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At least 1,027 records · Page 57

Additive Manufacture of Plasma Diagnostic Components Final Report Phase II

There is now a well-established set of plasma diagnostics (see e.g. [3]), but these remain some of the most expensive assemblies in fusion systems since for every system they have to be custom built, and time for diagnostic development can pace the project. Additive manufacturing (AM) has the potential to decrease production cost and significantly lower design time of fusion diagnostic subsystems, which would realize significant cost reduction for standard diagnostics. In some cases, these basic components can be additively manufactured for less than 1/100th costs of conventional manufacturing.In our DOE Phase II SBIR, we examined the impact that AM can have on plasma diagnostic cost by taking 15 separate diagnostics through an engineering design using Conventional Manufacturing (CM) techniques, then optimizing the design to exploit the benefits of AM. The impact of AM techniques on cost is found to be in several areas. First, the cost of materials falls because AM parts can be manufactured with little to no waste, and engineered to use less material than CM. Next, the cost of fabrication falls for AM parts relative to CM since the fabrication time can be computed exactly, and often no post-processing is required for the part to be functional. We find that AM techniques are well suited for plasma diagnostics since typical diagnostic complexity comes at no additional cost. Cooling channels, for example, can be builtin to plasma-facing components at no extra cost. Fabrication costs associated with assembly are lower for AM parts because many components can be combined and printed as monoliths, thereby mitigating the need for alignment or calibration. Finally, the cost of engineering is impacted by exploiting AM design tools that allow standard components to be customized through web-interfaces. Furthermore, we find that concept design costs can be impacted by scripting interfaces for online engineering design tools.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Additive Manufacturing for Highly Efficient Window Inserts

ORNL partnered with the Mackinac Technology Company to demonstrate how additive manufacturing can be used to create highly energy efficient window inserts for retrofit in pre-existing buildings. Many early iterations of the window inserts were fabricated using carbon fiber reinforced thermoplastics and polycarbonate films as a stand in for the low-e coated films produced by the Mackinac Technology Company. After demonstration of the proof of concept, i.e. custom window inserts with tensioned film, the materials used for the manufacture of the frames was more closely examined. Hollow particle-filled syntactic foam and low-density polymer composites formed by expandable microspheres were explored as the materials used to additively manufacture the frames of the inserts. It was concluded that low-cost retrofit window inserts in custom sizes could be easily fabricated using large scale additive manufacturing. Furthermore, the syntactic and expanded foams developed and tested satisfy the mechanical performance requirements for the application.

36 MATERIALS SCIENCE↗

BAAM Additive Manufacturing of Magnetically Levitated Wind Turbine

ORNL worked with Hover Energy LLC (Hover) on the design of Big Area Additive Manufacturing (BAAM) extrusion components. The objective of this technical collaboration was to identify and evaluate fabrication of components using alternative additive manufacturing techniques. Multiple candidate parts were identified. A design modification to fabricate diverters using additive manufacturing (AM) was performed and the part was analyzed based on anticipated wind loading. Scaled versions of two parts were printed using the BAAM for wind tunnel testing.

17 WIND ENERGY↗

Large Scale Metal Additive Manufacturing with Wolf Robotics

Large Scale Metal Additive Manufacturing (LSMAM) is a new additive manufacturing (AM) technology based on the metal arc welding. A continuously fed metal wire is melted by an electric arc that forms between the wire and the substrate, and deposited in the form of a bead of molten metal along the predetermined path. Objects are manufactured one layer at a time starting from the base plate. The final properties of the manufactured object are dependent on its geometry and the metal deposition path, in addition to depending on the basic welding process parameters. The focus of the first phase of this two phase program was the installation, initial operation and development of processing parameters to demonstrate the ability to manufacture metal large scale parts. If successful, the second phase will focus on the development, and validation, of process models for the system.

42 ENGINEERING↗

CHARACTERIZATION OF DIRECT ADDITIVE MANUFACTURED U3Si2 SURROGATE TO PREDICT U3Si2 MICROSTRUCTURES

The purpose of this research is to perform characterization exclusively on U3Si2 surrogate materials to predict the process envelope for future work with uranium compounds, considering potential microstructural properties. The surrogate material will be synthesized using a laser energy source. This characterization work will provide new property data to aid the concept development stages of fabricating U3Si2 by means of a novel INL-designed direct additive manufacturing methodology. This process not only seeks to potentially reduce production costs, but also to shorten the current silicide fuel fabrication process. U3Si2 has been downselected as a candidate for accident-tolerant fuel for commercial light-water reactors due to its improved thermal conductivity, higher atomic density, and fuel cycle economics when compared with UO2. The research efforts on this work are performed at Idaho National Laboratory (INL) in partnership with Westinghouse Electric. The initial stage of the surrogate research will include a thermodynamic study along with physical and mechanical property analyses to assist in the downselection of surrogate materials for initial experimentation. Initial characterization analyzed the microstructural effects to determine effectiveness of laser interaction on the surrogate materials. Additional characterization via scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD) may predict the end product morphology when working with uranium compounds. Complementary comparative studies were performed on the surrogate end products analyzing similarities in microstructural features present on the U3Si2 fuel fabricated by means of alternate methods. This stage provided novel microstructural data on surrogate silicide fuel fabrication by means of an additive manufacturing process (laser synthesis), and was crucial to confirm the formation of surrogate silicide fuels (Hf3Si2 and Zr3Si2) employing a laser synthesis.

42 ENGINEERING↗

Explore the Techno-Economic Viability of Using Large-Scale Additive Manufacturing (AM) For High-Performance Windows

Use of 3D printing, or additive manufacturing (AM) technology, in window design and construction is an under-explored area of research. Given the rapid advancements in AM technology and the potential for AM to address significant challenges associated with window design and manufacturing, there was a need to explore the feasibility of using AM technology. Alcoa’s Kawneer (Alcoa Building and Construction Systems) partnered with Oak Ridge National Laboratory’s (ORNL) Manufacturing Demonstration Facility (MDF) to explore the technical and commercial viability of large-scale 3D printing technologies with Kawneer’s AM window design. The project combined Alcoa/Kawneer’s design and expertise with ORNL’s equipment capability to create and study the world’s first 3D printed window using Big Area Additive Manufacturing (BAAM) technology. The results show that AM is useful for creating custom window shapes and sizes. With AM, more efficient windows can be made by sealing the glass pane into the printed frame during the printing process. In addition to energy savings, the use of AM reduces the manual labor required to produce custom windows.

36 MATERIALS SCIENCE↗

Additive Manufacturing of Sensors and Components for Non-Destructive Evaluation Applications

Additively manufactured machine components were designed for use in non-destructive evaluations. Additive manufacturing (3D printing) enables rapid production of simple or complex objects at a low cost for use in many fields of research and industry. 3D printed components were used to optimize an eddy current array probe to inspect various complex shaped objects, such as gears. Preliminary eddy current inspections were conducted to test the functionality and compatibility of the 3D printed components to the array probe and existing system. These were done by wrapping replica 3D printed gears with aluminum foil. The results were as expected, rough, uneven surface of the aluminum foil. Calibration scans were also executed to enable proper measurement of defect size in metal structures. For use in waveguide-based distributive sensing technologies, additively manufactured custom waveguides were designed for use in liquid environments to collect pressure and flow data. Waveguides were designed with membranes, thin sections of the walls, which would be pressed inward due to fluid pressure. Waveguide models continue to be developed and revised for most functional utility in liquid environments.

36 MATERIALS SCIENCE↗

In-situ Data Acquisition and Tool Development for Additive Manufacturing Metal Powder Systems

Metal additive manufacturing (AM) is a processing technology which builds 3D components from the bottom-up by selectively melting metal precursors to build a component part in a layer by layer fashion. This advanced manufacturing process promises to initiate a digital renaissance in American manufacturing by decreasing costs, increasing energy efficiency, enabling new component designs, and providing a manufacturing pathway for novel materials which cannot be processed by traditional means. In particular, additively produced parts offer designs that are otherwise impossible to fabricate, custom designs for a single part at no additional cost, and considerable weight savings when compared to conventional production techniques.

36 MATERIALS SCIENCE↗

PTT System Performance Evaluation in 3-D Imaging of Calibrated Defects: Pulsed Thermal Tomography Nondestructive Examination of Additively Manufactured Reactor Materials and Components

Research activity in this project is aimed at developing pulsed thermal tomography (PTT) architecture and algorithms for in-service non-destructive examination (NDE) of additively manufactured (AM) reactor components and materials. Recent advances in AM technology could allow cost-efficient fabrication of parts for operating reactors. However, because of stringent safety requirements, long-term performance of AM reactor components needs to be investigated before AM is widely accepted. Because of the complex shapes and significant surface roughness of components due to layer-by-layer welding process in AM, conventional methods might not be useful for in-service NDE of AM components. PTT is ideally suited for in-service NDE of AM metallic components because the method is non-contact, and offers high resolution #-D imaging of material flaws. The objective of this report is to provide initial evaluate of PTT performance sin detecting calibrated flaws in reactor structural materials. Preliminary COMSOL models were developed to conduct super computing simulations of PTT. In the experimental studies, high strength Stainless Steel 316 and Inconel 718 alloys were considered, as well as lower grade Stainless Steel 304, Nickel 200, and Hastelloy C276. Specimens investigated in this report consisted of approximately 1/4in-thick plates made out of these alloys using conventional manufacturing methods. The calibrated defects were created in the form of flat bottom holes (FBH) drilled in metallic plates. The diameters of FBH's varied from 1mm to 8mm, and their depths below the plate flat surface varied between 1mm and 6mm. The size of the smallest FBH was limited to 1mm because conventional mechanic drills were used for creating the holes. PTT imaging results have shown that 1mm-diameter FBH located 1mm and 2mm below the surface were detectable. Larger size FBH were detectable at greater depth. For example, 6mm-diameter FBH could be detected at 8mm depth. Image contrast varied slightly between the specimens, with the best reconstructions obtained in SS316 and C276 plates. In addition, a 2/3in-thick Inconel 718 nozzle plate produced with additive manufacturing method was imaged with PTT. It was shown that PTT can scan through the plate in approximately 20s. Several modes of 3-D data visualization were explored, including using ImageJ and MATLAB software packages.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Additive Manufacturing of Polymers: Materials Opportunities and Emerging Applications

Additive manufacturing (AM) has enabled the rapid prototyping of structures with complex geometries constructed via computer aided design (CAD). In recent years, AM has extended beyond simple prototyping and has begun to play a role in the fabrication of active components, especially for applications that do not require materials with robust mechanical properties (i.e. electronic components and biomedical scaffolds). This report reviews the current state of 3D printing with respect to polymeric and composite materials, focusing on applications, printing processes, and material selection perspectives. A particular focus is placed on the polymer chemistry of additive manufacturing in order to elucidate current materials limitations, R&D trends and developmental opportunities. Some unconventional thermoset cure reactions are proposed for AM which may overcome current limitations. In addition, potential degradation characteristics of AM polymer materials and expected property variations in comparison with traditional processing are discussed, which draws attention to the complexity of the structure/processing/property relationships for the optimization of innovative materials. AM polymer manufacturing and 3D printing approaches hold tremendous promises as long as polymer chemistry, material physics and processing aspects (cure on demand) are jointly embraced within evolving research strategies.

36 MATERIALS SCIENCE↗

An Approach to Upscaling SPPARKS Generated Synthetic Microstructures of Additively Manufactured Metals

Additive manufacturing (AM) of metal parts can save time, energy, and produce parts that cannot otherwise be made with traditional machining methods. Near final part geometry is the goal for AM, but material microstructures are inherently different from those of wrought materials as they arise from a complex temperature history associated with the additive process. It is well known that strength and other properties of interest in engineering design follow from microstructure and temperature history. Because of complex microstructure morphologies and spatial heterogeneities, properties are heterogeneous and reflect underlying microstructure. This report describes a method for distributing properties across a finite element mesh so that effects of complex heterogeneous microstructures arising from additive manufacturing can be systematically incorporated into engineering scale calculations without the need for conducting a nearly impossible and time consuming effort of meshing material details. Furthermore, the method reflects the inherent variability in AM materials by making use of kinetic Monte Carlo calculations to model the AM process associated with a build.

36 MATERIALS SCIENCE↗

Development and Demonstration of Large-Scale Metal Additive Manufacturing for Military Vehicle Applications (Final Report)

Additive Manufacturing (AM) is a process by which complex parts can be manufactured directly from a basic feedstock without the need for tooling. From a defense perspective, this will enable direct manufacture of parts for legacy equipment. However, current AM technologies are limited to small part sizes (approximately 1 cubic foot), slow production rates (approximately 1 cubic inch per hour) and expensive feedstocks (approximately $100/lb). The objective of this project was to explore the impact large-scale, high production rate additive manufacturing can have on military applications. First, the program explored the use of existing composite large-scale (Big Area Additive Manufacturing – BAAM) systems for both tooling and direct part replacement with the use of the Army’s Low Velocity Airdrop Delivery (LVAD) system and Willy’s Jeep. We report on the cost and time required for the development of both tooling and parts. Second, the program focused on expanding the BAAM technology to directly manufacture aluminum and steel components. A robotic welding system was developed, test articles manufactured and with a final deliverable of a steel bumper manufactured and installed on the Jeep. This report covers the results of the program and describes follow-on efforts to commercialize the technology.

36 MATERIALS SCIENCE↗

Low-Cost, Efficient and Durable High Temperature Wireless Sensors by Direct Write Additive Manufacturing for Application in Fossil Energy Systems

In-situ monitoring of physical parameters in fossil energy (FE) systems is challenging because of their high operating temperatures and oxidizing environments. This research aims utilize Aerosol Jet (AJ) nanoparticle printing, an advanced additive manufacturing method, to fabricate high temperature sensors for FE applications. Sensor films were fabricated by the AJ printing method with an excellent control over film microstructure and properties, in addition to creating less waste. Printing of six different materials, namely, silver (Ag), nickel (Ni), nickel-chromium (NiCr) alloy, copper (Cu), copper-nickel (CuNi), and carbon nanotubes (CNTs) was carried out for their evaluation of as sensor films. The films were then characterized using impedance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). Film microstructure was correlated with the sensor electrical and mechanical behavior at different temperatures (24-500 °C) and frequencies (0.02 - 300 kHz). This knowledge was then used to fabricate, test, and characterize strain and temperature sensors for high temperature applications. The strain sensors were shown to have a very low thermal strain up to 500 °C and a 57% higher gauge factor compared to the commercially available counterparts. This enhance performance was attributed to the inherent porosity in the sensor films that allowed the films to exhibit a metamaterial-like behavior when deformed. The AJ printed temperature sensors were shown to have the highest Seebeck coefficient amongst all the film-based temperature sensors. In addition, fundamental aspects of crystal structure and phase transformations in Ba(Fe0.7Ta0.3)O3-δ (BFTO), a high temperature sensor material, was investigated along with 3D printed antennas that can transmit sensor signals at high temperatures. Two PhD students, one from first generation college-going underrepresented minority community (URM), two postdoctoral fellows, and several masters and undergraduate students were supported by this award. This work opens up the possibility of realizing low-cost high-performance sensor devices using advanced manufacturing techniques for high temperature FE applications.

20 FOSSIL-FUELED POWER PLANTS↗

Additive Manufacturing Technologies Survey

A literature search of the most prominent and widely available additive manufacturing technologies was done to understand the current developments in this area. The first section provides the introduction and scope for this report, followed by a very detailed second section on the different types of additive manufacturing technologies, how they work, the materials used, advantages and disadvantages of each technology, and manufacturer information. For comparative purposes, a third section on the most widely used subtractive technology, Computer Numerical Control (CNC) machining, is presented with information about the parameters used and the benefits and limitations of this technology. A final section with a summary and conclusions is presented with information comparing the power and utility of the different additive manufacturing technologies compared to traditional manufacturing.

36 MATERIALS SCIENCE↗

Sulfur-Donor Additives Preferentially Coordinate Pb 2+ in Perovskite Precursor Solutions

Lewis base solvents, such as dimethylsulfoxide (DMSO), that strongly coordinate with Pb 2+ are commonly added to hybrid organic-inorganic perovskite (HOIP) precursor solutions to improve thin-film morphology and subsequent photovoltaic (PV) performance. Although nearly all previous studies of precursor solution chemistry have focused on oxygen-donor solvents as Lewis base additives, we expect “softer,” sulfur-donor solvents to coordinate more strongly with Pb 2+ , a borderline-soft Lewis acid. To confirm this hypothesis, we performed extended X-ray absorption fine structure (EXAFS) spectroscopy at the Pb LIII absorption edge to probe the coordination environment of Pb 2+ in solutions comprising mixtures of S- and O-donor solvents. Of the S- and O-donor solvent pairs examined, the S-donor solvent consistently outcompetes its O-donor structural analog for coordination sites around Pb 2+ . In the specific comparison between N-methyl-2-pyrrolidone thione (NMPT) and N-methylpyrrolidone (NMP), density-functional theory calculations indicate that NMPT coordination with Pb 2+ is favored by 10 kcal/mol relative to NMP coordination with Pb 2+ . Similar to the addition of DMSO to precursor solutions, the incorporation of NMPT in fractional quantities provides morphological control of the perovskite film. Unlike DMSO, however, we found NMPT to be stable against undesired transmethylation or disproportionation reactions with methylammonium [1]. Consequentially, films processed with NMPT exhibit no sub-gap electronic states near the valence band edge, in contrast with films prepared using DMSO. We thus believe NMPT merits serious consideration as a solution additive for producing stable HOIP precursor solutions and high-quality HOIP thin films. [1] Hamill, J. C.; Sorli, J. C.; Pelczer, I.; Schwartz, J. and Loo, Y. -L. Acid-catalyzed reactions activate DMSO as a reagent in perovskite precursor inks. Chemistry of Materials 2019, 31, 2114-2120.

Hamill, Joseph↗

Re-Additization of Commercial Biodiesel Blends During Long-Term Storage

Commercial biodiesel blends representative of the U.S. market were aged following procedure ASTM D4625, Standard Test Method for Middle Distillate Fuel Storage Stability at 43°C (110°F), with periodic monitoring of fuel properties indicative of oxidation. The oxidation stability—or oxidation reserve expressed as Rancimat induction period (IP)—gradually decreased from its initial value, as expected. At a predetermined IP threshold, an antioxidant was used to restore IP to the ASTM D7467 specification minimum of 6 six hours, referred to as re-additization. At lower IP values, the amount of antioxidant required increased significantly, and the effectiveness tended to be reduced. Once IP fell to essentially zero, the acid content increased to above the allowable limit. Insoluble material was detectable after the acid number increased out of specification. Storage life was increased with re-additization relative to the as-received fuels, as evidenced by longer time to produce acids. Experience in the field may vary based on storage conditions; however, these results indicate re-additization can significantly increase the storage life of biodiesel blends when used with regular monitoring of IP and acid number. An assessment of property changes during long-term storage showed the initial IP did not predict storage behavior, although fuels above the specification minimum remained stable for greater than 12 weeks of D4625 accelerated aging (1 one year simulated).

09 BIOMASS FUELS↗

Pulsed Thermal Tomography Nondestructive Examination of Additively Manufactured Reactor Materials (Second Annual Progress Report)

Additive manufacturing (AM) is an emerging method for cost-efficient fabrication of nuclear reactor parts. AM of metallic structures for nuclear energy applications is currently based on laser powder bed fusion (LPBF) process, which can introduce internal material flaws, such as pores and anisotropy. Integrity of AM structures needs to be evaluated nondestructively because material flaws could lead to premature failures due to exposure to high temperature, radiation and corrosive environment in a nuclear reactor. Thermal tomography (TT) provides a capability for non-destructive evaluation of sub-surface defects in arbitrary size structures. Thermal tomography is a computational method for heat diffusion-based imaging of solids, which provides 3D visualization of data from flash thermography measurements. We investigate thermal tomography imaging and nondestructive evaluation of stainless steel and nickel super alloy metallic structures produced with laser powder bed fusion (LPBF) additive manufacturing (AM) process. Metallic structures produced with LPBF contain defects, and there are limited capabilities to evaluate these structures non-destructively. Thermal tomography reconstruction of 3D apparent spatial effusivity provides information about AM structure geometry and internal material flaws. We study performance of thermal tomography in imaging of metallic structures through COMSOL computer simulations of transient heat transfer, and through reconstruction of data obtained from experimental measurements. Reconstruction of internal defects is investigated using a stainless steel 316L specimen with flat bottom hole (FBH) indentations, and Inconel 718 plate produced with laser powder bed fusion (LPBF) method, which contains imprinted hemispherical shape low density regions containing non-sintered metallic powder. The FBH’s have the same sizes as the imprinted defects in the LPBF specimens, but offer better imaging contrast. Thermal tomography reconstructions provide visualizations of internal defects, and allow for estimation of their sizes and locations. Detection sensitivity of TT is limited by noises. We investigate separation of signal from noise in thermography images using several machine learning (ML) methods, including new spatio-temporal blind source separation (STBSS) and spatio-temporal sparse dictionary learning (STSDL) methods. Performance of the ML methods is benchmarked using thermography data obtained from imaging stainless steel 316L and Inconel 718 specimens produced LPBF method with imprinted calibrated porosity defects. The ML methods are ranked by F-score and execution runtime. Finally, we investigate TT of AM stainless steel 316L specimen with imprinted internal porosity defects using relatively low-cost, small form factor infrared (IR) camera based on uncooled micro bolometer detector. Sparse coding related K-means singular value decomposition (SVD) machine learning, image processing algorithms are developed to improve quality of TT images through removal of Additive white Gaussian noise without blurring the images. Following initial qualification of an AM component for deployment in a nuclear reactor, a compact TT can also be used for in-service nondestructive evaluation (NDE). With capability to perform in-service NDE of the AM component lifecycle, TT data can be used for development of a component digital twin.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Feasibility of Using Additive Manufacturing to Produce Axial Flow Hydropower Turbine Housing, Runner, and Draft Tube

Oak Ridge National Laboratory (ORNL) worked with AMJET Turbine Systems, LLC (ATS), to demonstrate additive manufacturing of components for low head hydro turbine/generator applications. Several different types of additive manufacturing systems were used. Components were finished and assembled for testing in a turbine. However, one of the processes, Big Area Additive Manufacturing (BAAM),produced components that did not adequately perform due to persistent leaks that were caused by porosity in the parts produced. Therefore, the BAAM system was eliminated from contention. Vacuum infusion of rein into the parts eventually solved the porosity problem.Components were installed in anATS-8 turbine to be tested on the Keokuk Dam for operationally testing the unit.

13 HYDRO ENERGY↗