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Thermally and Stress Induced Phase Transformations and Reversibility in Shape Memory Alloys

  • O. AdiguzelEmail author
Conference paper
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Part of the NATO Science for Peace and Security Series C: Environmental Security book series (NAPSC)

Abstract

Shape memory alloys take place in class of functional materials due to the sensitivity to the external conditions and memory behavior and shape changes are governed by successive thermally and stress induced martensitic transformations in crystallographic level. Shape memory effect is performed on cooling by means of thermal induced martensitic transformation and stressing in the low temperature product phase region by means of stress induced martensitic transformation. Following these processes, shape memory materials cycle between original and deformed shapes on heating and cooling, by means of reverse and forward thermal induced transformations. Mechanical memory is performed only mechanically in a constant temperature in the parent phase region, on stressing and releasing.

This behavior is called superelasticity, which exhibits classical elastic material behavior, but stressing and releasing paths follow different paths in stress-strain diagrams. The hysteresis loop refers to the energy dissipation, and these alloys are mainly used as deformation absorbent materials in the buildings, due to the absorbance of strain energy during any disaster or earthquake. Thermal induced martensite occurs as twinned martensites by means of lattice invariant shears on close packed planes of parent structure, and the twinned martensites turn into detwinned structures with deformation by means of stress induced transformation. In the superelasticity, ordered parent phase structures turn into detwinned structure by means of stress induced transformation, and crystal structure cycles between these structures on stressing and releasing.

Copper based alloys exhibit this property in metastable beta-phase region, which has bcc based structures at high temperature parent phase field. Crystallographic studies; x-ray and electron diffraction studies performed two copper based CuZnAl and CuAlMn alloys reveal that diffraction profiles exhibit super lattice reflections, and crystal structures change with long term aging in martensitic condition. This result refers to the rearrangement of atoms in diffusive manner.

Keywords

Shape memory effect Thermal memory Martensitic Transformations Reversibility Thermoelasticity Superelasticity Twinning and detwinning 

References

  1. 1.
    Liu Y (2001) Detwinning process and its anisotropy in shape memory alloys. Smart Mater Proc SPIE 4234:82ADSCrossRefGoogle Scholar
  2. 2.
    Sun L, Huang WM, Ding Z, Zhao Y, Wang CC, Purnawali H, Tang C (2012) Stimulus-responsive shape memory materials: a review. Mater Des 33:577CrossRefGoogle Scholar
  3. 3.
    Huang WM et al (2010) Shape memory materials. Mater Today 13:54CrossRefGoogle Scholar
  4. 4.
    Adiguzel O (2017) Thermoelastic and pseudoelastic characterization of shape memory alloys. Int J Mater Sci Eng 5:95Google Scholar
  5. 5.
    de Castro Bubani F, Sade M, Lovey F (2012) Improvements in the mechanical properties of the 18R ↔ 6R high-hysteresis martensitic transformation by nanoprecipitates in CuZnAl alloys. Mater Sci Eng A 543:88CrossRefGoogle Scholar
  6. 6.
    de Castro Bubani F, Lovey F, Sade M, Cetlin P (2016) Numerical simulations of the pseudoelastic effect in CuZnAl shape-memory single crystals considering two successive martensitic transitions. Smart Mater Struct 25(1)Google Scholar
  7. 7.
    Adiguzel O (2013) Phase transitions and microstructural processes in shape memory alloys. Mater Sci Forum 762:483CrossRefGoogle Scholar
  8. 8.
    Adiguzel O (2012) Martensitic transformation and microstructural characteristics in copper based shape memory alloys. Key Eng Mater 510–511:105CrossRefGoogle Scholar
  9. 9.
    Casati R et al (2014) Thermal cycling of stress-induced martensite forhigh-performance shape memory effect. Scr Mater 80:13CrossRefGoogle Scholar
  10. 10.
    Li Z, Gong S, Wang MP (2008) Macroscopic shape change of Cu13Zn15Al shape memory alloy on successive heating. J Alloys Compd 452:307CrossRefGoogle Scholar
  11. 11.
    Adiguzel O (2007) Smart materials and the influence of atom sizes on martensite microstructures in copper-based shape memory alloys. J Mater Process Technol 185:120CrossRefGoogle Scholar
  12. 12.
    Guo YF et al (2007) Mechanisms of martensitic phase transformations in body-centered cubic structural metals and alloys: molecular dynamics simulations. Acta Mater 55:6634CrossRefGoogle Scholar
  13. 13.
    Aydogdu A, Aydogdu Y, Adiguzel O (2004) Long-term ageing behaviour of martensite in shape memory Cu–Al–Ni alloys. J Mater Process Technol 153–154:164CrossRefGoogle Scholar
  14. 14.
    Sade M, Pelegrina JL, Yawny A, Lovey FC (2015) Diffusive phenomena and pseudoelasticity in Cu–Al–Be single crystals. J Alloys Compd 622:309CrossRefGoogle Scholar
  15. 15.
    Kustov S, Corr M, Pons J, Cesari E, Van Humbeeck J (2006) Thermodynamic reversibility and irreversibility of the reverse transformation in stabilized Cu-Zn-Al martensite. Mater Sci Eng A 438–440:768CrossRefGoogle Scholar

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© Springer Nature B.V. 2020

Authors and Affiliations

  1. 1.Department of PhysicsFirat UniversityElazigTurkey

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