Effects of aging on the shape memory and superelasticity behavior of ultra-high strength Ni54Ti46 alloys under compression

Kaya I., Tobe H., Karaca H. E., Basaran B., Nagasako M., Kainuma R., ...More

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, vol.678, pp.93-100, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 678
  • Publication Date: 2016
  • Doi Number: 10.1016/j.msea.2016.09.078
  • Journal Name: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.93-100
  • Keywords: Ni-rich NiTi shape memory alloy, Thermomechanical loading, High strength shape memory alloy, Multiple step phase transformation, R-phase transformation, NITI SINGLE-CRYSTALS, MARTENSITIC-TRANSFORMATION, MECHANICAL-PROPERTIES, DEFORMATION-BEHAVIOR, PHASE-TRANSFORMATION, ELECTRON-MICROSCOPY, HOT-DEFORMATION, HYSTERESIS
  • Anadolu University Affiliated: Yes

Abstract

This study investigates the effects of aging on the shape memory and superelasticity behavior of a Ni-rich Ni54Ti46 (at%) alloy. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM) and compression test (thermal cycling under stress and superelasticity) were carried out after 3 h agin;g from 450 degrees C to 600 degrees C. The alloys show recoverable shape memory effect with transformation strains of about 1% and narrow hysteresis under high stress levels. The work output of 14.1 Jg(-1) was observed at an ultra-high stress level of 1500 MPa after 600 degrees C 3 h aging. 450 degrees C 3 h aging resulted in a very narrow temperature hysteresis of 8 degrees C under an ultra-high stress level of 1500 MPa. At room temperature, the superelastic response with 4% total strain was obtained even when high stress level of 2000 MPa is applied after 550 degrees C 3 h aging.