In-situ study of thermo-kinetics in sintering

The evolution of materials at high temperature is governed by a combination of driving forces and transport mediating mechanisms which have direct relation to the microstructure of the material. The thermokinetic parameters underlying this evolution are relevant to processing, properties, and performance for any materials which see high temperature during their life cycle. The field of sintering has so far been built successfully on the basis of diffusion-rate-limited kinetic models, but there remain unanswered questions in the literature regarding observations such as rapid heating effects, electric field effects, shear stress effects, and the evolution of residual stresses in sintered compacts, among others. This work introduces a series of in-situ, laser-heated microscopy techniques which aim to measure the underlying thermokinetic parameters of sintering, including surface energy, surface diffusivity, and grain boundary diffusivity. During this work, the close in-situ observation provided insight into the mechanistic details of high temperature transport, including evidence for nucleation-rate-limited grain boundary transport kinetics--a mechanism which has thus far received relatively little consideration in sintering science. We test this mechanism and offer arguments for its relevance to many of the unanswered questions in sintering. We conclude with a basic sintering model which demonstrates the explanatory power of this mechanism.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Coffman, Devon Keith

Contributors dc:contributor

• Dillon, Shen
• Bellon, Pascal
• Krogstad, Jessica
• Perry, Nicola

• Sintering
• Microscopy
• Laser Heating
• High Temperature
• Thermodynamics
• Kinetics
• Thermokinetics
• Densification
• Coarsening
• Tem
• In-situ
• Cantilever
• Dislocation
• Nucleation
• Rate-limiting

Statement dc:rights

• Copyright 2024 Devon Keith Coffman

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/125558

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F125558