Thermoelectric generators convert heat energy to electricity and can be used for waste heat recovery, enabling sustainable development. Selective Laser Melting (SLM) based additive manufacturing process is a scalable and flexible method that has shown promising results in manufacturing high ZT Bi2T e3 material and is possible to be extended to other material classes such as M g2Si. The physical phenomena of melting and solidification were investi- gated for SLM-based manufacturing of thermoelectric (M g2Si) powders through comprehen- sive numerical models developed in MATLAB. In this study, Computational Fluid Dynamics (CFD)-based techniques were employed to solve conservation equations, enabling a detailed understanding of thermofluid dynamics, including the temperature evolution and the con- vection currents of the liquid melt within the molten pool. This approach was critical for optimizing processing parameters in our investigation, which were also used for printing the M g2Si powders using SLM. Additionally, a phase field-based model was developed to sim- ulate the directional solidification of the M g2Si in MATLAB. Microstructural parameters like the Secondary and Primary Dendritic Arm Spacing were studied to correlate the effects of processing parameters to the microstructure of M g2Si. / Master of Science / Thermoelectric generators are devices that transform heat energy into electricity, offering a way to capture and utilize waste heat for sustainable purposes. A cutting-edge manufacturing method called Selective Laser Melting (SLM) has shown great potential in creating high-performance materials like Bi2T e3 for thermoelectric applications. Researchers are now exploring the extension of this technique to other materials, such as Mg2Si. This study delves into the intricate process of melting and solidifying Mg2Si powders using SLM. Advanced computer models were created in MATLAB, to simulate these processes in detail. By employing Computational Fluid Dynamics (CFD) techniques, heat and fluid flow within the molten material was also closely examined. These simulations were vital for fine-tuning the printing settings used to fabricate Mg2Si powders via SLM. Moreover, a specialized model based on phase field theory was developed to mimic the solidification of Mg2Si. The effects of changing manufacturing parameters on the microstructure of the final product were examined. Understanding these microstructural aspects is crucial for optimizing the manufacturing process and ultimately enhancing the performance of Mg2Si for thermoelectric applications.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/117843 |
| Date | 02 February 2024 |
| Creators | Suresh, Jagannath |
| Contributors | Mechanical Engineering, Zuo, Lei, Cheng, Jiangtao, Yu, Hang |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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