Texture, strain, and phase-fraction measurements during mechanical cycling in superelastic NiTi

    Authors

    R. Vaidyanathan; M. A. M. Bourke;D. C. Dunand

    Comments

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    Abbreviated Journal Title

    Metall. Mater. Trans. A-Phys. Metall. Mater. Sci.

    Keywords

    SHAPE-MEMORY ALLOYS; TI-NI ALLOYS; NEUTRON-DIFFRACTION; PSEUDOELASTICITY; CHARACTERISTICS; RIETVELD REFINEMENT; COMPOSITES; TRANSFORMATIONS; DEFORMATION; TEMPERATURE; FATIGUE; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

    Abstract

    Superelastic NiTi was subjected to simultaneous neutron diffraction and uniaxial compressive cycling between 10 and 980 MPa. The objective was an in-situ investigation of the evolution of the stress-induced, reversible transformation between austenite and martensite, to determine the cause of the changes in the macroscopic stress-strain response with cycling. Rietveld refinement was used to analyze the neutron spectra and quantify the phase fraction, texture, and elastic strain. The average phase strain in the mechanically loaded austenite (at a given stress) remained unaltered during the 100 load-unload cycles. However, differences in both the volume fraction and texture of austenite and martensite were noted as cycling progressed, suggesting that these factors are responsible for the changes in the macroscopic stress-strain response of NiTi with mechanical cycling.

    Journal Title

    Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science

    Volume

    32

    Issue/Number

    3A

    Publication Date

    1-1-2001

    Document Type

    Article

    Language

    English

    First Page

    777

    Last Page

    786

    WOS Identifier

    WOS:000167694700013

    ISSN

    1073-5623

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