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Results for “measured materials properties”

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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Screening and tests of materials for space applications

The outgassing properties of materials and other considerations on materials acceptance for space applications are discussed. The uses of the outgassing data for the evaluation of important performance characteristics of a space system are indicated. The deficiencies and advantages of the ASTM-E595-77 test method and materials acceptance criteria are discussed. Also discussed are the advantages for the selection of the materials and the uses of the data provided by the long-term measurements of the outgassing rates and surface re-emission of materials. The paper concludes that the results of the ASTM method with additional derived data on the material properties can be used for the initial evaluation of a space system's characteristics. Materials data on outgassing and re-emission rates at various temperatures obtained from the more expensive, long-term QCM and TGA measurements should be obtained when a detailed analysis of a system is suggested based on the various considerations discussed in the paper.

Scialdone, J. J.↗
DOE OSTI2024

Length scale effects of micro- and meso-scale tensile tests of unirradiated and irradiated Zircaloy-4 cladding

Zircaloy-4 is an essential material for cladding structures within fission-based reactors. To explore the changes in properties measured on differing length scales, FIB-machined micro-scale tensile tests were performed on both irradiated and control groups of Zircaloy-4. This was correlated with tensile testing on femtosecond laser-machined meso-scale specimens. Pronounced size effects were found when varying specimen geometry. Increases in tensile geometry size were associated with a reduction in measured yield stress for both irradiated and unirradiated samples. Here, meso-scale testing found strength and strain values similar to that of bulk-scale testing.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Structured illumination with thermal imaging (SI-TI): A dynamically reconfigurable metrology for parallelized thermal transport characterization

The recent push for the “materials by design” paradigm requires synergistic integration of scalable computation, synthesis, and characterization. Among these, techniques for efficient measurement of thermal transport can be a bottleneck limiting the experimental database size, especially for diverse materials with a range of roughness, porosity, and anisotropy. Traditional contact thermal measurements have challenges with throughput and the lack of spatially resolvable property mapping, while non-contact pump-probe laser methods generally need mirror smooth sample surfaces and also require serial raster scanning to achieve property mapping. Here, we present structured illumination with thermal imaging (SI-TI), a new thermal characterization tool based on parallelized all-optical heating and thermometry. Experiments on representative dense and porous bulk materials as well as a 3D printed thermoelectric thick film (~50 μm) demonstrate that SI-TI (1) enables paralleled measurement of multiple regions and samples without raster scanning; (2) can dynamically adjust the heating pattern purely in software, to optimize the measurement sensitivity in different directions for anisotropic materials; and (3) can tolerate rough (~3 μm) and scratched sample surfaces. Here, this work highlights a new avenue in adaptivity and throughput for thermal characterization of diverse materials.

42 ENGINEERING↗
DOE OSTI2022

Measuring the Electrochemical Corrosion of 233U-doped UO2 in a Microfluidic Device

We have developed a microfluidic, ‘particle-attached microfluidic electrochemical’ device, or PAMEC, that uses microgram quantities of radioactive materials, such as uranium dioxide (UO2), rather than bulk specimens to both observe electrochemical changes and measure spectroscopic properties. The PAMEC device reduces the need for running experiments in a shielded facility and allows for in-operando, real-time investigations of electrochemical properties and morphological changes of micrograms of particles. This novel design offers a promising platform to investigate spent nuclear fuel (SNF) and other nuclear materials under various controlled condition, and to provide insights to nuclear waste management, and fuel performance

Electrochemistry↗
NASA NTRS1998

Thermal Property Parameter Estimation of TPS Materials

Accurate knowledge of the thermophysical properties of TPS (thermal protection system) materials is necessary for pre-flight design and post-flight data analysis. Thermal properties, such as thermal conductivity and the volumetric specific heat, can be estimated from transient temperature measurements using non-linear parameter estimation methods. Property values are derived by minimizing a functional of the differences between measured and calculated temperatures. High temperature thermal response testing of TPS materials is usually done in arc-jet or radiant heating facilities which provide a quasi one-dimensional heating environment. Last year, under the NASA-ASEE-Stanford Fellowship Program, my work focused on developing a radiant heating apparatus. This year, I have worked on increasing the fidelity of the experimental measurements, optimizing the experimental procedures and interpreting the data.

Maddren, Jesse↗
NASA NTRS1984

Thermal control coatings experiment (A0138-6)

The objectives of this LDEF experiment are to verify the validity of space environment simulation performed in the laboratory in order to measure the stability of the thermo-optical properties of thermal control coatings, and to compare the behavior in space of some materials for which the available ultraviolet solar simulation is inadequate (especially in the far ultraviolet). The experimental approach is to passively expose samples of the thermal coatings of interest. These coatings include black paint, aluminum paint, white paint, a solar absorber, an optical surface reflector, second surface mirrors, metal coatings, and silica fabrics. Preflight and postflight measurements of thermo-optical properties will be compared to determine the effects of space environment exposure.

Paillous, A.↗
DOE OSTI2021

The Role of Interface in Additively Manufactured Interpenetrating Composites

Additively Manufactured Interpenetrating Composites (AMIPCs) are a relatively new metal-metal chain composite in development for use in high energy absorption systems. In this system, reinforcing phase of additively manufactured continuous lattice configurations 316L austenitic stainless-steel is in melt infiltrated with a matrix phase of A356 aluminum-silicon casting alloy. Measurements and observations of this material system have shown that weakly bonded or open/porous interface between the reinforcement and matrix phases exhibits dramatically different mechanical properties of AMIPCs, which is not currently well understood. In this work, Finite Element Models (FEM) are used to model the effects of interfaces between the composite phases. Mechanical tensile tests measurements of various composite volume fractions and varying degrees of casting infiltration are also examined and used to show consistency with the FEM results. The outcome provides insight into material design criteria and performance predictions for new hybrid material systems with exceptional damage tolerance.

Allen, Jason↗
NASA NTRS1990

Two Radiative/Thermochemical Instruments

Measurements of absorption and emission complement thermal measurements. Two laboratory instruments for research in combustion and pyrolysis equipped for radiative as well as thermal measurements. One instrument essentially differential scanning calorimeter (DSC) modified to detect radiation emitted by flames. Provides means to evaluate limits of flammability of materials exhibiting exothermic reactions in DSC's. Other instrument used to determine pyrolysis properties of specimens exposed to various gases by measurement of infrared absorption spectra of pyrolysis products.

Tapphorn, Ralph M.↗
DOE OSTI2021

Toward efficient elastocaloric systems: Predicting material thermal properties with high fidelity

A critical need to accurately model thermal behaviors of materials that exhibit strong elastocaloric effects, including predicting the effects themselves at varying stresses and temperatures, has been addressed using a simple and versatile physics-based approach. The key factor leading to the high precision is approximating the underlying elastic phase transition as a smooth modification of lattice entropy between coexisting phases. Once the phase transformation entropy is modeled to match experimentally measured strain as a function of temperature and applied stress, estimating the heat capacity, entropy, and isothermal entropy and adiabatic temperature changes in temperature-stress coordinates becomes straightforward. This approach provides insight into how thermal properties of elastocaloric materials vary through the transition based on strain measurements that are simple to perform and interpret. In addition to aiding in the rapid evaluation of new and existing elastocaloric materials, this advance is expected to prove invaluable for accurate heat transfer modeling aimed at designing efficient regenerative elastocaloric cooling devices.

36 MATERIALS SCIENCE↗
DOE OSTI2021

A Novel Variable Extensometer Method for Measuring Ductility Scaling Parameters From Single Specimens

Abstract Macro-scale ductility is not an intrinsic material property but is dependent on the overall geometry of the specimen. To account for variety in specimen geometries, multiple ductility scaling laws have been developed, which scale ductility between different specimen sizes. Traditionally, these ductility laws rely on testing multiple different specimens of varying sizes to obtain material parameters, often done by varying gauge lengths. With the use of digital image correlation (DIC), this study presents a technique where multiple different gauge lengths are extracted from a single specimen to obtain ductility scaling parameters from a single experiment. This technique provides orders of magnitude more data from each specimen than previous techniques. This variable extensometer method is then validated by testing multiple different geometries, and select scaling laws are then compared.

Mechanics↗
NASA NTRS1991

High-toughness graphite/epoxy composite material experiment

The experiment was designed to measure the effect of near-space exposure on mechanical properties of specially toughened 5208/T300 graphite-epoxy composites. The properties measured are elastic modulus, strength, and fracture toughness. Specimens were mounted on an external frame during the time of the LDEF mission. Specimen variables include angle of adjacent plies and fraction of interlaminar contact, which is controlled by the fraction of finely spaced holes in Mylar film placed between the prepreg monolayers of the composite.

Felbeck, David K.↗
NASA NTRS1999

Sensor Lead Wires Positioned on SiC-based Monolithic Ceramic and Fiber- reinforced Ceramic Matrix Composite Subcomponents with Flat and Curved Surfaces

There is strong interest in the development of silicon carbide-based monolithic ceramic and composite materials and components for demanding, high-temperature applications. Thorough characterization of material properties, including high-temperature testing under simulated or actual operating conditions, is a high priority for programs involved in developing these silicon carbide- (SiC) based materials and components. Members of the Sensors and Electronics Technology Branch at the NASA Lewis Research Center are developing minimally intrusive methods of measuring the properties (such as the surface temperature, strain, and heat flux characteristics) of components and subelements that are being tested or operated in hostile, high-temperature environments. Their primary goal is to instrument the test article or operating component with durable sensors that have a minimal effect on test conditions such as the gas flow across the surface of the item and the material response (including the through-thickness conduction of heat). Therefore, the main thrust of their work has been the development of thin-film sensors (e.g., thermocouples or strain gauges) for use on various advanced material test articles, including SiC/SiC composite components. There was a need for a better method of securing sensor lead wires on SiC-based components and subelements that would be tested at temperatures to 1000 C (or higher), to enhance the durability of the overall minimally intrusive sensor system. To address this need, Lewis researchers devised an alternative approach for positioning the sensor lead wires (which are connected to the thin-film sensors) on SiC or SiC/SiC components. A reaction-forming method of joining was used to strongly bond hoop-shaped monolithic SiC and SiC/SiC composite attachments of various sizes to both flat and curved surfaces of SiC/SiC composite subelements (see the photos). This approach is based on an affordable, robust ceramic joining technology, named ARCJoinT, which was developed at Lewis for the joining of SiC-based ceramics and fiber-reinforced composites.

Kiser, James D.↗
DOE OSTI2020

Nano-FET-enabled biosensors: Materials perspective and recent advances in North America

Field-effect transistor (FET) is a very promising platform for biosensor applications due to its magnificent properties, including label-free detection, high sensitivity, fast response, real-time measurement capability, low running power, and the feasibility to miniaturize to a portable device. 1D (e.g. carbon nanotubes, Si nanowires, conductive polymer nanowires, 1D metal oxides, and others) and 2D (e.g. graphene materials, transition metal dichalcogenides, black phosphorus, and 2D metal oxides) materials, with their unique structural and electronic properties that are unavailable in bulk materials, have helped improve the sensitivity of FET biosensors and enabled detection down to single molecule. In this article, we give insights into the rapidly evolving field of 1D and 2D materials-based FET biosensors, with an emphasis on structure and electronic properties, synthesis, and biofunctionalization approaches of these nanomaterials. In addition, the progress in the 1D/2D-FET biosensors in North America, in the last decade, is summarized in tables. Moreover, challenges and future perspectives of 1D/2D-FET biosensors are covered.

1D materials↗
DOE OSTI2024

Computational prediction of dielectric breakdown strength of a transformer paper in oil with uncertainty quantification

The determination of the dielectric breakdown strengths of microstructurally heterogeneous materials has been a primarily experimental endeavor. We report the development of a microstructure-level model for computationally predicting the breakdown strength and analyzing the interactions between electromagnetic pulses (EMP) and the constituents in a composite of cellulose-based paper and mineral oil found in electrical transformers. The model allows explicit simulation of the material breakdown process by tracking the transition of dielectric constituents from non-conductive to conductive states. The focus is on the electric fields induced in the materials and the overall conditions for dielectric breakdown (defined as the onset of avalanche) caused by the electric field induced in the composite. Responses to three distinct pulse shapes, i.e., Steep Front (SF), Lightning (L), and AC with spectra spanning 60–9 × 105 Hz are considered. It is found that the breakdown strength of the material is significantly affected by microstructure heterogeneities, the spatial variations of the constituent properties, and the pulse shapes. A probabilistic characterization of the breakdown strength is computationally obtained and compared with experimental measurements. Although one particular material is analyzed, the model and approach are applicable to other heterogeneous materials as well.

breakdowns↗
DOE OSTI2022

Predicting Solar Cell Performance from Terahertz and Microwave Spectroscopy

Abstract Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current‐voltage characteristics of a solar cell from such measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter‐laboratory variations are discussed using a (Cs,FA,MA)Pb(I,Br) 3 halide perovskite thin‐film as a case study. At 1 sun equivalent excitation, neither transport nor recombination is significantly affected by exciton formation or trapping. Terahertz, microwave, and photoluminescence transients for the neat material yield consistent effective lifetimes implying a resistance‐free JV‐curve with a potential power conversion efficiency of 24.6 %. For grainsizes above ≈20 nm, intra‐grain charge transport is characterized by terahertz sum mobilities of ≈32 cm 2 V −1 s −1 . Drift‐diffusion simulations indicate that these intra‐grain mobilities can slightly reduce the fill factor of perovskite solar cells to 0.82, in accordance with the best‐realized devices in the literature. Beyond perovskites, this work can guide a highly predictive characterization of any emerging semiconductor for photovoltaic or photoelectrochemical energy conversion. A best practice for the interpretation of terahertz and microwave measurements on photovoltaic materials is presented.

14 SOLAR ENERGY↗