@article{178a0f66d95d45a58333c0a1b62f6d42,
title = "Directions of zero thermal expansion and the peritectic transformation in HfTiO4",
abstract = "The anisotropic infinitesimal coefficients of thermal expansion (CTE) and the peritectic transformation of orthorhombic-HfTiO4 (space group: pbcn, #60) to tetragonal-HfO2 (space group: P42/nmc, #137) plus liquid at 1980 °C (O-HfTiO4⇄T-HfO2+L(Hf,Ti,O)) have been studied by in-situ X-ray powder diffraction from room temperature to complete melting (~2300 °C) in air, using a Quadrupole Lamp Furnace (QLF) and a Conical Nozzle Levitator (CNL) equipped with a 400 W CO2 laser. Directions of zero thermal expansion were identified in the temperature range ~25 – 580 ˚C and visualized in 3D using distorted cones and 2D stereographic projections. The directions of zero thermal expansion change as a function of temperature. The (021) pole of orthorhombic HfTiO4 was identified as having the lowest root mean squared (rms) thermal expansion, ~12 times lower than the highest rms thermal expansion direction [100] over the temperature range: 25 – 580 ˚C. The topotactic, peritectic transformation has been fully described by extracting the lattice correspondence, lattice variant deformation and a structural motif (grouping of cations) that relates the two structures at the transformation temperature. Symmetry decomposition was performed to show that the orthorhombic-HfTiO4 and tetragonal-HfO2 structures are simply related by polyhedral rotations and cation oxygen coordination changes, in addition to a slight adjustment in cation positions.",
keywords = "Peritectic, In-situ high temperature X-ray diffraction, Phase transformations, Thermal expansion, X-ray synchrotron radiation",
author = "McCormack, {Scott J.} and Wheeler, {William A.} and Hulbert, {Benjamin S.} and Kriven, {Waltraud M.}",
note = "Funding Information: This work was funded by National Science Foundation (NSF), Division of Materials Research (DMR) Grant number 1411032 and completed under Grant number 1838595 . This research was carried out, in part, at the Frederick Seitz Materials Research Laboratory, Centre for Microanalysis of Materials at the University of Illinois at Urbana Champaign. Funding Information: This research used resources of the Advanced Photon Source ( APS ) at Argonne National Lab ( ANL ) which was supported by the U.S. Department of Energy , Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 and was completed at beamline 6-ID-D with the assistance of Dr. Chris Benmore. This research also used resources of the Brookhaven National Lab (BNL) National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility under contract No. DE-SC0012704 and was completed at beamline 28-2 XPD with the assistance of Dr. Sanjit Ghose. Funding Information: This work was funded by National Science Foundation (NSF), Division of Materials Research (DMR) Grant number 1411032 and completed under Grant number 1838595. This research was carried out, in part, at the Frederick Seitz Materials Research Laboratory, Centre for Microanalysis of Materials at the University of Illinois at Urbana Champaign. This research used resources of the Advanced Photon Source (APS) at Argonne National Lab (ANL) which was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 and was completed at beamline 6-ID-D with the assistance of Dr. Chris Benmore. This research also used resources of the Brookhaven National Lab (BNL) National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility under contract No. DE-SC0012704 and was completed at beamline 28-2 XPD with the assistance of Dr. Sanjit Ghose. A special thanks go to members of the Kriven Research group: Kuo-ping Tseng and Andrew Steveson who provided support with the beamline experiments at ANL, APS, 6-ID-D and BNL, NSLS-II, 28-2 XPD. A special thanks go to members of the Sarin Research group: Prof. Pankaj Sarin and Daniel Lowry who provided support with the beamline experiments at BNL, NSLS-II, 28-2 XPD. A special thanks to our Illinois Scholar Undergraduate Research (ISUR) student, Whitney Tso for her assistance with sample preparation. Publisher Copyright: {\textcopyright} 2020",
year = "2020",
month = nov,
doi = "10.1016/j.actamat.2020.08.060",
language = "English (US)",
volume = "200",
pages = "187--199",
journal = "Acta Materialia",
issn = "1359-6454",
publisher = "Elsevier Limited",
}