Date of Award
Doctor of Philosophy (PhD)
Materials Science and Engineering
Rajendra K. Bordia
Kyle S. Brinkman
The heterogeneous structure is essential to obtain excellent performance in many ceramics or glass devices/components. Conventional fabrication on these heterogeneous structure composites usually requires multiple treatments, specific molds for certain structures, and post-processing to get desired structure and properties. Therefore, the flexibility of the structure is limited, and a long fabrication time is required.
Integrated additive/subtractive manufacturing and laser-based technologies have caught researchers` attention in ceramics/glass heterogeneous structure fabrication. This is because the integration of additive manufacturing (AM) with subtractive manufacturing (SM) not only maintained the advantages of AM in rapid prototyping, design complexity, and reduced material wastage but also improved the fabrication resolution, producing efficiency, and products’ fine finish. Besides, laser-based technologies have gained massive success by being combined into different AM or SM processing, including laser micromachining, laser surface polishing, and selective laser sintering/melting.
In recent years, a laser-selective integrated additive/subtractive manufacturing (L-IASM) system has been demonstrated, which has shown the capability in fabricating heterogeneous ceramics/glass components. However, the processing, microstructure, and corresponding property of the ceramics and glass fabrication via L-IASM still need studying. The knowledge of ceramics/glass composites and device fabrication via L-IASM is still lacking.
Based on these motivations, the ultra-fast, selective laser sintering of ceramics was first demonstrated in this work. The alumina, owning >95% relative density, was observed to be sintered within one minute, with significant grain-size suppression or enlarging. The microstructure and sintering master curve of laser sintering were shown to be different from that of conventional furnace sintering. Then, the processing-microstructure-properties (PMP) relationship of L-IASM was studied using high throughput sample fabrication and characterization and machine learning. High-throughput fabrications of alumina sample arrays and characterization of microstructure and hardness were demonstrated. The correlation between microstructure variation and laser power distribution was demonstrated. The correlation between microstructure and the hardness of laser-sintered alumina was studied. A deep learning algorithm successfully predicted highly realistic microstructure micrographs for different processing parameters or from target hardness. The effect of the network structure on the prediction was studied. Last, the fabrication of glass/ceramics devices and composites via L-IASM was demonstrated. Crack formation during L-IASM was studied according to the laser power and size effects. The bio-inspired bricks-and-mortar structure composite was fabricated via L-IASM. The corresponding mechanical properties were tested and discussed.
Geng, Xiao, "Processing, Microstructure, and Properties of Alumina Ceramics and Silica Glass During Laser Selective Additive/Subtractive Manufacturing" (2023). All Dissertations. 3419.
Author ORCID Identifier
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