Uranium alloys

The study of Coulomb transitions is especially valuable in actinide metals and intermetallic compounds (McEwen et al. 1990, Osborn et al. 1990). Because of the greater radial extent of the 5f charge distribution, the actinide f electrons tend to hybridise more strongly with band electron states than their lanthanide counterparts. In a number of actinide metals, it is evident that the f electrons contribute to the cohesive energy through the formation of 5f bands, either by direct f-f overlap, as in a-uranium, or by hybridisation with conduction bands, as in URUj or URhj (Oguchi and Freeman 1986, Johansson et al. 1987). In these cases, relativistic band theory is successful in predicting lattice constants, photoemission and Fermi surfaces (Arko et al. 1985) provided the f states are included as itinerant. 

On the other hand, good agreement with the de Haas-van Alphen measurements on UPdj (Ubachs et al. 1986) is only obtained by treating the f electrons as core states (Norman et al. 1987), whilst photo-emission results show that there is no f-electron density at the Fermi level in this compound (Baer et al. 1980). It is significant that UPdj is the only actinide metal in which well defined crystal-field excitations have been observed by neutron spectroscopy (Shamir et al. 1978, Murray and Buyers 1980, Buyers and Holden 1985). All these results indicate that the uranium ions in UPdj have a localised f configuration and behave more like stable lanthanide ions. 

LaClj (Carnall and Crosswhite 1985), would imply the development of intermediate valency. 

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In the determination of molybdenum in uranium alloys containing 2.5% molybdenum,20 the uranium had to be removed because its high absorbance made the method insensitive. After a single solvent extraction, the molybdenum could be determined with a standard deviation... 

Niobium-uranium alloy has a high tensile strength, making it ideal in the manufacture of fuel rods for nuclear reactors that resist separation. 

However, it became evident in the post-war period that, valuable as they were, these band-structure concepts could not be applied even qualitatively to key systems of industrial interest notably steels, nickel-base alloys, and other emerging materials such as titanium and uranium alloys. This led to a resurgence of interest in a more general thermodynamic approach both in Europe (Meijering 1948, Hillert 1953, Lumsden 1952, Andrews 1956, Svechnikov and Lesnik 1956, Meijering 1957) and in the USA (Kaufman and Cohen 1956, Weiss and Tauer 1956, Kaufman and Cohen 1958, Betterton 1958). Initially much of the work related only to relatively simple binary or ternary systems and calculations were performed largely by individuals, each with their own methodology, and there was no attempt to produce a co-ordinated framework. 

Two US military specifications currently exist for U alloys Uranium Alloy for Body Section Center of Ammunition Components , MIL-U-46126 (28 June 1968), and Uranium Alloy, Wrought, Bars, Billets and Tubular Shapes , MIL-U-46045C (24 June 1974)... 

Anon, Uranium Alloys for Critical Ordnance Components , WAL-MS-19, Watertown Ars Labs... 

Tardif, The Heat Treatability and Properties of Uranium Alloys , Canadian Mining Metallurgical Bull (Nov 1965), 1167 13) SM. Wolf... 

Uranium and Uranium Alloys , in J.J. Burke et al, Eds, Physical Metallurgy of Uranium Alloys , Brookhill Publ Co (1976) also see J.C. Bailer et al, Eds, Comprehensive Inorganic Chemistry , Vol 5, Pergamon Press, Oxford (1973), 40-42 26) LJ. Weirick, Corrosion Testing of the General Electric Mantech Gau 8/A Penetrator, SANDIA 76-8055 (1977) 27) W.C. Hanson... 

The earliest study of the ternary system was by Gulbransen and his associates (6, 17), who obtained data on the 50 weight % uranium alloy. Their chief concern was the possible weakening effects of hydrogen absorption by such alloys in a pressurized-water reactor. More recently, La Grange et al. (9) examined... 

Apparatus. The hydrogen-absorption system, a modified Sievert s apparatus, consisted of three self-contained units. The first unit provided a source of, and storage facilities for, pure hydrogen, which was obtained by the thermal decomposition of uranium hydride. The second unit provided precise metering of hydrogen at a known temperature, for delivery to the reaction system. The third unit was a constant-volume section in which the reaction of hydrogen with the zirconium-uranium alloy occurred at a controlled temperature ( 3° C.). The equilibrium pressures of hydrogen were measured in this section also. 

X-Ray Diffraction Study. The intensities of the phase patterns observed for the 1 weight % uranium alloy are presented in Table II. The intensity is indicative of the quantity of a given phase that is present, but the amount present is not necessarily proportional to the intensity. These data show that aZr was present in... 

Table II. Phases Detected by X-Ray Diffraction Examination of Hydrided Zirconium-1 Weight % Uranium Alloy...

Hydrogen-Absorption Isotherms. The isotherms for the 25 weight % uranium alloy constitute a family of curves closely resembling each other. Seven of the 13 isotherms which were measured are plotted in Figure 3. Isotherms intermediate between each adjacent pair were omitted to reduce the complexity of the plot. The isotherms at 572° C. (not shown) and at 601° C. cross only two phase boundaries, because they are below the eutectic temperature. 

Figure 3. Hydrogen-absorption isotherms for zirconium-25 weight % uranium alloy...

Zirconium-50 Weight % Uranium Alloy. This system was examined by Gulbransen and his associates (6, 17), but their x-ray studies were made on quenched samples, so there has been uncertainty as to the exact nature of the phases present at the higher temperatures. Consequently, x-ray diffraction patterns of the 50 weight % uranium alloy were taken over the range 500° to 800° C. (Table IV). 

A 50 weight % uranium alloy, free of interstitial impurities such as hydrogen, would consist of the intermetallic compound UZr2, designated as the delta phase. 

Heats of Solution of Hydrogen in Zirconium-Uranium Alloys... 

Ocourrenoe — History — Treatment of Uranium Minerals — Preparation of Uranium—Ph37sioal Properties—Spectrum—Chemical Properties—Pyrophoric Uranium—Colloidal Uranium— Atomic Weight—Isotope.s of Uranium—Alloys. 

The Chrome Azurol S method was used to determine aluminium in water [82], steel [83,84], uranium alloys [85], iron ores [86], and magnetic alloys [87]. Higher contents of aluminium (-10%) in magnesium and titanium compounds were determined by the differential spectrophotometry techniques [88]... 

The hydrogen peroxide method has been used for determining titanium in uranium alloys [83], ilmenite ore [84], and silicon-based catalysts [85]. Titanium was determined in steel by derivative spectrophotometry [86]. 

The method based on the use of PAR was used for determining vanadium in biological materials [27,100], sewage [24], natural waters [26,101,102], silicate rocks [103], petroleum [104], titanium tetrachloride [25], cerium dioxide [105], steel [29], uranium alloys [31], and titanium alloys [29,31]. 

Zirconium has been determined by the Alizarin S method in uranium alloys [45], titanium alloys [92], magnesium alloys [27], and rutile [3]. Determination of Zr by the differential technique has also been applied [44]. 

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