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Materials Science Research Lecture

Wednesday, November 17, 2021
4:00pm to 5:00pm
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Noyes 147 (J. Holmes Sturdivant Lecture Hall)
Real-time examination of shock-induced structural phase transitions
Sally Tracy, Staff Scientist, Carnegie Institution for Science,

NOTE: At this time, in-person Materials Research Lectures are open to all Caltech students/staff/faculty/visitors with a valid Caltech ID. Outside community members are welcome to join our online webinar.

Webinar Link:

Webinar ID: 832 7665 2110


New capabilities that couple dynamic compression drivers with high-flux x-ray sources provide a means to investigate shock-induced phase transformations. I will discuss the application of these techniques to investigate the high-pressure crystal structures of oxide and carbide materials, including SiO2 and SiC. SiO2 has been extensively examined under dynamic compression due to its far-reaching applications in materials science and geophysics, while the behavior of SiC under extreme conditions is of interest due to its application as a high-strength ceramic and its importance to planetary science. These experiments demonstrate that high-pressure phase transitions can be explored to multi-Mbar pressures on nanosecond timescales and resolve long-standing questions concerning the lattice-level structure and high-pressure stability of these materials.

More about the Speaker:

Sally June Tracy is a Staff Scientist at the Carnegie Institution for Science in Washington, DC. Tracy received her Ph.D. in Materials Science from Caltech in 2016. After a postdoctoral fellowship in the Department of Geosciences at Princeton, she joined Carnegie in 2019. Tracy's research spans Materials Science and Earth and Planetary Science. She uses high-pressure-temperature experiments to explore the physical properties and phase stability of materials under extreme conditions. Her primary tools include laser-heated diamond anvil cells as well as laser-driven and gas-gun dynamic compression. This work provides experimental constraints on subjects ranging from planetary impacts, high-pressure phases of deep planetary interiors, and materials for extreme applications. Currently, she is particularly interested in using light-source-based facilities to study crystallographic transformations during dynamic compression.

For more information, please contact Jennifer Blankenship by email at