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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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9 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Manufacture aluminum alloy tube from powder with a single-step extrusion via ShAPE

Mechanical performance of aluminum in terms of strength, wear and corrosion resistance, especially high-temperature strength has been shown to improve with the addition of transition metal (TM) elements of Fe, Cr, and Ti. However, these feedstock materials occur as powders. As such, the traditional fabrication process is complex and expensive because it requires multiple procedures and consumes considerable energy. This study developed Shear Assisted Processing and Extrusion (ShAPE) as a single-step process that manufactures tubes directly from Al-TM powders obtained via gas atomization. Meter-long Al-TM alloy tubes are extruded from powders with different processing conditions. The ShAPE tubes have very low porosity and the average density is 2.94 kg/cm 3 , which is equal to or higher than parts fabricated by hot extrusion and sintering. The powder-to-tube fabrication process was revealed and discussed by examining the microstructural evolution. The Vickers hardness of ShAPE tubes ranges from 110 to 140 HV through wall thickness and at different extrusion speeds. The variation in hardness was correlated with the extent of refinement of intermetallics and attributed to the shear deformation per unit extrusion length. Energy cost analysis shows that ShAPE save ~60% energy compared to the conventional sintering and extrusion processes. Results indicate ShAPE is a low-cost, high-efficiency manufacturing process for producing tubes from metallic powders.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Achieving strong and stable nanocrystalline Al alloys through compositional design

Abstract Al alloys often suffer from low mechanical strength and lack high-temperature microstructural and mechanical robustness. A series of binary and ternary nanocrystalline (NC) Al transition metal alloys with supersaturated solid solution and columnar nanograins have been recently developed by using magnetron sputtering, manifesting a new realm of mechanical properties and thermal stability. Distinct solutes cause evident differences in the phase transformations and efficiencies for grain refinement and crystalline-to-amorphous transition. Certain sputtered Al-TM alloys have shown room-temperature mechanical strengths greater than 2 GPa and outstanding thermal stability up to 400 °C. In addition, the NC Al alloys show mechanical anisotropy and tension–compression asymmetry, revealed by micromechanical tests. Through the process encapsulating various compositionally distinct systems, we attempt to illuminate the solute effects on grain refinement and properties and more importantly, tentatively unravel the design criteria for high-strength and yet thermally stable NC Al alloys. Graphic Abstract

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TmAl by Materials Project

TmAl crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded in a 2-coordinate geometry to eight Al atoms. There are a spread of Tm–Al bond distances ranging from 3.02–3.37 Å. In the second Tm site, Tm is bonded in a 6-coordinate geometry to eight Al atoms. There are a spread of Tm–Al bond distances ranging from 3.02–3.51 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to eight Tm and four Al atoms to form a mixture of distorted edge, corner, and face-sharing AlTm8Al4 cuboctahedra. There are two shorter (2.72 Å) and two longer (2.78 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 10-coordinate geometry to eight Tm and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TmAl3 by Materials Project

TmAl3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Tm is bonded to twelve equivalent Al atoms to form TmAl12 cuboctahedra that share corners with twelve equivalent TmAl12 cuboctahedra, edges with twenty-four equivalent AlTm4Al8 cuboctahedra, faces with six equivalent TmAl12 cuboctahedra, and faces with twelve equivalent AlTm4Al8 cuboctahedra. All Tm–Al bond lengths are 2.99 Å. Al is bonded to four equivalent Tm and eight equivalent Al atoms to form distorted AlTm4Al8 cuboctahedra that share corners with twelve equivalent AlTm4Al8 cuboctahedra, edges with eight equivalent TmAl12 cuboctahedra, edges with sixteen equivalent AlTm4Al8 cuboctahedra, faces with four equivalent TmAl12 cuboctahedra, and faces with fourteen equivalent AlTm4Al8 cuboctahedra. All Al–Al bond lengths are 2.99 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TmAl2 by Materials Project

TmAl2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Tm is bonded in a 12-coordinate geometry to four equivalent Tm and twelve equivalent Al atoms. All Tm–Tm bond lengths are 3.38 Å. All Tm–Al bond lengths are 3.23 Å. Al is bonded to six equivalent Tm and six equivalent Al atoms to form a mixture of edge, face, and corner-sharing AlTm6Al6 cuboctahedra. All Al–Al bond lengths are 2.76 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TmAl3 by Materials Project

TmAl3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tm is bonded to twelve equivalent Al atoms to form a mixture of corner and face-sharing TmAl12 cuboctahedra. There are six shorter (3.04 Å) and six longer (3.09 Å) Tm–Al bond lengths. Al is bonded in a 10-coordinate geometry to four equivalent Tm and six equivalent Al atoms. There are two shorter (2.76 Å) and four longer (2.81 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm3Al2 by Materials Project

Tm3Al2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. there are three inequivalent Tm sites. In the first Tm site, Tm is bonded in a distorted square co-planar geometry to four equivalent Al atoms. All Tm–Al bond lengths are 3.27 Å. In the second Tm site, Tm is bonded in a 6-coordinate geometry to six equivalent Al atoms. There are two shorter (3.06 Å) and four longer (3.08 Å) Tm–Al bond lengths. In the third Tm site, Tm is bonded in a 6-coordinate geometry to six equivalent Al atoms. There are two shorter (3.02 Å) and four longer (3.17 Å) Tm–Al bond lengths. Al is bonded in a 10-coordinate geometry to eight Tm and two equivalent Al atoms. There are one shorter (2.74 Å) and one longer (2.94 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm3Al by Materials Project

Tm3Al is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tm is bonded to eight equivalent Tm and four equivalent Al atoms to form distorted TmTm8Al4 cuboctahedra that share corners with four equivalent AlTm12 cuboctahedra, corners with fourteen equivalent TmTm8Al4 cuboctahedra, edges with six equivalent AlTm12 cuboctahedra, edges with twelve equivalent TmTm8Al4 cuboctahedra, faces with four equivalent AlTm12 cuboctahedra, and faces with sixteen equivalent TmTm8Al4 cuboctahedra. There are a spread of Tm–Tm bond distances ranging from 3.23–3.49 Å. There are two shorter (3.24 Å) and two longer (3.36 Å) Tm–Al bond lengths. Al is bonded to twelve equivalent Tm atoms to form AlTm12 cuboctahedra that share corners with six equivalent AlTm12 cuboctahedra, corners with twelve equivalent TmTm8Al4 cuboctahedra, edges with eighteen equivalent TmTm8Al4 cuboctahedra, faces with eight equivalent AlTm12 cuboctahedra, and faces with twelve equivalent TmTm8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Shear Assisted Processing and Extrusion (ShAPE) of Aluminum Alloy 7075, 2024, and Al-12.4TM

The most common aluminum alloys utilized in the aerospace industry are 7075 and 2024 due to their high strength-to-weight ratio compared to advanced high strength steels and other aluminum alloys. Despite excellent performance, these aluminum alloys have seen limited use outside of the aerospace industry due in part to high cost. If high-performance aluminum extrusions could be made more cost effectively by eliminating energy intensive process steps typical of conventional extrusion, then numerous opportunities exist for more widespread adoption. A key reason for the high cost of 7075 and 2024 extrusions (25-75% higher than 6061) is their slow extrusion speed. 7075 and 2024 are limited to 2 m/min and 3.5 m/min respectively, in contrast to 6061 which can be extruded at 20–80 m/min. In addition to slow speed, aluminum alloys require numerous thermal treatments throughout the extrusion process including homogenization and pre-heating prior to extrusion, and solution heat treating and artificial aging after extrusion. Each of these steps contribute to the total energy consumed during manufacturing of extruded components. This project investigates the use of ShAPE to improve extrusion speed and reduce, or even eliminate, the typical thermal treatments for high strength aluminum alloys, all while improving material performance. The overarching goal of this project was to demonstrate that Shear Assisted Processing and Extrusion (ShAPE) can manufacture high-performance aluminum alloy tubing with lower manufacturing energy and improved mechanical properties compared to conventional extrusion. Unlike conventional extrusion where the billet is rammed against a stationary die using a strictly linear motion, the ShAPE process superimposes a rotational shear force by spinning the die while the billet is plunged. Compared to conventional linear extrusion, the ShAPE process imparts significantly more strain into the feedstock material, which enables the formation of novel microstructures. These microstructures manifest an array of property and process improvements for extrusion of high-performance aluminum alloys. The following accomplishments were achieved for this project: Extrusion of 7075 at 12.2 meters/min compared to 2 meters/min for conventional extrusion; Elimination of 7075 billet homogenization (430 °C for 20 hours) which is required prior to conventional extrusion; Elimination of 7075 billet pre-heating (400 °C for 1 hour) in a separate furnace which is required prior to conventional extrusion; Achieved 7075-T6with yield strength = 595 MPa, ultimate tensile strength = 531MPa, and elongation = 17.4% for extrusions made from unhomogenized billets. Exceeds the ASTM and ASM standard, and typical industry values; Achieved 7075-T5 (i.e., no solution heat treatment) with yield strength = 588 MPa, ultimate tensile strength = 535 MPa, and elongation = 14.8% for extrusions made from homogenized billets; Extrusion of 2024 at 7.4 meters/min compared to 3.5 meters/min for conventional extrusion; Achieved 2024-T8510 yield strength = 522 MPa, ultimate strength = 510MPa, and elongation = 7.1% for extrusions made from wrought billets. Exceeds the ASTM and ASM standard, and typical industry values; Extrusion of Al-12.4TM high-performance aluminum powder directly into tubing, in a single step, which eliminates process steps typical of powder metallurgy extrusion.

36 MATERIALS SCIENCE↗