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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 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Three Sheet Al alloy assembly for automotive application

An update on joint characterization of three sheet friction stir lap welds (FSLW) in three aluminum alloys (7xxx, 5xxx, and 6xxx) for automotive assembly application is presented. Welding speed of 0.3-2.9m/min was used with pin length >5mm with the aim to reduce upturn hooking on the retreating side and avoid wormhole defect on the advancing side. Joints were also made in to enable T peel and U peel testing. Stitch welds were used to understand effects of weld length and ramp length on T peel performance. Hat sections were joined for 3-point bending and axial crush testing and tested with promising results. Several key issues that require further investigations are identified including flash management near the trim edge, weld quality with limited clamping, tool failures at speeds greater than 0.5m/min, and propensity of incipient melting for 7xxx stack-up.

Upadhyay, Piyush↗
DOE OSTI2021

Rapid Laser Reactive Sintering of Garnet Li 6.1 La 3 Zr 2 Al 0.3 O 12 Solid-State Electrolyte

All solid-state lithium-ion batteries (ASSLIBs) have gained significant interest in recent years due to their wide range of applications, including mobile devices, electric vehicles, and grid storage. Garnet-type Li 7 La 3 Zr 2 O 12 (LLZO) solid-state electrolyte (SSE) continues to be a significant player in the fabrication of ASSLIBs with excellent ionic conductivity on the order of 10 -3 S•cm -1 with the integration of dopants and sintering aids to assist conductivity and structural evolution during the sintering procedure. Traditional sintering techniques, such as solid-state sintering (SSS), have been proven to yield desirable crystal structures. However, the low ionic conductivity results from inferior microstructure, and lithium loss is a significant challenge. Recently, a relatively novel sintering process called rapid laser reactive sintering (RLRS) has shown great potential for achieving fully dense solid oxide electrolytes with less surface element loss, resulted in high ionic conductivity. Here, we applied the same RLRS method to fabricate LLZO dense electrolyte with different amounts of aluminum dopants. We hope the rapid high-temperature sintering can densify the electrolyte and avoid the lithium loss for achieving high lithium-ion conductivity. In this work, we optimized multiple combinations of laser parameters (speed, power, and defocus distance), initial precursor composition, and controlled atmospheres to discover the optimal conditions for reaching the efficacious crystal structure, microstructure, and ionic conductivity.

25 ENERGY STORAGE↗
DOE OSTI2023

Abnormal grain growth suppression in Al alloys

The present invention provides a process for suppressing abnormal grain growth in friction stir welded aluminum alloys by inserting an intermediate annealing treatment (“IAT”) after the welding step on the article. The IAT may be followed by a solution heat treatment (SHT) on the article under effectively high solution heat treatment conditions. In at least some embodiments, a deformation step is conducted on the article under effective spin-forming deformation conditions or under effective superplastic deformation conditions. The invention further provides a welded article having suppressed abnormal grain growth, prepared by the process above. Preferably the article is characterized with greater than about 90% reduction in area fraction abnormal grain growth in any friction-stir-welded nugget.

Hales, Stephen J.↗
DOE OSTI2023

High temperature lightweight Al—Fe—Si based alloys

Described herein are approaches to stabilizing AlFeSi ternary intermetallic compounds while destabilizing competing phases. The inclusion of metals such as Mn, Ni, Co, Cu, or Zn to produce quaternary systems accomplishes this problem associated with AlFeSi ternary intermetallic compounds.

Soto Medina, Sujeily↗
DOE OSTI2025

Characterizing Al quasiparticle diffusion using a positionable laser (Final Technical Report)

This Career Award accomplished most of its goals, in demonstrating for the first time a low- threshold nuclear recoil detector based on the quantum evaporation of helium-4. Through this work, we trained several PhD students and evolved this niche R&D topic into a central pillar of the DOE-funded TESSERACT project, which now plans to take underground helium data in 2028.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗