Processing and Performance of Materials Using Microwaves, Electric and Magnetic Fields, Ultrasound, Lasers, and Mechanical Work – Rustum Roy Symposium: Session I
Sponsored by: ACerS Basic Science Division, ACerS Manufacturing Division
Program Organizers: Morsi Mahmoud, King Fahd University Of Petroleum And Minerals; Dinesh Agrawal, Pennsylvania State University; Guido Link, Karlsruhe Institute of Technology; Motoyasu Sato, Chubu University; Rishi Raj, University of Colorado; Christina Wildfire, National Energy Technology Laboratory; Zhiwei Peng, Central South University
Monday 8:00 AM
October 10, 2022
Room: 402
Location: David L. Lawrence Convention Center
Session Chair: Rishi Raj, University of Colorado
8:00 AM
Consolidating Tungsten in 2s at a Furnace Temperature of 900 oC using Flash Sintering Approach: Emmanuel Bamidele1; Rishi Raj2; Syed Jalali2; 1University of Colorado, Boulder; 2University of Colorado Boulder
We show for the first time that metals powders can be consolidated by flash sintering, that is by applying electrical fields and currents, in this instance tungsten was sintered at a furnace temperature of 900 oC and specimen temperature of 1400 oC by applying an electrical current and increasing it at a rate of 7.14 A/mm^2 s-1. The method can be applied to other refractory metals. An engine for microflash additive manufacturing will also be presented.
8:20 AM
Spatially Tuned Properties of Soft Magnetic Alloys by Transverse Induction Annealing: Tyler Paplham1; Ahmed Talaat1; David Greve2; Paul Ohodnicki1; 1University of Pittsburgh; 2DWGreve Consulting, Carnegie Mellon University
Traditional induction heating setups wherein the workpiece is located inside the coil are known to produce homogeneous heating across the workpiece surface. However, by locating the workpiece outside the end of the coil, heating is highly inhomogeneous, with steady-state temperature differences greater than 300 °C predicted across the centimeter scale. This allows for the possibility of a continuously varied microstructure, and by careful choice of coil geometry, current, and frequency, controlled tuning of the magnetic/mechanical properties. This is particularly attractive in bulk crystalline soft magnetic alloys for motor applications, but may also be of interest for amorphous/nanocrystalline soft magnetic ribbon. Work presented will demonstrate ability to produce tuned microstructures across small length scales in both bulk and nanocrystalline alloys, develop an analytical model for transverse induction annealing corroborated by FEA simulation, and discuss potential challenges of this technique.
8:40 AM Invited
In-situ Diffraction of Ultrasonically-modified Phase Evolution in a Ternary Al-Si-Mg Alloy: Katherine Rader1; Jonova Thomas2; Chihpin Chuang2; Dileep Singh2; Adrian Sabau3; Aashish Rohatgi1; 1Pacific Northwest National Laboratory; 2Argonne National Laboratory; 3Oak Ridge National Laboratory
Ultrasonic melt processing (USMP) can refine the as-cast microstructure of aluminum alloys by changing the grain morphology from coarse dendritic grains to finer, non-dendritic grains. Recently published investigations utilized in-situ X-ray imaging techniques to provide fundamental evidence of the mechanisms controlling ultrasonically-induced microstructural refinement. This study expands on these previous studies by conducting in-situ experiments using time-resolved X-ray diffraction. Experiments were conducted at the Advanced Photon Source on beamline 1-ID using the high-speed detector system, which is capable of recording X-ray diffraction scans at rates of up to 250 Hz. Ultrasound was applied at a 20 kHz frequency to a molten ternary Al-Si-Mg alloy as it solidified. Phase nucleation and growth during solidification, both with and without the presence of ultrasonic excitation, were characterized. These data test various hypotheses regarding the mechanisms that govern ultrasonication-induced microstructural refinement, such as enhanced nucleation and dendrite fracture, expanding the fundamental knowledge of USMP.
9:00 AM Invited
Post-processing of Additively Manufactured 316 Stainless Steel by Electron Wind Force: Daudi Waryoba1; James Kidd1; Zahabul Islam1; Aman Haque1; 1Pennsylvania State University
Application of the electron wind force as a driver for low temperature post processing of metals and alloys has been demonstrated in additively manufactured 316 stainless steel. This was achieved by passing dc current while actively cooling the specimen to maintain ambient surface temperature. Since EWF is proportional to the electric current density, it was observed that as the current density is gradually increased, there is a critical current density at which the EWF is sufficient to cause grain boundary and defect migration. At this “BURST” point, the microstructure instantly transforms to a refined equiaxed microstructure in a manner similar to thermally activated recrystallization. Prolonged biasing, on the other hand, results to grain growth as well as abnormal grain growth. Microstructural characterization by electron backscattered diffraction (EBSD) reveals interesting results on grain size, grain boundary structure, microtexture, and local orientation spread in the grains.
9:20 AM Invited
Carbon-Carbon Composite Materials from 3D Printed Preforms Graphitized by Electric Field Assisted Sintering: Arin Preston1; Jorgen Rufner1; Joshua Kane1; Troy Holland1; Robert Fox1; Blesson Isaac1; Lu Cai1; Kunal Mondal1; 1Idaho National Lab
Formation of Carbon-Carbon (C-C) composite materials requires putting a carbon fiber preform through a cycle of densification, carbonization, and graphitization. In traditional furnaces this is quite time consuming as typical heating rates are low. C-C composites were formed by pyrolyzation of 3D-printed carbon fiber preforms, vacuum infiltration of naphthalene based mesophase pitch, and carbonization. The part was then graphitized in the Electric Field Assisted Sintering (EFAS) system. Graphitization of the composite matrix was achieved in less than an hour. A part density of over 1.6g/cc was achieved after two rounds of infiltration and a single graphitization. The process is significantly faster than traditional methods. SEM, XRD, and X-ray CT will be discussed to characterize the degree of graphitization, internal porosity, and evaluate the microstructure throughout the process. Mechanical testing of the part was performed showing the impact on fiber direction to strength of the final part.
9:40 AM Invited
The Coupled Effect of Temperature and Electric Field on Diffusion Welding of Alloy 617 via Electric Field Assisted Sintering: Xinchang Zhang1; Jorgen Rufner1; Michael McMurtrey1; Ryann Rupp1; 1Idaho National Laboratory
The application of stress, elevated-temperature, and electric field during electric field assisted sintering (EFAS) may offer unique benefits as a diffusion welding (DW) method. In comparison with conventional hot pressing (HP), this study investigated the effect of temperature and electric field during EFAS of Alloy 617 sheet material. DW of Alloy 617 was conducted using three different techniques: HP where only heat and pressure were applied, standard EFAS with electric current flowing partially through the die and sample, and flash EFAS with current flowing solely through the sample. Scanning electron microscopy reveals that different microstructures were generated for HP, standard EFAS and flash EFAS. Electric current plays a significant role in precipitation and grain boundary migration across the interface. Coupled with correct temperatures, the increase of current passing through the sample was found to improve grain boundary migration. The scale up of EFAS to industrially relevant size is also investigated.
10:00 AM Break
10:20 AM
Microwave Sintering of Bioinspired Porous Alumina Foams: Andre Cardoso1; Claudia Perdomo1; Julia Xaraba1; Rodolfo Gunnewiek1; 1UFSCar
Ceramic foams find applications in numerous technological fields, such as filters, catalytic supports, among others. To produce these ceramics, the most employed method known is the replica technique. This method consists of impregnating a ceramic slurry in a polymeric foam, followed by thermal treatment to densify the open-celled ceramic structure. In nature, it is possible to find complex and regular structures, like the Luffa sp. sponges, which present a good alternative to the synthetic sponges used in this method. In this work, we evaluated the microwave sinterability of open-celled alumina foams produced by the replica technique, sintered at 1550, 1600, and 1650 °C, with soaking times of 15, 30, 45, and 60 minutes. These samples were compared with conventionally sintered samples and evaluated regarding their macro and microstructural homogeneity, densification, mechanical resistance, and fluid permeability. Acknowledgements: FAPESP (Grant numbers 2019/25921-8 and 2017/13769-1) CAPES (Finance code 001) and CNPq (Grant 140180/2021-4).
10:40 AM
Graphene Infused High Conductivity Copper: Syed Jalali1; Rishi Raj1; 1University of Colorado Boulder
Graphene infused copper was prepared by the flash method. It is shown to have a conductivity that is significantly higher that the copper that it is made from. The high conductivity is attributed to the formation of a graphene network, which is also shown to prevent creep at 900 oC in uniaxial tension; indeed the primary creep is recovered upon unloading like a viscoelastic material.
11:00 AM
Using Organic Acids to Densify Ceramics: Julian Fanghanel1; Clive Randall1; 1Penn State
Cold sintering process (CSP) was used to fabricate dense monolithic samples of Mg2SiO4 (forsterite). This is a material of interest in microwave dielectric ceramics, particularly for ceramic based 5G antennas. Dense ceramics were achieved with relatively high densities (>90%) under mild temperature conditions (<200°C), using organic acids solutions as a transient solvent, and under pressure were obtained in 4 hours. A study of a simple series of commercially important organic acids with varying degrees of chelating power was used to assess densification and microstructural evolution. X-Ray Diffraction showed that the primary phase, Mg2SiO4 (forsterite), was maintained after CSP with minimal amounts of Magnesium oxide impurities. The microstructure of the material was characterized through SEM to determine the average grain size, make comparisons for the microstructure for various densities, and to demonstrate evidence of sintering via triple points, coarsening, and necking.
11:20 AM
Touch Free Flash Sintering of Ceramics: Syed Jalali1; Rishi Raj1; 1University of Colorado, Boulder
Plasmas instead of current carrying electrodes are shown of produce flash sintering in green specimens of yttria stabilized zirconia to full density with a uniform microstructure and a grain size of 150 nm.
11:40 AM
Mechanochemistry: From Scientific Mystery to Scalable Materials Preparation and Recycling Technique: Viktor Balema1; 1ProChem Inc.
The presentation addresses mechanochemical approach to solid-state synthesis technique that enables solvent-free preparation of a great variety of molecular, ionic and hybrid inorganic – organic materials. Current state of the art in the field of Mechanochemistry is briefly reviewed and possible mechanisms of mechanochemical transformations are summarized. Mechanochemical preparations of novel hybrid and complex materials such as 3D transition metal dichalcogenide heterostructures, high-entropy transition metal dichalcogenides (TMDCs) and rare earth-based metal organic frameworks (MOFs) are highlighted, and the recently discovered mechanochemical depolymerization of an addition polymer, polystyrene, to monomeric styrene at room temperature under ambient atmosphere is presented. Transformation of research materials into commercial products and scaling up laboratory protocols will be discussed using mechanochemical processes as an example.