Seminar: Engineering Materials Away From Equilibrium: 3D Printing Ceramics and Beyond

Reeja Jayan, PhD, Carnegie Mellon University

All dates for this event occur in the past.

Scott Laboratory
Scott Laboratory
Room E525
201 W 19th Ave
Columbus, OH 43210
United States

Abstract

The speaker's lab has two main goals: (1) Understand mechanisms behind field-matter coupling when applying electromagnetic (EM) fields during the synthesis of materials such as ceramics. (2) Apply this understanding to devise novel, energy-efficient methods to manufacture these materials (like 3D printing of ceramics). The lab finds that EM fields significantly reduce the temperatures required to assemble atoms into specific crystal structures, but the underlying mechanisms of what the field actually does in experiments remains unknown. It is hypothesized that the field depending on frequency and polarization modifies energy barriers for chemical reactions.

Accordingly, this talk will describe the merge of exploratory experiments and computation with data-driven methods to define new thermodynamic foundations that better explain processes occurring away from equilibrium, like the behavior of groups of atoms under externally applied fields. One example demonstrates that the application of 2.45 GHz microwave radiation can
crystallize cubic zirconia (ZrO2) thin films via an oxygen defect-mediated route at temperatures as low as 225°C without additional dopants; compared to temperatures over 2000 °C required conventionally. Structural characterization via synchrotron x-ray pair distribution function (PDF) analysis and x-ray absorption spectroscopy reveal local structural distortions caused by microwave
exposure that are consistent with oxygen vacancy formation. First-principles-validated molecular dynamics and density functional theory calculations confirm that these defect induced distortions impact the relative phase stability in ZrO2 to favor cubic phase formation. These results are additionally demonstrated for other transition metal oxides and suggest that field-driven defect concentrations can mediate low temperature phase transitions and stability in ceramic oxides. This result points towards deploying EM fields as a new processing tool to access high temperature ceramic phases with minimal thermal input, and creates the opportunity to explore regions of phase space, microstructures and properties not accessible via conventional synthesis routes.

Applying EM fields can engineer a novel platform that additively manufactures or “3D prints” ceramics at low temperatures. Additionally, these low temperature methods allow for direct processing of hybrid, multifunctional ceramic-polymer material assemblies on flexible, lightweight substrates for technologies related to energy storage and sensing.

 

About the speaker

B. Reeja Jayan is an assistant professor in mechanical engineering at Carnegie Mellon University. She also holds courtesy appointments in the materials science and engineering, chemical engineering and electrical and computer engineering departments. Her multidisciplinary lab explores ways by which electromagnetic fields can synthesize materials hitherto unavailable to conventional synthesis routes. These low temperature processed materials
directly grow on flexible, lightweight substrates, enabling structurally integrated energy and sensing. Jayan is a strong believer in game-based learning methodologies that she uses extensively in her undergraduate and graduate engineering courses. She is a recipient of the 2018 National Science Foundation (NSF) CAREER Award, 2017 Army Research Office (ARO)
Young Investigator Award, 2016 Air Force Office of Scientific Research (AFOSR) Young Investigator Award, the Donald L. and Rhonda Struminger Faculty Fellowship, the Berkman Faculty Development Fund and Pittsburgh Magazine’s 40 Under 40 Award. Her research is also funded by the Department of Energy (DOE), Defense Advanced Research Project Agency (DARPA) and by private sponsors.

 

Hosted by Prof. Jung Hyun Kim.