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

A. N. Bucsek, L. Casalena, D. C. Pagan, P. P. Paul, Y. Chumlyakov, M. J. Mills, A. P. Stebner

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

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 Σ3 and Σ9 grain boundaries emerge. The low volume and uneven dispersion of the emergent Σ boundaries across the volume show why previous transmission electron microscopy investigations of Σ grain boundary formation were inconsistent.

Original languageEnglish (US)
Pages (from-to)361-366
Number of pages6
JournalScripta Materialia
Volume162
DOIs
StatePublished - Mar 15 2019

Bibliographical note

Funding Information:
ANB acknowledges the support provided by the National Science Foundation Graduate Research Fellowship Program (award no. DGE-1057607 ). APS acknowledges support provided by the National Science Foundation (award no. CMMI-1454668 ). ANB and APS acknowledge XSEDE resources (award no. TG-MSS160032 and TG-MSS170002 ). LC and MJM acknowledge support provided by the U.S. Department of Energy Office of Science (award no. DE-SC0001258 ). The MatCI (NSF DMR-1121262) facility at Northwestern University was used for calorimetry. This work is based upon research conducted at the Cornell High Energy Synchrotron Source (CHESS), which is supported by the National Science Foundation under awards DMR-1332208 and DMR-0936384.

Publisher Copyright:
© 2018

Keywords

  • 3D reconstruction
  • Coincident lattice
  • Grain refining
  • Shape memory alloys
  • X-ray diffraction

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