SEARCH · Engineering Papers

Results for “Defects in solids”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35

All sources NASA NTRS DOE OSTI

DOE OSTI2025

Autonomous platform for solution processing of electronic polymers

The manipulation of electronic polymers’ solid-state properties through processing is crucial in electronics and energy research. Yet, efficiently processing electronic polymer solutions into thin films with specific properties remains a formidable challenge. We introduce Polybot, an artificial intelligence (AI) driven automated material laboratory designed to autonomously explore processing pathways for achieving high-conductivity, low-defect electronic polymers films. Leveraging importance-guided Bayesian optimization, Polybot efficiently navigates a complex 7-dimensional processing space. In particular, the automated workflow and algorithms effectively explore the search space, mitigate biases, employ statistical methods to ensure data repeatability, and concurrently optimize multiple objectives with precision. The experimental campaign yields scale-up fabrication recipes, producing transparent conductive thin films with averaged conductivity exceeding 4500 S/cm. Feature importance analysis and morphological characterizations reveal key design factors. This work signifies a significant step towards transforming the manufacturing of electronic polymers, highlighting the potential of AI-driven automation in material science.

Wang, Chengshi [Argonne National Laboratory (ANL),↗

DOE OSTI2026

Impact of Salt Chemistry and Interlayer Architecture on Solid Electrolyte Interphase Composition and Performance

Reversible lithium metal anodes require interphases that are chemically stable, mechanically robust, and compatible with scalable processing. Here, we use slot-die-coated, salt-rich PEO interlayers to design SEI nanolayers on Cu current collectors and isolate how salt anion chemistry controls interphase composition and lithium plating/stripping behavior in architectures relevant to Li plating and anode-free cells. Mesoscale modeling shows that dendrite initiation at SEI defects is governed by a tradeoff among interphase thickness, ionic conductivity, and stiffness through defect-driven current focusing, motivating controlled formation from thin precursor layers. Using UHV-transferred XPS and ToF-SIMS depth profiling after controlled Li deposition, we find that fluorinated sulfonylimide salts (LiTFSI, LiFSI) form mixed inorganic/organic interphases containing LiF and PEO-derived alkoxides, with LiFSI producing a more LiF-dominant Li-facing surface than LiTFSI under identical conditions. In contrast, LiNO 3 -containing interlayers yield a comparatively thick nitrate-derived interphase that reduces upon Li contact to an N-rich inorganic layer (Li–N/N 3− , LiN x O y ). In Cu| |Li cells, these designed interlayers reduce interfacial resistance and improve Coulombic efficiency (CE) and critical current density (CCD) relative to uncoated controls, with LiFSI- and LiNO 3 -based interlayers providing the highest CE/CCD. Overall, the results demonstrate a manufacturing-relevant approach to engineer SEI nanolayers by salt chemistry, providing pathways to improve reversible lithium metal anodes while reducing reliance on LiTFSI.

anion chemistry↗

NASA NTRSDate not supplied

TPSAS-NF1676L-32030-DND

Composite structures are often difficult to inspect due to the anisotropic nature of the material systems and the range of flaws and defects that can arise in the manufacturing process. NASA?s Advanced Composites Project, a public-private partnership between government, universities and industry, seeks to address improved methods, tools, and protocols to reduce the development and certification timeline for composite materials and structures. The rapid inspection of composites is one of the three focused research areas of the project. One deliverable of the project is to develop an NDE Methods and Capabilities Handbook. This Handbook provides a publically available guidance document that facilitates the selection of appropriate NDE techniques and provides recommended protocols for detecting and characterizing common flaw types in solid laminate polymer matrix composite (PMC) structures. The Handbook will reduce the time required to develop qualified inspection processes for composite aircraft structures during the development, certification, and manufacturing phases by providing a reference that helps minimize trial and error and provides guidance on best practices, techniques, and settings, for specific flaw types and geometries. The Handbook will include an NDE Guidance Matrix that provides an applicability rating for NDE techniques as they apply to given flaw types. NDE techniques will include, but is not limited to ultrasound, laser based ultrasound, infrared thermography, and x-ray CT. Flaw types will include, but are not limited to porosity, delamination, voids, AFP defects and impact damage. The Handbook will contain details that support the applicability rating including, but not limited to, specimen details, inspection parameters, data analysis techniques, inspection efficiency (speed & cost), and limitations. This presentation will describe key Handbook activities with examples of the techniques and flaw types examined by the Advanced Composite Consortium members.

Patricia A Howell↗

DOE OSTI2025

Insights into the Oxidation Mechanism of Vivianite to Metavivianite from First-Principles Calculations

Vivianite, a hydrous ferrous iron-phosphate mineral (Fe 3 (PO 4 ) 2 ·8H 2 O), readily oxidizes in contact with air yielding the less hydrous mixed-valent iron-phosphate mineral metavivianite. This topotactic transformation nominally occurs by oxidative dehydrogenation in which outgoing electrons from the iron sublattice are charge compensated by hydrolysis of structural water. However, the details of this internal charge balancing mechanism that allows the structure to remain electrostatically stable remain unknown. Here, in this study, we use density functional theory (DFT) calculations and ab initio thermodynamics (AIT) to evaluate the energetics of this process in terms of hydrogen release as a function of environmental variables such as partial pressure and temperature. The results show a thermodynamic driving force for vivianite phase transformation as oxidation progresses that is triggered by its rigid structure that has a limited accommodation for hydrogen vacancies. In contrast, metavivianite has a more flexible lattice and hydrogen bond network that stabilizes these hydrogen defects. Metavivianite is shown to be a stable intermediate for 66% residual Fe 2+ down to 33% Fe 2+ , below which other phases/structures such as santabarbarite should be more thermodynamically favorable. Our study provides a basis for experimental tests of our mechanistic findings and helps fill a basic knowledge gap about the solid-state process that defines how vivianite interacts with its surrounding environment.

Sassi, Michel [Pacific Northwest National Laborato↗

NASA NTRS1984

Activities of the Solid State Physics Research Institute

Three research programs are reviewed. These programs are muon spin rotation, studies of annealing in gallium arsenide and Hall effect studies in semiconductors. The muon spin rotation work centers around the development of a facility at the Alternating Gradient Synchrotron of BNL. Studies of annealing in GaAs concerns itself with the measurement of depolarization in GaAs. The Hall effect studies of proton damaged semiconductors provide new information on the nature of defects and dislocations in GaAs.

Source record↗

NASA NTRS2011

Ground Processing Affordability for Space Vehicles

Launch vehicles and most of their payloads spend the majority of their time on the ground. The cost of ground operations is very high. So, why so often is so little attention given to ground processing during development? The current global space industry and economic environment are driving more need for efficiencies to save time and money. Affordability and sustainability are more important now than ever. We can not continue to treat space vehicles as mere science projects. More RLV's (Reusable Launch Vehicles) are being developed for the gains of reusability which are not available for ELV's (Expendable Launch Vehicles). More human-rated vehicles are being developed, with the retirement of the Space Shuttles, and for a new global space race, yet these cost more than the many unmanned vehicles of today. We can learn many lessons on affordability from RLV's. DFO (Design for Operations) considers ground operations during design, development, and manufacturing-before the first flight. This is often minimized for space vehicles, but is very important. Vehicles are designed for launch and mission operations. You will not be able to do it again if it is too slow or costly to get there. Many times, technology changes faster than space products such that what is launched includes outdated features, thus reducing competitiveness. Ground operations must be considered for the full product Lifecycle, from concept to retirement. Once manufactured, launch vehicles along with their payloads and launch systems require a long path of processing before launch. Initial assembly and testing always discover problems to address. A solid integration program is essential to minimize these impacts, as was seen in the Constellation Ares I-X test rocket. For RLV's, landing/recovery and post-flight turnaround activities are performed. Multi-use vehicles require reconfiguration. MRO (Maintenance, Repair, and Overhaul) must be well-planned--- even for the unplanned problems. Defect limits and standard repairs need to be in-place as well as easily added. Many routine inspections and maintenance can be like an aircraft overhaul. Modifications and technology upgrades should be expected. Another factor affecting ground operations efficiency is trending. It is essential for RLV's, and also useful for ELV's which fly the same or similar models again. Good data analysis of technical and processing performance will determine fixes and improvements needed for safety, design, and future processing. Collecting such data on new or low-frequency vehicles is a challenge. Lessons can be learned from the Space Shuttle, or even the Concorde aircraft. For all of the above topics, efficient business systems must be established for comprehensive program management and good throughput. Drawings, specifications, and manuals for an entire launch vehicle are often in different formats from multiple vendors, plus they have proprietary constraints. Nonetheless, the integration team must ensure that all data needed is compatible and visible to each appropriate team member. Ground processing systems for scheduling, tracking, problem resolution, etc. must be well laid-out. The balance between COTS (commercial off the shelf) and custom software is difficult. Multiple customers, vendors, launch sites, and landing sites add to the complexity of efficient IT (Information Technology) tools.

Ingalls, John↗

DOE OSTI2023

Investigating the Role of Vacancies on the Thermoelectric Properties of EuCuSb‐Eu 2 ZnSb 2 Alloys

Abstract AMX compounds with the ZrBeSi structure tolerate a vacancy concentration of up to 50 % on the M ‐site in the planar MX ‐layers. Here, we investigate the impact of vacancies on the thermal and electronic properties across the full EuCu 1− x Zn 0.5 x Sb solid solution. The transition from a fully‐occupied honeycomb layer (EuCuSb) to one with a quarter of the atoms missing (EuZn 0.5 Sb) leads to non‐linear bond expansion in the honeycomb layer, increasing atomic displacement parameters on the M and Sb‐sites, and significant lattice softening. This, combined with a rapid increase in point defect scattering, causes the lattice thermal conductivity to decrease from 3 to 0.5 W mK −1 at 300 K. The effect of vacancies on the electronic properties is more nuanced; we see a small increase in effective mass, large increase in band gap, and decrease in carrier concentration. Ultimately, the maximum zT increases from 0.09 to 0.7 as we go from EuCuSb to EuZn 0.5 Sb.

Chanakian, Sevan↗

DOE OSTI2023

Investigating the Role of Vacancies on the Thermoelectric Properties of EuCuSb‐Eu 2 ZnSb 2 Alloys

36 MATERIALS SCIENCE↗

DOE OSTI2021

Thermodynamics of order and randomness in dopant distributions inferred from atomically resolved imaging

Abstract Exploration of structure-property relationships as a function of dopant concentration is commonly based on mean field theories for solid solutions. However, such theories that work well for semiconductors tend to fail in materials with strong correlations, either in electronic behavior or chemical segregation. In these cases, the details of atomic arrangements are generally not explored and analyzed. The knowledge of the generative physics and chemistry of the material can obviate this problem, since defect configuration libraries as stochastic representation of atomic level structures can be generated, or parameters of mesoscopic thermodynamic models can be derived. To obtain such information for improved predictions, we use data from atomically resolved microscopic images that visualize complex structural correlations within the system and translate them into statistical mechanical models of structure formation. Given the significant uncertainties about the microscopic aspects of the material’s processing history along with the limited number of available images, we combine model optimization techniques with the principles of statistical hypothesis testing. We demonstrate the approach on data from a series of atomically-resolved scanning transmission electron microscopy images of Mo x Re 1- x S 2 at varying ratios of Mo/Re stoichiometries, for which we propose an effective interaction model that is then used to generate atomic configurations and make testable predictions at a range of concentrations and formation temperatures.

25 ENERGY STORAGE↗

DOE OSTI2020

Imaging transient solidification behavior

Solidification processing offers the first opportunity to control microstructure, properties, and performance in metallic alloy components. Until recently, microstructural evaluations were limited to post-solidification characterization by destructive methods. We review the development of time-resolved, in situimaging techniques capable of capturing solid-liquid interfacial evolution in metallic alloys with high spatial and temporal resolution underdiverse solidification conditions relevant for applications ranging from conventional directional solidification, crystal growth, and casting,to welding and additive manufacturing. These experiments enable direct visualization of transient behaviors that would otherwise remain unknown, uniquely providinginsights into the physics that impact microstructure and defect development and strategies for microstructuralcontrol and defect mitigation. Understanding microstructural evolution and the characteristics that form under various solidification conditions is essential for the development of multiscale, experimentallyinformed predictive modeling. This is highlightedby solidification simulations that utilize in situmeasurements of solidification dynamics from state-of-the-art experimental techniques.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Hardness Prediction by Incorporating Heat Transfer and Molten Pool Fluid Flow in a Multi-pass, Multi-layer Weld for Onsite Repair of Grade 91 steel

Introduction: In the current fleet of fossil-fired power plants, creep strength enhanced ferritic steels (CSEF) are used to sustain the harsh service conditions. Enhanced properties of Grade 91 steel result from tempered martensite with a fine distribution of MX and M23C6 carbides. Grade 91 steel is subjected to onsite welding repair to remedy their degradation due to extreme service condition. Knowledge of weld repairability of these steels, such as as-welded hardness distribution, is essential to establishing sound repair procedures. Experimental trial and error tests can consume a lot of time as many welding variables need to be studied. For numerical modelling, most of the multi-pass multi-layer models are based on finite element method, which are limited to solve the heat conduction equation and ignore convective heat transfer due to melt flow. Moreover, the mesh has to be pre-built based on a known or assumed weld cross-section geometry. These finite element based models thus have limited predictive capability as defects are not considered and nugget size are pre-assumed. This research aims at developing a thermal and microstructure evolution model incorporating molten pool dynamics in a multi-pass multi-layer material deposition to predict the as-welded hardness distribution. Technical Approach: All the thermal, physical, and metallurgical properties of Grade 91 as a function of temperature are collected from the literature and inputted into the thermo-fluid model based on Flow-3D, a computational fluid dynamics software. A multi-pass, multi-layer material deposition is simulated where the melting of filler wire into the molten pool is directly considered based on the volume of fluid (VOF) method. The flow behaviour of the molten pool is used to understand the formation of deposition geometry and defects. The temperature profiles during the multi-pass, multi-layer welding are calculated. The results computed using the new model are compared against the experimental data of fusion zone geometry and thermal cycles. Hardness prediction in the heat-affected zone (HAZ) are made using Johnson-Mehl-Avrami (JMA) equation for solid-state phase transformation kinetics. The JMA parameters are extracted from the experimental data available in the literature. For comparison, a standard finite element heat conduction model is also developed to predict the thermal cycles and hardness distribution in the multi-pass, multi-layer weld. Expected Result: Results obtained using the molten pool dynamic simulation versus the finite element heat conduction model are compared. Specifically, the effects of convective heat transfer on the accuracy of the calculated thermal history, bead shape and size, and HAZ hardness distribution are examined.

Modeling, Grade 91 steel, Multi-pass multi-layer d↗

DOE OSTI2023

Thermodynamic controls on the synthesis, structure and reactivity of materials for energy (Final Report)

The major objectives of this renewal proposal, now entitled “Thermodynamic Controls on the Synthesis, Structure and Reactivity of Materials for Energy,” are: (a) to advance and use unique calorimetric capabilities to determine the energetics of materials relevant to energy applications, with an emphasis on new materials, (b) to understand, in terms of both macroscopic energetics and microscopic structure and bonding, the interplay of defect chemistry, oxidation-reduction and size effects at the nanoscale in determining the properties of functional oxide materials and of new classes of non-oxide materials. Recent developments have generated great excitement in organic-inorganic hybrid materials such as the alkylammonium lead halide perovskites. Our current work has emphasized fluorite-based solid electrolytes, perovskites and lithium battery materials. The systematic trends seen enable a more holistic view of the relation of thermodynamics to materials discovery and synthesis. The proposed work more explicitly targets thermodynamic controls on metastability, energy landscapes, surface and nanoscale effects, and pathways of synthesis and decomposition. This project is leveraged by many U.S. and international collaborations that both extend the science and provide opportunities for work in a diverse global setting.

36 MATERIALS SCIENCE↗

NASA NTRS1976

Fast Na/+/-ion transport in skeleton structures

The skeleton structures considered in the investigations consist of a rigid subarray with an interconnected interstitial space in which ions move in three dimensions. The classes of skeleton structures investigated include the Im3 phase of high-pressure KSbO3, the defect-pyrochlore structure illustrated by RbMgAlF6, and the carnegieite structure of high-temperature NaAlSiO4. A description is given of the results obtained in transport measurements involving dense polycrystalline ceramic disks. Results obtained in the case of the Na(+)-ion transport in Na3Zr2PSi2O12 appear particularly promising concerning the possible use of such substances in solid-electrolyte applications.

Goodenough, J. B.↗

DOE OSTI2022

Facile Electrochemical Mg-Ion Transport in a Defect-Free Spinel Oxide

Inversion, i.e. Mg/Mn antisite disorder, in a spinel oxide simultaneously causes blockage of favorable Mg 2+ migration paths, raising activation barriers for diffusion, and it reduces the number of redox-active metals, limiting the maximum capacity in the spinel. Here, an inversion-free spinel, MgCr 1.5 Mn 0.5 O 4 , was synthesized by exploiting the different intrinsic crystal field stabilization of redox-active Cr and Mn in the form of a solid-solution. The capability of the tailored spinel to reversibly (de)intercalate Mg 2+ at high redox potentials was investigated. The decrease in inversion dramatically lowered the electrochemical overpotential and hysteresis, and enabled utilization of high potentials at ~2.9 V (vs. Mg/Mg 2+ ) upon re-intercalation of Mg 2+ . A combination of characterization techniques reveals that the structural, compositional, and redox changes within the spinel oxide were consistent with the observed electrochemical Mg 2+ activity. Quantification of selective solely to lattice Mg 2+ upon the electrochemical reaction was investigated by monitoring NMR signals in isotope 25 Mg-enriched spinel oxides. Our findings enhance the understanding of Mg 2+ transport within spinel oxide frameworks and provide conclusive evidence for bulk Mg migration in oxide lattices at high redox potentials with minimized electrochemical hysteresis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Understanding the evolution of liquid and solid microjets from grooved Sn and Cu samples using radiography

Experiments were performed on grooved Sn and Cu samples to study the temporal evolution of microjets. Jets were generated by the impact of gun-launched flyer plates against the back of grooved targets made from either Cu or Sn (groove depth of ~250 μm). The Hugoniot states in the various Sn targets encompassed conditions where solid phases are maintained throughout (7 and 16 GPa) and also conditions where melting occurs upon the release of compression (25 and 34 GPa); the transition occurs near a Hugoniot pressure of 23 GPa. Cu targets at 27 and 56 GPa provide comparisons in which the jets move at similar speeds but remain solid. In all cases, the spatial distribution of mass within the microjets was measured using high-speed synchrotron radiography. The result is a time history of the jet thickness profile from which quantities like total jet mass and jet velocity can be derived. In both the solid and liquid states, we generally observe that an increase in the shock strength leads to an increase in jet mass. However, this trend breaks down for Hugoniot states near the transition from continuously solid to melted-on-release. This is evidenced by the observation that there was no difference in the rate of mass flow in Sn jets at 16 and 25 GPa, while similar pressure jumps on either side of this range caused substantial changes in the jet mass. This contrasts with the behavior of smaller polishing defects that were present on the same samples (~1 μm deep). From these, no ejecta mass was detected below the melt boundary, but obvious microjets were generated once melting occurred. This indicates that crossing the bulk melt-on-release threshold can alternately promote or inhibit the flow of mass into microjets based on the amplitude of the initial perturbation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2025

Soft phonon and the central peak at the cubic-to-tetragonal phase transition in SrTiO 3

The continuous displacive phase transition in SrTiO 3 near 𝑇 𝑐 ≈105 K features a central elastic peak in neutron-scattering investigations at temperatures above 𝑇 𝑐 , i.e., before the corresponding soft phonon mode is overdamped upon cooling. The origin of this central peak is still not understood. Here, in this work, we report an inelastic x-ray scattering investigation of the cubic-to-tetragonal phase transition in SrTiO 3 . We compare quantitatively measurements of the soft phonon mode on two differently grown samples and discuss the findings regarding results from thermodynamic and transport probes such as specific heat and thermal conductivity. Furthermore, we use inelastic x-ray scattering to perform elastic scans with both high momentum and milli-electronvolt energy-resolution and, thus, are able to separate elastic intensities of the central peak from low-energy quasielastic phonon scattering. Our results indicate that the evolution of the soft mode is similar in both samples though the intensities of the central peak differ by a factor of four. Measurements revealing anisotropic correlation lengths on cooling towards 𝑇 𝑐 , indicate that local properties of the crystals to which collective lattice excitations are insensitive are likely at the origin of the central elastic line in SrTiO 3 .

anharmonic lattice dynamics↗

DOE OSTI2025

Sound Speeds of Solids from Ultrasonic Pulse Receiver Measurements

A common method of determining elastic material properties is utilizing an ultrasonic pulse receiver. This is a non-destructive test (NDT) causing no plastic deformation of the material. It requires a pulse generator, oscilloscope, and two transducers to measure the sound velocity of a material. Both longitudinal and shear sound velocities may be obtained by utilizing the appropriate transducer. Acoustic nondestructive testing methods are often used in manufacturing certification processes and for material defect detection in industry. These methods can also be utilized to directly measure the elastic moduli of a material without damaging the material. Overall, it is a low-cost experiment with minimal preparation, and is easy to use.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Modeling the performance and faradaic efficiency of solid oxide electrolysis cells using doped barium zirconate perovskite electrolytes

Y-doped BaZrO 3 (BaZr 1 x Y x O 3 δ , or “BZY”), a proton-conducting ceramic featuring high bulk conductivity and good chemical stability, is a promising electrolyte material for solid oxide electrolysis cells. Further doping with Ce and/or Yb (creating materials “BCZY” and “BCZYYb”) can improve conductivity and sintering properties, but at significant penalty to cells’ faradaic efficiency (FE). Studies have proposed that reduction of lattice Ce can occur in the hydrogen electrode, which consumes some hydrogen produced by the hydrogen evolution reaction, leading to decreased FE. Despite studies suggesting this phenomenon, the mechanism is largely unknown. In this work, we developed a multiphysics model to study the transport of multiple defect species and the performance of BZY, BCZY, and BCZYYb, capturing the tradeoff between enhanced performance at the cost of FE for BCZY and BCZYYb electrolytes compared to BZY. We also found that increasing the water content of the anode gas supply lowers the current output of the cell but results in better FE. The model, which uses several parameters previously unavailable in the literature, was validated to experiments varying temperature, steam water content, and electrolyte material, as well as two performance metrics (performance curves and FE). Results verify and explain observed trends, informing future work on Ce-doped BZY electrolytes.

08 HYDROGEN↗