Advances in Powder and Ceramic Materials Science: Structure Design and Processing
Sponsored by: TMS Extraction and Processing Division, TMS Materials Processing and Manufacturing Division, TMS: Materials Characterization Committee, TMS: Powder Materials Committee
Program Organizers: Bowen Li, Michigan Technological University; Shefford Baker, Cornell; Kathy Lu, University of Alabama Birmingham; Faqin Dong, Southwest University of Science and Technology; Jinhong Li, China University of Geosciences; Eugene Olevsky, San Diego State University; Ruigang Wang, Michigan State University; Dipankar Ghosh, Old Dominion University
Tuesday 2:30 PM
March 1, 2022
Room: 213C
Location: Anaheim Convention Center
Session Chair: Dipankar Ghosh, Old Dominion University; Bowen Li, Michigan Tech
2:30 PM
Influence of Microstructure on Mechanical Properties in High Entropy Oxides: Justin Cortez1; Alexander Dupuy1; Hasti Vahidi1; Olivia Donaldson1; Tim Rupert1; William Bowman1; Julie Schoenung1; 1University of California Irvine
High Entropy Oxide (HEO) materials consist of five or more oxide components in equimolar amounts, which form a single-phase state after processing. These materials exhibit interesting functional properties and hold promise in electronic, optical, and thermal applications. However, little work has been done exploring the mechanical behavior of HEOs, the understanding of which is critical for implementation into practical applications. Here we investigate the role of microstructure on mechanical properties in (CoCuMgNiZn)O. Utilizing planetary ball milling and spark plasma sintering, we are able to produce fully dense single-phase HEO ceramics with grain sizes ranging from 70 nm to 1.4 µm. The mechanical properties of these samples were explored using various indentation methods. A clear Hall-Petch relationship was observed at larger grain sizes, which transitions to an inverse Hall-Petch relationship at nanocrystalline grain sizes. The deformation mechanisms contributing to the Hall-Petch and fracture toughness behavior will be discussed.
2:50 PM
A Novel Design Approach to Achieving High Strength and Ductility in Traditionally Brittle Nanoporous Silicon Nitride Membranes: Ali Shargh1; Gregory Madejski1; James McGrath1; Niaz Abdolrahim1; 1University of Rochester
Nanoporous silicon nitride membranes (NPN) are ceramic ultrathin films with nanoscale thickness and high porosity. It is well-established that mechanical properties including low strength and ductility of NPN place significant limits on applying them in life-saving filtration applications such as hemodialysis devices. We present a novel framework based on combined MD simulations and experiments to design the microstructure of NPN for improving their mechanical properties. Our MD results demonstrate that pore distribution is the only parameter among different parameters such as porosity and pore diameter that controls ductility of NPN while porosity and pore distribution are main factors affecting the strength in accordance with our companion experiments. We further develop a mathematical model from MD results for predicting the strength of the NPN with different microstructures. In addition, we suggest bottom-up design approach for controlling ductility of fabricated NPN via comparing their pore distribution with microstructures of NPN in simulations.
3:10 PM Invited
Low-temperature Pathways to Porous SiC Solids: Laura Quinn1; Taijung Kuo1; Katherine Faber1; 1California Institute of Technology
Solution-based freeze casting of preceramic polymers, such as polysiloxane or polycarbosilane, has been found to provide a powerful method to produce highly tailorable porous Si-based ceramics. The resulting ceramics from preceramic polymers are known to be amorphous to temperatures of 1000°C to 1800°C, and a devitrification step, which can be accomplished as part of the pyrolysis stage during freeze casting, still fails to induce complete crystallization. In this presentation, potential routes of conversion of preceramic polymers to crystalline SiC that can be embedded into freeze-casting processes will be described. As one illustration, our work seeks to translate chemistries used previously in additive manufacturing to freeze casting. In this procedure, a solution of polysiloxane and polymerization agents undergoes a UV-induced photopolymerization around frozen solvent crystals. This UV-induced photopolymerization allows the liquid polycarbosilane to retain the shape of the solvent crystals after the solvent has been sublimed.
3:30 PM
The Emergence of ZIA Phases: Matheus Araujo Tunes1; Rubens Ingraci Neto1; James Valdez1; Jon Baldwin1; Saryu Fensin1; Osman El-Atwani1; Stuart Maloy1; 1Los Alamos National Laboratory
Investigations on complex physico-metallurgical interactions between refractory elements has been attracting the attention of the materials' community on the challenge to synthesize alloys for applications in high-temperature and irradiation environments since the 1960s. This is the case of Ni-based superalloys and Nb-based refractory alloys which have a wide variety of applications in rockets, nuclear reactors and heat-exchanger components. Such interactions often impair the synthesis of pure terminal solid solutions with these elements due to the formation of complex (sometimes undesired) intermetallic phases. In this work, we focus on these intermetallics and we report the synthesis of the Zig-zag Intermetallics Advanced phases (simply ZIA phases) in the Nb--Ni--Si system. The ZIA phases will be shown to be a distinct class of refractory, highly-concentrated and nanolayered novel materials with a particular zig-zag structure at the atomic scale as opposed to new materials categories such as MAX phases and High-Entropy Alloys.
3:50 PM Break
4:05 PM
The Influence of Composition, Processing, and Microstructure on the Electrical Behavior of High Entropy Oxides: Arturo Meza1; Alexander Dupuy1; Julie Schoenung1; 1University of California Irvine
High entropy oxides (HEO), consist of five or more oxide components that form a random solid solution structure after processing. HEOs have garnered significant attention in the ceramic materials community due to their interesting functional properties and expanded compositional space. For example, (Cu,Co,Mg,Ni,Zn)O shows promise in applications related to energy storage such as batteries and solid oxide fuel cell components. In this work we explore the role of composition, stoichiometry, processing, and microstructure, including control of secondary phases, on the electrical behavior of bulk (Cu,Co,Mg,Ni,Zn)O. Samples were consolidated using conventional sintering of solid-state synthesized powders. Electron microscopy and energy dispersive X-ray spectroscopy (EDS) were used to characterize the microstructure, and electrochemical impedance spectroscopy (EIS) was used to evaluate the electrical behavior. Results show significant variability in behavior depending on material composition and process variables. Mechanisms governing these variations will be discussed.
4:25 PM
Phase Field Modeling of Silicon Carbide Microstructure Evolution: Elias Munoz1; Vahid Attari1; Marco Martinez1; Matthew Dickerson2; Miladin Radovic1; Raymundo Arroyave1; 1Texas A&M University; 2Air Force Research Lab
SiC/SiC ceramic matrix composites present an attractive option for cutting edge aerospace technology, but maximum operating conditions are plagued by existence of relatively low melting point of residual silicon. Residual silicon remaining in the microstructure of reactive melt infiltrated composites is a problem that hinders full potential of the technology. Eliminitation of residual Si is going to be analyzed by a comprehensive understanding of the evolution of microstructure through a phase field model which can be approximated as interface between a molten Si and solid graphite.