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Annihilation of Nuclei by Displacement Spikes

Description: At an Octcber, 1957 meeting between USAEC, AECL, and Bettis personnel, the theoretical aspects of the radiation effects on the gamma red and alpha + gamma /sub 2/ transformation in U-Nb alloys were discussed. A theoretical model is presented which involves the annihilation of nuclei of the new phase by the action of displacement spikes. (W.D.M.)
Date: November 1, 1957
Creator: Thomas, D. E.
Partner: UNT Libraries Government Documents Department


Description: (((Abstract unscannable)))<><DSN>13:014503<ABS>Thc Nb-O equilibrium system was determined by metallographic examination of arc-cast alloys made ot electron-gun-refined Nb metal and special purity Nb/sub 2/O/sub 5/. Two intermediate oxides. NbO and NbO/sub 2/, melt without decomposition at 1945 C and 1915 C, respectively. Eutectic reactions exist between Nb and NbO at 1915 C and between NbO and NbO/sub 2/ at 1810 C . Experimental evidence supports a peritectic reaction between NbO/sub 2/ and Nb/sub 2/O/sub 5/ at 1510 C. The maxinium solid solubility of 0 in Nb metal is 0.72 wt.%. (auth)
Date: February 1, 1959
Creator: Blumenthal, B.
Partner: UNT Libraries Government Documents Department

THE DIFFUSION OF CHROMIUM IN GAMMA URANIUM. Partial Report-Metallurgy Program 4.1.27

Description: The diffusion of tracer amounts of chromium in gamma uranium was studied by the radioactive tracer-sectioning method. The temperature dependence of the diffusion coefficient D is given by D = 1.98 x 10/sup -3/ exp(--2l,800/RT)cm/sup 2// sec, in poor agreement with the data of Mosse, Levy, and Adda. Possible reasons for the discrepancy are discussed, and it is concluded that the present data are to be preferred as a basis for theoretical studies of the diffusion of tracers in gamma uranium. The difference between the activation energy and that for self-diffusion is also discussed; no conclusions are reached. (auth)
Date: June 1, 1961
Creator: Rothman, S.J.
Partner: UNT Libraries Government Documents Department

Mechanical fabrication, heat treatment, and machining of uranium alloys

Description: From conference on physical metallurgy of uranium alloys; Vail, Colorado, USA (12 Feb 1974). A review of the state of the art is presented on the fabrication and properties of U-rich alloys in which the alloying elements are highly miscible in gamma -U (Nb, Zr, Ti, Mo). Processing of both low alloys (which will not retain a metastable gamma phase when quenched) and high alloys (which will retain a metastable gamma phase, usually greater than 6% Mo or Nb) is treated. Forging, extrusion, deep drawing, shear spinning, single-point turning, milling, drilling, tapping, and electrical discharge machining are discussed. Heat treatments (metastable, solution treatment, age hardening) to yield the desired mechanical properties are also discussed. (18 figures, 6 tables, 57 references) (DLC)
Date: January 1, 1974
Creator: Boland, J.F. & Sandstrom, D.J.
Partner: UNT Libraries Government Documents Department


Description: The self-diffusion coefficient or uranium was measured at four temperatures in the gamma phase. The data are fitted by an Arrhenius-tyoe equation D = 2.33 x well with previously reported results. The value of D/sub o/ is lower than that predicted by Zener's theory, and the activation energy is much less than the value expected from various empirical codelations. (auth)
Date: July 1, 1959
Creator: Rothman, S.J.; Lloyd, L.T.; Weil, R. & Harkness, A.L.
Partner: UNT Libraries Government Documents Department


Description: The identification of phases and interpretation of phase transformation through microstructural analysis are still difficult even with metallographic standards as a guide. Macrostructures provide a better guide to determination of the origin of the quenched phase and the degree of quenching. Grain sizes are of some assistance in determining the cooling conditions employed. Twinning concentration and grain boundry shape are inconclusive characteristrcs to use in determining the origin of the quenched phase and the degree of quenching. Subgrains are more prevalent in beta-treated uranium. Hardness profiles provide highly irregular data and are of little assistance in interpretation of heat- treating conditions. Single and multiple gamma-beta-alpha cycles appear severe enough to cause the formation of small voids in thc air-cooled zones of end quench samples. (auth)
Date: December 1, 1958
Creator: Lewis, L.
Partner: UNT Libraries Government Documents Department

THE TRANSFORMATION TEMPERATURES OF HIGH-PURITY URANIUM. Work completed: December 31, 1957. Final Report--Metallurgy Program 3.1.1.

Description: The transformation temperatures of high-purity uranium were determined by thermal analysis and dilatometry. Thermal analysis methods used include one in which the rates of heating and cooling were controlled by a differential thermocouple, and another in which repeated thermal analyses were made at independently controlled rates. The solid-state transformation temperatures and the logarithm of the heating or cooling rates at relatively low rates are related linearly. The extrapolated functions intersect at a point where the disturbing effects of hysteresis, superheating and undercooling disappear, i.e., at the equilibrium temperature. The mean transformation temperatures are 667 deg C for alpha in equilibrium beta and 775 deg C for beta in equilibrium gamma . The mean temperature for melting and freezing is 1132 deg C. (auth)
Date: June 1, 1960
Creator: Blumenthal, B.; Baumrucker, J.E. & Lloyd, L.T.
Partner: UNT Libraries Government Documents Department


Description: A study was made of the phase relations and the properties of uranium-- fissium alloys which have compositions bracketing that intpnded for the first core loading of Experimental Breeder Reactor II. The fissium aggregate in the alloys consisted of the elements Zr, Nb, Mo, Ru, Rh, and Pd. Phase relations are shown to parallel closely those in the dominant U--Mo--Ru ternary system. The uranium gamma phase is stabilized down to 552 deg C, while the beta phase is entirely suppressed at high fissium contents. Certain crystallographic data are given and the minor phases that occur in the alloys are identified. In cast and gammaquenched alloys the retention of the high-temperature gamma phase produced low hardness and low density. The thermal expsnsion behavior of the alloys is shown to be dependent upon composition and prior thermal history. Thermal conductivity data are presented for uranium and the uranium-- fission alloys. The thermal conductivities of the alloys decrease with increasing fissium concentration. (auth)
Date: July 1, 1961
Creator: Zegler, S.T. & Nevitt, M.V.
Partner: UNT Libraries Government Documents Department


Description: Advanced Water Reactor Program. Three firings were made of initial closed-porosity fuel pellet bodies. Each firing coatained pellets of the composition 90 wt.% ThO/sub 2/-10 wt.%fl U0/sub 2/ with various additives and firing variables. Fast Power Breeder Reactor Program. To determine the potential usefulness of a Zr-5 wt. % Pu alloy, the fabricability of the alloy was tested. The manufacture of rod stock from which fuel and blanket elements for the Mark III loading of the EBR-1 were prcduced has been completed. The effect of irradiation on extruded and heat-treated U-2 wt.% Zr alloy for the EBR- 1 is reported. Fabrication procedures for making graphite-U/sub 3/O/sub 8/ test specimens for the TREAT Reactor were investigated. Advanced Engineering and Development. Ultrasonic bond tests were conducted on 590 EBR-1 Mark III blanket fuel elemeats. The blanket rods and part of the fuel rcds for the EBR-1 Mark III loading are being checked for cladding thickness by an eddy current system. Investigations of corrosionresistant Zr-Nb alloy were coatinued. Corrosion of MR alloys is being studied Ln support of the Mighty Mouse reactor program. Dynamic corrosion tests were performed on aluminum alloys, and results are included. Prcduction, Treatment, and Properties of Materials. The progress of the program of preparing highpurity Pu by fused salt electrolysis is summarized. Velocities of ultrasonic waves propagated in directions suitable for determining the room- temperature elastic moduli C/sub 12/, C/sub 13/, and C/sub 23/ of alpha U were determined. investigation of recrystallization in heavily coldrolled alpha- uranium sheet without a texture change was essentially concluded during this quarter. Selfdiffasion runs in polycrystalline uranium in the gamma phase, using the sputtering technique, have yielded a tentative value for the diffusion coefficient between 10/sup -8/ and 10/sup -7/ cm/sup 2/second. The preparation of high-purity U-Pan alloys is reponted. The data for ...
Date: October 1, 1958
Partner: UNT Libraries Government Documents Department