Search NASA⌕ Search

SEARCH · Search NASA

Results for “Al-W”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Directed energy deposition additive manufacturing of functionally graded Al-W composites

Directed energy deposition using laser heat sources (DED-L) is a metal additive manufacturing method that can be used to fabricate functionally graded materials by feeding multiple powder streams directly into a laser-generated melt pool. Additionally, the composition can be spatially varied by independent control of the materials feed rates. DED-L additive manufacturing is used in this work to create continuously graded Al/W composites that span 0–55 vol% W in Al over length scales from 0.6 to 1.2 mm with individual layers on the order of 0.1 mm and powder particle sizes on the order of 10 µm. The obtained composition and thickness ranges are comparable to those typically achieved using conventional powder metallurgy approaches and enables fabrication of composites to be used as a high impedance graded density impactor (GDI) in dynamic ramp compression experiments to study matter under extreme conditions. DED-L additive manufacturing of a GDI presents an opportunity to reduce GDI fabrication time to less than a day compared to many weeks by conventional methods. It is also possible to scale the deposition by DED-L to essentially unlimited dimensions in the lateral directions, whereas conventional methods become limited.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Strengthening of nanocrystalline Al using grain boundary solute additions: Effects of thermal annealing and ion irradiation

Strengthening of nanocrystalline Al by grain boundary solute additions was investigated for a series of dilute aluminum alloys, Al-Sc, Al-Sb, Al-Cr, and Al-W with grain sizes in the range of 50–200 nm. Thermal annealing of the alloys at low temperatures led to alloy softening, but with negligible change in the grain size. The re- duction in strength can be attributed to the loss of solute in the grain boundaries arising from grain boundary diffusion and precipitation. Annealing at higher temperatures led to grain growth, but with little additional loss of strength, a result of precipitation hardening. The Al-Sc and Al-Sb alloys were additionally subjected to ion irradiation at various temperatures. Furthermore, these studies revealed that annealed samples regained their hardness due to solute redistribution by ion beam mixing. Alloy strength was independent of grain size between 50 and 150 nms. Irradiation-induced segregation of Sb to grain boundaries in Al-Sb further enhanced strengthening.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al12W by Materials Project

Al12W is Tungsten structured and crystallizes in the cubic Im-3 space group. The structure is zero-dimensional and consists of two Al12W clusters. W is bonded in a cuboctahedral geometry to twelve equivalent Al atoms. All W–Al bond lengths are 2.74 Å. Al is bonded in a distorted single-bond geometry to one W atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al2W by Materials Project

WAl2 is Titanium Disilicide-like structured and crystallizes in the hexagonal P6_422 space group. The structure is three-dimensional. W is bonded in a distorted q6 geometry to ten equivalent Al atoms. There are a spread of W–Al bond distances ranging from 2.66–2.82 Å. Al is bonded in a 10-coordinate geometry to five equivalent W and five equivalent Al atoms. There are a spread of Al–Al bond distances ranging from 2.67–2.85 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al4W by Materials Project

Al4W crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent W sites. In the first W site, W is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of W–Al bond distances ranging from 2.56–2.83 Å. In the second W site, W is bonded in a 11-coordinate geometry to eleven Al atoms. There are a spread of W–Al bond distances ranging from 2.55–2.85 Å. There are seven inequivalent Al sites. In the first Al site, Al is bonded in a 4-coordinate geometry to four W atoms. In the second Al site, Al is bonded in a 1-coordinate geometry to four W atoms. In the third Al site, Al is bonded in a distorted linear geometry to two W atoms. In the fourth Al site, Al is bonded in a 3-coordinate geometry to three W atoms. In the fifth Al site, Al is bonded in a 3-coordinate geometry to three W atoms. In the sixth Al site, Al is bonded in a 2-coordinate geometry to two equivalent W atoms. In the seventh Al site, Al is bonded in a 2-coordinate geometry to two equivalent W atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al5W by Materials Project

Al5W crystallizes in the hexagonal P6_322 space group. The structure is three-dimensional. there are two inequivalent W sites. In the first W site, W is bonded to twelve Al atoms to form WAl12 cuboctahedra that share corners with six equivalent WAl12 cuboctahedra, corners with twelve AlAl9W3 cuboctahedra, edges with six equivalent WAl12 cuboctahedra, and faces with eight AlAl9W3 cuboctahedra. There are six shorter (2.75 Å) and six longer (2.84 Å) W–Al bond lengths. In the second W site, W is bonded to twelve Al atoms to form WAl12 cuboctahedra that share corners with six equivalent WAl12 cuboctahedra, corners with twelve AlAl9W3 cuboctahedra, edges with six equivalent WAl12 cuboctahedra, and faces with eight AlAl9W3 cuboctahedra. There are six shorter (2.75 Å) and six longer (2.84 Å) W–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded to three equivalent W and nine Al atoms to form distorted AlAl9W3 cuboctahedra that share corners with nine WAl12 cuboctahedra, corners with nine equivalent AlAl9W3 cuboctahedra, edges with six equivalent AlAl9W3 cuboctahedra, faces with three equivalent WAl12 cuboctahedra, and faces with five AlAl9W3 cuboctahedra. There are six shorter (2.77 Å) and three longer (2.84 Å) Al–Al bond lengths. In the second Al site, Al is bonded to three equivalent W and nine Al atoms to form distorted AlAl9W3 cuboctahedra that share corners with three equivalent WAl12 cuboctahedra, corners with fifteen AlAl9W3 cuboctahedra, edges with six equivalent AlAl9W3 cuboctahedra, faces with three equivalent AlAl9W3 cuboctahedra, and faces with five WAl12 cuboctahedra. All Al–Al bond lengths are 2.75 Å. In the third Al site, Al is bonded in a distorted bent 150 degrees geometry to two W and four Al atoms.

36 MATERIALS SCIENCE↗