Synchrotron high energy X-ray diffraction study of microstructure evolution of severely cold drawn NiTi wire during annealing
Microstructure evolution of a cold-drawn NiTi shape memory alloy wire was investigated by means of in-situ synchrotron high-energy X-ray diffraction during continuous heating. The cold-drawn wire contained amorphous regions and nano-crystalline domains in its microstructure. Pair distribution function analysis revealed that the amorphous regions underwent structural relaxation via atomic rearrangement when heated above 100 °C. The nano-crystalline domains were found to exhibit a strong cold work induced lattice strain anisotropy having a preferential <111> fiber orientation along the wire axial direction. The lattice strain anisotropy systematically decreased upon heating above 200 °C, implying a structural recovery. A broad conical texture was formed in the wire specimen after crystallization similar in detail to the initial <111> texture axial orientation of the nano-crystalline domains produced by the severe cold wire drawing deformation.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- National Natural Science Foundation of China (NNSFC); National Basic Research Program of China; Australian Research Council; Northern Illinois University - Institute for Nanoscience, Engineering and Technology; USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1390813
- Journal Information:
- Acta Materialia, Vol. 115, Issue C; ISSN 1359-6454
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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