Shape Memory Behavior of [111]-Oriented NiTi Single Crystals After Stress-Assisted Aging

Kaya I., Tobe H., Karaca H. E., ACAR E., CHUMLYAKOV Y.

ACTA METALLURGICA SINICA-ENGLISH LETTERS, vol.29, no.3, pp.282-286, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 3
  • Publication Date: 2016
  • Doi Number: 10.1007/s40195-016-0386-1
  • Journal Name: ACTA METALLURGICA SINICA-ENGLISH LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.282-286
  • Keywords: Shape memory alloy (SMA), Two-way shape memory effect, Aging treatment, Precipitation, Phase transformations, ZN-AL ALLOYS, MARTENSITIC-TRANSFORMATION, TINI, PHASE, TEMPERATURE
  • Erciyes University Affiliated: Yes

Abstract

The shape memory behavior of [111]-oriented Ni51Ti49 (at.%) single crystals was investigated after stress assisted aging at 500 degrees C for 1.5 h under a compressive stress of -150 MPa. It was found that a single family of Ni4Ti3 precipitates with two crystallographically equivalent variants was formed after aging under compressive stress. Stress-assisted aging resulted in tensile two-way shape memory effect strain of 1.56% under -5 MPa. Thermal cycling under -600 MPa resulted in a transformation strain of -2.15%, while the subsequent thermal cycling under -5 MPa resulted in a tensile two-way shape memory effect strain of 2.2%.