Modeling the selective laser melting-based additive manufacturing of thermoelectric powders

Abstract Thermoelectric generators directly convert thermal energy to electricity when exposed to the proper temperature difference. The efficiency of the thermoelectric module has not been fully explored due to the drawbacks in conventional design and fabrication methods. Selective laser melting (SLM) additive manufacturing offers a unique potential scalable approach for the fabrication of flexible and functionally graded thermoelectric materials with high energy conversion efficiency. In this paper, we developed a physical model to simulate the SLM manufacturing process of thermoelectric materials (Mg2Si powders) with additive material (Si) mixed for better thermoelectric performance. A comprehensive thermal and fluid study of the SLM manufacturing was conducted to understand the phenomena associated with the melting and solidification processes in the melting pool. This physical model was established based on the conservation equations and provided a basis to study the fluid flow driven by the buoyancy force and surface tension in the melting pool. Using this model, the influences of the process parameters, such as laser scanning speed and power energy density, on the temperature distribution, powder bed shrinkage, pool size, and particle aggregation in the powder bed, were studied, which provided critical information for understanding SLM for thermoelectric device fabrication.