05/05/2026
By Danielle Fretwell

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a Doctoral Dissertation defense by Kyeongbin Min on: "High−Throughput Design and Analysis of Ultra−High−Temperature Ceramics Via Extrusion−Based Additive Manufacturing."

Candidate Name: Kyeongbin Min
Degree: Doctoral
Defense Date: Thursday, May 14, 2026
Time: 10 a.m. - noon
Location: Southwick 240

Committee:

  • Advisor: Christopher Hansen, PhD, Professor, Mechanical and Industrial Engineering, UMass Lowell
  • Amy Peterson, PhD/Professor, Plastics Engineering, UMass Lowell
  • Alireza Vakil Amirkhizi, PhD, Professor, Mechanical and Industrial Engineering, UMass Lowell
  • Lei Chen, PhD, Assistant Professor, Mechanical and Industrial Engineering, UMass Lowel

Abstract:
Ultra-high-temperature ceramics (UHTCs), including materials such as carbides, nitrides, and carbonitrides, are of significant interest for applications in extreme environments due to their high melting temperatures, excellent chemical stability, and superior mechanical properties. These materials are critical for technologies such as thermal protection systems, high-temperature structural components, and advanced energy systems. Despite their promising properties, the development of new UHTC materials remains challenging because their strong covalent bonding limits densification during conventional pressureless sintering, thereby requiring extensive experimental effort to explore the complex relationships between composition, processing conditions, and resulting material properties. Traditional materials development approaches can therefore be slow and resource-intensive. Additive manufacturing provides a promising pathway to accelerate materials development by enabling rapid fabrication of specimens with systematically varied compositions and processing parameters, thereby supporting high-throughput experimental studies of advanced ceramic systems.

The main objectives of this dissertation are: (1) to investigate the influence of the volume fraction of a single UHTC powder composition in an ink formulation on the grain structure and densification behavior of ceramic microstructures; (2) to investigate the influence of the ratio of multiple particle compositions in an ink formulation on the grain structure and densification behavior of UHTCs; and (3) to utilize machine-learning-based analysis to predict densification trends of UHTC compositions and experimentally evaluate their mechanical response through bending tests.

To address the first objective, extrusion-based additive manufacturing was used to fabricate SiC-based ceramic specimens with varying particle volume fractions and particle size distributions. The printed specimens were sintered at high temperatures, and their densification behavior was evaluated through measurements of relative density and shrinkage. Increasing the particle volume fraction from 42 to 48 vol% produced modest improvements in densification, while bimodal particle size distributions slightly enhanced particle packing.

The second part of this work expands the study to multi-material systems, with a particular focus on the SiC-B₄C-TaC composition space. Systematic experiments were performed across binary and ternary compositions to investigate how ceramic composition influences densification behavior. The results show that B₄C-containing systems generally exhibit improved densification compared with SiC-rich compositions, while compositions containing both B₄C and TaC achieved relative densities approaching 98% under identical sintering conditions. These findings highlight the strong influence of composition on densification behavior in UHTC systems.

To address the third objective, a data-driven model was developed to predict densification trends across the investigated composition space. The model was trained using the experimental dataset generated in this work and evaluated through additional experiments. The results indicate that the model captures the overall compositional trends in densification behavior across the ternary system. Flexural strength testing further confirmed that increased relative density corresponds to improved mechanical performance in additively manufactured ceramic components.

Overall, this work demonstrates that combining extrusion-based additive manufacturing with systematic experimentation and data-driven analysis provides an effective framework for accelerating the development of novel UHTC materials and enabling efficient exploration of complex composition spaces.