DOI
https://doi.org/10.25772/T0AH-GH42
Author ORCID Identifier
0000-0001-5552-3771
Defense Date
2022
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Mechanical and Nuclear Engineering
First Advisor
Carlos E. Castano
Abstract
The modern advanced manufacturing of parts from alloys bases its development on sintering processes. By sintering, powder particles are consolidated in a densified structure of the desired material. Nowadays, the processes are performed in out equilibrium high-heating rate conditions leading to material anisotropies and other technological challenges. This dissertation boards the microstructure problem from the powder feedstock perspective. Each powder particle may configure itself as a unit block in a core-shell structure for alloy design with a smart response under these challenging manufacturing methods. The core-shell powder preparation was approached by physical vapor deposition by magnetron sputtering variants to succeed in the research commitment. The flexibility of the set of deposition choices allows the deposition of high-purity materials and unique stoichiometries that are not possible for other methods. Several bi-materials structures and process conditions are deeply discussed in this dissertation. Forty-three substrate to deposit systems were used to test the equipment performance during two hundred fifty-eight batches. The findings during those experiments included changes in the ionization ratio of sputtered material. Also, glass-aluminum, aluminum-cerium oxide, glass chromium nitride, iron-chromium nitride, and copper-chromium powder preparation conditions are discussed across the text. The latter system was used to design a copper-chromium powder to be sintered in conventional and high-heating rate conditions. The microstructure of the alloy prepared by this route was evaluated, finding that the core-shell structure pins the grain growth within its boundaries controlling the microstructure and approaching the structure to an ideal chromium distribution.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
8-1-2022
Included in
Manufacturing Commons, Metallurgy Commons, Other Materials Science and Engineering Commons