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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 1,603 records · Page 89
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Ultrafast manipulation of mirror domain walls in a charge density wave

Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS 2 . A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photoinjected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Understanding Phase and Interfacial Effects of Spall Fracture in Additively Manufactured Ti-5Al-5V-5Mo-3Cr

Additive manufactured Ti-5Al-5V-5Mo-3Cr (Ti-5553) is being considered as an AM repair material for engineering applications because of its superior strength properties compared to other titanium alloys. Here, we describe the failure mechanisms observed through computed tomography, electron backscatter diffraction (EBSD), and scanning electron microscopy (SEM) of spall damage as a result of tensile failure in as-built and annealed Ti-5553. We also investigate the phase stability in native powder, as-built and annealed Ti-5553 through diamond anvil cell (DAC) and ramp compression experiments. We then explore the effect of tensile loading on a sample containing an interface between a Ti-6Al-V4 (Ti-64) baseplate and additively manufactured Ti-5553 layer. Post-mortem materials characterization showed spallation occurred in regions of initial porosity and the interface provides a nucleation site for spall damage below the spall strength of Ti-5553. Preliminary peridynamics modeling of the dynamic experiments is described. Finally, we discuss further development of Stochastic Parallel PARticle Kinteic Simulator (SPPARKS) Monte Carlo (MC) capabilities to include the integration of alpha (α)-phase and microstructural simulations for this multiphase titanium alloy.

36 MATERIALS SCIENCE↗
DOE OSTI2014

The Effect Of Electronic Energy Loss On Irradiation-induced Grain Growth In Nanocrystalline Oxides

Grain growth of nanocrystalline materials is generally thermally activated, but can also be driven by irradiation at much lower temperature. In nanocrystalline ceria and zirconia, energetic ions deposit their energy to both atomic nuclei and electrons. Our experimental results have shown that irradiationinduced grain growth is dependent on the total energy deposited, where electronic energy loss and elastic collisions between atomic nuclei both contribute to the production of disorder and grain growth. Our atomistic simulations reveal that a high density of disorder near grain boundaries leads to locally rapid grain movement. The additive effect from both electronic excitation and atomic collision cascades on grain growth demonstrated in this work opens up new possibilities for controlling grain sizes to improve functionality of nanocrystalline materials.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2025

Multiscale Characterization of Additive Manufacturing Components with Computed Tomography, 3D X-ray Microscopy, and Deep Learning

Additive manufacturing (AM) facilitates the creation of complex-geometry parts, driving advancements in lightweight aerospace components, high-efficiency engine cooling channels, and customized medical implants. However, ensuring the quality and reliability of AM parts remains challenging due to internal defects, surface irregularities, porosity, and residual trapped powder, which are often inaccessible to traditional inspection methods. Recent developments in X-ray computed tomography (XCT) and 3D X-ray microscopy (XRM), particularly systems equipped with resolution-at-a-distance (RaaD™) capabilities, enable high-resolution, non-destructive evaluation of AM components across multiple scales, from sub-micrometer to macroscopic levels. This paper explores modern XCT and XRM techniques for multiscale characterization of AM parts, focusing on their ability to detect and analyze defects such as porosity, cracks, inclusions, and surface roughness, while offering insights into defect formation mechanisms, material properties, and process-induced variations. The integration of deep learning (DL) frameworks, including Simurgh, DeepRecon, and DeepScout, enhances XCT/XRM workflows by reducing scan times, improving resolution recovery, and enabling accurate defect detection even with limited projection data. These DL-based methods overcome limitations of traditional reconstruction techniques, enabling faster, more reliable characterization of dense materials like Inconel 718 and novel alloys such as AlCe. Applications include process parameter optimization, high-throughput quality control, and multistage AM process evaluation, with DL-enhanced workflows accelerating analysis times from weeks to days. Correlative imaging approaches further validate XCT and XRM data against scanning electron microscopy (SEM) images of physically sectioned samples, confirming the accuracy of DL-based reconstructions and enabling comprehensive defect analysis. While challenges remain in generalizing DL models to diverse materials and imaging conditions, improvements in resolution, noise reduction, and defect detection highlight the transformative potential of these methods. This multiscale and correlative approach enables precise identification and correlation of microstructural features with the overall performance of AM components. By integrating advanced XCT, XRM, and DL techniques, this paper demonstrates a significant leap forward in AM characterization, offering valuable insights into the relationships between processing parameters, microstructure, and part performance, and driving innovations that enhance the quality and reliability of AM products for demanding industrial applications.

Additive manufacturing↗
DOE OSTI2019

Wide Band Gap Chalcopyrite Photoelectrodes for Direct Water Splitting (Final Technical Report)

The chalcopyrite material class, typically identified by its most popular alloy CuInGaSe 2 , provides exceptionally good candidates for photoelectrochemical (PEC) water splitting and has the potential to meet DoE EERE’s targets in terms of hydrogen production costs (less than $2/gge). Some key advantages of this class include remarkable photon-to-electron conversion efficiency and a high Faradaic efficiency for the hydrogen evolution reaction, two characteristics essential for efficient PEC water splitting. However, the band gaps of commonly used chalcopyrites in the photovoltaic field (1.0-1.6 eV) are too narrow to be compatible with the multi-junction approach for efficient PEC hydrogen production, in which a stack of solar absorbers generates the bias required for water splitting. Nonetheless, previous studies performed by our team demonstrated that chalcopyrites’ narrow band gaps could be effectively widened using simple conversion steps, leading to functional chalcopyrite-based PEC electrodes with optical band gap in the 1.8-2.4 eV range, making this class highly suitable for renewable hydrogen production via water splitting. This multi-disciplinary research program lead by the University of Hawai’i/Hawai’i Natural Energy Institute combined unique analytical techniques (UNLV), state-of-the-art theoretical modeling (LLNL) with advanced thin film materials synthesis (HNEI, NREL and Stanford) to provide deeper understanding of wide band gap chalcopyrite-based PEC materials and engineer high performance/corrosion-resistant photocathodes with tunable energetics and compatible with the multi-junction approach. The goals of this project were to demonstrate photoelectrochemical (PEC) solar-hydrogen production using a dual absorber system with a solar-to-hydrogen conversion efficiency of at least 15% with an operational life up to 2,000 hours and capable of generating at least 3 liters of hydrogen in 8 hours. After a brief introduction (Section 1) and description of our work plan (Section 2), we present in Section 3 our results on the development of new wide bandgap copper chalcopyrites absorbers for PEC waters splitting. We first show through modeling how alloying can be used to tailor the optical properties and/or surface energetics of various material candidates. We also present how specific defects (e.g., GaCu) can lead to recombination centers within the forbidden gap of copper-poor chalcopyrites. Then, we present our efforts to synthesize high efficiency wide band gap CuGa 3 Se 5 , CuGa(S,Se) 2 and Cu(In,Ga)S 2 photocathodes capable of generating photocurrent density over 10 mA/cm 2 . We also demonstrate that Cu-rich absorbers should be avoided as they lead to poor sub-band gap optical transmission. In Section 4, we first report on our efforts to tune the energetics of chalcopyrites toward the hydrogen evolution reaction. First, we quantified the energetics of wide band gap chalcopyrites interfaced with conventional CdS buffer layer, as measured with X-ray photoelectron spectroscopy techniques, and evidence the presence of a large (and undesirable) conduction band offset at this interface. Then, we highlight some of the work performed with alternative buffer layers, including In 2 S 3 . Durability improvements with various ultra-thin protective layers are presented in Section 5. Our data show that TiO 2 combined with MoS 2 can significantly improve chalcopyrites lifetime up to 350 hours under continuous operation at 8 mA/cm 2 . Finally, in Section 6 we report strategies to integrate chalcopyrite photocathodes into standalone tandem PEC devices. Although promising methods were proposed for both mechanical and monolithic stacking with narrow band gap PV drivers, no functional device was fabricated on time to fulfill the program end goals.

08 HYDROGEN↗
DOE OSTI2022

Benchmarking Solid-State Batteries Containing Sulfide Separators: Effects of Electrode Composition and Stack Pressure

Integrating sulfide separators into solid-state batteries (SSBs) containing high energy cathodes typically requires one or more materials and engineering solutions including: (i) applying interfacial coatings to mitigate electrolyte decomposition, (ii) applying high stack pressures to form robust solid-solid contacts, and (iii) using alloying anodes to avoid Li dendrite formation. Despite the promise of these approaches, a lack of standardized testing protocols makes it difficult to directly compare results among different studies. To address this problem, the present work benchmarks the performance of SSBs containing β-Li 3 PS 4 (LPS) separators and composite cathodes. By systematically varying the anode/cathode composition and stack pressure, this work demonstrates that cathode design is a major bottleneck for solid-state cells cycled at low rates (<100 µA cm -2 ). Operando stack pressure measurements show that, while mechanical confinement generally promotes higher active material utilization and cycling stability, this strategy alone does not address interfacial reactivity between LPS and high voltage cathodes. Here, these results also demonstrate that stress evolution during cycling is dominated by volume changes at the Li metal anode. Finally, we show that FeS 2 cathodes with moderate operating voltages (<3 V vs Li/Li + ) exhibit superior cycling performance compared to high voltage cathodes by facilitating formation of stable cathode/electrolyte interfaces.

25 ENERGY STORAGE↗
DOE OSTI2026

Nonlinear viscoelastic response of silicone additively manufactured direct ink write (DIW) foams under repetitive compression

To investigate dynamic fatigue behavior of foam in military protective applications, such as helmets, additively manufactured (AM) foams were compressively strained into the plateau region using a reduced design of experiments. A simple power law was found to govern the decline in dynamic stiffness (complex modulus) as the foams underwent the purchase order requirement of 10,000 cycles of small deformation in the plateau region. This rate of decline was newly found to correlate with the degree of nonlinearity in the material’s deformation, quantified using total harmonic distortion. Materials with low nonlinearity exhibited relatively stable stiffness across cycles, while those with high nonlinearity experienced greater losses. The observed nonlinearity depended on both applied stress and strain rate. A strong linear correlation (R 2 = 0.78) was identified between second-order nonlinearity and the time-dependent stiffness response. Two lattice structures were examined: face-centered tetragonal (FCT) and simple cubic (SC). The SC material exhibited higher total harmonic distortion (5%) and lower stiffness retention than the FCT (2%). In conclusion, these results suggest that for cyclic compression applications in a wide variety of industries such as packaging, personal protective equipment, or aerospace, selecting materials with lower stress and greater structural uniformity can enhance the stability of dynamic performance.

42 ENGINEERING↗
DOE OSTI2025

Learning robust parameter inference and density reconstruction in flyer plate impact experiments

Estimating physical parameters or material properties from experimental observations is a common objective in many areas of physics and material science. In many experiments, especially in shock physics, radiography is the primary means of observing the system of interest. However, radiography does not provide direct access to key state variables, such as density, which prevents the application of traditional parameter estimation approaches. Here we focus on flyer plate impact experiments on porous materials, and resolving the underlying parameterized equation of state (EoS) and crush porosity model parameters given radiographic observation(s). We use machine learning as a tool to demonstrate with high confidence that using only high impact velocity data does not provide sufficient information to accurately infer both EoS and crush model parameters, even with fully resolved density fields or a dynamic sequence of images. We thus propose an observable data set consisting of low and high impact velocity experiments/simulations that capture different regimes of compaction and shock propagation, and proceed to introduce a generative machine learning approach which produces a posterior distribution of physical parameters directly from radiographs. We demonstrate the effectiveness of the approach in estimating parameters from simulated flyer plate impact experiments, and show that the obtained estimates of EoS and crush model parameters can then be used in hydrodynamic simulations to obtain accurate and physically admissible density reconstructions. Finally, we examine the robustness of the approach to model mismatches, and find that the learned approach can provide useful parameter estimates in the presence of out-of-distribution radiographic noise and previously unseen physics, thereby promoting a potential breakthrough in estimating material properties from experimental radiographic images.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2010

S09 Symposium KK, Structure-Property Relationships in Biomineralized and Biomimetic Composites

The technical presentations and discussions at this symposium disseminated and assessed current research and defined future directions in biomaterials research, with a focus on structure-function relationships in biological and biomimetic composites. The invited and contributed talks covered a diverse range of topics from fundamental biology, physics, chemistry, and materials science to potential applications in developing areas such as light-weight composites, multifunctional and smart materials, biomedical engineering, and nanoscaled sensors. The invited speakers were chosen to create a stimulating program with a mixture of established and junior faculty, industrial and academic researchers, and American and international experts in the field. This symposium served as an excellent introduction to the area for younger scientists (graduate students and post-doctoral researchers). Direct interactions between participants also helped to promote potential future collaborations involving multiple disciplines and institutions.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Failure Criteria and Temperature Dependent Elastic Constants in the 3-D Elastic Orthotropic Model

Recent points of emphasis in the Library of Advanced Materials for Engineering (LAMÉ) have been to enable flexibility in formulations via the adoption of a variety of modular frameworks. While more established phenomenologies such as plasticity and viscoelasticity have been considered, elastically orthotropic models (e.g. elastic_3D_orthotropic) have not. For the elasticity component, not much can be modularized. However, a potential feature of interest would be the evaluation of failure criteria to consider the possibility of damage. Many such forms exist in the literature providing a good basis for modularity.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Life Cycle Assessment of Innovative Carbon Dioxide Selective Membranes from Low Carbon Emission Sources: A Comparative Study

Carbon capture has been an important topic of the twenty-first century because of the elevating carbon dioxide (CO2) levels in the atmosphere. CO2 in the atmosphere is above 420 parts per million (ppm) as of 2022, 70 ppm higher than 50 years ago. Carbon capture research and development has mostly been centered around higher concentration flue gas streams. For example, flue gas streams from steel and cement industries have been largely ignored due to lower associated CO2 concentrations and higher capture and processing costs. Capture technologies such as solvent-based, adsorption-based, cryogenic distillation, and pressure-swing adsorption are under research, but many suffer from higher costs and life cycle impacts. Membrane-based capture processes are considered cost-effective and environmentally friendly alternatives. Over the past three decades, our research group at Idaho National Laboratory has led the development of several polyphosphazene polymer chemistries and has demonstrated their selectivity for CO2 over nitrogen (N2). Poly[bis((2-methoxyethoxy)ethoxy)phosphazene] (MEEP) has shown the highest selectivity. A comprehensive life cycle assessment (LCA) was performed to determine the life cycle feasibility of the MEEP polymer material compared to other CO2-selective membranes and separation processes. The MEEP-based membrane processes emit at least 42% less equivalent CO2 than Pebax-based membrane processes. Similarly, MEEP-based membrane processes produce 34–72% less CO2 than conventional separation processes. In all studied categories, MEEP-based membranes report lower emissions than Pebax-based membranes and conventional separation processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1981

On the relationship between engineering properties and delamination of composite materials

Delamination of composite materials has been investigated with emphasis on the relationship between the engineering properties of the individual layers and edge effects. It is shown that interlaminar shear stresses are primarily a function of the mismatch in coefficients of mutual influence which can be as much as ten times greater than the mismatch in Poisson's ratio. The mismatch in coefficients of mutual influence has a high peak value in the 10-15 deg range for plus or minus theta laminates (where theta is the angle of fiber orientation measured from the axis of the coupon). This mismatch is reduced by a factor of two when the plus or minus theta layers are interspersed between 0 and 90 deg layers. Application of the results to composite design is illustrated by an example.

Herakovich, C. T.↗
DOE OSTI2017

Fragmentation Prediction for a Brittle Ceramic: An Integrated Two-Scale Model Approach

A new implementation of a multi-scale fragmentation model is introduced that combines existing independent macro and micro-scale models into a single material model within the Library of Advanced Materials for Engineering (LAME) that can be used directly by the finite element structural mechanics code SIERRA/SM, developed at Sandia National Laboratories. The implementation not only joins existing independent fragmentation models into a single framework, but also enables further development by virtue of being integrated into SIERRA/SM. Integration with a finite element structural mechanics code for a true two-way coupling of the fragmentation models that were previously independent. Hereafter, the prior implementation will be referred to as the sequentially applied fragmentation model. In contrast, the newly developed model will be called the integrated two-scale model. The sequentially applied fragmentation model consists of two independent models applied sequentially to account for the macro-scale and microscale fragmentation. The macro-scale fragmentation behavior is calculated using an elastic gradient damage explicit material model developed to model fracture in brittle materials. The micro-scale fragmentation model is an implementation of the 1D cohesive-zone model developed by Zhou, et al. The micro-scale model is implemented by post-processing the macro-scale data that provides initial conditions for the 1D analysis. The micro-scale model is necessary to predict the resulting fragment size distribution at length scales inaccessible to the finite element based macro-scale model. The full range of fragmentation behavior is then predicted by combining the results from the two independent models. The sequentially applied fragmentation model was used to predict the fragments that result from impact loading of a brittle material, which in that case was a ceramic cylinder of commercial UO{sub 2} nuclear fuel. Understanding the fragmentation behavior of such materials is important for evaluating the risk of airborne particulate release under impact loading scenarios. This work will verify the implementation of the integrated two-scale model using the same experiment modeled by the existing sequentially applied model. The purpose of this manuscript is to introduce the new integrated two-scale fragmentation model and validate the implementation against the existing sequentially applied model for a specific case of impact loading of a brittle material. This validation case will not fully utilize the benefits of having the model integrated into the finite element code as a material model. Rather, this study will demonstrate consistency between the two fragmentation models to ensure that the success of the sequentially applied model will be duplicated by the integrated two-scale approach. Once validated, further development of the model can be made by utilizing the integration into the finite element code to create a fully two-way coupled fragmentation model that will be extended to include higher fidelity models.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1998

Computational Chemistry and Lubrication

Members of NASA Lewis Research Center's Tribology and Surface Science Branch are applying high-level computational chemistry techniques to the development of new lubrication systems for space applications and for future advanced aircraft engines. The next generation of gas turbine engines will require a liquid lubricant to function at temperatures in excess of 350 C in oxidizing environments. Conventional hydrocarbon-based lubricants are incapable of operating in these extreme environments, but a class of compounds known as the perfluoropolyether (PFAE) liquids (see the preceding illustration) shows promise for such applications. These commercially available products are already being used as lubricants in conditions where low vapor pressure and chemical stability are crucial, such as in satellite bearings and composite disk platters. At higher temperatures, however, these compounds undergo a decomposition process that is assisted (catalyzed) by metal and metal oxide bearing surfaces. This decomposition process severely limits the applicability of PFAE's at higher temperatures. A great deal of laboratory experimentation has revealed that the extent of fluid degradation depends on the chemical properties of the bearing surface materials. Lubrication engineers would like to understand the chemical breakdown mechanism to design a less vulnerable PFAE or to develop a chemical additive to block this degradation.

Zehe, Michael J.↗
DOE OSTI2022

Nitrile-Containing Renewable Polymers Based on Lignin, (CRADA) No. NFE 1807437 (CRADA Final Report)

Lignin remains one of the world’s largest sources of renewable carbon, with significant potential to positively impact our carbon footprint by replacing fossil-fuel derived materials, including engineering thermoplastics and their composites. Efforts to incorporate significant quantity of lignin into engineering thermoplastics as anything other than an inert filler have to date been largely unsuccessful, however due to limitations imposed by the degradation temperature of the lignin (220 °C) and poor compatibility between the lignin and non-polar or slightly polar polymers. Recent work at Oak Ridge National Laboratory has however shown under the right conditions excellent compatibility between lignin and nitrile containing rubber compounds such as nitrile-butadiene rubber (NBR). The present work extends these findings to the incorporation of lignin into acrylonitrile-butadiene-styrene (ABS) engineering plastics. While simple binary mixing of lignin into commercial ABS resins leads to poor interfacial adhesion and resultant low toughness and ductility, appropriate matching of the lignin and ABS components, and as appropriate compatibilizing agents, leads to polymer blends incorporating 20-35% by weight lignin with a useful range of mechanical properties for many current ABS applications. By modifying the composition, the balance of properties can be readily tailored to meet the demands of specific end-user applications.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Electromagnetic levitation containerless processing of metallic materials in microgravity: rapid solidification

Space levitation processing allows researchers to conduct benchmark tests in an effort to understand the physical phenomena involved in rapid solidification processing, including alloy thermodynamics, nucleation and growth, heat and mass transfer, solid/liquid interface dynamics, macro- and microstructural evolution, and defect formation. Supported by ground-based investigations, a major thrust is to develop and refine robust computational tools based on theoretical and applied approaches. This work is accomplished in conjunction with experiments designed for precise model validation with application to a broad range of industrial processes.

42 ENGINEERING↗
DOE OSTI2025

Optimizing structured surfaces for diffractive waveguides

We introduce universal diffractive waveguide designs that can match the performance of conventional dielectric waveguides and achieve various functionalities. Optimized using deep learning, diffractive waveguides can be cascaded to form any desired length and are comprised of transmissive diffractive surfaces that permit the propagation of desired modes with low loss and high mode purity. In addition to guiding the targeted modes through cascaded diffractive units, we also developed various waveguide components and introduced bent diffractive waveguides, rotating the direction of mode propagation, as well as spatial and spectral mode filtering and mode splitting diffractive waveguide designs, and mode-specific polarization control. This framework was experimentally validated in the terahertz spectrum to selectively pass certain spatial modes while rejecting others. Without the need for material dispersion engineering diffractive waveguides can be scaled to operate at different wavelengths, including visible and infrared spectrum, covering potential applications in, e.g., telecommunications, imaging, sensing and spectroscopy.

Applied optics↗