipative and elastic energies, respectively). The derivatives of non-chemical free energies (∂D/∂ξ=d(ξ),∂E/∂ξ= e(ξ) as a function of the transformed martensite fraction (ξ) can be expressed from the experimental data obtained from the temperature-elongation, temperature-resistance, etc hysteresis loops. This method, developed in our laboratory, was used for the investigation of non complete, partial thermoelastic transformation cycles. In the first set of experiments the subsequent cycles were started below the Mf temperature and the maximum temperature was decreased gradually from a value above Af (series U). In the second (L) set the cycles were started above the Af and the minimum temperature was gradually increased from a value below Mf. In the third (UL) set the minor loops were positioned into the centre of the two phase region (i.e. the cycling was made with an increasing ΔT temperature interval with ΔTf-Mf). From the minor hysteresis loops the d(ξ) and e(ξ) functions were evaluated as the function of ξ. The ξ dependence of the elastic energy contribution, e(ξ), is nearly identical in all subcycles (showing moderate downward as well as upward branches around the end points, for the U and L branches, respectively). In the UL set the downward and upward branches appear for ξ>0.5 and ξ

AB - Thermoelasic martensitic transformations are controlled by the local equilibrium of chemical and non-chemical free energy contributions (D and E being the dissipative and elastic energies, respectively). The derivatives of non-chemical free energies (∂D/∂ξ=d(ξ),∂E/∂ξ= e(ξ) as a function of the transformed martensite fraction (ξ) can be expressed from the experimental data obtained from the temperature-elongation, temperature-resistance, etc hysteresis loops. This method, developed in our laboratory, was used for the investigation of non complete, partial thermoelastic transformation cycles. In the first set of experiments the subsequent cycles were started below the Mf temperature and the maximum temperature was decreased gradually from a value above Af (series U). In the second (L) set the cycles were started above the Af and the minimum temperature was gradually increased from a value below Mf. In the third (UL) set the minor loops were positioned into the centre of the two phase region (i.e. the cycling was made with an increasing ΔT temperature interval with ΔTf-Mf). From the minor hysteresis loops the d(ξ) and e(ξ) functions were evaluated as the function of ξ. The ξ dependence of the elastic energy contribution, e(ξ), is nearly identical in all subcycles (showing moderate downward as well as upward branches around the end points, for the U and L branches, respectively). In the UL set the downward and upward branches appear for ξ>0.5 and ξ

KW - Free energy contributions

KW - Hysteretic behaviour

KW - Shape memory alloys

KW - Thermal cycles

UR - http://www.scopus.com/inward/record.url?scp=84874062566&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84874062566&partnerID=8YFLogxK

U2 - 10.4028/www.scientific.net/MSF.738-739.38

DO - 10.4028/www.scientific.net/MSF.738-739.38

M3 - Conference contribution

AN - SCOPUS:84874062566

SN - 9783037856109

VL - 738-739

T3 - Materials Science Forum

SP - 38

EP - 45

BT - Materials Science Forum

ER -