Advances in Powder and Ceramic Materials Science: Advanced Ceramics and Processes
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 8:00 AM
March 1, 2022
Room: 213C
Location: Anaheim Convention Center
Session Chair: Eugene Olevsky, San Diego State University; Faqin Dong, Southwest University of Science and Technology
8:00 AM Invited
Tailored and Bioinspired Porous Ceramics from Extrinsically-controlled Freeze Casting: Steven Naleway1; Debora Lyn Porter1; Josh Fernquist1; Tony Yin1; Josh Alexander1; Max Mroz1; 1University of Utah
Freeze casting is a bioinspired technique for the fabrication of tailored, porous ceramic materials with structuring down to the nanoscale. Mimetic of the growth of mammalian bone and other biomaterials where biopolymers template the deposit of biominerals to create complex composites, freeze casting employs a template of growing ice crystals to create a complex porous microstructure in any ceramic. We propose that this bioinspired technique can be controlled through either intrinsic (those that modify from within by altering the constituents) or extrinsic (those that apply external forces or templates) means. Through these classifications, examples of extrinsic (through energized magnetic and ultrasound external fields) freeze cast, bioinspired structures will be discussed with a focus on providing advanced control of the final material structure and properties. Applications in biomedical and filtration technologies will be discussed.
8:20 AM
Atomistic Modeling of the Effect of External Electric Field on Diffusivity and Flash Sintering of 8YSZ: Wenwu Xu1; Md. Shahrier Hasan1; Eugene Olevsky1; 1San Diego State University
The atomistic structural modification and ionic diffusivity in 8YSZ at elevated temperature with an external electric field (E-field) were investigated by molecular dynamics (MD) simulations. As an example, a sufficiently large system of atomic configuration for a bi-crystal ∑5(310)/[001] grain boundary (GB) model was studied. MD results show that the E-field promotes the formation of Frenkel pair defects. Notably, some Zr ions diffuse out of GB regions at E-field≳500-1000V/cm, resulting in an “avalanche” of cation vacancies at GBs and reduced GB space charge. Consequently, the diffusivities of cations and anions are enhanced in the 8YSZ system with the presence of an E-field. The atomistic level understanding of E-field induced structural modifications, and ionic diffusivities provide an in-depth insight to unravel the flash sintering mechanisms of ionic ceramics, especially the coupled thermal-field effect during the flash sintering process.
8:40 AM
Consolidation of Cemented Tungsten Carbide with FeNiZr Binder via Tandem Field Assisted Sintering and Hot Isostatic Pressing: Sean Fudger1; Thomas Luckenbaugh1; B. Chad Hornbuckle1; Anit Giri1; Kris Darling1; 1DEVCOM - Army Research Laboratory
The use of cemented tungsten carbide (WC) spans numerous commercial applications. Due to the extreme hardness and high modulus, provided by the WC phase combined with added plasticity and resulting toughness contributed by the cobalt (Co) binder, cemented WC-Co is a good candidate for cutting tools, ammunition, and mining equipment. Co has been identified as a strategic and critical material from the Department of the Interior (DOI), and is "anticipated to be a human carcinogen" by the US Department of Health and Human Services (HHS). Nanostructured FeNiZr is being evaluated as a plausible binder replacement to Co which doesn't exhibit these concerns. Preliminary consolidations of WC-FeNiZr powders utilizing Field Assisted Sintering followed by Hot Isostatic Pressing have generated (near) fully dense samples with hardness and toughness values exceeding 16 GPa and 11 MPa-m^1/2 respectively. Electron Backscatter Diffraction and Transmission Electron Microscopy are used to explain the structure-property relationship.
9:00 AM
Effect of Copper Doping on the Thermal Stability of Mayenite Electride: Liam Fisher1; Kaka Ma1; 1Colorado State University
Electrides have promising applications for catalysis and electronics due to the presence of anionic electrons, defined as electrons that trapped in cavities and serve as the counter anions to positive charges in a crystalline lattice. The stability with respect to temperature, moisture, or oxygen, remains a bottleneck for electrides. Mayenite electride can be thermally stable up to 400 °C under ambient conditions. Cation-doped derivatives of mayenite electride emerged in recent years to improve its electron density, electrical conductivity, or catalytic activity. However, the effects of cationic doping on thermal stability of mayenite electride remained unknown. To provide an insight in this regard, Cu-doped mayenite electride was fabricated via spark plasma sintering in this work. Characterization of the structure, electrical conductivity, and oxidation behavior showed that Cu-doping improved the thermal stability of mayenite electride by increasing the oxidation onset temperature with reduced oxidation rates, as well as decreasing the lattice parameter.
9:20 AM
Rapid Synthesis of Zirconia-ceria Mixed Oxides by Flash Sintering: Rubens Ingraci1; Darrin Byler1; Kenneth McClellan1; Erofili Kardoulaki1; 1Los Alamos National Laboratory
Zirconia-ceria mixed oxides were synthesized by solid-state reaction during flash sintering in a few minutes at low furnace temperatures. A comprehensive study of the effects of flash sintering parameters such as electric field and electric current intensities, furnace temperature, and furnace atmosphere was carried out to optimize the phase purity of the resulting mixed oxide and the microstructure of the dense pellet produced. Oxidizing atmospheres were demonstrated to improve final phase purity, while reducing atmospheres hinder the reaction. It was also verified that although high electric current densities favor the ZrO2-CeO2 reaction, it could also cause cracks and inhomogeneous microstructure along the dense pellet. Further characterization, such as differential scanning calorimetry and electrical conductivity, improved the understanding of the effects of flash sintering on the material’s microstructure.
9:40 AM Break
9:55 AM
Multiscale Phase Homogeneity in Bulk (CoCuMgNiZn)O High Entropy Oxides: Alexander Dupuy1; Mohammed Reda Chellali2; Xin Wang1; Horst Hahn2; Julie Schoenung1; 1University of California, Irvine; 2Karlsruhe Institute of Technology
High entropy oxide (HEO) materials contain at least five oxide components, which form a single phase that is stabilized through entropy. However, HEO materials require a complex solid-state reaction process and often exhibit phase segregation and inhomogeneity after processing, which can lead to modifications in properties and stability. Here we explore the phase heterogeneity in (CoCuMgNiZn)O prepared using two different processing routes. Coarse-grain samples were prepared through reaction sintering of unreacted powders using conventional sintering, while fine-grain samples were prepared by sintering pre-synthesized nanopowders using spark plasma sintering. By leveraging these processing routes, we show that it is possible to produce single phase fully dense HEO ceramics with grain sizes spanning several orders of magnitude. Using X-ray diffraction, electron microscopy and atom probe tomography, we confirm that the samples are chemically homogenous across multiple length scales. Critically, no chemical segregation is observed regardless of processing method and grain size.
10:15 AM
Kinetic Investigations of Phase Formation Processes in the Ba(Ca,Sr)O-Al2O3-ZrO2 System: Nickolai Iliukha1; 1Kyiv University
ABSTRACT The kinetic investigations of phase formation processes in the mixture which contains BaO,CaO,SrO,Al2O3,ZrO2 were carried out. The degree of conversion and the activation energy were calculated, the dependence of the reaction rate and the rate constant on reaction temperature was determined. New high temperature ceramics composites materials based on this system is using for the monolithic composites refractory for high temperature channels and combustor of MHD generator. Keywords:ceramics,composites, kinetic investigation,high-temperature materials, reaction, temperature, process.
10:35 AM
Containerless Processing and Characterization of Potential Host Crystals for Photorefractive Devices: Elizabeth Hodges1; Michael Sansoucie2; Robert Hyers1; 1University of Massachusetts-Amherst; 2NASA
Photorefractive materials have a refractive index changed by exposure to light. Such devices allow control of light by light, enabling new kinds of photonic devices ranging from holographic storage to adaptive optics. Photorefractivity is characteristic of materials that are both photoconductive (light excites mobile charge carriers) and electro-optic (the index of refraction changes under an electric field). Two of the most promising host materials for these devices are Bismuth Sillenite (Bi12SiO20, BSO) and Bismuth Germanate (Bi12GeO20, BGO). It is theorized that the photorefractive properties are caused by a particular crystallographic defect, the Bi on Si antisite defect arising from the formation of metastable clusters in the molten material during the growth of the crystals. Containerless processing of these materials in Electrostatic Levitation (ESL) has allowed the characterization of surface tension, viscosity, density, and phase selection for these materials, for use in improving the quality of crystals that can be grown.
10:55 AM
Microstructures and Mechanical Properties of á-SiC Ceramics after High-temperature Laser Shock Peening: Fei Wang1; Xin Chen2; Daniel DeLellis3; Amanda Krause3; Yongfeng Lu4; Bai Cui4; 1University of Nebraska Lincoln; 2University of Nebraska-Lincoln; 3University of Florida; 4University of Nebraska–Lincoln,
A novel high-temperature laser shock peening (HT-LSP) process was applied to polycrystalline á-SiC to improve the mechanical performance. HT-LSP prevents microcrack formation on the surface while induces plastic deformation in the form of dislocation slip on the basal planes, which may be caused by the combination of high shock pressure and a lower critical resolve sheat stress at 1000 ℃. A maximum compressive residual stress of 650 MPa was introduced into the surface of á-SiC by HT-LSP, which can increase the in-plane fracture toughness of á-SiC by 36%. This work presents a fundamental base for the promising applications of HT-LSP to brittle ceramics to increase their plasticity and mechanical properties.