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At least 1,171 records · Page 65

System and method for controlling oxidation of metals during freeform casting

A system is disclosed for printing a component. The system may have a nozzle controlled for movement within a plane. The nozzle may be configured to dispense a molten metal. A substrate may be positioned within a reservoir. The substrate may receive the molten metal to form the component in a printing operation. A heated barrier material in a molten state may be contained within the reservoir for forming a liquid barrier between an atmosphere and the substrate. The nozzle has a tip which is submerged within the liquid barrier while dispensing the molten metal during the printing operation. The liquid barrier forms a barrier between an atmosphere in a vicinity of the substrate and the substrate.

Pascall, Andrew J.↗

Heat treatments for high temperature cast aluminum alloys

Disclosed herein are embodiments of an aging heat treatment that can be used to replace conventional aging steps when making alloy embodiments of the present disclosure. Embodiments of the disclosed aging heat treatment reduce cost and complexity in producing aluminum alloy-based components while also promoting and/or improving microstructure stability of the aluminum alloys.

Shyam, Amit↗

Porous materials via freeze-casting of metal salt solutions

Disclosed here is a method for making a nanoporous material, comprising aerosolizing a solution comprising at least one metal salt and at least one solvent to obtain an aerosol, freezing the aerosol to obtain a frozen aerosol, and drying the frozen aerosol to obtain a nanoporous metal compound material. Further, the nanoporous metal compound material can be reduced to obtain a nanoporous metal material.

Bagge-Hansen, Michael↗

Low-cost, high-strength, cast creep-resistant alumina-forming alloys for heat-exchangers, supercritical CO2 systems and industrial applications

An austenitic Ni-base alloy includes, in weight percent: 2.5 to 4.75 Al; 13 to 21 Cr; 20 to 40 Fe; 2 to 5 total of at least one element selected from the group consisting of Nb and Ta; 0.25 to 4.5 Ti; 0.09 to 1.5 Si; 0 to 0.5 V; 0 to 2 Mn; 0 to 3 Cu; 0 to 2 of Mo and W; 0 to 1 of Zr and Hf; 0 to 0.15 Y; 0.01 to 0.45 C; 0.005 to 0.1 B; 0 to 0.05 P; less than 0.06 N; and balance Ni (38 to 46 Ni). The weight percent Ni is greater than the weight percent Fe. An external continuous scale comprises alumina. A stable phase FCC austenitic matrix microstructure is essentially delta-ferrite-free, and contains one or more carbides and coherent precipitates of γ′ and exhibits creep rupture life of at least 100 h at 900° C. and 50 MPa.

Muralidharan, Govindarajan↗

Creep and corrosion-resistant cast alumina-forming alloys for high temperature service in industrial and petrochemical applications

An austenitic Ni-base alloy, consisting essentially of, in weight percent: 2.5 to 4.75 Al; 21 to 26 Cr; 20 to 40 Fe; 0.75 to 2.5 total of at least one element elected from the group consisting of Nb and Ta; 0 to 0.25 Ti; 0.09 to 1.5 Si; 0 to 0.5 V; 0 to 2 Mn; 0 to 3 Cu; 0 to 2 of at least one element selected from the group consisting of Mo and W; 0 to 1 of at least one element selected from the group consisting of Zr and Hf; 0 to 0.15 Y; 0.3 to 0.55 C; 0.005 to 0.1 B; 0 to 0.05 P; less than 0.06 N and balance Ni (30 to 46 Ni), wherein the weight percent Ni is greater than the weight percent Fe, and wherein the ratio Ni/(Fe+2*C) is between 1.02 and 1.067.

Muralidharan, Govindarajan↗

Novel Synthesis and Characterization of Uranium-Zirconium Carbonitride by Direct Casting

UZrCN has exhibited thermophysical properties beneficial to high temperature reactor applications such as nuclear thermal rockets. The present work investigates a novel liquid phase synthesis method involving the admission of nitrogen gas during arc melting of uranium, zirconium, and carbon. Initial microstructural examinations using SEM indicated that the samples remain heterogenous with zirconium-rich cores in a uranium-rich matrix. Heterogeneity resulted from large differences in melting temperature of the major constituents and rapid solidification. Additional EDS, combustion analysis, and inert gas fusion analysis proved that the core regions have both uranium and zirconium and establish that carbon and nitrogen are retained during the fabrication process. XRD clarifies that the light elements did not form compounds with the uranium matrix but rather incorporated into the core region forming a sub-stoichiometric UZrCN. Heat treatment performed on equimolar U-Zr-C resulted in an increase in the homogenous phase present with an XRD pattern reflecting a ternary UZrCN despite small amounts of segregation in the final button.

36 - MATERIALS SCIENCE↗

On Uranium-Zirconium Carbonitride Formation by Direct Casting - A Novel Synthesis Study

UZrCN has exhibited thermophysical properties beneficial to high temperature reactor applications such as nuclear thermal rockets. The present work investigates a novel liquid phase synthesis method involving the admission of nitrogen gas during arc melting of uranium, zirconium, and carbon. Initial microstructural examinations using SEM indicated that the samples remain heterogenous with zirconium-rich cores in a uranium-rich matrix. Heterogeneity resulted from large differences in melting temperature of the major constituents and rapid solidification. Additional EDS, combustion analysis, and inert gas fusion analysis proved that the core regions have both uranium and zirconium and establish that carbon and nitrogen are retained during the fabrication process. XRD clarifies that the light elements did not form compounds with the uranium matrix but rather incorporated into the core region forming a sub-stoichiometric UZrCN. Heat treatment performed on equimolar U-Zr-C resulted in an increase in the homogenous phase present with an XRD pattern reflecting a ternary UZrCN despite small amounts of segregation in the final button.

36 - MATERIALS SCIENCE↗