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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Directional solidification of Cu-Pb and Bi-Ga monotectic alloys under normal gravity and during parabolic flight

Cu-Pb and Bi-Ga monotectic alloys of nominal hypermonotectic compositions were directionally solidified under various furnace translation rates, temperature gradients, and gravity levels. Gravity was varied by solidifying the alloys under ground conditions and in the furnace aboard NASA KC-135 aircraft, flying on parabolic trajectories. High translation rates, high gradients, high gravity levels, and higher density and lower thermal conductivity of the L2 phase favored the formation of fiber composite structure, while the opposite conditions resulted in structures consisting of L2 droplets in alpha matrix. A modified particle engulfment theory as originally enunciated by Ulhmann et al. (1964) is proposed to explain these observations.

Dhindaw, B. K.↗
NASA NTRS1985

Liquid Phase Miscibility Gap Materials

The manner in which the microstructural features of liquid-phase miscibility gap alloys develop was determined. This will allow control of the microstructures and the resultant properties of these alloys. The long-duration low gravity afforded by the shuttle will allow experiments supporting this research to be conducted with minimal interference from buoyancy effects and gravitationally driven convection currents. Ground base studies were conducted on Al-In, Cu-Pb, and Te-Tl alloys to determine the effect of cooling rate, composition, and interfacial energies on the phase separation and solidification processes that influence the development of microstructure in these alloys. Isothermal and directional cooling experiments and simulations are conducted. The ground based activities are used as a technological base from which flight experiments formulated and to which these flight experiments are compared.

Gelles, S. H.↗
DOE OSTI2020

Materials Data on CuPb3 by Materials Project

CuPb3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cu is bonded to twelve Pb atoms to form CuPb12 cuboctahedra that share corners with four equivalent CuPb12 cuboctahedra, corners with eight equivalent PbCu4Pb8 cuboctahedra, edges with eight equivalent CuPb12 cuboctahedra, edges with sixteen equivalent PbCu4Pb8 cuboctahedra, faces with four equivalent CuPb12 cuboctahedra, and faces with fourteen PbCu4Pb8 cuboctahedra. There are eight shorter (3.33 Å) and four longer (3.40 Å) Cu–Pb bond lengths. There are two inequivalent Pb sites. In the first Pb site, Pb is bonded to four equivalent Cu and eight Pb atoms to form distorted PbCu4Pb8 cuboctahedra that share corners with twelve equivalent PbCu4Pb8 cuboctahedra, edges with eight equivalent CuPb12 cuboctahedra, edges with sixteen PbCu4Pb8 cuboctahedra, faces with four equivalent CuPb12 cuboctahedra, and faces with fourteen PbCu4Pb8 cuboctahedra. There are four shorter (3.33 Å) and four longer (3.40 Å) Pb–Pb bond lengths. In the second Pb site, Pb is bonded to four equivalent Cu and eight equivalent Pb atoms to form PbCu4Pb8 cuboctahedra that share corners with four equivalent PbCu4Pb8 cuboctahedra, corners with eight equivalent CuPb12 cuboctahedra, edges with twenty-four PbCu4Pb8 cuboctahedra, faces with six equivalent CuPb12 cuboctahedra, and faces with twelve PbCu4Pb8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuPb3 by Materials Project

CuPb3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cu is bonded to twelve equivalent Pb atoms to form CuPb12 cuboctahedra that share corners with twelve equivalent CuPb12 cuboctahedra, edges with twenty-four equivalent PbCu4Pb8 cuboctahedra, faces with six equivalent CuPb12 cuboctahedra, and faces with twelve equivalent PbCu4Pb8 cuboctahedra. All Cu–Pb bond lengths are 3.37 Å. Pb is bonded to four equivalent Cu and eight equivalent Pb atoms to form distorted PbCu4Pb8 cuboctahedra that share corners with twelve equivalent PbCu4Pb8 cuboctahedra, edges with eight equivalent CuPb12 cuboctahedra, edges with sixteen equivalent PbCu4Pb8 cuboctahedra, faces with four equivalent CuPb12 cuboctahedra, and faces with fourteen equivalent PbCu4Pb8 cuboctahedra. All Pb–Pb bond lengths are 3.37 Å.

36 MATERIALS SCIENCE↗