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Electric Field and Laser Assisted Manufacturing of Advanced Materials for Extreme Environments
Abstract
The field-assisted sintering/processing techniques involve additional factors such as pressure, electric, magnetic, and electromagnetic fields to increase the energy efficiency and improve the final properties of the processed parts. In this dissertation, one sintering technique assisted by electric-field called spark plasma sintering (SPS) has been applied to consolidate lunar soil simulant (FJS-1) for the first time. The densification behavior of FJS-1 and the significance of SPS parameters have been studied in a series of SPS conditions using the Taguchi method. The chemical/phase composition and microstructure were systematically analyzed by utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), and the focused ion beam (FIB) lift-out lamella for transmission electron microscopy (TEM). Besides SPS, direct selective laser sintering (d-SLS) is a well-known field-assisted sintering technique that exploits the electromagnetic field to enhance densification. In this dissertation, the laser has been applied to consolidate ZrC powder compacts to evaluate the feasibility of laser processing for UHTCs. The densification behavior and mechanical properties of the laser processed ZrC have been investigated. This dissertation also explored and discussed the effect of electric and electromagnetic fields on the microstructure evolution, phase transformation, and physical properties of the selected model materials, including FJS-1, ZrC, BaTiO3, and oxide-dispersion-strengthened CoCrFeMnNi high entropy alloy (ODS-HEA). The hardness and strength test results show that all model materials prepared by field-assisted sintering techniques perform improved mechanical properties, which further exhibited the benefits introduced by the applied fields. Besides, the as-processed specimens also exhibited some featured microstructures, including the stabilized nanostructure, modified grain boundary, and metastable/secondary phases, which might be the underlying mechanism of the enhanced mechanical properties.
Subject Area
Engineering|Materials science
Recommended Citation
Zhang, Xiang, "Electric Field and Laser Assisted Manufacturing of Advanced Materials for Extreme Environments" (2022). ETD collection for University of Nebraska-Lincoln. AAI29167175.
https://digitalcommons.unl.edu/dissertations/AAI29167175