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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14

Variation in surface properties as error sources in dynamic temperature measurements

Most temperature measurement methods rely upon the assumption of a single uniform source as part of the analysis in inferring an observed temperature T from the surface of a material. This is true for the radiometric and spectroscopic methods we rely upon in shock physics. However, there are obvious cases where this is a poor assumption that can cause large errors in analysis, such as the measurement of emission from a surface composed of more than one material, such as a rusted surface of Fe and Fe 2 O 3 , or a multi-material surface that could be produced through alloying methods (e.g., mokume gane) or 3D printing. Here we perform an initial examination of the effects of varied surface properties upon the analysis using idealized test data to constrain when we may have better confidence in the resulting calculations. We also examine the structures of the fits to test whether, in principle, comparing the fit with ideal gray bodies would reveal such a structure and enable the researcher to identify when a two-temperature fitting model should be used instead of a single- T model or a wavelength-dependent emissivity model.

36 MATERIALS SCIENCE↗

Material migration in W and Mo during bubble growth and fuzz formation

Growth of helium (He) induced bubbles and fuzz in tungsten (W) and molybdenum (Mo) is investigated using samples of W films on Mo substrates and Mo films on W substrates exposed to He-containing plasma in the temperature range of 340 to 1075 K, fluence range of 1.0–14 × 10 25 He·m -2 , and incident ion energy of <50 eV. No fuzz (only up to 2 nm diameter bubbles) and no material transport occur in W films at ≤750 K, while precursors-of or fully-developed fuzz and material mixing occur in W and Mo films at ≥800 K. This suggests that fuzz forms in multi-material systems as long as one material meets the conditions for fuzz formation, namely T s / T m ~ 0.27–0.5 where T s and T m are the sample exposure and material melting temperatures, respectively. Larger He bubbles, more material mixing, and further-developed fuzz occur at higher temperature due to increased mobility of He atoms and small He clusters. Accumulation of substrate material at the surface of fuzzy W and Mo thin-film (<80 nm) samples suggests fuzz growth by material transport from the bubble layer in the bulk up to the fiber tip, likely by a two-step process: (i) diffusion of punched dislocation loops in the bulk toward the fuzz base and (ii) diffusion of adatoms along the fuzz base and fiber surface (with effective transport of adatoms upwards due to trapping of adatoms at curved surfaces of fiber tips and/or due to the continuous generation of adatoms at the fuzz base). While the bubble size and fuzz thickness increase with reduced W concentration in Mo thin-film samples at 838 K likely due to an increase in trap mutation and dislocation loop punching in Mo compared to W, the fuzz thickness decreases with reduced W concentration at 1075 K despite an increase in the bubble size likely due to slower diffusion of interstitial loops in Mo.

Physics↗

Portage: A Modular Data Remap Library for Multiphysics Applications on Advanced Architectures

Portage is a scalable and extensible remap library for numerical simulations. It supports state-of-the-art remap schemes for meshes and particles in 2D and 3D up to a second-order accuracy. Portage ensures critical properties such as local/global conservation and bounds preservation for mesh remap. It enables multi-material field remap through a dedicated plugin, and leverages the hybrid parallelism exposed by advanced architectures using multi-processing and multi-threading.

97 MATHEMATICS AND COMPUTING↗

Thermal Analysis of Magnetically-Coupled Pump for Cryogenic Applications

Magnetically-coupled pump is under evaluation at Kennedy Space Center for possible cryogenic applications. A major concern is the impact of low temperature fluid flows on the pump performance. As a first step toward addressing this and related issues, a computational fluid dynamics and heat transfer tool has been adopted in a pump geometry. The computational tool includes (i) a commercial grid generator to handle multiple grid blocks and complicated geometric definitions, and (ii) an in-house computational fluid dynamics and heat transfer software developed in the Principal Investigator's group at the University of Florida. Both pure-conduction and combined convection-conduction computations have been conducted. A pure-conduction analysis gives insufficient information about the overall thermal distribution. Combined convection-conduction analysis indicates the significant influence of the coolant over the entire flow path. Since 2-D simulation is of limited help, future work on full 3-D modeling of the pump using multi-materials is needed. A comprehensive and accurate model can be developed to take into account the effect of multi-phase flow in the cooling flow loop, and the magnetic interactions.

Senocak, Inanc↗

A Shock Stabilization of the HLLC Riemann Solver for the Carbuncle Instability

The HLLC approximate Riemann solver improves upon the HLL Riemann solver by resolving contact discontinuities. This is a particularly desirable property for multi-material codes in which problems usually contain material interfaces. However, the HLLC solver is known to suffer from the carbuncle phenomenon, a numerical instability most apparent at grid-aligned shocks in multi-dimensional simulations. Many problems of interest, including high energy-density physics applications, require the accurate resolution of both material interfaces and hydrodynamic shocks. A variety of methods have been developed to cure this instability, with varying degrees of complexity. The objective of this work is to describe a simple approach to modify the HLLC Riemann solver and prevent the carbuncle instability. Here, the method is then demonstrated for assorted two-dimensional test problems known to exhibit the shock instability. The performance of the new solver is compared with that of the standard HLL and HLLC Riemann solvers.

97 MATHEMATICS AND COMPUTING↗

Strength-ductility synergy through microstructural and compositional heterogeneity in directed energy deposition additive manufacturing of face-centered cubic materials

Directed energy deposition (DED) is an additive manufacturing (AM) process based on welding technology and offers the advantages of large build volume, high deposition rate, and ability to fabricate multi-material parts. Epitaxial continuous columnar grain growth is a characteristic microstructural feature of DED processed alloys. In this study, a bamboo-like microstructure (periodic alternation of equiaxed and columnar structure) was produced by adopting an intermittent deposition strategy in 316L stainless steel and Inconel 625. The formation of a bamboo-like alternating microstructure was confirmed through electron backscattered diffraction (EBSD) analysis. Hardness mapping showed that the columnar to equiaxed transition (CET) occurred at the region right below the fusion line. A finite element (FE) model was used to investigate the relationship between the temperature gradient (G) and the solidification rate (R). The FE model showed a low G/R ratio at the region right below the interface promoting the CET. The grain size and material-dependent deformation behaviors are analyzed using digital image correlation (DIC). The lower deformation on the fine-grain regions observed in DIC analysis is attributed to a higher strain hardening rate, which is confirmed through dislocation density analysis on a tensile-interrupted specimen. The periodically alternating grain size coupled with the microstructural changes caused by intermittent deposition strategy result in a better strength-ductility synergy in both single-material and bimetallic specimens.

36 MATERIALS SCIENCE↗

Bioinspired energy absorbing material designs using additive manufacturing

Nature provides many biological materials and structures with exceptional energy absorption capabilities. Few, relatively simple molecular building blocks (e.g., calcium carbonate), which have unremarkable intrinsic mechanical properties individually, are used to produce biopolymer-bioceramic composites with unique hierarchical architectures, thus producing biomaterial-architectures with extraordinary mechanical properties. Several biomaterials have inspired the design and manufacture of novel material architectures to address various engineering problems requiring high energy absorption capabilities. For example, the microarchitecture of seashell nacre has inspired multi-material 3D printed architectures that outperform the energy absorption capabilities of monolithic materials. Using the hierarchical architectural features of biological materials, iterative design approaches using simulation and experimentation are advancing the field of bioinspired material design. However, bioinspired architectures are still challenging to manufacture because of the size scale and architectural hierarchical complexity. Notwithstanding, additive manufacturing technologies are advancing rapidly, continually providing researchers improved abilities to fabricate sophisticated bioinspired, hierarchical designs using multiple materials. This review describes the use of additive manufacturing for producing innovative synthetic materials specifically for energy absorption applications inspired by nacre, conch shell, shrimp shell, horns, hooves, and beetle wings. Potential applications include athletic prosthetics, protective head gear, and automobile crush zones.

36 MATERIALS SCIENCE↗

Understanding and Developing Dual-Wavelength Olefin Metathesis Polymerizations for the Rapid, Continuous Additive Manufacturing of High-Performance Thermosets

This report details the goals, approach, results, and future needs of a three-year Laboratory Directed Research and Development project funded by Sandia’s Materials Science Research Foundation. In this project, we established basic principles and mechanistic understanding of orthogonal or sequential chemistries for fabricating multi-material or robust materials. We developed numerous additive manufacturing, or 3D-printing, techniques including volumetric solid-state printing, dual-wavelength printing, and lithographic regulation of polymer crystallinity. We leveraged these new printing motifs to expand upon what is possible with manufacturing to give bespoke optical and mechanical performance. Moreover, we discovered new techniques for depolymerization enabling recovery of pristine carbon-fiber and high value electronics under moderate conditions.

36 MATERIALS SCIENCE↗

Rapid Prototyping of Biological Materials for In-Space Applications

The topics include: 1) Why is this technology needed? 2) In-Situ Fabrication and Repair (ISFR) and In-Situ Resource Utilization (ISRU); 3) Multi-Material Fabricator; 4) Medical Products; 5) Bioplotter; 6) Closing Remarks; and 7) Additional Information.

Frazier, Natalie↗

Sorption of Anionic Iodine and Molybdenum to Multi-sorbing Barrier (MSB) Materials - 20030

A multi-sorbing barrier (MSB) material containing sodium bentonite (NaB), organoclay, and anion resin is being evaluated for containment of anionic radionuclides. Batch tests on the MSB were conducted using two non-radioactive analog isotopes ({sup 127}I, {sup 95}Mo) as surrogates for {sup 129}I and {sup 99}Tc due to their similar valence and molecular weight relative to the radionuclides. Tests were conducted on the organoclay, anion resin, and NaB individually and on NaB-resin blends with resin contents of 1% and 5% by mass. The anion resin exhibits very strong sorption of {sup 127}I and {sup 95}Mo relative to the other materials. The organoclay exhibited modest sorption of {sup 95}Mo and {sup 127}I, and NaB little sorption. The sorption isotherms follow a linear model for NaB, a Freundlich model for the organoclay, and a Langmuir model for the anion resin and NaB-resin mixtures. Combining resin with NaB significantly enhances sorption relative to NaB alone, with a larger resin fraction yielding greater sorption. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Modeling atomically mixed graded density impactors

Graded density impactors (GDIs) are multi-material composite impactors used in gas gun experiments to tailor the drive conditions imparted to a sample test material. Previous graded density impactors generally rely on thin, but discrete, layers of different materials. The thinner and the greater number of layers will result in smoother compression. Taken to the limit of very thin layers would be pure material 1 at one surface, such as the front surface of an impactor, smoothly transitioning at the atomic scale to pure material 2 on the back surface. Such an impactor can initially shock, then smoothly compresses a material during a dynamic experiment. This type of experiment can serve to explore a larger region of thermodynamic space than a single or even multi-shock experiments. An overview of how graded density impactors are made is reviewed and sample results are given. Additionally, a strategy for modeling these kinds of impactors is presented. The length scales of constituent mixing are given from the experimental build through electrochemical-deposition. Equation of state models for pure constituents and their subsequent mixtures are presented. It is demonstrated that the time scales for pressure and temperature equilibration, for atomically mixed GDIs, are short enough to be a justifiable closure for the resulting multiphase flow. Furthermore, we present simulation results of dynamic shock followed by a ramp compression, utilizing a silver/gold graded density impactor, onto a tantalum sample.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Vehicle lightweighting energy use impacts in U.S. light-duty vehicle fleet

In this article, we estimate the potential energy benefits of lightweighting the light-duty vehicle fleet from both vehicle manufacturing and use perspectives using plausible lightweight vehicle designs involving several alternative lightweight materials, low- and high-end estimates of vehicle manufacturing energy, conventional and alternative powertrains, and two different market penetration scenarios for alternative powertrain light-duty vehicles at the fleet level. Cumulative life cycle energy savings (through 2050) across the nine material scenarios based on the conventional powertrain in the U.S. vehicle fleet range from -29 to 94 billion GJ, with the greatest savings achieved by multi-material vehicles that select different lightweight materials to meet specific design purposes. Lightweighting alternative-powertrain vehicles could produce significant energy savings in the U.S. vehicle fleet, although their improved powertrain efficiencies lessen the energy savings opportunities for lightweighting. A maximum level of cumulative energy savings of lightweighting the U.S. light-duty vehicle through 2050 is estimated to be 66.1billion GJ under the conventional-vehicle dominated business-as-usual penetration scenario.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Toward Multiscale, Multimaterial 3D Printing

Biological materials and organisms possess the fundamental ability to self-organize, through which different components are assembled from the molecular level up to hierarchical structures with superior mechanical properties and multifunctionalities. These complex composites inspire material scientists to design new engineered materials by integrating multiple ingredients and structures over a wide range. Additive manufacturing, also known as 3D printing, has advantages with respect to fabricating multiscale and multi-material structures. The need for multifunctional materials is driving 3D printing techniques toward arbitrary 3D architectures with the next level of complexity. In this paper, the aim is to highlight key features of those 3D printing techniques that can produce either multiscale or multimaterial structures, including innovations in printing methods, materials processing approaches, and hardware improvements. Several issues and challenges related to current methods are discussed. Ultimately, the authors also provide their perspective on how to realize the combination of multiscale and multimaterial capabilities in 3D printing processes and future directions based on emerging research.

36 MATERIALS SCIENCE↗

Incompressible Multimaterial Flow in Pececillo

Pececillo is a Truchas mini-app for testing new design ideas, algorithms, physics, etc, before implementing them in Truchas. This report describes the multimaterial flow algorithms now implemented in Pececillo, presents some basic verification tests, and provides a basic code map. Truchas’s algorithms for the incompressible Navier-Stokes and onion-skin material advection were re-implemented in Truchas, with special attention given to cache use, future threading, and code cleanliness. A nested-dissection algorithm for multi-material advection was also implemented, allowing for a more accurate treatment of dynamic contact lines in 3+ material flow systems.

36 MATERIALS SCIENCE↗

Advances in Binder Jet Additive Manufacturing

Binder Jetting is a powerful additive manufacturing technology due to its low cost and wide range of types of materials it can shape. The industry partner ExOne has a range of binder jet products for applications such as casting tools, composite layup tools, single-alloy metal components, and more. As such, research and development is of high interest in the area of specialized binders for each type of material, processing technology that improves reliability and quality, and materials to enhance the performance of the final parts. Thus, this work focuses on developing novel binders for sand tools and metal prints, new capabilities in multi-material printing, and build monitoring and correction. The result of this work includes a novel binder system that makes binder jet sand stronger than concrete while still being water soluble, a casting binder that is environmentally friendly and produces better surface finishes on castings, and a binder for metals that reduces the residual carbon.

36 MATERIALS SCIENCE↗

Combining 3D printing of copper current collectors and electrophoretic deposition of electrode materials for structural lithium-ion batteries

Serving as a proof of concept, additive manufacturing and electrophoretic deposition are leveraged in this work to enable structural lithium-ion batteries with load-bearing and energy storage dual functionality. The preparation steps of a complex 3D printed copper current collector, involving the formulation of a photocurable resin formulation, as well as the vat photopolymerization process followed by a precursors-based solution soaking step and thermal post-processing are presented. Compression and microhardness testing onto the resulting 3D printed copper current collector are shown to demonstrate adequate mechanical performance. Electrophoretic deposition of graphite as a negative electrode active material and other additives was then performed onto the 3D printed copper collector, with the intention to demonstrate energy storage functionality. Half-cell electrochemical cycling of the 3D multi-material current collector/negative electrode versus lithium metal finally demonstrates that structural battery components can be successfully obtained through this approach.

25 ENERGY STORAGE↗

Vehicle Lightweighting: 40% and 45% Weight Savings Analysis: Technical Cost Modeling for Vehicle Lightweighting

The U.S. Department of Energy’s Vehicle Technologies Office, Materials area commissioned a study to model and assess manufacturing economics of alternative design and production strategies for a series of lightweight vehicle concepts. The strategic targets were a 40% and a 45% mass reduction relative to a standard North American midsize passenger sedan at an effective cost of $3.42 per pound (lb) saved. The baseline vehicle was an average of several available vehicles in this class. Mass and cost breakdowns from several sources were used, including original equipment manufacturers’ (OEMs’) input through U.S. Department of Energy’s Vehicle Technologies Office programs and public presentations, A2Mac1 LLC’s teardown information, Lotus Engineering Limited and FEV, Inc. breakdowns in their respective lightweighting studies, and IBIS Associates, Inc.’s decades of experience in automotive lightweighting and materials substitution analyses. Information on lightweighting strategies in this analysis came from these same sources and the ongoing U.S. Department of Energy-funded Vehma International of America, Inc. /Ford Motor Company Multi-Material Lightweight Prototype Vehicle Demonstration Project, the Aluminum Association Transportation Group, and many United States Council for Automotive Research’s/United States Automotive Materials Partnership LLC lightweight materials programs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

BNL Irradiation Damage Studies of the Metal Matrix Composite Mo-GR Considered for High Luminosity LHC Collimator Upgrade

A comprehensive experimental/analytical effort on the resilience of Mo-GR metal matrix composite to high energy proton beam irradiation combined with elevated temperatures has been undertaken at BNL on behalf of the CERN LHC Collimation effort as part of an effort to identify novel materials that will exhibit optimal performance in the high luminosity LHC upgrade. While the Mo-Gr composite was one of the four (4) different materials or composites (Mo, Glidcop, Cu-CD and Mo-Gr) that constituted the High Luminosity LHC collimation material campaign, this report focuses solely on Mo-GR with some reference to its constituents Mo and graphite (graphite studied in previous research or irradiation campaigns along with the carbonfiber composites). The multi-faceted study on Mo-GR (one of several different alloys and matrices) performed at BNL included the following stages: Irradiation damage phase using the 200 MeV proton beams of the BNL Linac and the BLIP target beamline. Specifically, Mo-GR samples encapsulated under vacuum in special capsules were exposed to direct protons as part of a multi-capsule, multi-material irradiation array. The long-term irradiation of ~8 weeks resulted in an accumulated fluence at the Mo-GR of ~10 21 p/cm 2 . The irradiation was conducted in two sessions (RUN 2013 and RUN 2014 of the BLIP operations in tandem with isotope production). Irradiation damage experiments using spallation neutrons at the BLIP beamline generated by 118 MeV protons that interact with and are stopped by an array of isotope producing targets. The Mo-GR capsule combined the effects of short-term proton irradiation and the effects of the mixed irradiating spectrum. Spallation-induced irradiation of Mo-GR at sub-zero temperatures utilizing the mixed field generated by spallation of 28 MeV protons of the BN Tandem on Mo targets Gamma spectrum analysis of the heavily irradiated Mo-Gr to enable the correlation of predicted isotope profile from Mo-Gr by transport codes and therefore the utilization of the validated transport code in other aspects of the damage induced on Mo-Gr by irradiation.

43 PARTICLE ACCELERATORS↗