| Metallic foams possess a unique array of mechanical, thermal, and acoustic properties that have led to an increasing portfolio of potential applications. One of the newest additions includes solid-oxide fuel cells (SOFCs), where commercialization hinges on the development of improved materials and designs that can withstand the severe operational requirements of high temperature (up to 850 °C) and long service lifetimes (>10,000 hours). These demands place strict design limitations on the interconnect, which serves as a current path and fluid barrier between fuel and oxidant gases in the SOFC stack. Materials with excellent oxidation and creep resistance are sought. Chromia-forming Iron and Nickel-based alloy families have shown the most promise in preliminary studies. While a wealth of knowledge is available on these alloys as dense interconnects, limited research has also explored the option of porous metallic interconnects that offer the potential for cheaper, lightweight, and more mechanically robust stacks.;This thesis aims to provide a more thorough examination of porous metallic interconnect construction beginning with refinement of the place-holder replication techniques to create fully-interconnected, open porosity in a E-Brite (Fe-26Cr-1Mo, wt.%) and J5 (Ni-22.5Mo-12.5Cr-1Ti-0.5Mn-0.1Al-0.1Y, wt.%) alloy. Mechanical response of the E-Brite was examined at room temperature and found good agreement with existing, beam-based models for stiffness and yield strength. High temperature mechanical deformation was also recorded and a creep strengthening effect due to the formation of oxide was characterized. Electrochemical properties of porous E-Brite including the activation energy of oxide formation and area-specific resistance were also determined and found to be comparable to existing literature on bulk response. Finite element modeling (FEM) of the creep of unoxidized and oxidized E-Brite was also performed and successfully captured the qualitative behavior demonstrated in experiments.;Finally, sandwich structures with porous facings and a dense core were prepared by extending the powder metallurgy and melt infiltration processes, respectively. Flexural behavior of fabricated beams was characterized by three-point bend testing and demonstrated good repeatability. Existing analytical models for predicting beam stiffness and yield load were in rough agreement with experimental results. |
