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Showing papers on "Zirconium alloy published in 1968"


Journal ArticleDOI
TL;DR: In this paper, the physical appearance of the room temperature hydride phase in zirconium alloys is described, with particular reference to the orientation of the hydrate platelets relative to specified reference directions.

180 citations


Journal ArticleDOI
TL;DR: In this article, the habit planes for precipitation of zirconium hydride in Zircaloy-2 and Zircalooy-4 have been determined to be {1017}.

99 citations


Journal ArticleDOI
TL;DR: In this article, the creep rate of cold-worked Zircaloy is due to dislocation climb caused by the supersaturation of vacancies and interstitials introduced by irradiation.

74 citations


Journal ArticleDOI
TL;DR: In this paper, the experimental results of 24 uniaxial in-reactor creep tests on various zirconium alloys, covering a range of stresses from 7 to 42 kg/mm2 and temperatures between 200 and 400 °C.

63 citations


Journal ArticleDOI
TL;DR: The experimental data on the effect of fission fragment, neutron and gamma irradiation on the oxidation of zirconium alloys have been reviewed in this article, where it is shown that both fast neutron irradiation and the presence of free oxygen or oxidising radiolytic species must be simultaneously present before any effect can be observed in high temperature water.

58 citations


Journal ArticleDOI
C.J. Rosa1
TL;DR: In this paper, the authors present a review of the kinetics and phenomena associated with the oxidation of pure zirconium metal by oxygen gas, and the obtained results can be used for investigating more complex oxidation kinetics, e.g., oxidation of titanium.
Abstract: Perhaps, with the exception of copper and nickel, zirconium has undergone the most extensive oxidation studies within the last decade or so. The vast interest in the oxidation behavior of zirconium stems mainly from two reasons. Firstly, zirconium alloys are of primary importance in nuclear reactor technology. Due to their low cross section for thermal neutrons and because of their relatively good corrosion resistance against water and steam, these alloys may be considered as favourable materials for many structural components, e.g., cladding tubes for water-cooled nuclear reactors. Consequently, investigations into the oxidation behavior of zirconium are necessary if the more intricate corrosion characteristics of zirconium alloys are to be better understood. Secondly, the zirconium-oxygen system is rather simple when compared with many other metal-oxygen systems. Because of this simplicity, zirconium is amenable to fundamental studies of the oxidation mechanism(s) and the obtained results can be of paramount importance in investigating more complex oxidation kinetics, e.g., oxidation of titanium. The present review is primarily concerned with the kinetics and phenomena associated with the oxidation of “pure” zirconium metal by oxygen gas.

56 citations


Journal ArticleDOI
TL;DR: In this article, the presence of the ordered phase Zr 3 O in thin foils of oxidized zirconium was established by selected area diffraction, and the hardness was measured in the diffusion zone and the non-linear relation between hardness and oxygen concentration was derived.

26 citations



Journal ArticleDOI
TL;DR: In this paper, solid cylindrical specimens of the monocarbides of Ti, Zr, Ta, Nb, and W, made by 1) hot pressing, 2) slip casting and sintering, and 3) explosion-pressing, were irradiated.
Abstract: Solid cylindrical specimens (½- × ½-in.) of the monocarbides of Ti, Zr, Ta, Nb, and W, made by 1) hot pressing, 2) slip casting and sintering, and 3) explosion-pressing and sintering, were irradiat...

17 citations



Patent
27 Sep 1968
TL;DR: In this paper, the authors describe a procedure in which Zirconium and its alloYS are subjected to a bETA phase HEAT TREATMENT and a SURFACE ACTIVE AGENT is admitted to the heating environment.
Abstract: A PROCESS IS DESCRIBED IN WHICH ZIRCONIUM AND ITS ALLOYS ARE SUBJECTED TO A BETA PHASE HEAT TREATMENT AND DURING SAID HEAT TREATMENT A SURFACE ACTIVE AGENT IS ADMITTED TO THE HEAT TREATING ENVIRONMENT. THEREAFTER, THE METAL OR ALLOY IS COOLED TO A TEMPERATURE BELOW THE ALLOTROPIC TRANSFORMATION TEMPERATURE. THE METAL OR ALLOY THUS TREATED IS CHARACTERIZED BY A PREFERRED ORENTATION WHICH INCLUDES A HIGH VOLUME PROPORTION OF THE GRAINS EXHIBITING THE BASAL PLANE (0002) ORIENTED TO WITHIN 15* OF THE SURFAE OF THE MATERIAL.

Journal ArticleDOI
TL;DR: In this paper, grain boundaries lying in certain directions relative to adjacent grains have been found to be preferred sites for zirconium hydride precipitation in Zircaloy-2, and the most favourable sites are those grain boundaries which make angles of 35°−40° and 60°−75° to the basal planes of the adjacent grains.

ReportDOI
01 Oct 1968
TL;DR: In this article, phase composition and associated microstructure of alpha and beta titanium alloys were compared to stress corrosion cracking (SCC) and showed that only a low-interstitial, commercially pure alpha alloy (Ti-50A) was immune to SCC.
Abstract: : Four alpha titanium alloys and 11 alpha + beta titanium alloys were characterized to relate phase composition and associated microstructure to stress corrosion cracking (SCC). Of these alloys, only a low-interstitial, commercially pure alpha alloy (Ti-50A) was immune to SCC. Addition of oxygen, aluminum, or aluminum and tin restricted slip in the alpha phase and promoted stress corrosion susceptibility. Formation of ordered domains of Ti3(Al, Sn) further restricted slip and increased susceptibility. Stress corrosion resistance was improved by thermomechanical treatments that reduced alpha grain size or increased dislocation density. Alpha-phase susceptibility is qualitatively related to the intensity of the stress field surrounding a dislocation pileup. Alloying with molybdenum and/or vanadium increased strength and often improved stress corrosion resistance. This is attributed to stabilization of the ductile beta phase. However, precipitation of a fine dispersion of alpha or omega in beta caused embrittlement and reduced the stress corrosion threshold. Intermetallic compound formation in alloys containing copper or silicon similarly promoted susceptibility. Thermomechanical processing of Ti-4Al-4Mo-2Sn-0.5Si limited the embrittlement, probably by refining Ti5Si3 particles in the beta phase.

Patent
24 May 1968
TL;DR: An ABSORBER ELEMENT for the regulation and control of NEUTRON FLUX in a NUCLEAR REACTOR and ESPECIALLY "stackeded-ball," "STACKed-particle" or "ordered-bed" REACTORS whereIN a BODY of graphite or zirconium alloys CONTAINS a MASS OF COated ABSorber PARTICLES HAVING CORES OF HIGH-MELTING-POINT BORIDES, I.E.
Abstract: AN ABSORBER ELEMENT FOR THE REGULATION AND CONTROL OF NEUTRON FLUX IN A NUCLEAR REACTOR AND ESPECIALLY "STACKED-BALL," "STACKED-PARTICLE" OR "ORDERED-BED" REACTORS WHEREIN A BODY OF GRAPHITE OR ZIRCONIUM ALLOY CONTAINS A MASS OF COATED ABSORBER PARTICLES HAVING CORES OF HIGH-MELTING-POINT BORIDES, I.E. THE DIBORIDES OF ZIRCONIUM, VANADIUM, HAFNIUM OR TANTALUM. THE PARTICLES, HAVING A PARTICLE SIZE OF THE ORDER OF 100 TO 500 MICRONS (SEVERAL HUNDREDS OF MICRONS), ARE FORMED BY COATING THESE CORES WITH PYROLYTIC CARBON, AND CONVENTIONAL COATED-PARTICLE CARBIDES OR OXIDES.

Journal ArticleDOI
C.J. Rosa1
TL;DR: In this article, the parabolic rate constants of α-zirconium at 850 °, 800 ° and 750 °C were derived in terms of a unidirectional volume diffusion model for a two-phase system.
Abstract: Theoretical evaluation of oxidation rates of α-zirconium at 850 °, 800 ° and 750 °C is given in terms of a unidirectional volume diffusion model for a two-phase system. The calculated results conform to the parabolic rate law, Δm A = k p √ t , and are in good agreement with experimental determinations. It is possible to express the parabolic rate constants, k p , for both the oxide phase and zirconium in terms of diffusion parameters. The amount of oxygen confined to the metal phase is about 98% of the total amount of oxygen consumed during oxidation of zirconium for periods up to 144 h.


Journal ArticleDOI
01 Jan 1968-Analyst
TL;DR: In this paper, a reaction based on the formation of a purple-coloured complex between niobium and 4-(2-pyridylazo)resorcinol (PAR) in a tartrate-ethylenediaminetetra-acetate (EDTA) solution has been successfully applied to the direct spectrophotometric determination of Niobium, in the range 50 p.p.m. to about 1 per cent.
Abstract: A reaction based on the formation of a purple-coloured complex between niobium and 4-(2-pyridylazo)resorcinol (PAR) in a tartrate-ethylenediaminetetra-acetate (EDTA) solution has been successfully applied to the direct spectrophotometric determination of niobium, in the range 50 p.p.m. to about 1 per cent., in zirconium, zirconium alloys, hafnium, tungsten and molybdenum. The absorbance is measured at 550 mµ.By modification, this direct procedure can be used for the determination of down to 200 p.p.m. of niobium in titanium and its alloys.Following an extractive concentration, amounts of niobium down to about 10 p.p.m. can be determined in titanium, zirconium, and their alloys, and in hafnium, molybdenum and iron. For tungsten (and molybdenum), a preliminary collection of niobium on zirconium hydroxide is recommended.The effects of common alloying elements, and likely impurities, have been investigated.The absorption of the tantalum complex is only about one eighth of that of the niobium-PAR complex.

Journal ArticleDOI
TL;DR: In this paper, the maximum quantities of mangenese, silicon, tin, aluminum, beryllium, and iron which are acceptable as impurities in magnesium alloys with zirconium were established.
Abstract: 1. It was found that zinc, copper, misch metal, and calcium do not affect the solubility of zirconium in magnesium but promote refining of the structure of the Mg-Zr alloy, while nickel, manganese, silicon, tin, aluminum, beryllium, and iron lower the solubility of zirconium and promote coarsening of the structure. A lower solubility of zirconium in magnesium is promoted by elements which combine with zirconium to form compounds with melting points above 1200°C. 2. We established the maximum quantities of mangenese, silicon, tin, aluminum, beryllium, and iron which are acceptable as impurities in magnesium alloys with zirconium. 3. We determined the joint solubilities of impurities of zirconium and iron in the molten ML5 alloy. We found that the zirconium solubility decreases with increasing iron concentrations. 3. We propose an effective means of reducing the harmful zirconium impurity in the ML5 alloy to 0,0015%. It consists of enriching the alloy with iron by overheating to 900°C and holding at this temperature 30 min.


Journal ArticleDOI
TL;DR: In this article, the authors measured I-V curves and energy loss per cycle in Nb and Nb-Zr superconducting wires and showed that the energy loss is proportional to the number of cycles.
Abstract: AC induced voltages in Nb and Nb-Zr superconducting wires, measuring I-V curves and energy loss per cycle


Journal ArticleDOI
TL;DR: In this article, a direct spectrophotometric determination of niobium in zirconium alloys with 4-(2-pyridylazo)resorcinol is described.


Journal ArticleDOI
TL;DR: In this paper, the authors examined the effect of fused and sized yttria particles on the microstructure of zirconium alloys and showed that the best hot-rolled dispersions were comparable in rupture properties to annealed Zr/2.5 wt % Nb.


Patent
Gerd Urban1, Erwin Schmidt1
20 Nov 1968
TL;DR: In this article, the authors present a method for providing a super-convex coating of a metal, such as NICKEL, COPPER ZINC, INDIUM, TIN OR GOLD, with this coating being provided by a galvaneic ETch-plating process.
Abstract: A METHOD FOR PROVIDING ON A SUPERCONDUCTIVE METAL, PARTICULARLY NIOBIUM AND ALLOYS OF NIOBIUM AND ZIRCONIUM, A COATING OF A METAL SUCH AS NICKEL, COPPER ZINC, INDIUM, TIN OR GOLD, WITH THIS COATING BEING PROVIDED BY A GALVANIC ETCH-PLATING PROCESS. ACCORDING TO THE METHOD THE BASE METAL WHICH INITIALLY HAS BEEN CLEANED IS ANODICALLY ETCHED IN AN AQUEOUS SOLUTION OF HYDROFLUORIC ACID, AMMONIUM FLUORIDE, AND A FLUORIDE OF THE METAL WHICH IS TO FORM THE COATING. THEN THE POLARITY OF THE CIRCUIT IS REVERSED SO THAT THE METAL IS THEN TREATED IN THE SAME SOLUTION CATHODICALLY. THE REVERSAL OF POLARITY TAKES PLACE WITH SUCH RAPIDITY THAT AN INACTIVATION OF THE EXTERIOR SURFACE OF THE BASE METAL CANNOT OCCUR.

Journal ArticleDOI
TL;DR: In this paper, a study was made of conditions under which the zirconium suicides were produced by the silicothermic reduction of ZIRconium dioxide in a vacuum, and it was shown that lower-silicon phases Zr5Si3 and Zr2Si cannot be produced by this technique.
Abstract: 1. A study was made of conditions under which the zirconium suicides ZrSi2, ZrSi, Zr5Si3, and Zr2Si are produced by the silicothermic reduction of zirconium dioxide in a vacuum. 2. It has been established that silicothermic reduction in graphite furnaces can yield only the suicides ZrSi2 and ZrSi. The lower-silicon phases Zr5Si3 and Zr2Si cannot be produced by this technique. 3. At temperatures in excess of 1700°C, owing to the low thermodynamic stability of the lower suicides and the occurrence of several secondary reactions, the principal reaction products are silicon, which vigorously evaporates, and zirconium carbide.

Journal ArticleDOI
TL;DR: In this article, the superconducting transition temperature, Tc, upper critical field and normal state resistivity have been measured on a wide range of Zr-Nb alloys heat treated at 585 °C.
Abstract: Measurements of the superconducting transition temperature, Tc, upper critical field and normal state resistivity, have been carried out on a wide range of Zr-Nb alloys heat treated at 585 °C. An extremely rapid rise in transition temperature, from 0.7 °K to 3.5 °K, has been observed in the α-Zr solid solution region (0%–1.25% Nb) which lends support to a recent theoretical model for the density of states of Zr9. The transition temperature continues to increase in the early part of the two-phase region, reaching a value of 10 °K at 6% Nb. The precise value of Tc, in fact, depends on the distribution of the β-precipitate for compositions between 1.25% and 6% Nb. Thereafter tc remains approximately constant with composition up to the β-solid-solubility boundary at 88% Nb. The upper critical field and the normal state resistivity show maxima at 75% Nb, which are discussed in terms of the microstructure.


Journal ArticleDOI
TL;DR: In this paper, the authors propose a framework to improve the quality of the data collected by the data collection system, which is based on the concept of "global positioning system" (GPS).
Abstract: メチレン青-ジクロルエタン抽出法を用いるジルコニウムおよびジルカロイ中の微量ホウ素の定量法について研究した.試料をフツ化水素酸および硫酸に溶解し,生成したテトラフルオロホウ酸イオン(BF4-と略記)とメチレン青との錯体をジクロルエタンで抽出する.有機相を水で洗浄し,波長657mμにおける吸光度を測定してホウ素を定量する.本法によれば,ジルコニウムおよびジルカロイの主成分,ならびに通常含まれるほかの元素は妨害しない.定量下限は添加法を用いた場合,約0.2ppmである.