Title

On elastic moduli and elastic anisotropy in polycrystalline martensitic NiTi

Authors

Authors

S. Qiu; B. Clausen; S. A. Padula; R. D. Noebe;R. Vaidyanathan

Comments

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Abbreviated Journal Title

Acta Mater.

Keywords

Elastic modulus; Martensite; Shape memory; Anisotropy; Neutron; diffraction; ACQUIRED IN-SITU; DIFFRACTION SPECTRA; RIETVELD REFINEMENT; SUPERELASTIC; NITI; TEXTURE; STRAIN; STRESSES; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

Abstract

A combined experimental and computational effort was undertaken to provide insight into the elastic response of B19' martensitic NiTi variants as they exist in bulk, polycrystalline aggregate form during monotonic tensile and compressive loading. The experimental effort centered on using in situ neutron diffraction during loading to measure elastic moduli in several directions along with an average Young's modulus and a Poisson's ratio. The measurements were compared with predictions from a 30,000 variant, self-consistent polycrystalline deformation model that accounted for the elastic intergranular constraint, and also with predictions of single crystal behavior from previously published ab initio studies. Variant conversion and detwinning processes that influenced the intergranular constraint occurred even at stresses where the macroscopic stress strain response appeared linear. Direct evidence of these processes was revealed in changes in texture, which were captured in inverse pole figures constructed from the neutron diffraction measurements. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Journal Title

Acta Materialia

Volume

59

Issue/Number

13

Publication Date

1-1-2011

Document Type

Article

Language

English

First Page

5055

Last Page

5066

WOS Identifier

WOS:000293113600001

ISSN

1359-6454

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