Three-dimensional in situ characterization of phase transformation induced austenite grain refinement in nickel-titanium

SCRIPTA MATERIALIA

卷:162

Article

Bucsek, A. N.^1,6  Casalena, L.^2,7  Pagan, D. C.³  Paul, P. P.⁴  Chumlyakov, Y.⁵  Mills, M. J.²  Stebner, A. P.¹ 

[1] Colorado Sch Mines, Mech Engn, 1500 Illinois St, Golden, CO 80401 USA

[2] Ohio State Univ, Mat Sci & Engn, 2041 N Coll Rd, Columbus, OH 43210 USA

[3] Cornell High Energy Synchrotron Source, 161 Wilson Lab, Ithaca, NY 14853 USA

[4] Northwestern Univ, Mech Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA

[5] Tomsk State Univ, Dept Phys Met, Lenin Ave 36, Tomsk 634050, Russia

[6] Univ Minnesota, Aerosp Engn & Mech, 110 Union St SE, Minneapolis, MN 55455 USA

[7] Thermo Fisher Sci, 5350 NE Dawson Creek Dr, Hillsboro, OR 97142 USA

关键词: Shape memory alloys;    Coincident lattice;    Grain refining;    X-ray diffraction;    3D reconstruction;   

DOI  :  10.1016/j.scriptamat.2018.11.043

来源: Elsevier

【 摘 要 】

Near-field and far-field high-energy diffraction microscopy and microcomputed tomography X-ray techniques were used to study a bulk single crystal nickel-titanium shape memory alloy sample subjected to thermal cycling under a constant applied load. Three-dimensional in situ reconstructions of the austenite microstructure are presented, including the structure and distribution of emergent grain boundaries. After 1 cycle, the subgrain structure is significantly refined, and heterogeneous Sigma 3 and Sigma 9 grain boundaries emerge. The low volume and uneven dispersion of the emergent Sigma boundaries across the volume show why previous transmission electron microscopy investigations of Sigma grain boundary formation were inconsistent. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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