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Title: Texture evolution during nitinol martensite detwinning and phase transformation

Nitinol has been widely used to make medical devices for years due to its unique shape memory and superelastic properties. However, the texture of the nitinol wires has been largely ignored due to inherent complexity. In this study, in situ synchrotron X-ray diffraction has been carried out during uniaxial tensile testing to investigate the texture evolution of the nitinol wires during martensite detwinning, variant reorientation, and phase transformation. It was found that the thermal martensitic nitinol wire comprised primarily an axial (1{sup ¯}20), (120), and (102)-fiber texture. Detwinning initially converted the (120) and (102) fibers to the (1{sup ¯}20) fiber and progressed to a (1{sup ¯}30)-fiber texture by rigid body rotation. At strains above 10%, the (1{sup ¯}30)-fiber was shifted to the (110) fiber by (21{sup ¯}0) deformation twinning. The austenitic wire exhibited an axial (334)-fiber, which transformed to the near-(1{sup ¯}30) martensite texture after the stress-induced phase transformation.
Authors:
;  [1] ;  [2] ;  [3]
  1. Fort Wayne Metals Research Products Corporation, 9609 Ardmore Ave., Fort Wayne, Indiana 46809 (United States)
  2. Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., 433/D008, Argonne, Illinois 60439 (United States)
  3. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, 102249 Beijing (China)
Publication Date:
OSTI Identifier:
22253810
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 24; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AUSTENITIC STEELS; DEFORMATION; EQUIPMENT; FIBERS; MARTENSITE; MARTENSITIC STEELS; NICKEL ALLOYS; PHASE TRANSFORMATIONS; SHAPE MEMORY EFFECT; STRAINS; STRESSES; TEXTURE; TITANIUM ALLOYS; WIRES; X-RAY DIFFRACTION