Insitu High Temperature Ferroelastic Phase Transformations in Oxide Ceramics Waltraud M' Kriven, Uni - PowerPoint PPT Presentation

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Insitu High Temperature Ferroelastic Phase Transformations in Oxide Ceramics Waltraud M' Kriven, Uni

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Title: Insitu High Temperature Ferroelastic Phase Transformations in Oxide Ceramics Waltraud M' Kriven, Uni


1
In-situ High Temperature Ferroelastic Phase
Transformations in Oxide CeramicsWaltraud M.
Kriven, University of Illinois at
Urbana-Champaign, DMR 0211139
Introduction High temperature phase
transformations in oxide ceramics are being
studied in-situ, in air, using a thermal-image
quadrupole lamp furnace (QLF) in conjunction with
synchrotron radiation. The emphasis is on oxide
materials exhibiting polymorphic phase
transformations of ferroelastic nature, at
elevated temperatures (up to 2000ºC). Potential
applications include tough ceramic composites,
actuators and shape memory ceramics.
  • Accomplishments
  • Significant instrumental improvements in
    conducting rapid high temperature XRD
    experiments
  • The CIP detector is a one-dimensional detector
    which
  • simultaneously records XRD pattern for 2? range
    of 0 to 38
  • has intrinsic resolution 0.007º.
  • can acquire entire XRD pattern in 30 seconds.
  • In-situ high temperature phase transformation
    investigations on powder oxide ceramics including
    Ta2O5, HfO2 x Ta2O5 (for x 0 to 6 mol)
    compounds, RNbO4 (where R Y, Dy, or La), DyVO4,
    and CePO4 analysis is underway.

Figure 1. The curved image plate (CIP) detector
system at the XOR/UNI 33-BM-C beam line at APS in
ANL, IL, is used in conjunction with the
quadrupole lamp furnace for rapid in situ high
temperature XRD (HTXRD) measurements, up to 2000
C in air. This set up was used to study phase
transformations in oxide ceramics including
Ta2O5, RNbO4 (where R Y, Dy, or La), etc. The
CIP detector was designed and built under an
AFOSR DURIP award number FA9550-04-1-0345.
Figure 2. Selected 2q ranges of diffraction data
collected on cooling high temperature form of
Ta2O5 indicated peak splitting. The temperature
dependence of (0 1 7), (0 1 11) and (1 1 6) peaks
is shown. Ta2O5 underwent abrupt and apparently
displacive phase transformations at 1273 and
613 K during heating/cooling. This work was done
in collaboration with Geoffrey Brennecka (Ph.D.
May'06) an NSF Fellow working with Prof. David A.
Payne at UIUC.
2
In-situ High Temperature Ferroelastic Phase
Transformations in Oxide CeramicsWaltraud M.
Kriven, University of Illinois at
Urbana-Champaign, DMR 0211139
Education Ms Bo Moon Yee, a graduate student,
completed her MS in Materials Science and
Engineering, and has started her work with a
federal agency. Melissa Smith, an
African-American undergraduate who has been an
REU student for 4 years has graduated and is
starting Ph.D. studies at MIT this Fall 2006.
Mike Mulholland, an REU student for 2 years has
started his graduate studies at Northwestern
University in Fall 2005. Several students, both
undergraduate and graduate, as well as
postdoctoral research fellows had the opportunity
to learn, develop and design instrumentation, as
well as become trained in conducting in situ,
high temperature XRD experiments at synchrotron
facilities. Ryan Haggerty, a graduate student,
was one of the 60 students across the country who
were selected to attend the National School on
Neutron and X-ray Scattering at Argonne National
Laboratory, Argonne IL.
Outreach Students and PI together have presented
their findings at more than 40 international
conferences, as contributed talks, and invited
and plenary lectures over the last two years. The
CIP detector developed by the PIs research group
was featured as a Novel X-ray Technique and
Instrumentation in the APS Annual Report, May
2005. Besides being an advisor and mentor to
students, the PI has served as Chair of the
Engineering Ceramics Division of the American
Ceramic Society was elected Academician in the
World Academy of Ceramics has co-edited 14
books was an NSF panel reviewer and served as a
review instructor for the Illinois Society of
Professional Engineers. The PI has also started a
series of lectures on Special Topics in Science
and Engineering at the local High School, to
encourage high school students to learn more
about materials science and engineering. The PI
also serves on the National Screening Committee
for the US International Fulbright Science and
Technology Award, to select international Ph.D.
students.
Figure 3. The PI with her students, scientists at
beam line 33BM-C at APS. Dr. Brian Toby and Dr.
Robert B. Von Dreele were visiting to learn about
the PIs experiments and the new CIP detector.
Shown in picture are (L to R) Dr. Brian Toby and
Dr. Robert B. Von Dreele, Ryan P. Haggerty,
Jonathan L. Bell, Dr. Paul Zschack, Dr. Pankaj
Sarin, Prof. Waltraud M. Kriven, and Evgenia
Karapetrova.
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