Research
Graduate Student: Sara Gorske
Fracture Mechanics of Brittle Materials Studied Using Synchrotron X-ray Radiation
Fracture is a critical mode of failure in brittle materials, particularly ceramics, which undergo little plastic deformation before cracking. While traditional fracture studies often rely on ex-situ analysis of fracture surfaces after failure, our group investigates how cracks form and propagate inside ceramics in real time. In collaboration with the Advanced Photon Source at Argonne National Laboratory, we use phase-contrast micro-computed tomography to visualize crack surfaces, high-energy diffraction microscopy to map microstructure and stresses, and the Rotational and Axial Motion System to load specimens in compression while rotating them for 3D analysis. By registering cracks to the surrounding microstructure, we aim to understand how inclusions, grain orientation, anisotropy, and local stress fields influence crack direction and growth rate. These synchrotron experiments are paired with mechanical testing, chemical analysis, and microscopy at Caltech. The resulting data help guide experimental design and support collaborations with phase-field modelers, improving predictive models of fracture in ceramics and other brittle materials.
Graduate Student: Zachary A. Chase
Microstructural Manipulation in 3D Printed Ceramics using Reaction Bonding and Eutectic Activation
Binder-free additive manufacturing of ceramics can produce complex shapes, but printed ceramic composites often retain isolated metal-rich pools, weak oxide connectivity, and persistent porosity after firing. Our group is developing reaction-bonding strategies that convert these heterogeneous printed preforms into more continuous ceramic frameworks. We treat laser-printed Al–Al₂O₃–YSZ composites with a room-temperature indium–gallium eutectic before firing in air. During reaction bonding, the eutectic disrupts the native alumina skin on aluminum, improves wetting at oxide contacts, and activates capillary pathways through the printed microstructure. This allows isolated aluminum pools to oxidize into a more connected Al₂O₃–YSZ framework, with the best response occurring within an intermediate eutectic dose window. By combining microscopy, thermogravimetry, electron-probe microanalysis, and X-ray diffraction, we show that the treatment modifies both microstructure and phase chemistry: gallium associates with alumina-rich regions, indium partitions into zirconia, and the zirconia phase assemblage shifts toward the cubic fluorite structure. This project establishes eutectic activation as a late-stage, alloy-free route for improving the uniformity of additively manufactured ceramic composites.
Graduate Student: Wesley Patel
Manipulating Fundamental Solidification Parameters to Design Tunable Porous Ceramic Materials for High Throughput Filtrations and Imaging of Microbial Dynamics
Freeze casting offers a tunable and scalable route to engineer porous materials with precise control over microstructure, motivating its use in applications requiring coupled transport, reactivity, and imaging functionality. With a focus on controlling solidification and reaction pathways with tunable transport and surface properties, freeze casting serves as a central platform to investigate how nucleation, growth, and coarsening govern pore architecture. Particularly, templated nucleation strategies are employed in systems exhibiting significant supercooling, and emphasis is placed on the interplay between diffusion and reaction kinetics, spanning crosslinking during structure formation to gas–solid reactions during pyrolysis of preceramic polymers in controlled atmospheres. These efforts enable precise tuning of porosity, permeability, and chemical functionality for applications in high-throughput filtration, catalysis, and microbial imaging. Complementary studies on functional surface coatings, including ITO and cryolite, introduce additional control over optical, physicochemical, and electrochemical properties for advanced filtration processes, catalysis, and imaging microbial dynamics. Collectively, this work establishes fundamental processing–structure–property relationships that position freeze casting as a versatile route for porous materials synthesis.
Graduate Student: Maia Hannahs
Processing Investigation of Historical Pb-Sn Pigment
Lead-Tin oxides have been found as an opacifier and pigment in glazes and glass ware from antiquity in a variety of stoichometry and with recipes and historical processes only occasionally recorded. This research focuses on the processing of two varieties of pigments known as Lead-Tin yellow each with distinct atomic structures, type I is described as a precursor of Type II in 15th century recipes, however the occurrence of type II predates these recipes by centuries. Recent finding of both types coexisting in one manuscript has launched investigations into the phase space surrounding the Lead Tin oxide systems with special attention to the vitrification behaviors, and common secondary elements such as antimony. This research seeks to investigate how this material may have been first established within certain historical glass and ceramics industries and then may have been adapted as a manuscript pigment. Modern understandings of solid state reactions, kinetics and crystallography can be applied to the complexity and uncertainty of historical systems in order to bring new understandings to the limitations of how these pigments may have been synthesized and used.