Powder Materials Processing and Fundamental Understanding: Control Macro and Microstructures II
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Powder Materials Committee
Program Organizers: Elisa Torresani, San Diego State University; Kathy Lu, University of Alabama Birmingham; Eugene Olevsky, San Diego State University; Ma Qian, Royal Melbourne Institute of Technology; Diletta Giuntini, Eindhoven University of Technology; Paul Prichard, Kennametal Inc.; Wenwu Xu, San Diego State University

Thursday 8:30 AM
March 23, 2023
Room: 25B
Location: SDCC

Session Chair: Claude Estournès, CIRIMAT/CNRS; Iver Anderson, Iowa State University Ames Laboratory; Charles Maniere, CRISMAT laboratory


8:30 AM  
Investigation of Gas Atomization Reaction Synthesis (GARS) Processing Parameters for Controlled Synthesis of Oxide Dispersion Strengthened (ODS) Ferritic Stainless Steels for Advanced Nuclear Reactor Applications: Jordan Tiarks1; Landon Hickman1; Emma Cockburn1; Ralph Napolitano2; Trevor Riedemann1; Nicolas Argibay1; Iver Anderson1; 1Ames National Laboratory; 2Iowa State University
    Development of materials capable of surviving extreme irradiation and thermal environments is critical to adoption of advanced nuclear reactors for producing safe, reliable C-free energy. Oxide dispersion strengthened (ODS) ferritic stainless steels show excellent promise for surviving these extreme conditions while maintaining oxidation and creep resistance under harsh conditions. Commercial adoption of ODS ferritic alloys has been limited due to the high costs of mechanical alloying (MA) for producing these alloys. Gas atomization reaction synthesis (GARS) production of ODS precursor powders with vacuum hot pressing and hot rolling is a simplified transformative approach for creating structural ODS alloy sheet/plate for nuclear reactors. This talk overviews new work at Ames Laboratory intended to produce ferritic ODS alloy sheet from GARS precursor powders with uniform control over alloying elements and oxide dispersoids after exchange reaction annealing to enable cost-effective production of ODS parts. Supported by US-DOE-NE program through Ames lab contract DE-AC02-07CH11358.

8:50 AM  
Additive Manufacturing of Powder Components Based on Subtractive Sintering Approach: Maricruz Carrillo1; Eugene Olevsky1; Charles Maniere1; Geuntak Lee1; 1San Diego State University
    Powder-based 3D printing is popular due to its ease of use and versatility. However, many powder-based methods utilize high power lasers which generate thermal shock conditions in ceramics. In this work, a novel approach of producing high density net-shaped prototypes using Subtractive Sintering (SS) and Solvent Jetting (SJ) is developed. Additive Manufacturing combined with Subtractive Sintering (AM-SS) is a five simple step process that produces reliable results. A zirconia dental crown with a density of 97% was fabricated. Advantages of this method include the ability to efficiently fabricate parts using any powder including nano-sized ceramics, the utilization of conventional furnace only to consolidate, and the elimination of the difficult debinding step. The conducted studies include a predictive finite element model for the evolution of the complex-shape powder assembly during the AM-SS process. The model is based on the continuum theory of sintering embedded in a finite element code.

9:10 AM  
Immobilization of Laccases on ZnO and CuO Nanoparticles and the Effect of Copper Ions on Their Stability and Catalytic Activity: F. Suarez1; Eesa Khan1; Rafael Vazquez-Duhalt2; Olivia Graeve1; 1University of California San Diego; 2Universidad Nacional Autónoma de México
    Laccases are enzymes capable of oxidizing a large variety of organic compounds, including textile dyes for water bioremediation applications. However, laccases show low stability under industrial conditions that decrease their applicability. Laccase immobilization is a good methodology that can be used to increase their stability and catalytic activity. In this study we immobilized Coriolopsis gallica laccases on copper oxide nanoparticles and zinc oxide nanoparticles by covalent attachment. The activity of the immobilized laccase on the nanoparticles was measured using UV-Vis spectroscopy. The results demonstrate a decrease in the catalytic activity of laccase on the ZnO nanoparticles, while exhibiting an increase on the CuO nanoparticles, as compared to the free laccase. Inductively coupled plasma mass spectrometry showed a direct relationship between the stability of laccase and the release of copper ions by the CuO nanoparticles. This study is important to understand the role of CuO nanoparticles in the stability of laccases.

9:30 AM  
Evolution of Microstructure and Defects in Laser Powder Bed Fused Alloys after Hot Isostatic Pressing: Penn Rawn1; Le Zhou1; 1Marquette University
    Hot isostatic press (HIP) has been proven effective in improving the density of laser powder bed fused (LPBF) metals that are subjected to internal defects. To further understand the defect closure kinetics, HIP was performed on as-built LPBF alloys with various initial defect morphology and fraction. In this study, representative LPBF alloys, including Ti6Al4V, AlSi10Mg and Cu were manufactured with different processing parameters. This resulted in keyhole pores and lack of fusion defects with distinct morphology and size distribution. The density of the as-built and HIP’ed alloys was determined by Archimedes' principle and image analysis of the cross-sections. The morphology and distribution of defects were quantitatively analyzed by optical microscopy and X-ray microtomography. The microstructure was characterized by scanning electron microscopy. The effectiveness of HIP in closing defects other than gas pores was discussed with respect to the HIP mechanisms, which has important implications on future optimization of HIP parameters.

9:50 AM  Invited
Toward the Flash Sintering of Complex Shapes, the Key Steps of Microwave Energy and 3D Printing: Charles Maniere1; Geuntak Lee2; Elisa Torresani2; Guillaume Riquet3; Sylvain Marinel3; Eugene A. Olevsky2; 1CRISMAT laboratory; 2San Diego State University; 3CRISMAT Laboratory
    Flash sintering is a sintering process presenting a very interesting prospect for rapid prototyping, shorten today ceramic production time and to prevent undesired phase reaction, grain growth, etc. Today, numerous studies shown the interesting possibilities of flash sintering by different approaches to sinter ceramics with interesting microstructures and properties. However, reaching the flash complex shaping challenge is a mandatory step for the industrialization of this particular sintering process. In this presentation, we will present the interest of the 3D printing / flash sintering coupling to reach later objective. We will present the establishment of flash microwave sintering that benefit a volumetric and contactless heating and the interesting possibilities of flash SPS.

10:20 AM Break

10:40 AM  Invited
Spark Plasma Sintering of Stabilized Zirconia: Strategies to Design Ceramics with Tailored Properties: Claude Estournes1; Andréas Flaureau2; Amaud Fregeac3; Mélanie Rousselle3; Thomas Herisson de Beauvoir1; Geoffoy Chevallier1; Alicia Weible1; Florence Ansart1; Guillaume Fradet4; Serge Selezneff4; Catherine Elissalde5; Fabrice Mauvy5; 1CIRIMAT, Université de Toulouse; 2CIRIMAT; 3CIRIMAT, Université de Toulouse, SAFRAN Aircraft Engines; 4SAFRAN Aircraft Engines; 5ICMCB, CNRS Université Bordeaux
     Ceramics exhibit interesting mechanical properties (hardness, stiffness, wear resistance...) but are penalized by their low toughness (KIc). However, zirconia based ceramics (ZrO2) described as "ceramic steel" because, while retaining the usual properties of ceramics, exhibit exceptionally high toughness which paved the way for many applications. SPS allows to densify materials, at lower temperature and shortest time, leading to nanoscale microstructures that are hardly achieved by others methods. Few years ago, we have densified 200 nm grain size yttria stabilized zirconia (3Y-ZrO2) ceramics exhibiting excellent mechanical properties (f = 692 MPa and KIc = 10.3 MPa.m1/2). The presentation will be focused on: – A study of the sintering mechanisms (densification and grain growth) of two stabilized zirconia powders (3- and 8Y-ZrO2). – In- and ex-situ impedance spectroscopy measurements on 3- and 8Y-ZrO2, the results are discussed to assess any influence of the sintering parameters and/or specific effects of the SPS process on their electrical conductivity.– The effect of the nature, size and morphology of the grains of YSZ starting powders and SPS conditions on the microstructure of the ceramics obtained and how their mechanical properties are impacted.

11:10 AM  
Understanding Solidification and Alloying Effects in Oxide Dispersoid Strengthened Alloy Powders Produced by Gas Atomization Reaction Synthesis: Emma Cockburn1; Iver Anderson2; Nicolas Argibay2; Jordan Tiarks2; Trevor Reidemann2; Ralph Napolitano1; 1Iowa State University; 2Ames National Laboratory
    Mechanical alloying (MA) has been a focus in developing processing methods for oxide dispersion strengthened (ODS) alloys for ultrahigh temperature and/or high-flux radiation tolerant applications. MA is time-consuming and may introduce contamination and inhomogeneities. Gas atomization reaction synthesis (GARS) can produce cleaner powders for ODS alloy processing with Cr-enriched surface oxides and Y-containing intermetallics, creating oxide dispersoids during laser-powder bed fusion additive manufacturing and solid-state friction/stir consolidation by indirect extrusion fabrication. This work will investigate the ability to control/suppress intermetallics by adjusting the amount of alloying elements, including yttrium additions beyond the limits of MA, and oxygen available during the solidification reaction in the atomization process. Relating the solidification rate to particle size will demonstrate the influence the rate has on segregation and intermetallic phase formation, while also providing insight to the kinetics of solute redistribution. Funded by USDOE-ARPA-e program through Ames Lab contract no. DE-AC02-07CH11358.

11:30 AM  
Morphology Control of Doped Hafnium Carbide Powders: Shari Estrada1; Rafael Chavez1; Olivia Graeve1; 1University of California San Diego
    Hafnium carbide (HfC) is an ultra-high temperature refractory ceramic material that possesses high melting point (3886°C), high hardness (26 GPa), high density (12.8 g/cm3), and high elastic modulus (350-510 GPa). These characteristics are suitable for extreme environments. Previous studies have shown that the particle morphology of carbides can be controlled through the addition of transition metal dopants, which leads to tiled morphology of their sintered grains. Achieving this may enhance creep resistance of doped HfC due to mechanical interlocking of its grains. In this research, we implemented a solvothermal synthesis to fabricate a series of doped powders with the addition of Ni (Hf1-xNixC; x = 0.15, 0.20, 0.25, 0.30, 0.35) as a dopant. Resultant powders were characterized by X-ray diffraction and scanning electron microscopy to explore the effect the dopant has on the corresponding crystal structure and particle morphology.