Bio

Leora studies how modern methods can enable new opportunities to update "old-school" materials processing and manufacturing for sustainability. This includes designing new microscopes and using them to get a deeper view into the extraction, forming, and functional properties of metallic materials. Leora's group works on thrusts in sustainable steelmaking (specifically ironmaking), metal 3D printing, and studies of the fundamental mechanisms underlying properties in materials.

Leora is an Assistant Professor in the Department of Materials Science & Engineering, with a courtesy appointment in Mechanical Engineering, and a term appointment in Photon Science at the SLAC National Accelerator Lab. Leora was also appointed as a Precourt Center Fellow and a Gabilan Fellow at Stanford University, and was selected for a Young Investigator Research Program (YIP) Award from the AFOSR in 2023. Before coming to Stanford, Leora was a Lawrence Fellow in the Physics Division of the Physics and Life Sciences Directorate at Lawrence Livermore National Labs, where she developed the tools to study time-resolved defect dynamics in bulk materials -- giving new insights into long-standing problems in materials science. Leora did her PhD in Physical Chemistry with Prof. Keith Nelson at MIT, where she demonstrated how shock waves initiate chemistry in RDX that couples to deformations in unique ways that enhance the sensitivity. Leora did her BA and MSc in Chemistry at the University of Pennsylvania.

Academic Appointments

Administrative Appointments

  • Gabilan Fellow, Stanford University (2021 - Present)
  • Terman Fellow, School of Engineering, Stanford (2021 - Present)
  • Courtesy Appointment, Mechanical Engineering, Stanford (2021 - Present)
  • Precourt Center Fellow, Precourt Center for Renewable Energy, Stanford (2021 - Present)
  • Term Appointment, Photon Science, SLAC (2021 - Present)

Honors & Awards

  • Young Investigator Research Program Award, Air Force Office of Scientific Research (2023-2026)

Contact

  • Academic
    leoradm@stanford.edu
    University - Faculty Department: Materials Science and Engineering Position: Asst Professor
    • 476 LOMITA MALL
    • STANFORD,  California  94305 

Additional Info

Links

Current Research and Scholarly Interests

The Dresselhaus-Marais research group develops new methods to update 19th-century manufacturing processes with modern approaches. Our approach focuses on a holistic view of metals fabrication, from the mining and extraction of ores into metals to a deep look at how specific microstructural features (e.g. dislocations and grain boundaries) during the forming and forging give rise to mechanical and thermal properties we can tune or print.

To get this deep view of modern processing, we develop and use new optical/X-ray and analytical tools to reveal how imperfections deep inside materials instigate the dynamics that transform them. Spanning length- and time-scales from bonds breaking at single atoms through long-duration dwell times in 100-m tall blast furnace reactors, these defect dynamics define complex high-dimensional problems that are difficult to reconcile at intermediate scales in order to predict or understand a material's behavior and chemistry. To address this challenge, we develop new types of time-resolved experiments aimed at the elusive "mesoscale" to directly visualize how large populations of subsurface defects drive them. With these new approaches, we tackle fundamental studies of how temperature drives materials, and applied problems.

Our applied work focuses on two important steps of the supply chain: metals extraction and metal forming. Most metals extraction processes have been perfected for centuries to millennia, but are done today at scales that make our effective processing strategies unsustainable. In cases like steel (8% of global CO2 emissions), this arises from coal-intensive steps that produce Gigatons of CO2 per year that contribute significantly to climate challenges. For metals like lithium and rare earth elements, our present mining and extraction strategies simply cannot reach a high enough throughput to sustain our current demand for the elements, making them Critical Materials. My group studies how an updated multiscale characterization and modeling approach can enable key opportunities to advance these fields.

2023-24 Courses

Stanford Advisees

All Publications

  • Precision Calcination Mechanism of CaCO<sub>3</sub> to High-Porosity Nanoscale CaO CO<sub>2</sub> Sorbent Revealed by Direct In Situ Observations ADVANCED MATERIALS INTERFACES Martinez, J., Wardini, J. L., Zheng, X., Moghimi, L., Rakowsky, J., Means, J., Guo, H., Kuzmenko, I., Ilavsky, J., Zhang, F., Dholabhai, P. P., Dresselhaus-Marais, L., Bowman, W. J. 2024

    View details for DOI 10.1002/admi.202300811

    View details for Web of Science ID 001197614400001

  • Static and shock compression studies of eutectic high-entropy alloy AlCoCrFeNi<sub>2.1</sub> to ultrahigh pressures JOURNAL OF APPLIED PHYSICS Katagiri, K., Irvine, S. J., Hari, A., Kodama, R., Ozaki, N., Sano, T., Ren, J., Yang, W., Chen, W., Clay, M. P., Pope, A. D., Iwan, S., Dresselhaus-Marais, L. E., Vohra, Y. K. 2024; 135 (9)

    View details for DOI 10.1063/5.0192103

    View details for Web of Science ID 001184182200003

  • Correlating chemistry and mass transport in sustainable iron production. Proceedings of the National Academy of Sciences of the United States of America Zheng, X., Paul, S., Moghimi, L., Wang, Y., Vilá, R. A., Zhang, F., Gao, X., Deng, J., Jiang, Y., Xiao, X., Wu, C., Greenburg, L. C., Yang, Y., Cui, Y., Vailionis, A., Kuzmenko, I., Llavsky, J., Yin, Y., Cui, Y., Dresselhaus-Marais, L. 2023; 120 (43): e2305097120

    Abstract

    Steelmaking contributes 8% to the total CO2 emissions globally, primarily due to coal-based iron ore reduction. Clean hydrogen-based ironmaking has variable performance because the dominant gas-solid reduction mechanism is set by the defects and pores inside the mm- to nm-sized oxide particles that change significantly as the reaction progresses. While these governing dynamics are essential to establish continuous flow of iron and its ores through reactors, the direct link between agglomeration and chemistry is still contested due to missing measurements. In this work, we directly measure the connection between chemistry and agglomeration in the smallest iron oxides relevant to magnetite ores. Using synthesized spherical 10-nm magnetite particles reacting in H2, we resolve the formation and consumption of wüstite (Fe1-xO)-the step most commonly attributed to whiskering. Using X-ray diffraction, we resolve crystallographic anisotropy in the rate of the initial reaction. Complementary imaging demonstrated how the particles self-assemble, subsequently react, and grow into elongated "whisker" structures. Our insights into how morphologically uniform iron oxide particles react and agglomerate in H2 reduction enable future size-dependent models to effectively describe the multiscale aspects of iron ore reduction.

    View details for DOI 10.1073/pnas.2305097120

    View details for PubMedID 37847734

  • Simultaneous bright- and dark-field X-ray microscopy at X-ray free electron lasers. Scientific reports Dresselhaus-Marais, L. E., Kozioziemski, B., Holstad, T. S., Ræder, T. M., Seaberg, M., Nam, D., Kim, S., Breckling, S., Choi, S., Chollet, M., Cook, P. K., Folsom, E., Galtier, E., Gonzalez, A., Gorkhover, T., Guillet, S., Haldrup, K., Howard, M., Katagiri, K., Kim, S., Kim, S., Kim, S., Kim, H., Knudsen, E. B., Kuschel, S., Lee, H. J., Lin, C., McWilliams, R. S., Nagler, B., Nielsen, M. M., Ozaki, N., Pal, D., Pablo Pedro, R., Saunders, A. M., Schoofs, F., Sekine, T., Simons, H., van Driel, T., Wang, B., Yang, W., Yildirim, C., Poulsen, H. F., Eggert, J. H. 2023; 13 (1): 17573

    Abstract

    The structures, strain fields, and defect distributions in solid materials underlie the mechanical and physical properties across numerous applications. Many modern microstructural microscopy tools characterize crystal grains, domains and defects required to map lattice distortions or deformation, but are limited to studies of the (near) surface. Generally speaking, such tools cannot probe the structural dynamics in a way that is representative of bulk behavior. Synchrotron X-ray diffraction based imaging has long mapped the deeply embedded structural elements, and with enhanced resolution, dark field X-ray microscopy (DFXM) can now map those features with the requisite nm-resolution. However, these techniques still suffer from the required integration times due to limitations from the source and optics. This work extends DFXM to X-ray free electron lasers, showing how the [Formula: see text] photons per pulse available at these sources offer structural characterization down to 100 fs resolution (orders of magnitude faster than current synchrotron images). We introduce the XFEL DFXM setup with simultaneous bright field microscopy to probe density changes within the same volume. This work presents a comprehensive guide to the multi-modal ultrafast high-resolution X-ray microscope that we constructed and tested at two XFELs, and shows initial data demonstrating two timing strategies to study associated reversible or irreversible lattice dynamics.

    View details for DOI 10.1038/s41598-023-35526-5

    View details for PubMedID 37845245

    View details for PubMedCentralID 8279502

  • Transonic dislocation propagation in diamond. Science (New York, N.Y.) Katagiri, K., Pikuz, T., Fang, L., Albertazzi, B., Egashira, S., Inubushi, Y., Kamimura, G., Kodama, R., Koenig, M., Kozioziemski, B., Masaoka, G., Miyanishi, K., Nakamura, H., Ota, M., Rigon, G., Sakawa, Y., Sano, T., Schoofs, F., Smith, Z. J., Sueda, K., Togashi, T., Vinci, T., Wang, Y., Yabashi, M., Yabuuchi, T., Dresselhaus-Marais, L. E., Ozaki, N. 2023; 382 (6666): 69-72

    Abstract

    The motion of line defects (dislocations) has been studied for more than 60 years, but the maximum speed at which they can move is unresolved. Recent models and atomistic simulations predict the existence of a limiting velocity of dislocation motion between the transonic and subsonic ranges at which the self-energy of dislocation diverges, though they do not deny the possibility of the transonic dislocations. We used femtosecond x-ray radiography to track ultrafast dislocation motion in shock-compressed single-crystal diamond. By visualizing stacking faults extending faster than the slowest sound wave speed of diamond, we show the evidence of partial dislocations at their leading edge moving transonically. Understanding the upper limit of dislocation mobility in crystals is essential to accurately model, predict, and control the mechanical properties of materials under extreme conditions.

    View details for DOI 10.1126/science.adh5563

    View details for PubMedID 37796999

  • Real-time imaging of acoustic waves in bulk materials with X-ray microscopy. Proceedings of the National Academy of Sciences of the United States of America Holstad, T. S., Dresselhaus-Marais, L. E., Ræder, T. M., Kozioziemski, B., Driel, T. v., Seaberg, M., Folsom, E., Eggert, J. H., Knudsen, E. B., Nielsen, M. M., Simons, H., Haldrup, K., Poulsen, H. F. 2023; 120 (39): e2307049120

    Abstract

    The dynamics of lattice vibrations govern many material processes, such as acoustic wave propagation, displacive phase transitions, and ballistic thermal transport. The maximum velocity of these processes and their effects is determined by the speed of sound, which therefore defines the temporal resolution (picoseconds) needed to resolve these phenomena on their characteristic length scales (nanometers). Here, we present an X-ray microscope capable of imaging acoustic waves with subpicosecond resolution within mm-sized crystals. We directly visualize the generation, propagation, branching, and energy dissipation of longitudinal and transverse acoustic waves in diamond, demonstrating how mechanical energy thermalizes from picosecond to microsecond timescales. Bulk characterization techniques capable of resolving this level of structural detail have previously been available on millisecond time scales-orders of magnitude too slow to capture these fundamental phenomena in solid-state physics and geoscience. As such, the reported results provide broad insights into the interaction of acoustic waves with the structure of materials, and the availability of ultrafast time-resolved dark-field X-ray microscopy opens a vista of new opportunities for 3D imaging of materials dynamics on their intrinsic submicrosecond time scales.

    View details for DOI 10.1073/pnas.2307049120

    View details for PubMedID 37725646

  • Dynamic optical spectroscopy and pyrometry of static targets under optical and x-ray laser heating at the European XFEL JOURNAL OF APPLIED PHYSICS Ball, O. B., Prescher, C., Appel, K., Baehtz, C., Baron, M. A., Briggs, R., Cerantola, V., Chantel, J., Chariton, S., Coleman, A. L., Cynn, H., Damker, H., Dattelbaum, D., Dresselhaus-Marais, L. E., Eggert, J. H., Ehm, L., Evans, W. J., Fiquet, G., Frost, M., Glazyrin, K., Goncharov, A. F., Husband, R. J., Hwang, H., Jaisle, N., Jenei, Z. S., Kim, J. Y., Lee, Y., Liermann, H. P., Mainberger, J., Makita, M., Marquardt, H., McBride, E. E., McHardy, J. D., McMahon, M. I., Merkel, S., Morard, G., O'Bannon III, E. F., Otzen, C., Pace, E. J., Pelka, A., Pepin, C. M., Pigott, J. S., Plueckthun, C., Prakapenka, V. B., Redmer, R., Speziale, S., Spiekermann, G., Strohm, C., Sturtevant, B. T., Talkovski, P., Wollenweber, L., Zastrau, U., McWilliams, R. S., Konopkova, Z., EuXFEL Community Proposal 2292 2023; 134 (5)

    View details for DOI 10.1063/5.0142196

    View details for Web of Science ID 001042073600001

  • Opinion 35+1 challenges in materials science being tackled by PIs under 35(ish) in 2023 MATTER Allen, M., Bediako, K., Bowman, W. J., Calabrese, M., Caretta, L., Cersonsky, R. K., Chen, W., Correa, S., Davidson, R., Dresselhaus-Marais, L., Eisler, C. N., Furst, A., Ge, T., Hook, A., Hsu, Y., Jia, C., Lu, J., Lunghi, A., Messina, M. S., Moreno-Hernandez, I. A., Nichols, E., Rao, R., Seifrid, M., Shulenberger, K., Simonov, A. N., Su, X., Swearer, D. F., Tang, E., Taylor, M. K., Tran, H., Trindade, G. F., Truby, R., Utzat, H., Yang, Y., Yee, D. W., Zhao, S., Cranford, S. 2023; 6 (8): 2480-2487

    View details for DOI 10.1016/j.matt.2023.06.046

    View details for Web of Science ID 001053707600001

  • Automatic Determination of the Weak-Beam Condition in Dark Field X-ray Microscopy INTEGRATING MATERIALS AND MANUFACTURING INNOVATION Huang, P., Coffee, R., Dresselhaus-Marais, L. 2023

    View details for DOI 10.1007/s40192-023-00295-6

    View details for Web of Science ID 000976604300001

  • Extensive 3D mapping of dislocation structures in bulk aluminum. Scientific reports Yildirim, C., Poulsen, H. F., Winther, G., Detlefs, C., Huang, P. H., Dresselhaus-Marais, L. E. 2023; 13 (1): 3834

    Abstract

    Thermomechanical processing such as annealing is one of the main methods to tailor the mechanical properties of materials, however, much is unknown about the reorganization of dislocation structures deep inside macroscopic crystals that give rise to those changes. Here, we demonstrate the self-organization of dislocation structures upon high-temperature annealing in a mm-sized single crystal of aluminum. We map a large embedded 3D volume ([Formula: see text] [Formula: see text]m[Formula: see text]) of dislocation structures using dark field X-ray microscopy (DFXM), a diffraction-based imaging technique. Over the wide field of view, DFXM's high angular resolution allows us to identify subgrains, separated by dislocation boundaries, which we identify and characterize down to the single-dislocation level using computer-vision methods. We demonstrate how even after long annealing times at high temperatures, the remaining low density of dislocations still pack into well-defined, straight dislocation boundaries (DBs) that lie on specific crystallographic planes. In contrast to conventional grain growth models, our results show that the dihedral angles at the triple junctions are not the predicted 120[Formula: see text], suggesting additional complexities in the boundary stabilization mechanisms. Mapping the local misorientation and lattice strain around these boundaries shows that the observed strain is shear, imparting an average misorientation around the DB of [Formula: see text] 0.003 to 0.006[Formula: see text].

    View details for DOI 10.1038/s41598-023-30767-w

    View details for PubMedID 36882517

  • Nanolamellar phase transition in an additively manufactured eutectic high-entropy alloy under high pressures AIP ADVANCES Pope, A. D., Iwan, S., Clay, M. P., Vohra, Y. K., Katagiri, K., Dresselhaus-Marais, L., Ren, J., Chen, W. 2023; 13 (3)

    View details for DOI 10.1063/5.0138668

    View details for Web of Science ID 000952386200005

  • Analytical methods for superresolution dislocation identification in dark-field X-ray microscopy JOURNAL OF MATERIALS SCIENCE Brennan, M. C., Howard, M., Marzouk, Y., Dresselhaus-Marais, L. E. 2022

    View details for DOI 10.1007/s10853-022-07465-5

    View details for Web of Science ID 000836694600010

  • An automated approach to the alignment of compound refractive lenses JOURNAL OF SYNCHROTRON RADIATION Breckling, S., Kozioziemski, B., Dresselhaus-Marais, L., Gonzalez, A., Williams, A., Simons, H., Chow, P., Howard, M. 2022; 29: 947-956

    Abstract

    Compound refractive lenses (CRLs) are established X-ray focusing optics, and are used to focus the beam or image the sample in many beamlines at X-ray facilities. While CRLs are quite established, the stack of single lens elements affords a very small numerical aperture because of the thick lens profile, making them far more difficult to align than classical optical lenses that obey the thin-lens approximation. This means that the alignment must be very precise and is highly sensitive to changes to the incident beam, often requiring regular readjustments. Some groups circumvent the full realignment procedure by using engineering controls (e.g. mounting optics) that sacrifice some of the beam's focusing precision, i.e. spot size, or resolution. While these choices minimize setup time, there are clear disadvantages. This work presents a new automated approach to align CRLs using a simple alignment apparatus that is easy to adapt and install at different types of X-ray experiments or facilities. This approach builds on recent CRL modeling efforts, using an approach based on the Stochastic Nelder-Mead (SNM) simplex method. This method is outlined and its efficacy is demonstrated with numerical simulation that is tested in real experiments conducted at the Advanced Photon Source to confirm its performance with a synchrotron beam. This work provides an opportunity to automate key instrumentation at X-ray facilities.

    View details for DOI 10.1107/S1600577522004039

    View details for Web of Science ID 000824201700003

    View details for PubMedID 35787560

    View details for PubMedCentralID PMC9255570

  • X-ray free-electron laser based dark-field X-ray microscopy: a simulation-based study JOURNAL OF APPLIED CRYSTALLOGRAPHY Holstad, T., Raeder, T., Carlsen, M., Knudsen, E., Dresselhaus-Marais, L., Haldrup, K., Simons, H., Nielsen, M., Poulsen, H. 2022; 55: 112-121

    View details for DOI 10.1107/S1600576721012760

    View details for Web of Science ID 000749998900012

  • In situ visualization of long-range defect interactions at the edge of melting. Science advances Dresselhaus-Marais, L. E., Winther, G., Howard, M., Gonzalez, A., Breckling, S. R., Yildirim, C., Cook, P. K., Kutsal, M., Simons, H., Detlefs, C., Eggert, J. H., Poulsen, H. F. 2021; 7 (29)

    Abstract

    Connecting a bulk material's microscopic defects to its macroscopic properties is an age-old problem in materials science. Long-range interactions between dislocations (line defects) are known to play a key role in how materials deform or melt, but we lack the tools to connect these dynamics to the macroscopic properties. We introduce time-resolved dark-field x-ray microscopy to directly visualize how dislocations move and interact over hundreds of micrometers deep inside bulk aluminum. With real-time movies, we reveal the thermally activated motion and interactions of dislocations that comprise a boundary and show how weakened binding forces destabilize the structure at 99% of the melting temperature. Connecting dynamics of the microstructure to its stability, we provide important opportunities to guide and validate multiscale models that are yet untested.

    View details for DOI 10.1126/sciadv.abe8311

    View details for PubMedID 34261647

https://orcid.org/0000-0002-0757-0159