Microstructure and transformation related behaviors of a Ni45.3Ti29.7Hf20Cu5 high temperature shape memory alloy

H. E. Karaca, E. Acar, G. S. Ded, S. M. Saghaian, B. Basaran, H. Tobe, M. Kok, H. J. Maier, R. D. Noebe, Y. I. Chumlyakov

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Effects of heat treatment temperature and time on the microstructure and shape memory behaviors (e.g. transformation temperatures, load-biased shape memory effect, superelasticity, two-way shape memory effect, and related properties) were investigated in a Ni45.3Ti29.7Hf20Cu5 (at%) high temperature polycrystalline shape memory alloy. Heat treatments could be used to control the TTs and to a lesser extent recoverable and irrecoverable strains. The Ni45.3Ti29.7Hf20Cu5 alloy was capable of recovering shape memory strains of up to 2% at temperatures above 100°C under high compressive stresses (700MPa) and up to 0.8% TWSME strain was possible after a non-intense stress-cycling training process. However, due to high Clausius-Clapeyron slopes, large temperature hysteresis, and a strong dependence of transformation stress on temperature, fully recoverable superelastic behavior was not observed because plastic deformation occurred concurrently with the stress-induced martensitic transformation.

Original languageEnglish
Pages (from-to)82-94
Number of pages13
JournalMaterials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
StatePublished - Mar 1 2015

Bibliographical note

Funding Information:
This work was supported in part by the NASA Fundamental Aeronautics Program, and Aeronautical Sciences and Transformational Tools & Technologies Projects (Technical Discipline Lead Dale Hopkins), the NASA EPSCOR program under Grant NNX11AQ31A , the NASA Kentucky Space Grant Consortium 516171-10-165 and RSF Grant 14-29-00012 . HJM acknowledges financial support from Deutsche Forschungsgemeinschaft ( FOR 1766 ).

Publisher Copyright:
© 2015 Elsevier B.V.


  • NiTiHfCu alloys
  • Phase transformation
  • Shape memory alloys
  • Shape memory effect

ASJC Scopus subject areas

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


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