Research on electric heating of metals for thermal treatment Final report
Electric heat treatment process for aluminum and titanium aluminum vanadium alloys
ALUMINUM ALLOY↗
SEARCH · Engineering Papers
Results for “treatment”
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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Thermal and mechanical treatments for precipitation-hardenable stainless steels and their effect on mechanical properties
Mechanical and heat treatments for precipitation hardenable stainless steels and effects on mechanical properties
STAINLESS STEEL↗
The part played by oxygen in the structural changes of silicon single crystals during thermal treatment
Influence of oxygen on structure of silicon single crystals during short and prolonged heat treatment
SINGLE CRYSTAL↗
Change of electrical conductance of CdS single crystals during heat treatments in sulfur vapor between 500 deg and 700 deg C
Change of electric conductance of cadmium sulfide single crystals during heat treatments in sulfur vapor between 500 and 700 deg C
SINGLE CRYSTAL↗
Vacuum heat treatment of CdS single crystals.
Spectral distribution of photoconductance and conductance glow curves of CdS single crystals after vacuum heat treatment
HEAT TREATMENT↗
The heat treatment of duralumin
When certain light aluminum alloys are heat-treated, quenched and aged, there is considerable improvement in their tensile properties. This paper presents different methods of accomplishing these heat treatments.
DURALUMIN - HEAT TREATMENT↗
Coatings and Surface Treatments for Reusable Entry Systems
This talk outlines work in coatings for TPS done at NASA Ames. coatings and surface treatments on reusable TPS are critical for controlling the behavior of the materials. coatings discussed include RCG, TUFI and HETC. TUFROc is also discussed.
coatings↗
Location-Specific Microstructure and the Effect of Heat Treatment on Electron-Beam Melted Ni-Based Superalloy LSHR
Examine set-to-set variability with 4 build sets with the same layout Establish the effect of solutioning heat treatments (HT) on as-fabricated grain structure and microstructure – (gamma)’-solvus= 1156 ºC (1) As-fabricated (2) 2 hour subsolvus HT(-15 ºC) + conventional 2-step aging (3, 4, 5) 0.5 hour, 2 hours, 4 hours supersolvus HT (+18 ºC) + 2 step aging Gain insight into location-specific microstructure to correlate later to mechanical properties (tensile, creep, LCF behavior)
heat treatment↗
Fatigue Behavior of Laser Powder Bed Fused HAYNES 214: Effects of Different Surface Treatments
In this study, under NASA’s Rapid and Analysis Manufacturing Propulsion Technology (RAMPT) project, effects of different surface post-treatments on surface texture and fatigue behavior of L-PBF Alloy 214 were investigated. Various subtractive SPTs including abrasive flow machining (AFM), machining (M), shot peening (SP), vapormatt (VM), dry electropolishing (DE), chemical milling (CM), chemical-mechanical polishing (CMP), electro chemical (ECP) were applied to study the variations of the surface texture, microstructure and uniaxial fatigue behavior under fully reversed strain-controlled condition at four different strain amplitudes of 0.005, 0.004, 0.003, and 0.0025 mm/mm. The insights gained regarding the relationship between structural and mechanical properties for different SPTs can help establish guidelines for selecting the most effective process to enhance the performance of Laser Powder Bed Fusion (L-PBF) Alloy 214, especially for critical aerospace applications.
Post-Processing↗
Nutrient Recovery from Algae Residues Using Mild Oxidative Treatment
Algal biorefining to fuels and chemicals frequently requires both fuel production and nutrient recycle pathways. Mild Oxidative Treatment (MOT) is a promising wet oxidation route that simultaneously converts nitrogen and carbon in algae hydrolysate and extracted residues into ammonia and carboxylic acids (up to C5), respectively. The latter can be converted to sustainable aviation fuel by ketonization, condensation, and hydrodeoxygenation. We show that for a Scenedesmus algae under certain oxidation conditions, the nitrogen in the residues can be converted quantitatively to ammonia and recovered by cation exchange, while almost half of the carbon can be converted to carboxylic acids, mainly acetic acid. At the same time, we also show that soluble phosphorus in the form of phosphate can be selectively recovered by anion exchange, leaving a clean aqueous carboxylic acid stream for upgrading to fuels.
algae↗
Anode Upcycling via Tailored Solvent Treatment
To achieve a truly closed-loop direct recycling process for lithium-ion batteries, all component materials must be recovered. To date, direct recycling method development has primarily focused on the high-value transition-metal cathode materials, while the inherently lower-value graphite has been challenging to recover in a cost-effective manner. However, end-of-life graphite contains a unique engineered value due to the presence of the solid electrolyte interphase (SEI). Growth of the SEI during the cell's active lifetime stabilizes the electronically reactive graphite surface through an irreversible consumption of Li, and thus necessitates both excess lithiation of the cathode and a costly and time-intensive formation procedure during manufacturing. An optimized pre-formed SEI that capitalizes on existing SEI components from end-of-life batteries has the potential to significantly reduce cathode lithiation requirements and eliminate the critical bottleneck of formation cycling during cell remanufacturing. Further, retaining Li at the anode obviates the need for a separate Li leaching and recovery step, improving the overall efficiency of the direct recycling line. In this work, we present a novel approach to "upcycling" spent graphite through use of tailored chemical treatment to remove adverse (i.e., highly resistive and/or poorly passivating) SEI species while retaining beneficially passivating components. We have explored a rational set of solvents spanning a range of polarity, proticity, and molecular size to evaluate structure-property-performance relationships between applied solvent(s), removed and remaining SEI species, and electrochemical response of the resulting graphite product. Further, we have developed and optimized a robust and holistic analysis procedure that couples symmetric-cell electrochemical testing, multi-modal materials characterization, and advanced electrochemical modeling. These analysis results inform a set of correlative metrics for graphite performance relative to both solvent properties and upcycled SEI composition. We demonstrate effective tunability in the residual SEI composition by varying solvent identity and concentration, and report on several promising solvent systems that achieve comparable or performance to pristine graphite.
anode recycling↗
Stability of Cu(In x Ga 1− x )Se 2 Solar Cells Utilizing RbF Postdeposition Treatment under a Sulfur Atmosphere
Alkali halide postdeposition treatments (PDTs) have become a key tool to maximize efficiency in Cu(In x Ga 1− x )Se 2 (CIGS) photovoltaics. RbF PDTs have emerged as an alternative to the more common Na‐ and K‐based techniques. This study utilizes temperature‐dependent current–voltage ( JVT ) measurements to study a unique RbF PDT performed in a S atmosphere. The samples are measured before and after 6 months in a desiccator to study device stability. Both samples contain Na and K which diffuse from the soda–lime glass substrate. A reference sample and a RbF + S PDT sample both show the development of a rear contact barrier after aging. The contact barrier is higher for the RbF + S PDT sample, leading to decreased current in forward bias. Series resistance is also higher in the RbF + S PDT device which leads to lower fill factor. However, after aging the reference sample has a larger decrease in open‐circuit voltage ( V OC ). Ideality factor measurements suggest Shockley–Read–Hall recombination dominates both samples. V OC versus temperature and a temperature‐dependent activation energy model are used to calculate diode activation energies for each sample condition. Both techniques produce similar values that indicate recombination primarily occurs within the bulk absorber.
14 SOLAR ENERGY↗
Global functional connectivity density alterations in patients with bipolar disorder with auditory verbal hallucinations and modest short‐term effects of transcranial direct current stimulation augmentation treatment—Baseline and follow‐up study
Abstract Objectives To investigate the neuroimaging characteristics of auditory verbal hallucinations (AVHs) in patients with bipolar disorder (BP) experiencing depressive episodes with and without AVHs, and alterations in those characteristics after transcranial direct current stimulation (tDCS). Methods For a baseline pilot study, we recruited 80 patients with BP and depressive status (40 with and 40 without AVHs), and 40 healthy controls (HCs). Their global functional connectivity density (gFCD) was screened by functional magnetic resonance imaging (fMRI). Voxel‐wise one‐way analysis of covariance (ANCOVA) was conducted to detect intergroup differences in gFCD. In a follow‐up study, the effects of 5 weeks of tDCS augmentation treatment on clinical symptoms and gFCD were assessed in the 40 BP patients with AVHs. Results Compared to HCs, BP patients with and without AVHs exhibited increased gFCD in the central parietal lobe, insular lobe, and middle cingulate cortex, with decreased gFCD in the posterior parietal cortex, lateral prefrontal cortex, and occipital lobe (all bilateral). Only patients with AVHs showed increased gFCD in the Broca and Wernicke regions, and decreased gFCD in the hippocampus (all bilateral). After 5 weeks of tDCS, AVHs were slightly alleviated and gFCD abnormalities in the hippocampus were mildly attenuated. Conclusions Patients with BP and AVHs showed disturbances in the brain's communication capacity mainly in the left frontoparietal network, control network, and memory circuitry. Five weeks of tDCS alleviated AVHs slightly, without improving depressive symptoms, and attenuated hippocampal gFCD alterations in these patients.
Zhuo, Chuanjun↗
Morphological–Electrical Property Relation in Cu(In,Ga)(S,Se) 2 Solar Cells: Significance of Crystal Grain Growth and Band Grading by Potassium Treatment
Abstract Solution‐processed Cu(In,Ga)(S,Se) 2 (CIGS) has a great potential for the production of large‐area photovoltaic devices at low cost. However, CIGS solar cells processed from solution exhibit relatively lower performance compared to vacuum‐processed devices because of a lack of proper composition distribution, which is mainly instigated by the limited Se uptake during chalcogenization. In this work, a unique potassium treatment method is utilized to improve the selenium uptake judiciously, enhancing grain sizes and forming a wider bandgap minimum region. Careful engineering of the bandgap grading structure also results in an enlarged space charge region, which is favorable for electron–hole separation and efficient charge carrier collection. Besides, this device processing approach has led to a linearly increasing electron diffusion length and carrier lifetime with increasing the grain size of the CIGS film, which is a critical achievement for enhancing photocurrent yield. Overall, 15% of power conversion efficiency is achieved in solar cells processed from environmentally benign solutions. This approach offers critical insights for precise device design and processing rules for solution‐processed CIGS solar cells.
Kim, Joo‐Hyun↗
On the statistical treatment of the Cabibbo angle anomaly
We point out that testing the equality of the Cabibbo angle as extracted from $\Gamma(K\rightarrow \pi l\nu)$, the ratio $\Gamma(K\rightarrow l\nu)/\Gamma(\pi\rightarrow l\nu)$ and nuclear $\beta$ decays is not identical to a test of first row unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. The reason is that a CKM unitarity test involves only two parameters, while the degrees of freedom for the assessment of the goodness-of-fit of the universality of the Cabibbo angle entailed by the Standard Model (SM) is equal to the number of measurements minus one. Beyond the SM all different processes could in principle give different Cabibbo angles. Consequently, the difference between the two tests becomes relevant starting from three observables giving results for the Cabibbo angle that are in tension with each other. With current data, depending on the treatment of the nuclear $\beta$ decays, we find that New Physics is favored over the SM at $5.1\,\sigma$ or $3.6\,\sigma$ while CKM unitarity is rejected at $4.8\sigma$ or $3.0\sigma$, respectively. We argue that the best method to test the SM is to test the equality of the Cabibbo angle, because CKM unitarity is only one aspect of the SM.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Full treatment of the thrust distribution in single inclusive e + e – → h X processes
Extending the transverse momentum dependent factorization to thrust dependent observables entails a series of difficulties, ultimately associated to the behavior of soft radiation. As a consequence, the definition of the transverse momentum dependent functions has to be revised, while preserving (and possibly extending) their universality properties. Moreover, the regularization of the rapidity divergences generates non trivial correlations between rapidity and thrust. In this paper, we show how to deal with these correlations in a consistent treatment of the thrust dependence of e + e – → h X cross section, where the hadron transverse momentum is measured with respect to the thrust axis. In this framework all results obtained in the past few years properly fit together, leading to a remarkable phenomenological description of the experimental measurements.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
The Effect of Homogenization Heat Treatment on the Texture Evolution in U-10Mo Alloy
Uranium alloyed with 10 wt% Mo (U-10Mo) undergoes discontinuous precipitation (DP) when subjected to sub-eutectoid heat-treatment. It is hypothesized that the crystallographic texture of the U-10Mo can be modified to minimize the degree of DP, however the evolution of texture throughout the manufacturing process is not well understood. Crystallographic textures of two U-10Mo samples homogenized at 900°C and 1000°C were studied after uniaxial rolling and annealing. A total of 6 samples were analyzed upon rolling using a combination of hot and cold rolling conditions to strains of 83%, 90% and 97% and subsequently annealed at 700°C for one hour. Microstructures and textures were analyzed via electron backscatter diffraction (EBSD) for each homogenization, strain and post-annealed states. Results show that the U-10Mo exhibits typical rolling textures seen in body-centered cubic materials with increasing intensities of both a- and ?-fibers with increasing strain. After recrystallization, the texture appeared to be effectively randomized in all samples. Homogenization temperature showed no effect on the rolling and recrystallization behavior. Potential factors leading to the randomization of texture are discussed along with the implications of textures on the minimization of DP.
nuclear fuel, texture, rolling↗
Optimizing Conductivity and Hardness in Cu–Nb Nanolamellar Composites Fabricated Through Accumulative Roll Bonding Without Intermittent Heat Treatments
High strength/high conductivity Cu–XNb nanolamellar bimetallic composites (where X < 50 pct) were successfully processed via accumulative roll bonding. No intermittent heat treatments were used which increases industrial applicability. Estimates of conductivity from published models were validated at length scales of ~ 150 nm but were shown to be four times too low for composites with layer thicknesses < 40 nm. Nanoscale composites with conductivity of ~ 47 pct IACS and 99 Rockwell B hardness were fabricated.
36 MATERIALS SCIENCE↗