In-situ High Temperature Ferroelastic Phase Transformations in Oxide Ceramics Prof. Waltraud M. Kriven, University of Illinois at Urbana-Champaign, DMR Accomplishments: Significant instrumental improvements in conducting in situ high temperature XRD experiments: (a) development of a curved image plate detector (CIPD), and (b) design of a temperature control module for remote operation. The CIPD is a one-dimensional detector which Simultaneously records XRD pattern for 2  range from 0° to 37°. Has an intrinsic resolution ~ 0.007º, which translates into accuracy in peak position of < 0.001°. Requires small exposure times of few seconds to a few minutes In-situ high temperature phase transformation investigations on powder oxide ceramics including Ta 2 O 5, HfO 2 – x Ta 2 O 5 (for x = 0 to 6 mol%) compounds, and DyNbO 4. Development and validation of experimental setup for demonstrating ferroelastic behavior using monofilament fibers of candidate materials. 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 a ferroelastic nature, at elevated temperatures (up to 2000ºC). Potential applications include tough ceramic composites, actuators and shape memory ceramics. Figure 1. The progress of phase transformation in DyNbO 4 as captured using high temperature XRD experiments using QLF and CIPD setup. Note: A small segment of data is presented, and only set temperatures are reported, which are different from actual sample temperatures which are measured in situ.

Education: 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. In addition, three REU program students: Mike Mulholland, Melissa Smith, and David Parsons, were also trained in methods of ceramic powder synthesis and materials characterization. Ms Bo Moon Yee, a graduate student, is completing her MS in Materials Science and Engineering, and will soon start her work with a federal agency. Students and PI together have presented their findings at more than 30 international conferences, as contributed talks, and invited and plenary lectures over the last two years. In-situ High Temperature Ferroelastic Phase Transformations in Oxide Ceramics Waltraud M. Kriven, University of Illinois at Urbana-Champaign, DMR Outreach: Besides being an advisor and mentor to students, over the last year, the PI has served as Chair of the Engineering Ceramics Division of the American Ceramic Society; was elected to be an 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. Figure 2. David Parsons, an REU student, with the PI working on synthesis of ceramic powders.