Shape memory and transformation behavior of high strength 60NiTi in compression

Kaya I.

SMART MATERIALS AND STRUCTURES, vol.25, no.12, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 25 Issue: 12
  • Publication Date: 2016
  • Doi Number: 10.1088/0964-1726/25/12/125031
  • Journal Name: SMART MATERIALS AND STRUCTURES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: NiTi, shape memory alloys (SMA), mechanical properties, phase transformation, TI-50.9 AT.PERCENT NI, MARTENSITIC-TRANSFORMATION, PHASE-TRANSFORMATION, MECHANICAL-PROPERTIES, DEFORMATION-BEHAVIOR, MICROSTRUCTURAL EVOLUTION, PLASTIC-DEFORMATION, PSEUDOELASTIC NITI, HOT-DEFORMATION, AGING TREATMENT
  • Anadolu University Affiliated: Yes

Abstract

This study investigates the transformation behavior of highly Ni-rich 60NiTi alloys after aging at 600 degrees C for 3 h. After 600 degrees C-3h aging, R-phase disappeared and alloy transformed in one step. The latent heats of austenite to martensite and martensite to austenite transformations were 13 Jg(-1) and 16.4 Jg(-1), respectively, for 600 degrees C-3h aged alloy. The elastic strain energy of 0.75 Jg(-1) was obtained in aged alloy. The maximum recoverable transformation strain of 1.7% is obtained under 500 MPa in compression. The superelastic behavior was observed accompanied with a recoverable strain of 1.4%, even high stress level of 1000 MPa is applied.