| Abstract: | Powder-bed additive manufacturing (PBAM) processes, including powder bed fusion and binder jetting, fabricate parts in a powder bed by employing a laser or electron beam or liquid binders. With the capability of processing a wide range of materials such as ceramics and metals, PBAM processes have potential applications in many industries, such as healthcare, aerospace, and energy. Parts that are ⁰́₋impossible⁰́₊ to manufacture with conventional manufacturing processes can be realized with PBAM. However, the current feedstock powders, which are mainly designed for conventional manufacturing, are not optimized for PBAM, and the understanding of fundamental physics in PBAM is still not sufficient. This dissertation presents one literature review and five studies focused on feedstock powders development, processing of advanced materials, and fundamental physics in PBAM. Specifically, a novel electroless plating method was developed to overcome the inhomogeneity issue associated with composite powder feedstock in PBAM. Advancements in the processing of two composite materials (i.e., Ni/Al²́²O²́³ and Cu/Diamond) and the effects of critical parameters were investigated with PBAM. In addition, an up-to-date literature review on binder jetting of metals provides a comprehensive summary of the printing quality (e.g., density, shrinkage, and mechanical properties) collected from both academia and industry for the first time. Lastly, the formation of powder bed was discussed via investigations of (1) the difference between green density and powder bed density and (2) the relationship between powder properties and powder bed density. The electronic version of this dissertation is accessible from https://hdl.handle.net/1969.1/197755 |
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