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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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10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Synthesis of precipitation-strengthened Al-Sc, Al-Zr and Al-Sc-Zr alloys via selective laser melting of elemental powder blends

Selective laser melting is used to create Al-1.5Sc, Al-1.5Zr and Al-0.75Sc-0.75Zr (at.%) alloys from blends of elemental Al, Sc, and Zr powders. This study investigates elemental alloying elements (Sc and Zr) which are high-melting and highly reactive, unlike previous work which focused on more concentrated elemental additions of lower-melting, lower-reactivity Cu and Si to aluminum. High-speed in situ synchrotron x-ray imaging and diffraction show that the 20–30 μm Al, Sc, and Zr powders fully melt and sufficiently mix in the molten state to create, on solidification, a homogeneous distribution of primary, micron-size L12 precipitates (Al 3 Sc, Al 3 Zr, and Al 3 (Sc,Zr), respectively) and nucleate micron-size Al matrix grains, as confirmed by SEM imaging of cross-sections. Here, a second laser pass, simulating a realistic additive-manufacturing build condition, fully remelts the initial volume which shows, after solidification, the same Al 3 (Sc,Zr) L1 2 primary micro-precipitates and very fine Al grains. After aging at 300–400°C, the alloys show large increases in hardness, consistent with an exceptionally high number density (1.4 × 10 24 m –3 ) and volume fraction (2.5%) of secondary Al 3 (Sc,Zr) nano-precipitates with a Sc-rich core and Zr-rich shell, as measured via atom-probe tomography.

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 Sc2Al by Materials Project

AlSc2 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Sc sites. In the first Sc site, Sc is bonded in a 6-coordinate geometry to eight Sc and six equivalent Al atoms. There are two shorter (3.09 Å) and six longer (3.22 Å) Sc–Sc bond lengths. All Sc–Al bond lengths are 3.22 Å. In the second Sc site, Sc is bonded to six equivalent Sc and five equivalent Al atoms to form a mixture of distorted face and corner-sharing ScSc6Al5 trigonal bipyramids. There are three shorter (2.83 Å) and two longer (3.09 Å) Sc–Al bond lengths. Al is bonded in a 11-coordinate geometry to eleven Sc atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAl3 by Materials Project

Al3Sc is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded to twelve equivalent Al atoms to form ScAl12 cuboctahedra that share corners with twelve equivalent ScAl12 cuboctahedra, edges with twenty-four equivalent AlSc4Al8 cuboctahedra, faces with six equivalent ScAl12 cuboctahedra, and faces with twelve equivalent AlSc4Al8 cuboctahedra. All Sc–Al bond lengths are 2.90 Å. Al is bonded to four equivalent Sc and eight equivalent Al atoms to form AlSc4Al8 cuboctahedra that share corners with twelve equivalent AlSc4Al8 cuboctahedra, edges with eight equivalent ScAl12 cuboctahedra, edges with sixteen equivalent AlSc4Al8 cuboctahedra, faces with four equivalent ScAl12 cuboctahedra, and faces with fourteen equivalent AlSc4Al8 cuboctahedra. All Al–Al bond lengths are 2.90 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAl by Materials Project

AlSc is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded in a body-centered cubic geometry to eight equivalent Al atoms. All Sc–Al bond lengths are 2.93 Å. Al is bonded in a body-centered cubic geometry to eight equivalent Sc atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAl2 by Materials Project

Al2Sc is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Sc is bonded in a 12-coordinate geometry to four equivalent Sc and twelve equivalent Al atoms. All Sc–Sc bond lengths are 3.28 Å. All Sc–Al bond lengths are 3.15 Å. Al is bonded to six equivalent Sc and six equivalent Al atoms to form a mixture of corner, edge, and face-sharing AlSc6Al6 cuboctahedra. All Al–Al bond lengths are 2.68 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc3Al by Materials Project

Sc3Al is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Sc is bonded to eight equivalent Sc and four equivalent Al atoms to form distorted ScSc8Al4 cuboctahedra that share corners with four equivalent AlSc12 cuboctahedra, corners with fourteen equivalent ScSc8Al4 cuboctahedra, edges with six equivalent AlSc12 cuboctahedra, edges with twelve equivalent ScSc8Al4 cuboctahedra, faces with four equivalent AlSc12 cuboctahedra, and faces with sixteen equivalent ScSc8Al4 cuboctahedra. There are a spread of Sc–Sc bond distances ranging from 3.07–3.25 Å. There are two shorter (3.08 Å) and two longer (3.16 Å) Sc–Al bond lengths. Al is bonded to twelve equivalent Sc atoms to form AlSc12 cuboctahedra that share corners with six equivalent AlSc12 cuboctahedra, corners with twelve equivalent ScSc8Al4 cuboctahedra, edges with eighteen equivalent ScSc8Al4 cuboctahedra, faces with eight equivalent AlSc12 cuboctahedra, and faces with twelve equivalent ScSc8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc3Al by Materials Project

Sc3Al is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded to eight equivalent Sc and four equivalent Al atoms to form ScSc8Al4 cuboctahedra that share corners with twelve equivalent ScSc8Al4 cuboctahedra, edges with eight equivalent AlSc12 cuboctahedra, edges with sixteen equivalent ScSc8Al4 cuboctahedra, faces with four equivalent AlSc12 cuboctahedra, and faces with fourteen equivalent ScSc8Al4 cuboctahedra. All Sc–Sc bond lengths are 3.13 Å. All Sc–Al bond lengths are 3.13 Å. Al is bonded to twelve equivalent Sc atoms to form AlSc12 cuboctahedra that share corners with twelve equivalent AlSc12 cuboctahedra, edges with twenty-four equivalent ScSc8Al4 cuboctahedra, faces with six equivalent AlSc12 cuboctahedra, and faces with twelve equivalent ScSc8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAl3 by Materials Project

Al3Sc is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sc is bonded to twelve Al atoms to form ScAl12 cuboctahedra that share corners with four equivalent ScAl12 cuboctahedra, edges with eight equivalent ScAl12 cuboctahedra, edges with sixteen equivalent AlSc4Al8 cuboctahedra, faces with four equivalent ScAl12 cuboctahedra, and faces with eight equivalent AlSc4Al8 cuboctahedra. There are four shorter (2.85 Å) and eight longer (2.99 Å) Sc–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Sc and eight Al atoms to form AlSc4Al8 cuboctahedra that share corners with twelve equivalent AlSc4Al8 cuboctahedra, edges with eight equivalent ScAl12 cuboctahedra, edges with eight equivalent AlSc4Al8 cuboctahedra, faces with four equivalent ScAl12 cuboctahedra, and faces with ten equivalent AlSc4Al8 cuboctahedra. There are four shorter (2.85 Å) and four longer (2.99 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a distorted square co-planar geometry to four equivalent Sc and eight equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAl by Materials Project

AlSc crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Sc is bonded in a 5-coordinate geometry to seven equivalent Al atoms. There are a spread of Sc–Al bond distances ranging from 2.92–3.16 Å. Al is bonded in a 9-coordinate geometry to seven equivalent Sc and two equivalent Al atoms. Both Al–Al bond lengths are 2.59 Å.

36 MATERIALS SCIENCE↗