COMPACT: A Customizable System for Characterization Of Materials Processing And Chemical Transformations
Abstract
We will construct a novel characterization system (COMPACT) by integrating non-destructive optical tools, such as Raman and Infrared (IR) spectroscopy to monitor in-situ the structural, phase, and chemical transformations in materials processed using externally applied fields. The modular nature of the proposed instrument will further enable plug and play addition of auxiliary systems for measuring surface temperatures and metrology, simultaneously with other (e.g., mechanical) test set-ups, to discover processing-structure-property relationships for structural materials produced using external fields. By serving as a fast, non-destructive, high-throughput screening technique for these far-from-equilibrium materials, COMPACT can complement advanced (e.g., synchrotron based) characterization methods, which are expensive, time consuming, and not widely available to the average user without significant investments in infrastructure development and training. While this proposal focuses on ceramics processing, COMPACT could be also used for in-situ monitoring during processing of polymer and hybrid or composite materials. Field-assisted processing can enhance the kinetics of powder synthesis, accelerate sintering processes, and drive phase transformations at significantly lower temperatures compared to conventional methods. However, several scientific questions remain about the low temperature, non-thermal effects hypothesized to produce far-from-equilibrium phase transitions and microstructural evolution in materials under external fields. Currently used ex-situ characterizations fail to provide details about the dynamics of these complex phenomena. Application of external fields further results in nanoscale materials and lattice disorder that cannot be easily distinguished using conventional x-ray diffraction. Raman spectroscopy can be a powerful tool for the characterization of such non-equilibrium materials, as Raman vibrational modes can quantify local atomic structure (defect types and concentrations), microstructural features like grain sizes and can relate interatomic bond distances and bond stress to macroscopic mechanical properties in structural materials. Complementary to Raman, IR spectroscopy can be used to monitor changes in local bonding environments that Raman is insensitive to, without suffering from interference (e.g., fluorescence) seen in Raman spectra of some materials. Accordingly, we will combine Raman and IR spectroscopy to characterize the effects of external fields in processing structural materials of interest to the DoD. One project focuses on quantifying localized temperature changes under the transient conditions and fast heating rates that exist under external electric fields to synthesize mixed amorphous-crystalline ceramics that combine mechanical strength and toughness. Another example is studying the unusual mechanical behavior (e.g., low temperature plasticity) seen in electric field (flash)-sintered ceramics to explain whether microstructural changes, like grain size reduction, and ductility in these ceramics follows the well-known Hall-Petch relation for metals. This proposal will additionally have a significant impact on educating both graduate and undergraduate students in (1) engineering design, assembly, and testing of the COMPACT instrument; and (2) using COMPACT to characterize how external fields can engineer highly resilient structural ceramics for Army relevant technologies including high strength, tough, light-weight, multifunctional protective armor, vehicles, and weapons. We also collaborate with DoD laboratories (ARL, AFRL) for fundamental studies on experimentally de-coupling thermal effects from specific effects caused by the field excitation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 13, 2019
- Source ID
- W911NF1910255
Entities
People
- B. Reeja‐Jayan
Organizations
- Army Contracting Command
- Massachusetts Institute of Technology
- United States Army