Tensile shape memory behavior of Ni50.3Ti29.7Hf20 high temperature shape memory alloys

S. M. Saghaian, H. E. Karaca, M. Souri, A. S. Turabi, R. D. Noebe

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


The effects of heat treatment on the shape memory characteristics of a polycrystalline Ni50.3Ti29.7Hf20 alloy were studied via thermal cycling under stress and isothermal stress cycling experiments in tension. It was revealed that transformation temperatures could be increased above 100 °C with aging at temperature above 500 °C and in particular were stabilized against stress-free thermal cycling after aging at 500 °C. Recoverable strain of ~5% was observed for the as-extruded samples and decreased to ~4% after aging due to the formation of non-transformable precipitates. The aged alloys demonstrated near perfect shape memory effect under tensile stresses as high as 700 MPa and perfect superelasticity at temperatures up to 230 °C. Finally, the tension-compression asymmetry observed in NiTiHf alloys was discussed.

Original languageEnglish
Pages (from-to)340-345
Number of pages6
JournalMaterials and Design
StatePublished - Jul 5 2016

Bibliographical note

Publisher Copyright:
© 2016 Elsevier Ltd.


  • Heat treatments
  • NiTiHf
  • Shape memory alloys
  • Tensile testing

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


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