Powder Materials for Energy Applications: Metal Powder Systems
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Powder Materials Committee
Program Organizers: Kathy Lu, University of Alabama Birmingham; Eugene Olevsky, San Diego State University; Somayeh Pasebani, Oregon State University; Hang Yu, Virginia Polytechnic Institute And State University

Wednesday 2:00 PM
February 26, 2020
Room: 17A
Location: San Diego Convention Ctr

Session Chair: Hang Yu, Virginia Tech; Somayeh Pasebani, Oregon State University; Yousub Lee, Oak Ridge National Laboratory


2:00 PM  Invited
Flash Sintering: From Fundamental Science to Energy-saving Materials Processing: Jian Luo1; 1University of California, San Diego
    This talk will first review our recent studies on the scientific questions and technological opportunities of flash sintering using ZnO as a model system [Scripta Mater. 146: 260 (2018)]. A thermal runaway model has been developed to forecast the onset flash temperatures [Acta Mater. 94:87 (2015)]. The rapid heating profiles enable the ultrafast densification rates [Acta Mater. 125:465 (2017)]. A two-step flash sintering (TSFS) technology was invented to densify ceramics with suppressed grain growth [Scripta Mater. 141:6 (2017)]. Using water-assisted flash sintering (WAFS), we can start a flash at room temperature to subsequently densify a ZnO specimen to ~98% densities in 30 s [Scripta Mater. 142:79 (2018)]. Flash spark plasmas sintering was used to sinter high-entropy ultrahigh temperature ceramics for potential applications in extreme environments [Scripta Mater. 170:106 (2018)]. Our most recent ongoing research in several related areas, including materials for energy applications, will also be presented and discussed.

2:30 PM  
Cold Spray Deposition of 304L Stainless-steel Powder on Used Fuel Dry Cask Storage Systems to Control Potential Stress Corrosion Cracking: Hwasung Yeom1; Kenneth Ross2; John Kessler3; Gary Cannell4; Jay Rozzi5; Frank Pfefferkorn1; Kumar Sridharan1; 1University of Wisconsin Madison; 2Pacific Northwest Research Laboratory; 3J Kessler and Associates; 4Fluor Corporation; 5Creare LLC
    Long-term safe storage of used fuel is an important aspect of nuclear energy systems. The results of an initial study include the development of cold spray process for the deposition of 304L stainless steel powder for field mitigation of potential chloride-induced stress corrosion cracking (CISCC) in used fuel dry cask storage canisters. As expected the welded regions of these austenitic stainless canisters may be more prone to CISCC due to the presence of tensile stresses and thermally-induced microstructures during fusion welding. This experimental study evaluated a feasibility of cold spray process for simulated microstructural and surface conditions that may exist in the weld regions of actual stainless-steel canisters. Thickness, microstructure, and phases in the cold spray deposits and substrate-deposit interfaces were characterized by scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. Adhesion strength between the stainless-steel deposit and the substrate were measured for various cold spray parameter was evaluated.

2:50 PM  
Effect of Particle Spreading Dynamics on Powder Bed Quality: Yousub Lee1; Kate Gurnon2; Srdjan Simunovic1; 1Oak Ridge National Laboratory; 2GE Global Research
    In powder bed additive manufacturing (AM), powder spreading process often leads to inhomogeneity in layer height, porosity level, and particle size distribution. Hence, the creating of homogeneous layers is the first task for optimal printing. The conventional assessment methods for powder bed quality are limited to a measurement of powder morphology, flowability, particle size distribution, surface roughness, and packing density. However, those techniques may not be the most appropriate to quantify the bed characteristics since it is not able to capture local particle configuration and does not provide any vectoral information (e.g., arrangement of contacts between particles during spreading). In this study, 1) discrete element method (DEM) model was developed for multiple-layer powder spreading process, 2) powder spreading dynamics including angle of repose (AOR) was measured using high-speed camera, 3) the effect of particle spreading dynamics on spatial powder bed structure and quality were investigated using scalar and tensorial methods.

3:10 PM  
Fabrication of Uniform-sized Hemispherical Mesopores on Gold-coated Silver Nanocubes for Enzyme Immobilization: Seongcheol Choi1; Olivia Graeve1; 1University of California, San Diego
    We demonstrate a procedure to fabricate gold-coated silver nanocubes containing hemispherical mesopores for applications as a catalytic substrate for enzyme immobilization. First, polyvinylpyrrolidone-covered silver nanocubes (45 nm) and uniform-sized silica nanoparticles (6 nm) were fabricated. The silica nanoparticles were deposited onto the polyvinylpyrrolidone-covered silver nanocubes by using physical adsorption. An ultra-thin gold layer was then grown on the surface of the silver nanocubes and the attached silica nanoparticles were etched off the particles using an alkali hydroxide solution at high temperature. Characterization of the materials was completed using scanning electron microscopy and X-ray diffraction. The mono-sized mesopores in the gold layer are designed to serve as sites to physically confine the enzyme, chloroperoxidase, to maximize their life span and enzymatic activity for desulfurization. This nano-architectured enzymatic catalyst is expected to increase the energy efficiency of the desulfurization of petroleum refining processes.

3:30 PM  
Influence of Powder Microstructure on Cold Spray Deposited Cr Coatings for High Temperature Oxidation Resistance: Tyler Dabney1; Hwasung Yeom1; Greg Johnson1; Ben Maier1; Mia Lenling1; Kumar Sridharan1; 1University of Wisconsin Madison
    The cold spray deposition process is being developed to deposit oxidation resistant coatings onto Zr-alloy fuel cladding to improve accident tolerance under high temperature accident scenarios. By virtue of the solid-state cold spray process, microstructure and morphology of the feedstock powder are important factors that determine deposition efficiency and the properties of the subsequent coating. Optimization of the powder is necessary to ensure high deposition efficiency and a dense coating. In this work, cold spray was used to deposit Cr coatings onto Zr-alloy substrates using a variety of commercially available Cr powders produced by different methods. Each powder was characterized using nanoindentation, X-ray diffraction, scanning and transmission electron microscopy techniques. The correlation between powder microstructure and subsequent coating microstructure and deposition efficiency is proposed qualitatively. Finally, results from high temperature air oxidation exposure of the coatings will be presented.

3:50 PM Break

4:10 PM  Invited
Toward New Flash and Energy Efficient Fabrication Processes based on Sintering: Charles Maniere1; Geuntak Lee2; Elisa Torresani2; Sylvain Marinel1; Lise Durand3; Claude Estournès4; Eugene A. Olevsky2; 1CRISMAT Laboratory; 2Powder Technology Laboratory; 3CEMES; 4CIRIMAT
    With the rise of additive manufacturing and 3D printing, the sintering of powder-based materials appears to be a very important process for tomorrow advanced manufacturing. In parallel, flash sintering and energy efficient processes have emerged and represent an interesting opening for an ultra-fast manufacturing with a significant energy saving. The flash and energy efficient approaches will be presented with a focus on the spark plasma sintering (SPS). In particular, the essential problem of complex shapes manufacturing using this technology will be highlighted. The Multiphysics simulation tool will be introduced to support the investigation of these advanced sintering based technologies. The productivity and energy efficiency of flash and energy efficient approaches will be compared to conventional approaches via the simulation tool.

4:40 PM  
Investigation of the Powder Processing of Near-final Shape AlNiCo Magnets for Eventual Use in Electric Drive Motors: Emily Rinko1; Iver Anderson2; Emma White2; Wei Tang2; Lin Zhou2; Matthew Kramer2; 1Iowa State University; 2Ames Laboratory
    Although rare earth elements (REE) are highly localized and vulnerable to price instability, REE-based permanent magnets (PM) are frequently the magnet of choice for interior PM motors found in many electric vehicles. Alnico, a REE-free alternative that can operate at higher temperatures compared to REE-PMs, can be fabricated via advanced powder processing techniques to yield textured, large grained, near-final shape alnico PMs. However, recent findings indicate established processing could be improved for unique alnico alloys (designed to improve magnetic properties) due to significant deviations observed from theoretical grain growth kinetics and grain rotation during sintering and solid state grain alignment (SSGA) respectively. This study offers a careful evaluation of the processing of alnico PMs and methods to improve processing. These methods will be discussed along with their impacts on sintering, SSGA, and magnetic properties. Work supported by USDOE-OTT-TCF program with funds from EERE-VTO through Ames Lab contract no. DE-AC02-07CH11358.