Powder Materials Processing and Fundamental Understanding: On-Demand Oral Presentations
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; Hang Yu, Virginia Polytechnic Institute And State University; Ruigang Wang, Michigan State University; Isabella Van Rooyen, Pacific Northwest National Laboratory
Monday 8:00 AM
March 14, 2022
Room: Additive Technologies
Location: On-Demand Room
Microdroplet-based Manufacturing of Metal-organic Frameworks Powder Materials: Fundamentals and Applications: Weining Wang1; 1Virginia Commonwealth University
Metal-organic frameworks (MOFs) have attracted much attention in the past decades owing to their amazing properties, including rich surface chemistry, flexible porous structure, and superior surface area. MOFs are conventionally synthesized via wet-chemistry methods, which, however, suffer from long reaction durations and inhomogeneous mixing. To address these issues, we have developed a microdroplet-based nanomanufacturing process to fabricate MOFs-based powder materials with controlled nanostructures in a rapid, continuous, and scalable manner. The mechanisms of MOFs formation inside the microdroplets were investigated by experimental and theoretical approaches. Further, we have also developed strategies to integrate MOFs with semiconductors to form hybrid photocatalysts for environmental applications, such as gas adsorption, CO2 photoreduction, and pollutant degradation. The quantitative pathways of gas adsorption, activation, and charge transfer within the hybrid nanostructures were explored by various in-situ techniques, such as diffuse reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy, coupled with density functional theory calculations.
Particle Packing in Powder Spreading for Selective Laser Melted Additive Manufacturing Using the Discrete Element Method: Priscilla Ng1; Xuan Wang1; Thomas Mackin1; 1California Polytechnic State University San Luis Obispo
In this talk, a Discrete Element Method (DEM) model was created in Abaqus to simulate the spreading behavior for particles. Spreading behavior was investigated for three different build plate configurations: a flat build plate, a build plate with a small protruding feature, and a build plate with the same protruding feature split into quarters. For each configuration, the 2D packing behavior of the particles were analyzed during the powder spreading process. Different packing patterns seen in the 2D packing behavior were further analyzed to determine circular packing density, to draw parallels to unit cell packing, and to predict 3D packing behavior and packing density. Additionally, particle packing was evaluated on a 2D scale using image analysis to draw conclusions about powder spreading and interactions with obstacles on the build plate.
Rapid Solidification Behavior of Cast Ni-based Superalloy IN-100 by EBM Process: Yusaku Hasebe1; Takehito Hagisawa1; Satoru Ohsaki1; Kazuya Kubo1; Cheng Yang1; Kenta Aoyagi1; Kenta Yamanaka1; Akihiko Chiba1; 1The Japan Steel Works Ltd
Rapid solidification behavior of cast Ni-based superalloy IN-100 was investigated by using electron beam melting (EBM) process. Arcam A2X was used for the single bead experiments, and 30 single scans of electron beam with various beam power and speeds were scanned on the plate pre-heated to 1323K under 2×10-3 mbar of He atmosphere after evacuation. Melt pool depth and width were increased with increasing current and decreasing scan speed. Electron backscatter diffraction (EBSD) analysis revealed that epitaxial growth with the crystal orientation of the underlying substrates was observed when the melt pool is shallow. With increasing the melt pool depth, columnar grain nucleation got dominated with regardless crystal orientation of substrate. Computational fluid dynamics (CFD) simulation was performed considering the experimental results, then evaluated columnar-equiaxed transition of the alloy based on the theory of dendritic growth.
Investigating Particle Size-shape Effects on Flowability and Moisture Content of Metallic Powders after Environmental Exposure for Additive Manufacturing Applications: Jack Grubbs1; Brent Ditzler1; Aaron Birt2; Danielle Cote1; 1Worcester Polytechnic Institute; 2Solvus Global
Properly controlling powder properties, such as flowability and moisture content, is essential for successful processing in additive manufacturing (AM). During powder handling and storage, powder properties can change after exposure to the ambient temperature and humidity, necessitating a root-cause analysis of factors influencing powder properties to best understand their variation with environmental exposure. Particle size distribution (PSD), size, and morphology have all been shown to be critical factors affecting these properties. Therefore, it is the aim of this study to systematically evaluate particle size-shape effects on flowability and moisture content after exposure to controlled laboratory conditions. Particle size and PSD were varied through mechanical sieving, while morphology was manipulated by surveying powders atomized through different methods. This study will ideally inform AM powder users of how to best handle and store their specific size and shape powder to mitigate property degradation prior to AM processing.
Analysis of Additive Manufacturing Powders' Behaviors Using Discrete Element Method-based Simulation: Safwat Shenouda1; 1Lawrence Livermore National Laboratory
Utilizing simulations as a tool to investigate the physical behavior of additive manufacturing powders and their interparticular interactions will lead to process improvements in the manufacturing of critical components. Discrete Element Analysis is used to analyze discontinuous granular particles to be used in the manufacturing of pharmaceuticals, complex aerospace structures, and agricultural processes. Defects caused by vacancy voids during powder distribution processes may lead to manufactured parts with variable densities, reduced mechanical strength, and reduces the overall performance of critical components. Various contact models will be compared, and simulations will be used as a tool to demonstrate how cohesive forces affect the flowability and the distribution of powders in additive manufacturing processes.