Showing papers on "Zirconium alloy published in 1973"

Method of making tubes and similar products of a zirconium alloy

Abstract: The creep strength of a tube formed from a "Zircaloy" material is improved by prefacing the final cold working step of the manufacturing procedure by heating the material to the beta -range and then cooling to room temperature.

Nuclear fuel element

Abstract: A nuclear fuel element for use in the core of a nuclear reactor is disclosed. A heat conducting, fission product retaining metal liner of a refractory metal is incorporated in the fuel element between the cladding and the nuclear fuel to inhibit mechanical interaction between the nuclear fuel and the cladding, to isolate fission products and nuclear fuel impurities from contacting the cladding and to improve the axial thermal peaking gradient along the length of the fuel rod. The metal liner can be in the form of a tube or hollow cylindrical column, a foil of single or multiple layers in the shape of a hollow cylindrical column, or a coating on the internal surface of the cladding. Preferred refractory metal materials are molybdenum, tungsten, rhenium, niobium and alloys of the foregoing metals.

Method for making aluminum alloy product

Abstract: An aluminum base alloy containing zinc, copper and magnesium together with zirconium or both zirconium and manganese and with specially controlled composition limits exhibits very high strength when thermally treated to a condition having high resistance to stress corrosion cracking. Improved products of the alloy also exhibit low quench sensitivity and, accordingly, high strength even in very thick sections. A special aging treatment produces the optimum combination of strength and resistance to stress corrosion cracking properties.

Mass spectrographic determination of hydrogen thermally evolved from uranium and uranium alloys

Abstract: A hot-extraction, high-vacuum technique using mass-spectrographic detection has been used to determine the hydrogen content in uranium metal and uranium alloys. The time dependence of the evolution of hydrogen from the bulk metal and that from surface contamination was sufficiently different to resolve these two components. During the transient temperature portion of the analysis the hydrogen evolution rate from various uranium alloys was strongly influenced by the solubility of hydrogen in the alloy. Hydrogen due to sample surface contamination was approximately 0.5 weight-parts-per-million (wppM) which limited the lower limit of detection for bulk hydrogen to 0.05 wppM. Diffusion coefficients for hydrogen in uranium alloys were determined from hydrogen evolution rate data. (auth)

Preparation of technical zirconium diboride by the carbothermic reduction of mixtures of zirconium and boron oxides

Abstract: A study was made of the preparation of technical zirconium diboride by the reduction of mixtures of zirconium and boron oxides with carbon under industrial conditions. It is shown that the optimum conditions for the preparation of zirconium diboride by the carbothermic method are established when a charge having the composition ZrO2+1.2 B2O3+5 C (i.e., with a 20% excess of boric anhydride over the stoichiometric composition) is reduced at 2000°C in a hydrogen or converted gas atmosphere. The resultant ZrB2 contains 18–19% B (compared with the theoretical boron content of 19.25%) and not more than 0.8% C.

Radiation hardening in Zircaloy-2

Abstract: Annealed Zircaloy-2 was exposed to fast neutron fluences in the range 0.46 to 6.71 × 1019 nvt, E > 1 MeV, at temperatures of up to 450°C. The level of radiation hardening, as measured by the change in yield stress after irradiation, increased with irradiation temperature at least up to 380°C. Post-irradiation annealing treatments showed that radiation anneal hardening occurred after irradiation at temperatures up to 325°C. After irradiation at 375°C, annealing treatments did not produce a further increase in the yield stress above that produced by the irradiation, however the radiation hardening persisted to 450°C. The uniform strain tended to decrease as the amount of radiation anneal hardening increased and as the fast neutron fluence increased above ∼5 × 1018 nvt, E > 1 MeV. The effects of irradiation temperature and post-irradiation annealing on the yield stress and on uniform strain are explained in terms of the strengthening of radiation damage defect clusters and their increased effectiven...

Stability of reactive and refractory metal borides in ternary chromium-base alloys.

Abstract: Dispersion hardening by the Group IVb and Vb metal carbides has been demonstrated to improve the high temperature strength of chromium significantly 1 , and has created interest in the similar use of the borides of these metals. The purpose of this work was to characterize the elevated temperature formation and stability of these borides in chromium-base alloys, about which little is currently known.

Effect of solutes in binary columbium /Nb/ alloys on creep strength

Abstract: The effect of seven different solutes in binary columbium (Nb) alloys on creep strength was determined from 1400 to 3400 F for solute concentrations to 20 at.%, using a new method of creep-strength measurement. The technique permits rapid determination of approximate creep strength over a large temperature span. All of the elements were found to increase the creep strength of columbium except tantalum. This element did not strengthen columbium until the concentration exceeded 10 at.%. Hafnium, zirconium, and vanadium strengthed columbium most at low temperatures and concentrations, whereas tungsten, molybdenum, and rhenium contributed more to creep strength at high temperatures and concentrations.

High temperature oxidation of zirconium boride in oxygen

Abstract: Translated from Zh Fiz Khim; 47: No 4 887-891(Apr 1973) The growth kinetics of oxide films on zirconium boride exposed to oxygen at high temperatures were investigated as a function of temperature and oxygen pressure The phase composition of the scale formed on ZrB/sub 2/ under different conditions is discussed (auth)

Simultaneous Measurement of Specific Heat, Electrical Resistivity, and Hemispherical Total Emittance of Niobium-1 (Wt. %) Zirconium Alloy in the Range 1500 to 2700 K by a Transient (Subsecond) Technique.

Abstract: Simultaneous measurements of specific heat, electrical resistivity, and hemispherical total emittance of niobium-1 (wt. %) zirconium alloy in the temperature range 1500 to 2700 K by a subsecond duration pulse heating technique are described. Estimated inaccuracy of measured properties are: 3 percent for specific heat and hemispherical total emittance, and 0.5 percent for electrical resistivity. Properties of the alloy are compared with the properties of pure niobium. It was found that specific heat and emittance of the alloy were approximately 0.5 percent and 1.5 percent, respectively, higher than those of pure niobium. Electrical resistivity of the alloy was 0.5 percent lower than that of pure niobium. Like niobium, the alloy showed a negative departure from linearity in the curve of electrical resistivity versus temperature.

Critical role of nitrogen during high temperature scaling of zirconium

Abstract: The mechanisms of scale cracking, scale color changes, and scale growth, and their interrelations, were studied in zirconium specimens at elevated temperatures in air, oxygen and nitrogen. Nitrogen was found to be responsible for monoclinic-to-cubic ZrO2 conversion, for scale cracking and breakaway on zirconium nitride, and for the formation of ZrN on the metal interface underneath an outer oxide layer.

Temperature dependence of deformation for β phase niobium 16–40% zirconium alloys

Abstract: The object of this investigation was to establish some deformation characteristics of niobium-zirconium alloys in a composition range with optimum superconducting properties. The tensile properties of polycrystalline β-phase niobium 16–40% zirconium have been established within the temperature range 4.2 to 800 K. The resolved shear stresses for yield (τy) and fracture (τf) decreased with increasing temperature up to approximately 0.2 T M above which an athermal plateau forms. Within the athermal range, solid solution strengthening occurs, which up to ~ 25% zirconium, obeys a relationship based upon an atomic misfit parameter. Above ~ 25% zirconium there is a decrease in strengthening. A model which describes the variation of τy within the thermally activated temperature range is the Peierls mechanism which involves thermal activation of kinked dislocation pairs. The deformation modes, both slip and twinning, together with the dislocation structures have been analysed and correlated with changes in yield and fracture. At temperatures within the athermal temperature range ductile fracture occurs, but at lower temperature brittle fracture is observed. Basically, additions of zirconium up to ~ 25% have a similar effect on deformation behaviour as decreasing the temperature of deformation in pure niobium.

The properties of directionally-solidified eutectic and hypo-eutectic copper-zirconium alloys

Abstract: Alloys of the copper-Cu5Zr eutectic have been directionally solidified over a range of growth rates. The tensile strength was found to be high, 0.6 to 1.0 GN m−2, in contrast to the poor electrical conductivity, typically 22 m Ω−1 mm−2. In order to improve the latter at the expense of the former, hypo-eutectic (copper-rich) alloys were also studied. Alloys of composition in the region of copper-4 wt % zirconium possessed a useful combination of properties but these were not superior to the properties of conventionally cast samples. These alloys were shown to be stable against exposure to elevated temperatures.

Reactions of boron nitride with transition metals and their borides and nitrides

Abstract: Interaction of boron nitride with titanium, zirconium, hafnium, zirconium nitride, and zirconium boride was studied using highpressed powder mixtures within the range of temperatures 1200 to 2000 deg C During interaction of boron nitride with- metals the mixture of nitride and boride phases of metals is formed, the content of metal nitride being decreased with temperature elevation Interaction of boron nttride with zirconium nitride resulte in formation of zirconium diboride No irteractions of boron nitride with zirconium diboride are found (auth)

The analysis of hydrides in hydrogen–zirconium alloys cooled from the α-zirconium phase field

Abstract: An X-ray powder diffraction method is described which can determine the phases present in hydrogen–zirconium alloys containing ≥ 100 p.p.m. hydrogen. The method is applied to show that γ- and δ-hydrides are formed when hydrogen–zirconium alloys are cooled from the α-phase field. It is shown that quenching favours the formation of the γ phase.

High temperature, low-cycle fatigue of copper-base alloys in argon. Part 2: Zirconium-copper at 482, 538 and 593 C

Abstract: Zirconium-copper (1/2 hard) was tested in argon over the temperature range from 482 to 593 C in an evaluation of short-term tensile and low-cycle fatigue behavior. The effect of strain rate on the tensile properties was evaluated at 538 C and in general it was found that the yield and ultimate strengths increased as the strain rate was increased from 0.0004 to 0.01/sec. Ductility was essentially insensitive to strain rate in the case of the zirconium-copper alloy. Strain-rate and hold-time effects on the low cycle fatigue behavior of zirconium-copper were evaluated in argon at 538 C. These effects were as expected in that decreased fatigue life was noted as the strain rate decreased and when hold times were introduced into the tension portion of the strain-cycle. Hold times in compression were much less detrimental than hold times in tension.