Shape memory behavior of Ni40.3Ti39.7Hf15Pd5 and Ni40.3Ti44.7Hf10Pd5 alloys

Guher P. Toker, Soheil Saedi, Emre Acar, Osman Ozbulut, Haluk E. Karaca

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The microstructure and shape memory properties of Ni40.3Ti39.7Hf15Pd5 and Ni40.3Ti44.7Hf10Pd5 alloys were investigated. It was revealed that transformation temperatures of these alloys can be tailored by thermal treatments and composition alteration. Heat treated Ni40.3Ti39.7Hf15Pd5 can show shape memory effect at above 100 °C. Both alloys showed shape memory effect, however, superelasticity was not observed due to the large thermal hysteresis and high rate of increase in transformation temperatures with stress. Both alloys have higher strength but considerably lower transformation strain than NiTi. Microstructure features also were investigated for grains, distribution and composition of secondary phase. It was revealed that secondary phases lead to decrease the recoverable strains of the NiTiHfPd alloys. As-received Ni40.3Ti44.7Hf10Pd5 and Ni40.3Ti39.7Hf15Pd5 have recoverable strains of 1.12% and 0.43% under 700 MPa, respectively.

Original languageEnglish
Pages (from-to)1012-1017
Number of pages6
JournalJournal of Alloys and Compounds
Volume763
DOIs
StatePublished - Sep 30 2018

Bibliographical note

Publisher Copyright:
© 2018 Elsevier B.V.

Keywords

  • Mechanical characterization
  • Shape memory alloys
  • Superelasticity

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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