Hard X-ray studies of stress-induced phase transformations of superelastic NiTi shape memory alloys under uniaxial load

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:481

Article; Proceedings Paper

Hasan, M.^1,2  Schmahl, W. W.¹  Hackl, K.³  Heinen, R.³  Frenzel, J.⁴  Gollerthan, S.⁴  Eggeler, G.⁴  Wagner, M.⁴  Khalil-Allafi, J.⁵  Baruj, A.⁶ 

[1] Univ Munich, Dept Geo & Umweltwissensch, Sekt Kristallog, D-80333 Munich, Germany

[2] Ruhr Univ Bochum, Fak Geowissensch, D-44780 Bochum, Germany

[3] Ruhr Univ Bochum, Inst Mech, Lehrstuhl Allgemeine Mech, D-44780 Bochum, Germany

[4] Ruhr Univ Bochum, Inst Werkstoffe, D-44801 Bochum, Germany

[5] Sahand Univ Technol, Fac Mat Engn, Tabriz, Iran

[6] Inst Balseiro, Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina

关键词: twin variant texture;    superelasticity;    stress-induced martensite;    cold rolled B2 austenite;    NiTi;   

DOI  :  10.1016/j.msea.2007.02.156

来源: Elsevier

【 摘 要 】

We examined the texture evolution in a superelastic Ni50.7Ti49.3 (numbers indicate at.%) alloy under applied uniaxial stress using high-energy synchrotron X-ray diffraction in transmission geometry. Texture information is identified from the intensity variations along Debye-Scherrer rings recorded on area detector diffraction images. The 110(A) austenite plane normals are aligned in the rolling direction and 200(A) is in the transverse direction. Due to the 132-B19' lattice correspondence, the 110(A) peak splits into four martensite peaks 020(M), (1) over bar 11(M), 002(M) and 111(M). The stress-induced martensite is strongly textured from twin variant selection in the stress field with 020(M) aligned in the loading direction while the maxima corresponding to (1) over bar 11(M), 0 0 2m and 111(M) are at 60 degrees, 67 degrees and 75 degrees from the loading direction. (B19' unit cell setting: a = 2.87 angstrom, b = 4.59 angstrom, c = 4.1 angstrom, gamma = 96.2 degrees). A comparison between the experimental and recalculated distribution densities for the polycrystalline NiTi shows a reasonable agreement. In addition, we compare our experimental results with a micromechanical model which is based on total energy minimization. In this case, we also observe an overall agreement. (C) 2007 Published by Elsevier B.V.

【 授权许可】

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