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Transformations in uranium-base alloys : summary report, December 14, 1955 - March 31, 1957

Description: From abstract: "Transformation kinetics of binary U -Nb and ternary U-Nb-base alloys were investigated. Additions included zirconium, chromium, titanium, silicon, nickel, nnthenium, and vanadium. Encapsulated samples were given a homogenizstion anneal at 1000 or 1100/sup o/C, water-quenched from 906/sup o/C to retain the phase, and reheated to temperatures between 360 and 600/sup o/C. The metastability of the phase was examined by metallographic, hardness, resistometric, dilatometric and x-ray-diffraction techniques. The U -Nb system is characterized by a monotectoid decomposition of the high temperature allotrope at about 645/sup o/C to form alpha and ₂, a niobium-rich cubic structure. Decomposition in U-Nb and in most U-Nb-X alloys occurred by a continuous precipithtion of alpha from the body-centered cubic phase with a resultant enrichment in niobium of until the equilibrium ₂ composition was reached. In the U-Nb-Ti and U-Nb-V systems, alpha and /sub 2/ were coprecipitated. Annealing at 550 and 600/sup o/C produced decomposition products which, in most materials, originated at the grain boundaries; a fine precipitate which initiated throughout the matrix was observed at lower annealing temperatures. Increasing the niobium content resulted in greatly increased stability. The following elements added to a U-Nb base were found to retard transformation of the phase: zirconium, chromium, ruthenium, and vanadium. Additions of titanium, silicon, and nickel produced alloys which were less stable than the U-Nb base to which they were added. Cold-working a U-7 wt. % Nb-2 wt. % Zr composition caused a more rapid transformation upon annealing at 360 and 450/ sup o/C, and the resulting microstructures were different. Continuous cooling transformation studies were conducted on U-10 wt. % Nb materials, solution annealed at 700 and 950°C, and cooled at various linear rates to temperatures between 300 and 600/sup o/C. Cooling rates between 8.5 and 14.5/sup o/C per minute were required to prevent transformation of ...
Date: 1957
Creator: Parry, Sidney J. S.; Holtz, F. C. & Van Thyne, R. J.

Studies of Reactor Containment

Description: The following report includes a description of apparatus and techniques for the observation of the behavior of blast shield segments and materials when impulsively loaded, some preliminary dynamic stress-strain data, and some observations of compression wave propagation in porous media.
Date: August 1958
Creator: Napadensky, H. S.; Pinsky, J. & Stresau, R.

A Wide-Range Neutron Detector and Monitoring Instrument : Final Report

Description: This is the final report on the progress, "A Wide-Range Neutron Detector and Monitoring Instrument," ARF 1118-6. This report covers activities from May 8, 1958 to May 8, 1959. This report describes the basic design principles of a proportional counter that has been constructed whose cathode diameter increases towards one end.
Date: April 22, 1959
Creator: Porges, K. G.

Niobium Phase Diagrams : Manuscript Report on Niobium-Oxygen System

Description: Abstract: "The niobium-oxygen equilibrium has been determined by metallographic examination of arc-cast alloys made of electron-gun-refined niobium metal and special purity niobium pentoxide. Two intermediate oxides, NbO and NbO2, melt without decomposition at 1945 C and 1915 C, respectively. Eutectic reactions exist between niobium and NbO and 1915 C and between NbO and NbO2 at 1810 C. Experimental supports a peritectic reaction between NbO2 and Nb2O5 1510 C. The maximum solid solubility of oxygen in niobium metal is 0.72 weight per cent."
Date: April 27, 1959
Creator: Elliott, Rodney P.

Preliminary Studies of Scavenging Systems Related to Radioactive Fallout : Summary Report, April 1, 1958 to March 31, 1959

Description: This report is the final in a series of preliminary reports that follow the studies of scavenging systems related to radioactive fallout. The project consisted of two phases: preliminary experiments to relate the sizes of particles in air to specific radioisotopes, and preliminary laboratory studies of scavenging of particles by liquid drops, including studies of sticking probability and effects of Brownian motion and water vapor diffusion.
Date: April 30, 1959
Creator: Rosinski, John & Stockham, John D.

Niobium Phase Diagrams : Manuscript Report on Niobium-Carbon System

Description: Abstract: "The niobium-carbon system has been determined by X-ray and metallographic examination of sintered and arc-cast alloys. Two carbides exist: hexagonal Nb2C with a limited range of homogeneity, and cubic NbC with a solubility range from 8.25 to 10.25 weight per cent carbon. Dilute alloys freeze by eutectic reaction at 2230 C. The solubility of carbon in niobium is 0.80 at the eutectic temperature, but this decreases rapidly with temperature. Metallographic evidence indicates a peritectic reaction between melt, Nb2C, and NbC; alloys richer in carbon than NbC freeze by eutectic reaction."
Date: May 6, 1959
Creator: Elliott, Rodney P.

Investigation of Graphite Bodies : Progress Report No. 3 for the Period March 1, 1959 to May 31, 1959

Description: This document is the third in a series of progress report that records investigations of graphite bodies. Along with the report, two appendices are given to describe the different graphite bodies: "Synthetic Binders for Carbon and Graphite" and "High Temperature Physical Properties of Molded Graphites".
Date: June 10, 1959
Creator: Bradstreet, Samuel W.

Development and Evaluation of High-Temperature Tungsten Alloys : Summary Report

Description: Abstract: "Tungsten-rich alloys, developed for use at temperatures up to 2000F, exhibit ductility, fabricability and joinability not found in commercially-available materials. An envelope type of microstructure was produced in compositions containing at least 90 wt% tungsten by liquid-phase sintering of cold-pressed powders in hydrogen. At room temperature the alloys could be rolled extensively, and tensile elongations up to 25% were noted. Strength properties of a W-Ni-Fe base were improved by small quaternary additions. The ultimate tensile strength of a 90W-4.8Ni-3.2Fe-2Ru alloy was 46,700 psi at 2000F, compared to 30,000 - 35,000 psi for unalloyed tungsten or W-Ni-Fe; the 100-hour stress-rupture strength at 1600F was 15,000 psi. Excellent joints were produced by spot welding and localized induction heating. The oxidation resistance of unprotected 90 wt% tungsten compositions was not significantly affected by alloying."
Date: November 12, 1959
Creator: Holtz, F. C. & Van Thyne, R. J.

Design Studies on Cesium-137 as a Source for High Level Gamma Irradiators : Quarterly Progress Report No. 1 Covering the Period from June 1 to August 31, 1959

Description: "A study was made of radiation physics problems involved in the design of high-level cesium-137 gamma sources. The radiation properties of cesium-137 sources are reviewed and design and dosimetry problems are discussed. The economics, efficiency, and dose distribution for material undergoing process irradiation were calculated. A comparison of cesium-137 with cobalt-60 gamma sources indicated that in the case of irradiators specifically designed for high efficiency of useful energy conversion, the performance of cesium-137 source material should be at least comparable to the performance of cobalt-60 source material. (C.H.)."
Date: December 11, 1959
Creator: Voyvodic, L.