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Full-Text Articles in Engineering
Methods Of Extrusion On Demand For High Solids Loading Ceramic Paste In Freeform Extrusion Fabrication, Wenbin Li, Amir Ghazanfari, Ming-Chuan Leu, Robert G. Landers
Methods Of Extrusion On Demand For High Solids Loading Ceramic Paste In Freeform Extrusion Fabrication, Wenbin Li, Amir Ghazanfari, Ming-Chuan Leu, Robert G. Landers
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Fabrication of highly dense parts with complex geometry by paste-extrusion-based solid freeform fabrication processes requires a precise control of the extrusion flow rate to dispense material on demand, which is often referred as Extrusion-On-Demand (EOD). The extrusion process for aqueous ceramic pastes is complex and difficult to control due to their non-Newtonian behavior, compressibility and inhomogeneity. In this study, three methods of EOD (based on ram extruder, needle valve, and auger valve) are introduced and investigated for the extrusion of high solids loading (i.e., > 50%, volumetric) aqueous alumina paste. Optimal extrusion process parameters for these methods are determined through printing …
Control Of Fluid Dynamics By Nanoparticles In Laser Melting, Chao Ma, Lianyi Chen, Jiaquan Xu, Jingzhou Zhao, Xiaochun Li
Control Of Fluid Dynamics By Nanoparticles In Laser Melting, Chao Ma, Lianyi Chen, Jiaquan Xu, Jingzhou Zhao, Xiaochun Li
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Effective control of fluid dynamics is of remarkable scientific and practical significance. It is hypothesized that nanoparticles could offer a novel means to control fluid dynamics. In this study, laser melting was used to investigate the feasibility of tuning fluid dynamics by nanoparticles and possibly breaking existing limits of conventional laser processing techniques. Alumina nanoparticles reinforced nickel samples, fabricated through electrocodeposition, were used for laser melting experiments. Since the melt pool surface is controlled by the fluid dynamics, surface topographies were carefully studied to reveal the nanoparticle effect on the fluid dynamics. Characterizations of surface topographies and microstructures of pure …