Advances in Powder and Ceramic Materials Science: Advanced Ceramics and Processes
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Bowen Li, Michigan Technological University; Shefford Baker, Cornell; Huazhang Zhai, Beijing Institute of Technology; Sergio Monteiro, Instituto Militar de Engenharia; Rajiv Soman, Eurofins EAG Materials Science LLC; Faqin Dong, Southwest University of Science and Technology; Jinhong Li, China University of Geosciences; Ruigang Wang, Michigan State University

Monday 2:30 PM
February 24, 2020
Room: Theater A-6
Location: San Diego Convention Ctr

Session Chair: Shefford Baker, Cornell University; Hongjuan Sun, Southwest University of Science and Technology

2:30 PM Introductory Comments

2:35 PM  Cancelled
Design of Cell-Windows Structure Macroporous Ceramics Derived from Particle-stabilized Emulsions: Jinhong Li¹; ¹China University of Geosciences (Beijing)
    The foamed ceramics with high porosity presently exhibit disadvantages of low strength and inability of tailoring micron-sized open pore structure. The surface properties of inorganic particles are modified by addition of short-chain amphiphilic molecules, which make the formation of particle-stabilized emulsions due to balanced particle adsorption behavior at oil/water interfaces. Designing of cell structure and bubble orientation can be achieved by stacking droplets in three dimensions and adjusting rheological behavior of stabilized slurry. In addition, porous ceramics with hierarchical pore structures are developed by implanting microporous and mesoporous particles into three-dimensional network of ceramics matrix. The introduction of Templated Grain Growth or Reactive Templated Grain Growth method induces an in-situ toughening of ceramic foam. The formation of “window” is due to cell shrinkage during liquid sintering suffering from template rearrangements and grain coarsening. Mechanisms for controlling tunable window and for templated grain growth induced in-situ toughening are studied in detail.

2:55 PM
Effect of B₄C Addition on (Hf,Zr)B₂ Based Ultra High Temperature Ceramics : Shipra Bajpai; Sudhanshu Shekhar Singh¹; Kantesh Balani¹; ¹IIT kanpur
    Lower damage tolerance of (Hf,Zr)B₂ based refractory ceramics restrict them to be used for re-entry conditions. B₄C as sintering additive helps in improving the damage tolerance by enhancing the densification. Herein novel equimolar HfB₂/ZrB₂ composite with 6 vol% B₄C reinforcement are spark plasma sintered at 1850⁰C and 30 MPa pressure. Densification increases from 90% for HfB₂¬-ZrB₂ to 99% with B₄C addition. Due to B₄C addition, hardness and elastic modulus increases from 25 GPa to 38 GPa (+52%) and 465 GPa to 868 GPa (+87%), respectively. During sintering, compressive residual stresses get generated within the matrix due to CTE mismatch between HfB₂, ZrB₂ and, B₄C. These residual stresses along with densification and solid solution formation, deflects the crack, and thus increases fracture toughness (from 2.6 MPa.m^0.5 to 3.7 MPa.m^0.5) of the composite. Further, tribological damage is also assessed for (Hf,Zr)B₂ composites reinforced with B₄C.

3:15 PM
ICME-Based Design of Cermet Tool Material for Friction Stir Welding (FSW) of High-strength Materials: Amit Behera¹; Qiaofu Zhang¹; Greg Olson¹; Rajiv Mishra²; ¹QuesTek Innovations LLC; ²Univeristy of North Texas
    The economic and processing advantages of using FSW has been well established for welding of low melting point, Al and Mg alloys. However, tool material development has been the major limitation for the application of FSW/FSP on high-strength materials such as Ni-based alloys and high-strength steels over the past decade. The weld temperature for these materials can exceed 1000⁰C and thereby, a desirable tool material needs to be strong enough to sustain wear and deformation forces at elevated temperatures for long periods of time while being cost-effective for commercial use. QuesTek has applied its ICME-based processing-structure-property models to design novel cermet materials with different hard phases and high entropy alloys (HEA) as the binder phase. The designed alloys were manufactured via spark plasma sintering (SPS) of powder compacts. Experimental investigations on the processing, microstructure and mechanical properties of the composite material to showcase property improvements will be discussed.

3:35 PM
Structural and Dielectric Properties of InCr1−xTixO3+x/\2 (x = 2/6, 2/7, and 2/8): Victor Emmanuel Alvarez Montano¹; Raul Escamilla²; Francisco Brown¹; Subhash Sharma²; Noboru Kimizuka¹; Alejandro Durán²; ¹Universidad de Sonora; ²Universidad Nacional Autonoma de México
    In the present work, we synthetized a ceramic material, InCr1−xTixO3+x/2 (x = 2/6, 2/7, and 1/4) which structure belongs to a modulated group with Cr(III) in a coordination number (CN) 5, whose cation can also be substituted by Ti(IV). X-ray Powder Diffraction (XRD) was used to identify the formation of the monoclinic phase and the least squares method to obtain lattice parameters. The microstructure was characterized by Scanning Electron Microscopy (SEM) and the ratio weight/volume to know the apparent densification of the pellets with the applied sintering process. Dielectric behavior from room temperature up to 450 oC shows a relaxation process as the Ti(IV) is introduced in the solid solution. The combined presence of cations in different CN and valence state seems to be responsible for the high dielectric loses as Cr is replaced by Ti ions.

3:55 PM Break

4:10 PM
Microstructure-processing Relationships in Rare Earth Doped Alumina Ceramics for Lighting/laser Applications: Xingzhong Wu¹; Matthew Duarte¹; Yasuhiro Kodera¹; Elias Penilla¹; Javier Garay¹; ¹University of California San Diego
    Rare earth (RE) doped ceramics are important for solid-state lighting/lasing in medical and industrial applications. Alumina (Al2O3) as one of the most useful ceramics, has a variety of structural and optical applications due to its chemical, thermal stability and excellent mechanical properties. However, low equilibrium solubility of RE in alumina and its birefringent nature pose great challenge to making transparent RE:Al2O3 for photoluminescence (PL) applications. Here we present synthesis of Al2O3 powder doped with various REs through both mechanical mixing and co-precipitation, as well as fabrication of sub-micrometer grained RE:Al2O3 ceramics using current-activated, pressure-assisted densification (CAPAD). We discuss the effect of synthesis/processing on the microstructure (RE distribution, grain size) and optical properties (transmission, absorption and emission). These ceramics show high transparency and characteristic PL from RE3+, providing emission in the 1 – 2um range, suggesting the possibility of using co-precipitation synthesis/CAPAD to incorporate RE into Al2O3 ceramics for optical applications.

4:30 PM
Toughening Mechanism of ZTA-TiC-Fe Ceramic Materials Produced by High Gravity Combustion Synthesis: Hongwei Zhao¹; ¹China Iron and Steel Research Institute Group
    Through coupling of high gravity field and high temperature field of combustion synthesis, ZTA-TiC-Fe composite materials were prepared by high gravity combustion synthesis. The composite toughening of Al2O3-TiC ceramic materials was realized, including phase change toughening of tetragonal zirconia, zirconia fiber toughening and metal ductile phase toughening. The results showed that the fracture toughness of ZTA-TiC-Fe composite materials reached 9-11MPa·m1/2, which was 2-3 times higher than pure Al2O3-TiC commercial tool materials.