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


Karaca H. E. , Acar E. , Ded G. S. , Saghaian S. M. , Basaran B., Tobe H., ...Daha Fazla

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, cilt.627, ss.82-94, 2015 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 627
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1016/j.msea.2014.12.111
  • Dergi Adı: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
  • Sayfa Sayıları: ss.82-94

Özet

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 Us 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 degrees C under high compressive stresses (700 MPa) 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. (C) 2015 Elsevier B.V. All rights reserved.