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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Evaluation of Pozzolan-substituted Cast Stone for Pretreated Hanford Tank Waste

Portland cement. The future availability of quality Class F fly ash has come into question as coal-fired power plants are being converted to gas or taken offline. Consequently, alternative pozzolanic reagents are being evaluated for fly ash replacement in cementitious matrices for treating radioactive waste and debris. In 2023 and 2024, Savannah River National Laboratory (SRNL) was funded to evaluate natural pozzolans for the replacement of Class F fly in the Savannah River Site (SRS) Saltstone formulation. Based on the promising results and uncertain availability of Class F fly ash in the northwestern US, Hanford Tank Waste Operations & Closure, LLC (H2C) requested SRNL to evaluate the potential for substituting natural pozzolans in the Hanford West Area Pretreated Low Activity Tank Waste (PTW/LAW) Cast Stone formulation1 . Task 1 in this request was to determine the change in Cast Stone volume resulting from stabilization/solidification of 1 L of PTW/LAW tank waste. The densities of three (Hess Pumice, tephra pumice, and clinoptilolite zeolite) pozzolan-substituted Baseline Cast Stone mixes were determined, and volume changes relative to the fly ash-Baseline Mix with a water-to-dry mix = 0.40 were calculated.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

The Effect of Membrane Casting Irregularities on Initial Fuel Cell Performance

Membrane electrode assemblies (MEA) for polymer electrolyte membrane fuel cells (PEMFC) may possess as-manufactured non-uniformities in any of its constituent components. This article studies casting irregularities located within the PEM to understand their potential impact on MEA initial performance. Membrane material was cast on a lab-scale polymer casting line operating either within or at the boundaries of the process window. The resulting membrane material was either pristine in the former case, or, in the latter case, contained air bubbles, cracks, and other irregularities, ranging in size from about 0.6 to 3 mm. Spatial polarization experiments were conducted using a 121-channel segmented fuel cell system, and thermal imaging was performed subsequently to map hydrogen crossover to spatial performance. While total-cell polarization data was minimally impacted by the irregularities, the spatial diagnostics showed local performance impacts that, in operation over time, could cause degradation in performance or earlier failure of the MEA. Such impacts could lead to these irregularities being classified as defects, i.e., manufacturing variations that should be identified and not included in a fuel cell stack. Classification of irregularities as defects will ultimately assist the industry by contributing to the development of threshold detection limits for in-line quality control diagnostics.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2023

Results from a controlled depleted uranium metal casting experiment designed to investigate nuclear Forensic Radiochronometry Signatures

The accurate interpretation of uranium metal 230 Th/ 234 U and 231 Pa/ 235 U radiochronometry model ages requires an understanding of how uranium parent nuclides and decay progeny ( 230 Th and 231 Pa) behave during uranium metal casting. In order to directly measure the spatial distribution of 230 Th and 231 Pa in uranium metal before and after vacuum induction melting (VIM), Los Alamos National Laboratory identified uranium metal feedstock, characterized the metal feedstock, conducted a controlled casting experiment of an approximately 120 kg uranium metal rod, and characterized the cast metal. Herein this study presents radiochronometry results and quantified 230 Th and 231 Pa VIM separation factors from bulk uranium.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

Superior electrochemical performance and reduced heat generation in 3D printed vs. 2D tape-casted NMC622 electrodes

This study compares the charge storage mechanisms, thermodynamics behavior, ion transport, and heat generation in NMC622 electrodes fabricated using a novel 3D printing process and the conventional 2D tape casting process. First, potentiometric entropy measurements revealed that the charge storage mechanisms for both types of electrodes consisted of lithium deintercalation in a homogeneous solid solution of NMC622 followed by a transition from a hexagonal (H1) phase to another hexagonal (H2) phase through a monoclinic (M) phase. Both types of electrodes had similar thermodynamics behavior with overlapping entropic potential profiles. Furthermore, operando isothermal calorimetry at high C-rates indicated that the 3D printed electrodes featured larger specific capacity and better rate performance than the 2D tape-casted electrodes. The better performance of 3D printed electrodes was attributed to their larger electrode/electrolyte interfacial surface area and electrical conductivity as well as their faster lithium ion transport. As a result, the instantaneous heat generation rates were smaller in 3D printed electrodes than in 2D tape-casted electrodes, thus resulting in lower overall specific electrical energy and thermal energy dissipation per unit charge stored. Overall, additive manufacturing techniques offer great potential in producing electrodes with superior electrochemical performance and reduced heat generation for fast charging batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Search for Dark Matter Axions with CAST-CAPP

The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74 μeV to 22.47 μeV mass range. The detection concept follows the Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to g aγγ = 8 × 10 –14 GeV –1 at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Corrosion evaluation of Al-Cu-Mn-Zr cast alloys in 3.5% NaCl solution

Corrosion behavior of cast Al-Cu-Mn-Zr (ACMZ) and RR350 alloys was compared to a cast 319 alloy in 3.5 wt.% NaCl. After 168 h immersion, ACMZ and RR350 alloys suffered from preferential attack adjacent to intermetallic particles decorated at grain boundaries while the attack in 319 occurred in eutectic Al-Si dendritic boundaries. Electrochemical data allowed semiquantitative comparison of alloy resistance to corrosion initiation, and ACMZ type alloys, including RR350 and three alloys with higher Cu, were considered more resistant than 319 due to the absence of deleterious Si particles. In case of 319, such Si particles presumably drove higher micro-galvanic influence to initiate and sustain Al corrosion. With lower susceptibility to corrosion initiation, ACMZ alloys should exhibit higher or at minimum similar resistance compared to cast 319.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Microstructural stability and mechanical properties of the as-cast and heat-treated newly developed TiNbCrTa refractory complex concentrated alloy

In this study, a TiNbCrTa refractory complex concentrated alloy (RCCA) was prepared using vacuum arc remelting. The microstructural evolution and mechanical properties of both as-cast and heat-treated RCCA samples were analyzed. Heat treatment (HT) was performed at 800–1200 °C for 1 h in a vacuum-sealed environment. These samples exhibited a formation of Cr 2 Nb and Cr 2 Ti Laves phases. A variation in elemental distribution was observed, with interdendritic (ID) regions showing higher fractions of Ti and Cr, while the dendritic regions had a greater concentration of Ta and Nb. Micro-segregation at the IDs was confirmed through energy dispersive x-ray spectroscopy mapping, which inferred the formation of Cr- and Ti-rich phases during HT at 800–1200 °C. High-temperature HT at 1200 °C for 1 h led to the evolution of the hcp omega phase. Prolonged HT at 1200 °C for 96 h resulted in the evolution of a Cr-rich Laves phase (Cr 2 Ta), which was homogeneously distributed within the microstructure, indicating an unstable microstructure. Furthermore, despite prolonged HT, a variation in the elemental distribution persisted due to the presence of dendritic and ID regions. Electron backscattered diffraction analysis revealed the presence of bcc and hcp phases in the dendritic and ID regions, respectively, of the as-cast and HTed samples. The as-cast samples demonstrated a high compressive strength of approximately 2 GPa. Micro-hardness values increased with the HT temperature up to 1000 °C. Further increases under HT conditions did not significantly reduce the microhardness value, whereas prolonged HT at 1200 °C led to an increase in the microhardness value. Overall, the newly developed TiNbCrTa RCCA exhibited high-strength behavior even after the phase transformation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

The pathfinder X-Ray axion telescope for the International Axion Observatory (IAXO) and axion searches at the CERN Axion Solar Telescope (CAST)

The axion, a hypothetical pseudo-scalar particle proposed by Peccei and Quinn to resolve the strong CP problem in quantum chromodynamics, remains one of the most compelling dark matter candidates. Axions and Axion-Like Particles (ALPs) are characterized by a broad and largely unconstrained parameter space in mass and coupling strength, motivating extensive experimental searches. The International Axion Observatory (IAXO) is a next-generation axion helioscope designed to achieve over an order of magnitude improvement in sensitivity to the axion-photon coupling constant gaγ relative to previous experiments such as the CERN Axion Solar Telescope (CAST). IAXO will employ large-scale superconducting magnets, precision x-ray optics, and ultra-low-background detectors to search for solar axions produced primarily via the Primakoff effect. This work presents the design and performance of the IAXO pathfinder x-ray optic, a technological demonstrator that validated the optical concepts for IAXO through axion searches at CAST. Comprehensive ray-tracing simulations and experimental measurements were conducted to assess the optic's effective area, detection efficiency, and background suppression capabilities. Deployed at CAST in conjunction with Micromegas and GridPix detectors, the Pathfinder demonstrated record-setting sensitivity to both gaγ and the axion-electron coupling gae, establishing the most stringent laboratory constraints on solar axions to date. These results confirm the viability of the IAXO optical design and detector concept, providing a critical technological benchmark that informs the ongoing development of the BabyIAXO and full-scale IAXO telescopes.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Development of Casting Techniques for d-phase Uranium-Zirconium Alloys: CRADA 524 [Abstract only]

Casting of d-phase HALEU UZr2 alloy is an early milestone in the fabrication process for Lightbridge Fuel™. The Radiochemical Processing Laboratory at PNNL has been identified as having both the capability and expertise to perform the necessary high temperature casting of samples of Lightbridge’s alloy. The necessary equipment, facility licensing, and shipping capabilities for special nuclear material coupled with its expertise in uranium casting techniques makes PNNL uniquely suited to this project.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Cast Components for High Temperature Concentrated Solar Power Thermal Systems

Concentrating Solar-Thermal Power (CSP) components such as piping, valves fittings are required for use at temperatures up to 800°C. These are anticipated to be made using Nickel-based alloys such as Haynes ® 230 ® , Haynes ® 282 ® , or IN ® 740H ® and can contribute significantly to the cost of a CSP Gen 3 plant. Thus, there is a significant motivation to lower the cost of materials and components so that the capital costs can be minimized. In all these cases, the cost of the component has two contributions: 1. Materials cost, and 2. Manufacturing cost. Both materials cost and manufacturing costs must be kept low to attain the lowest possible cost. Materials cost can be lowered by using materials that have the ideal combination of properties at the lowest cost. Another avenue to lower cost is chose a manufacturing process that has the potential to lower the cost. Traditionally tubes are made from billets through a wrought process and can be expensive. An alternative process to consider is the centrifugal casting process where the tube is directly fabricated from molten metal. In this case, the molten metal is poured inside a cylindrical metallic mold with an insulating layer and is spun rapidly. A wide range of sizes (diameter, wall thickness, and length) can be cast using this process. The objective of this project was to develop the process for fabricating pipes and related components using a centrifugal casting process and to measure the properties of alloys fabricated using this process.

14 SOLAR ENERGY↗
DOE OSTI2024

Evaluation of the Mechanical Properties of Cast and Wrought CF8C-Plus Relevant to ASME Code Case Qualification

The mechanical behavior of a cast form of an advanced austenitic stainless steel, CF8C-Plus, is compared with that of its wrought equivalent in terms of both tensile and creep-rupture properties and estimated allowable stress values for pressurized service at temperatures up to about 850°C. A traditional Larson-Miller parametric model is used to analyze the creep-rupture data and to predict long-term lifetimes for comparison of the two alloy types. The cast CF8C-Plus exhibited lower yield and tensile strengths, but higher creep strength compared to its wrought counterpart. Two welding methods, shielded-metal-arc welding (SMAW) and gas-metal-arc welding, met the weld qualification acceptance criteria in ASME BPVC Section IX for the cast CF8C-Plus. However, for the wrought CF8C-Plus, while SMAW and gas-tungsten-arc welding passed the tensile acceptance criteria, they failed the side bend tests due to lack of fusion or weld metal discontinuities.

Chen, Xiang↗
NASA NTRS1973

Feasibility of producing cast-refractory metal-fiber superalloy composites

A study was conducted to evaluate the feasibility of direct casting as a practical method for producing cast superalloy tungsten or columbium alloy fiber composites while retaining a high percentage of fiber strength. Fourteen nickel base, four cobalt, and three iron based matrices were surveyed for their degree of reaction with the metal fibers. Some stress-rupture results were obtained at temperatures of 760, 816, 871, and 1093 C for a few composite systems. The feasibility of producing acceptable composites of some cast nickel, cobalt, and iron matrix alloys with tungsten or columbium alloy fibers was demonstrated.

Mcintyre, R. D.↗
NASA NTRS1974

Casting copper to tungsten for high-power arc lamp cathodes

Voids forming at interface when copper is cast onto tungsten can be eliminated by adding wetting agent during casting process. Small amount of copper and nickel are cast onto thoriated tungsten insert, insert is recast with more copper to form electrode. Good thermal conductance results in long-lived cathode.

Will, H. A.↗
NASA NTRS1974

Magnesium-lithium casting alloys

The strength properties of magnesium-lithium alloys at room, low, and high temperatures are investigated. It is found that the alloys may have practical application at ambient temperatures up to 100 C, that negative temperatures have a favorable influence on the alloy strength, and that cyclic temperature variations have practically no effect on the strength characteristics. The influence of chemical coatings on corrosion resistance of the MgLi alloys is examined. Several facilities based on pressure casting machines, low-pressure casting machines, and magnetodynamic pumps were designed for producing MgLi alloy castings. Results were obtained for MgLi alloys reinforced with fibers having a volumetric content of 15%.

Latenko, V. P.↗
NASA NTRS1978

Rheology of composite solid propellants during motor casting

In a study conducted to evaluate flow parameters of uncured solid composite propellants during motor casting, two motors (1.8M-lb grain wt) were cast with a PBAN propellant exhibiting good flow characteristics in a 260-in. dia solid rocket motor. Attention is given to the effects of propellant compositional and processing variables on apparent viscosity as they pertain to rheological behavior and grain defect formation during casting. It is noted that optimized flow behavior is impaired with solid propellant loading. Non-Newtonian pseudoplastic flow is observed, which is dependent upon applied shear stress and the age of the uncured propellant.

Rogers, C. J.↗
NASA NTRS1979

Silicon ingot casting: Heat exchanger method. Multi-wire slicing: Fixed abrasive slicing technique, phase 3

In the area of ingot casting the proof of concept of heat exchanger method (HEM) was established. It was also established that HEM cast silicon yielded solar cell performance comparable to Czochralski grown material. Solar cells with conversion efficiencies of up to 15% were fabricated. It was shown that square cross-section ingots can be cast. In the area of crystal slicing, it was established that silicon can be sliced efficiently with the fixed abrasive slicing technique approach. This concept was carried forward to 10 cm diameter workpiece.

Schmid, F.↗
NASA NTRS1979

Composites for Advanced Space Transportation Systems (CASTS)

A summary is given of the in-house and contract work accomplished under the CASTS Project. In July 1975 the CASTS Project was initiated to develop graphite fiber/polyimide matrix (GR/PI) composite structures with 589K (600 F) operational capability for application to aerospace vehicles. Major tasks include: (1) screening composites and adhesives, (2) developing fabrication procedures and specifications, (3) developing design allowables test methods and data, and (4) design and test of structural elements and construction of an aft body flap for the Space Shuttle Orbiter Vehicle which will be ground tested. Portions of the information are from ongoing research and must be considered preliminary. The CASTS Project is scheduled to be completed in September 1983.

Davis, J. G., Jr.↗
NASA NTRS1978

Fracture resistance of Ti-5Al-2.5Sn extra-low interstitial castings

Fracture toughness and cyclic crack propagation data for Ti-5Al-2.5Sn extra-low interstitial (ELI) castings, 0.51 and 2.54 cm (0.20 and 1.00 in.) thick, at 394, 294, 77, and 20 K (250, 70, -320, and -423 F), are presented. Both surface flaw and compact tension geometries were tested. Comparison is made with other titanium alloys in both wrought and cast forms. Crack propagation resistance is comparable to wrought Ti-5Al-2.5Sn ELI, even with the extremely coarse as-cast grain size encountered.

Fiftal, C. F.↗