Neutron diffraction study of NiTi during compressive deformation and after shape-memory recovery
- Massachusett Inst. of Technology, Cambridge, MA (United States). Dept. of Materials Science and Engineering
- Los Alamos National Lab., NM (United States)
Neutron diffraction measurements of internal elastic strains and texture were performed during compressive deformation of martensitic NiTi deforming by twinning. Rietveld refinement of the diffraction spectrum was performed in order to obtain lattice parameter variations and preferred orientation of martensitic variants. The elastic internal strains, are proportional to the externally applied stress but strongly dependent on crystallographic orientation. Plastic deformation by matrix twinning is consistent with type I (1-1-1) twinning, whereby (100) and (011) planes tend to align perpendicular and parallel to the stress axis, respectively. The preferred orientation ratio r according to the model by March and Dollase is proportional to the macroscopic plastic strain for (100) and (011) planes for loading, unloading and shape-memory recovery. To the best of our knowledge, this is the first in situ bulk measurement of reversible twinning in NiTi. Finally, shape-memory recovery results in a marked change of NiTi cell parameters.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Schweizerischer Nationalfonds zur Foerderung der Wissenschaftlichen Forschung, Bern (Switzerland); Massachusetts Inst. of Tech., Cambridge, MA (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 100006
- Report Number(s):
- LA-UR-95-2345; CONF-9508145-2; ON: DE95016835
- Resource Relation:
- Conference: 8. international conference on martensitic transformations (ICOMAT-8), Lausanne (Switzerland), 20-25 Aug 1995; Other Information: PBD: [1995]
- Country of Publication:
- United States
- Language:
- English
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