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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 1,567 records · Page 87
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Tritium Retention in Hexavalent Chromate-Conversion–Coated Aluminum Alloy

In this work, 6061-T6 aluminum samples were subjected to MIL-DTL-5541F type I, class-3 anodic coatings, where a yellow irradiate finish was achieved. Both chromate-conversion coatings (CCC) and unmodified samples were exposed to DT (PT = 0.51 atm) gas for 24 h at room temperature. Following loading, the samples were subjected to one of two desorption techniques: temperature-programmed desorption, or a surface stripping technique. The results show that chromic-acid anodizing of aluminum dramatically increases the total quantity of tritium retained by the treated surface as compared to unmodified aluminum. X-ray photoelectron spectroscopy and scanning electron microscopy studies of both treated aluminum and unmodified samples indicate that the CCC coating contain significant quantities of hydrated chromium. Using transmission electron microscopy, the surface is shown to have significant cracking and fracturing of the film and leads to a highly grained and porous surface. Such surface defects coupled with the vast quantity of hydration sites are likely reasons for the increased retained tritium inventory observed for CCC samples. Finally, due to the physical and chemical properties of unmodified CCC samples, they are not suitable for use in tritium environments.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Development of Uncertainty and Material Property "Truth" Models and Results for Cantilever Beam End-to-End UQ Problem

Construction of a test problem that quantitatively tests the effectiveness and robustness of the many features and capabilities that a comprehensive E2E UQ framework should have is very challenging. Accordingly, this report illustrates many of the considerations and numerical investigations that went into the construction of the Sandia Cantilever Beam End-to-End UQ test problem.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Machine Learning Enhanced Development of Functionally Graded Materials Enabled by Directed Energy Deposition

The ability to functionally grade materials provides designers with a new dimension of design flexibility that can be leveraged to improve functionality, reduce cost, or improve efficiency in a wide range of applications. This program was specifically focused on FGMs for hot and harsh gas path environments. These environments are common for the hot sections of jet engines and gas turbines, where parts undergo high temperature and mechanical loads in a corrosive environment. Expensive high γ' strengthened Ni superalloys such as René 41 (R41) and René 80 (R80) are generally used exclusively for a whole part, although only a section of the part demands such superalloys. To minimize cost, low/no γ' strengthened Ni superalloys such as Inconel 718 (INC718) could be used at less-demanding sections of the part could be welded to the high γ' strengthened Ni superalloys. However, the welding typically is a failure site due to the low durability at the welding interface. Functionally grading provides a welding alternative that can allow cost reduction without sacrificing mechanical performance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Summary of FY2024 Experimental Results to Support Development of New Inelastic Material Models and Validation of Section III, Division 5, Class A Design Rules

To address the data gap crucial for updating existing viscoplastic constitutive material models for the Class A materials in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section III, Division 5, High Temperature Reactors (ASME, 2023) for inelastic design analysis, Oak Ridge National Laboratory (ORNL) conducted experimental studies on Alloy 800H and Alloy 617 across a range of temperatures up to their maximum temperature limits in Section III, Division 5. The studies aim to characterize the materials' deformation behavior under both strain-controlled mechanical cyclic loading and thermal cycling conditions. This report summarizes ORNL's FY 2024 experimental findings on Alloy 800H and Alloy 617, focusing on pure fatigue tests, cyclic stress-strain curves, thermomechanical fatigue experiments, and verification of the high temperature cyclic damage summation design rules.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Development Results on Replacement Materials for Current Scarce or High Supply Chain Risk Materials

In September 2020, the U.S. government issued an executive order to address the threat to the domestic supply chain from its reliance on critical minerals (CMs) from foreign competitors and to support the domestic mining and processing industry. The Advanced Materials and Manufacturing Technology (AMMT) program is addressing this executive order by evaluating advanced manufacturing (AM) and its impact on the demands of CMs for energy production in general and how the deployment of AM in nuclear energy will support the projected goals of the Paris Accord and further a net-zero carbon economy (NZE) by 2050. Three strategic reports were previously prepared by the AMMT program to date and identified two areas for more detailed exploration: (1) the replacement of high-risk CMs such as cobalt and niobium by more abundant minerals and (2) the minimization and utilization of CM waste streams. The design of nuclear materials without critical elements as alloying elements, is a part of the nuclear materials strategy to overcome the critical minerals scarcity. In this report, two approaches are evaluated namely (1) replacement of critical elements as alloying elements in nuclear materials, and (2) the design of a new alloys that does not contain critical minerals as an alloying element.

36 MATERIALS SCIENCE↗
NASA NTRS1966

Development of porous ionizer materials.

Porous structures for ion engine application, discussing ionizer materials preparation, based on powder metallurgy and two-phase tungsten base alloy

POWDER METALLURGY↗
NASA NTRS1967

Development of porous ionizer materials.

Porous structures for ion engine application, discussing ionizer materials preparation, based on powder metallurgy and two-phase tungsten base alloy

TUNGSTEN ALLOY↗