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NASA NTRSDate not supplied

Novel Ceramic Dispersion Strengthened Refractory Metals for Improved Printability and Properties

Refractory metals and alloys are of major interest for nuclear fusion systems, space nuclear power and propulsion, and hypersonic applications due to their desirable properties at elevated temperatures (>1500°C). Limitations of refractory materials include their low ductility, poor oxidation resistance, and high manufacture cost using traditional techniques. Additive manufacturing (AM) can reduce material waste associated with manufacture, but AM fabrication is impacted by the brittleness of these refractory metals, resulting in excessive cracking during printing. Cracking reduces the effectiveness of hot isostatic pressing (HIP) which is commonly used to improve density and mechanical properties of AM components. The goal of this work is to improve refractory metal printability without majorly affecting the material properties which are the main reason these materials are used. Ceramic nanoparticles have been shown to help improve material properties after heat treatment. Results will be shown that demonstrate the effectiveness of adding nanoparticles to refractory metals. Additionally, there will be discussion regarding how these nanoparticles change the effect of heat treatments such as HIP compared with the AM pure metal samples.

Carly J. Romnes↗

NASA NTRSDate not supplied

A Procedure to Quantify Interlaminar Damage in Refractory Composites by In-Situ Micro-X-Ray Computed Tomography

Refractory composites are relevant for hot-structure applications on re-entry vehicles. To develop optimized high-performance hot structures, accurate material property data is required. Material properties that often limit design in two-dimensional (2-D) composites are interlaminar strengths. A better understanding of the failure mechanisms for interlaminar shear (ILS), interlaminar tension (ILT), and curved-beam interlaminar tension (CB-ILT) tests can provide insight on improving the design and fabrication of refractory composites. In-situ tests were performed to capture the progressive failure in American Society for Testing and Materials (ASTM) sized ILS (ASTM D3846), ILT (ASTM D7291), and CB-ILT (ASTM D6415) specimens. Before measuring internal damage of refractory composites specimens, the methodology of the test setup warrants a complete and thorough discussion. Detail on the test procedure, test stand design, micro-x-ray computed tomography (CT) configuration, data processing, and CT system uncertainty is discussed. Through keeping the many parameters of the CT system consistent, the uncertainty of the CT system was minimized, optimizing the quality of measurements. The overall quality of a CT scan can be quantified by three metrics: voxel resolution, minimal voxel resolution feature detection, and directional variability. A better understanding of the progressive failure mechanisms of refractory composites is provided by the results of both the present discussion and the one found in the accompanying paper titled “Analysis of Interlaminar Damage in Refractory Composites by In-Situ Micro-X-Ray Computed Tomography”.

In-situ micro-x-ray CT↗

DOE OSTI2022

Use of novel refractory design and installation techniques for improved energy efficiency in iron and steel and other energy intensive industries

This paper describes the planned work to be performed under a United States Department of Energy funded project to bring together the key players necessary to develop and deploy new technology which could increase the thermal efficiency of the steel industry as well as other energy intensive industries. It is hoped that such improvements in energy efficiency will reduce the overall energy and environmental footprint of domestic industry, as well as provide economic benefit to the individual companies. The described project brings together a vertically integrated collaborative team consisting of the end user (U.S. Steel), material producers/suppliers (Allied Mineral Products and Reno Refractories), raw material suppliers (American Metallurgical Services, Minerals Manufacturing), and research organizations (Oak Ridge National Laboratory, National Energy Technology Laboratory and University of Alabama-Birmingham) with the objective of designing and producing new refractory materials based on novel aggregates, improved particle packing, and engineered surface texture. In addition, the recycling and use of spent refractory materials will be investigated and a novel installation technique will be developed taking advantage of new additive manufacturing technology and existing refractory shotcrete technology. It is hoped that the combination of these new technologies will allow for the improvement of the energy, environmental, and economic efficiency of the steel industry while also reducing the environmental footprint of the refractory and steel industries. Additionally, the developed technology is expected to be applicable to other energy intensive industries such as cement, glass, pulp and paper, and non-ferrous metals processing.

Hemrick, James↗

DOE OSTI2022

Additive manufacturing of complex objects using refractory matrix materials

A method for the manufacture of a three-dimensional object using a refractory matrix material is provided. The method includes the additive manufacture of a green body from a powder-based refractory matrix material followed by densification via chemical vapor infiltration (CVI). The refractory matrix material can be a refractory ceramic (e.g., silicon carbide, zirconium carbide, or graphite) or a refractory metal (e.g., molybdenum or tungsten). In one embodiment, the matrix material is deposited according to a binder-jet printing process to produce a green body having a complex geometry. The CVI process increases its density, provides a hermetic seal, and yields an object with mechanical integrity. The residual binder content dissociates and is removed from the green body prior to the start of the CVI process as temperatures increase in the CVI reactor. The CVI process selective deposits a fully dense coating on all internal and external surfaces of the finished object.

Terrani, Kurt A.↗

DOE OSTI2023

Refractory Wear Characterization in Lime Recovery Kilns

The industry standard for lime recovery kiln calcining zone refractories is 60% or 70% alumina brick. Rapid unexpected refractory wear in lime recovery kilns has often been attributed to excess alkali carryover in the lime kiln feed. Recent laboratory work attributes refractory wear to overheating and the lime charge fluxing the refractory. This paper corroborates this laboratory work with some case history post-mortem examinations of bricks removed from rotary lime kiln linings. The paper concludes with methods to manage refractory wear, including kiln burner performance.

Hemrick, James↗

DOE OSTI2024

Additive manufacturing of complex objects using refractory matrix materials

Terrani, Kurt A.↗

DOE OSTI2024

Metal coated articles comprising a refractory metal region and a platinum-group metal region, and related methods

A metal coated article includes a platinum-group metal region adjacent a refractory metal region, which is adjacent a substrate comprising an inorganic material. A refractory metal carbide layer is adjacent the substrate and the refractory metal layer is adjacent the refractory metal carbide layer. The platinum-group metal region comprises a refractory metal/platinum-group metal layer and a platinum-group metal layer. Related methods are also disclosed.

Tripathy, Prabhat K.↗

DOE OSTI2014

Condensation of refractory metals in asymptotic giant branch and other stellar environments

The condensation of material from a gas of solar composition has been extensively studied, but less so condensation in the environment of evolved stars, which has been mainly restricted to major compounds and some specific element groups such as the Rare Earth elements. Also of interest, however, are refractory metals like Mo, Ru, Os, W, Ir, and Pt, which may condense to form refractory metal nuggets (RMNs) like the ones that have been found in association with presolar graphite. We have performed calculations describing the condensation of these elements in the outflows of s-process enriched AGB stars as well as from gas enriched in r-process products. While in carbon-rich environments (C > O), the formation of carbides is expected to consume W, Mo, and V (Lodders and Fegley), the condensation sequence for the other refractory metals under these conditions does not significantly differ from the case of a cooling gas of solar composition. The composition in detail, however, is significantly different due to the completely different source composition. Condensation from an r-process enriched source differs less from the solar case. Elemental abundance ratios of the refractory metals can serve as a guide for finding candidate presolar grains among the RMNs in primitive meteorites—most of which have a solar system origin—for confirmation by isotopic analysis. We apply our calculations to the case of the four RMNs found by Croat et al., which may very well be presolar.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2019

Influence of Al{sub 2}O{sub 3} Level in CaO-SiO{sub 2}-MgO-Al{sub 2}O{sub 3} Refining Slags on Slag/Magnesia-Doloma Refractory Interactions

The influence of the Al{sub 2}O{sub 3} level in CaO-SiO{sub 2}-MgO-Al{sub 2}O{sub 3} (CSMA) stainless steel refining slags on the degradation of magnesia-doloma refractories was investigated through static refractory finger corrosion tests. The tests were performed at 1620 °C under Ar atmosphere, using slags with Al{sub 2}O{sub 3} contents of 5, 10, and 20 wt pct, respectively. The results indicate that the formation of 2CaO·SiO{sub 2} at the slag/refractory interface was suppressed by increasing the Al{sub 2}O{sub 3} content to 20 wt pct, thereby changing the corrosion mechanism from an indirect dissolution to a direct dissolution of CaO and MgO from the refractories. The increased solubility limit of MgO by the Al{sub 2}O{sub 3}-rich CSMA slags results in an overall higher corrosion rate of the MgO-doloma refractory.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Interaction of magnesia-carbon refractory with metallic iron under flash ironmaking conditions

The interaction of a magnesia-carbon refractory with iron under flash ironmaking conditions has been investigated in this work. Oxidation of carbon from the magnesia-carbon refractory took place and the formation of magnesiowustite (Mg x Fe 1-x O) solid solution occurred as a result of the interaction between magnesia (MgO) in the refractory with iron (Fe). A kinetics model for the growth of magnesiowustite (Mg x Fe 1-x O) was developed based on the counterdiffusion of Fe 2+ and Mg 2+ cations through it. Experiments were conducted with iron powder and magnesia-carbon refractory in the temperature range 1200–1400 °C under gas atmospheres relevant to flash ironmaking and analyses of reacted samples using SEM-EDX and EPMA techniques confirmed the formation of magnesiowustite (Mg x Fe 1-x O). Using the kinetics model and the composition profiles determined with EPMA, the values of interdiffusion coefficient ( D ¯ F e - M g ), averaged over the composition range, were calculated. The activation energy ( E a ) for the solid-state diffusion process was determined to be 377 kJ/mol.

36 MATERIALS SCIENCE↗

DOE OSTI2026

A critical review on additive manufacturing of refractory alloys from a data analytics perspective- beyond nickel-based superalloys

Refractory alloys (RAs) are promising materials due to their exceptional physicochemical properties, but most research remains at the laboratory scale. For broader adoption, advancements in manufacturing are essential. Because their high stability makes conventional methods like machining and casting difficult, additive manufacturing (AM) is emerging as an effective approach for fabricating refractory alloy components. However, AM's repeated non-equilibrium thermal cycles introduce undesired features (e.g. defects, anisotropic microstructures, and residual stresses), which are magnified due to RAs’ unique properties. This paper comprehensively reviews the state-of-the-art methods of AM for refractory alloys. It explores data analytics techniques to establish design rules based on multi-fidelity experimental and computational methods. Furthermore, it investigates integrated, collaborative efforts to harmonise standalone databases, information, knowledge, and predictive models at multi-physics, multi-stage, and multi-scale. Unlike the existing literature that focuses primarily on material systems or process fundamentals, this work provides an integrated perspective on AM of refractory alloys from a data analytics standpoint, highlighting the roles of integrated computational materials engineering (ICME), verification, validation, and uncertainty quantification (VV&UQ), and digital twin-driven qualification in overcoming data scarcity and accelerating rapid qualification.

Additive manufacturing↗

DOE OSTI2015

TOWARD THE FORMATION OF CARBONACEOUS REFRACTORY MATTER IN HIGH TEMPERATURE HYDROCARBON-RICH ATMOSPHERES OF EXOPLANETS UPON MICROMETEOROID IMPACT

We report on laboratory simulation experiments mimicking the chemical processing of model atmospheres of exoplanets containing C3 and C4 hydrocarbons at moderate temperatures of 400 K upon interaction of catalytic surfaces of micrometeoroids. By utilizing an ultrasonic levitator device and heating singly levitated particles under simulated microgravity conditions, Raman spectroscopy is utilized as a non-invasive tool to probe on line and in situ the conversion of C3 and C4 hydrocarbons to refractory carbonaceous matter on the surfaces of levitated particles. Secondary Ion Mass Spectrometry and electron microscopic imaging were also conducted to gain further insight into the elementary composition and structures of the refractories formed. Our results provide compelling evidence that in the presence of a catalytic surface, which can be supplied in the form of micrometeoroids and atmospheric dust particles, hydrocarbon gases present in the atmospheres of exoplanets can be converted to refractory, carbon-rich carbonaceous matter of mainly graphitic structure with a carbon content of at least 90% at elevated temperatures. This finding might explain the low methane to carbon monoxide (CH{sub 4}–CO) ratio in the hot Neptune GJ 436b, where the abundant methane photochemically converts to higher order hydrocarbons and ultimately to refractory graphite-like carbon in the presence of a silicon surface.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Transparent Refractory Aerogels for Efficient Spectral Control in High–Temperature Solar Power Generation

Although spectrally selective materials play a key role in existing and emerging solar thermal technologies, temperature-related degradation currently limits their use to below 700 °C in vacuum and even lower temperatures in air. Here a solar-transparent refractory aerogel that offers stable performance up to 800 °C in air is demonstrated, which is significantly greater than its silica counterpart. This improved stability is attributed to the formation of a refractory aluminum silicate phase, which is synthesized using a conformal single cycle of atomic layer deposition within the high-aspect-ratio pores of silica aerogels. Furthermore, based on direct heat loss measurements, the transparent refractory aerogel achieves a receiver efficiency of 75% at 100 suns and an absorber temperature of 700 °C, which is a 5% improvement over the state of the art. Transparent refractory aerogels may find widespread applicability in solar thermal technologies by enabling the use of lower-cost optical focusing systems and eliminating the need for highly evacuated receivers. In particular, a shift to higher operating temperatures while maintaining a high receiver efficiency can enable the use of advanced supercritical CO 2 power cycles and ultimately translate to an ≈10% (absolute) improvement in solar-to-electrical conversion efficiency relative to existing linear concentrating systems.

14 SOLAR ENERGY↗

DOE OSTI2018

The Role of Radiation Therapy in Patients With Relapsed or Refractory Hodgkin Lymphoma: Guidelines From the International Lymphoma Radiation Oncology Group

Relapsed and refractory Hodgkin lymphoma (HL) challenges clinicians to devise treatment strategies that are effective and safe. This problem is particularly prominent in an era when de-escalation trials are designed to minimize therapeutic toxicities in both early- and advanced-stage disease. Radiation therapy is the single most effective treatment modality for HL, and its integration into salvage regimens, or its independent use in select patients, must be understood to maximize our success in treating these patients. The complexity of treating relapsed or refractory HL derives from the spectrum of primary treatment approaches currently in use that creates heterogeneity in both treatment exposure and the potential toxicities of salvage therapy. Patients can have relapsed or refractory disease after limited or aggressive primary therapy (with or without radiation therapy), at early or delayed time points, with limited or extensive disease volumes, and with varying degrees of residual morbidity from primary therapy. Their response to salvage systemic therapy can be partial or complete, and the use of consolidative stem cell transplantation is variably applied. New biologics and immunotherapeutic approaches have broadened but also complicated salvage treatment approaches. Through all of this, radiation therapy remains an integral component of treatment for many patients, but it must be used effectively and judiciously. The purpose of this review is to describe the different treatment scenarios and provide guidance for radiation dose, volume, and timing in patients with relapsed or refractory HL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2026

Solidification cracking of refractory alloys: a computational and machine learning study to investigate composition-dependence for improved weldability and additive manufacturability

Large-batch numerical, CALculation of PHAse Diagrams (CALPHAD)-based solidification cracking calculations are performed and then analyzed with machine learning methods to generate models that relate chemistry of refractory alloys to cracking susceptibility. Kou’s solidification cracking index is used to study the refractory alloys including O, N, C binary mixtures with Mo, Ta, Nb, and W, the molybdenum-based TZM, Niobium-based C103, and Tantalum-based T111 and Ta-10 W, as well as hypothetical refractory ternary alloys. Findings strongly validate Kou’s Crack Susceptibility Index (CSI) against Varestraint test data for Nb- and Ta-based alloys, establishing CSI thresholds where refractory alloys with CSI < 15,000 K are likely weldable, CSI > 15,000 K are prone to cracking, and CSI > 25,000 K are likely unweldable (or unprintable). Furthermore, interstitial elements C, N, and O significantly increase crack susceptibility, with some existing material specifications coinciding with peak cracking susceptibility concentrations. Finally, machine learning-derived elemental potency factors enable rapid prediction of CSI from alloy chemistry for C103, TZM, Ta-10 W, and T-111 alloys. These results provide practical guidance for feedstock selection, powder reuse limits, and alloy specification amendments for welding and additive manufacturing applications.

36 MATERIALS SCIENCE↗

DOE OSTI2025

A new method for measuring refractory corrosion of ceramics in glass

Abstract Nuclear waste glass vitrification furnaces are lined with refractory ceramic blocks to contain the molten glass. The refractory liner is susceptible to corrosion and has a finite service lifetime. For this reason, predicting the refractory corrosion in contact with molten glass is integral to estimating melter service lifetime. Standardized laboratory tests varying time and temperature are commonly performed to estimate refractory material loss as a function of glass composition. These data are time and resource‐intensive to collect and are susceptible to considerable measurement error. In order to accelerate glass formulation and design for nuclear waste vitrification, methods are needed to increase laboratory‐scale throughput while maintaining data quality. In this work, a method to remove the residual glass from a corroded coupon using hydrofluoric acid is presented that accelerates the throughput of sample analysis while simultaneously facilitating more accurate measurements.

Amoroso, Jake W. [Savannah River National Laborato↗

DOE OSTI2021

Heating events in the nascent solar system recorded by rare earth element isotopic fractionation in refractory inclusions

Equilibrium condensation of solar gas is often invoked to explain the abundance of refractory elements in planets and meteorites. This is partly motivated, by the observation that the depletions in both the least and most refractory rare earth elements (REEs) in meteoritic group II calcium-aluminum–rich inclusions (CAIs) can be reproduced by thermodynamic models of solar nebula condensation. We measured the isotopic compositions of Ce, Nd, Sm, Eu, Gd, Dy, Er, and Yb in eight CAIs to test this scenario. Contrary to expectation for equilibrium condensation, we find light isotope enrichment for the most refractory REEs and more subdued isotopic variations for the least refractory REEs. This suggests that group II CAIs formed by a two-stage process involving fast evaporation of preexisting materials, followed by near-equilibrium recondensation. The calculated time scales are consistent with heating in events akin to FU Orionis– or EX Lupi–type outbursts of eruptive pre–main-sequence stars.

58 GEOSCIENCES↗

DOE OSTI2015

Distributed Fiber Optic Sensor for On-Line Monitoring of Coal Gasifier Refractory Health

This report summarizes technical progress on the program “Distributed Fiber Optic Sensor for On-Line Monitoring of Coal Gasifier Refractory Health,” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The scope of work entails analyses of traveling grating generation technologies in an optical fiber, as well as the interrogation of the gratings to infer a distributed temperature along the fiber, for the purpose of developing a real-time refractory health condition monitoring technology for coal gasifiers. During the project period, which is from 2011-2015, three different sensing principles were studied, including four-wave mixing (FWM), coherent optical time-domain reflectometer (C-OTDR) and Brillouin optical time-domain analysis (BOTDA). By comparing the three methods, the BOTDA was selected for further development into a complete bench-top sensing system for the proposed high-temperature sensing application. Based on the input from Eastman Chemical, the industrial collaborator on this project, a cylindrical furnace was designed and constructed to simulate typical gasifier refractory temperature conditions in the laboratory, and verify the sensor’s capability to fully monitor refractory conditions on the back-side at temperatures up to 1000°C. In the later stages of the project, the sensing system was tested in the simulated environment for its sensing performance and high-temperature survivability. Through theoretical analyses and experimental research on the different factors affecting the sensor performance, a sensor field deployment strategy was proposed for possible future sensor field implementations.

01 COAL, LIGNITE, AND PEAT↗