Mode of carbide TiC-ZrC alloy fracture at various temperatures

International Nuclear Information System (INIS)

Paderno, V.N.; Lesnaya, M.I.; Martynenko, A.N.; Chugunova, S.I.

1983-01-01

Bending strength is studied for mutual TiC-ZrC alloys within a temperature range of 20-600 deg C. Structure of the material failure surface is studied from replicas by scanning and transmission electron microscopy. The data obtained are compared with concentration dependences of some physical properties of these alloys. Bending strength is shown to be minimum for the alloy with 40 mol % of zirconium carbide. It is stated that within the temperature range under study the carbide alloys undergo macroscopic brittle failure. The materials are characterized by a mixed type of failure with transcrystalline failure somewhat prevailing

Effect of strain on evolution of dynamic recrystallization in Nb-1 wt%Zr-0.1 wt%C alloy at 1500 and 1600 °C

Energy Technology Data Exchange (ETDEWEB)

Behera, A.N. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094 (India); Kapoor, R., E-mail: rkapoor@barc.gov.in [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094 (India); Paul, B. [Materials Processing & Corrosion Engineering Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Chakravartty, J.K. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2017-04-15

Uniaxial compression tests were carried out on Nb-1 wt%Zr-0.1 wt%C alloy at temperature of 1500 and 1600 °C and strain rate of 0.1 s{sup −1} to study the evolution of dynamic recrystallization with strain. Electron back scatter diffraction was used to quantify the microstructural evolution. Nb-1Zr-0.1C alloy showed a necklace structure at a strain of 0.9 when deformed at 1500 °C and at strain of 0.6 when deformed at 1600 °C, both at strain rate of 0.1 s{sup −1}. This suggested the occurrence of dynamic recrystallization. At 1500 °C and strain of 0.9 the local average misorientation and the grain orientation spread was low confirming the presence of dynamic recrystallization at this deformation condition. At both 1500 and 1600 °C and all measured strains the recrystallized grains had a strong fiber component of <001>. - Highlights: • Necklace formation of dynamically recrystallized grains occurred at strain of 0.6 and 0.9 for 1500 and 1600 °C, respectively. • Equiaxed microstructures were seen with increase in strain for both 1500 and 1600 °C. • At large strains the predominant recrystallized texture evolved to <001> pole.

Phase transformations on Zr-Nb alloys

International Nuclear Information System (INIS)

Doi, Sergio Norifumi

1980-01-01

This research intended the laboratory scale experimental development of Zr-Nb alloys with adequate characteristics for use as fuel element cladding or for the making of irradiation capsules. Zr-Nb alloys with different Nb contents were melted and the resulting material was characterised. The following metallurgical aspects were considered: preparation of Zr-Nb alloys with various Nb contents; heat and thermomechanical treatments; microstructural characterization; mechanical properties; oxidation properties. The influence of the heat treatment and thermomechanical treatment, on the out-of-pile mechanical and oxidation properties of the Zr-Nb alloys were studied. It was found that the alloy microhardness increases with the Nb content and/or with the thermomechanical treatment. Mechanical properties such as yield and ultimate tensile strength as well as elongation were determined by means of compression tests. The results showed that the alloy yield stress increases with the Nb content and with the thermomechanical treatment, while its elongation decreases. Thermogravimetric analysis determined the alloy oxidation kinetics, in the 400 - 800 deg C interval, at 1 atm. oxygen pressure. The results showed that the alloy oxidation rate increases with the temperature and Nb content. It was also observed that the oxidation rate increases considerably for temperatures higher than 600 deg C.(author)

Heat treatment effect on the properties of welded joint of niobium alloys of the Nb-1Zr-C system

International Nuclear Information System (INIS)

Aref'ev, Yu.V; Chernyshova, T.A.; Pokosov, V.S.

1976-01-01

Thermal treatment of weld joints of the alloys Nb-1 Zr-(0.01-0.12)C at 800-900 deg C leads to decomposition of the solid solution of the weld metal which is accompanied with a decrease in plasticity and impact strength. The decomposition of the solid solution takes place even in a relatively pure alloy containing only 0.025% of intrusion impurities. Thermal treatment is reasonable only when carbon content in the alloys is no less than 0.1%. The decomposition of the solid solution in the weld metal of the alloy containing 0.12% of C takes place during thermal treatment at the expense of liberating niobium carbides Nb 3 C 2 and Nb 2 C. When rearrangement takes place, i it is Nb 2 C that liberates mainly

The corrosion behaviour of Zr3Al-based alloys

International Nuclear Information System (INIS)

Murphy, E.V.; Wieler, R.

1977-07-01

The corrosion resistance of several zirconium-aluminum alloys with aluminum contents ranging from 7.6 to 9.6 wt% was examined in 300 deg C and 325 deg C water, 350 deg C and 400 deg C steam and in air and wet CO 2 at 325 deg C and 400 deg C. In the transformed alloys there are three phases present, αZr, Zr 2 Al and Zr 3 Al of which the αZr phase is the least corrosion resistant. The most important factor controlling the corrosion behaviour of these alloys was found to be the size, distribution and amount of the αZr phase in the transformed alloys, which in turn was dependent upon the microstructural scale of the untransformed alloys

Features of ultrafine-grained structure forming in Zr-1Nb alloy

Energy Technology Data Exchange (ETDEWEB)

Stepanova, Ekaterina N.; Prosolov, Konstantin A. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Grabovetskaya, Galina P.; Mishin, Ivan P. [Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences, Tomsk (Russian Federation)

2013-07-01

Ultrafine-grained structure forming by the method combined reversible hydrogenation and hot pressing in Zr-1Nb alloy was investigated. Preliminary hydrogenation to concentrations of (0.14–0.4) % at 873 K is found to lead to yield strength decreasing in Zr-1Nb alloy during hot pressing by 1,5–2 times. During uniaxial compression at (70–72) % under isothermal conditions at a temperature of 873 K in Zr-1Nb alloy, hydrogenated to concentration of 0.22 %, homogeneous ultrafine grained structure with an average grain size of 0,4 P m was formed. Key words: zirconium alloy, ultrafine-grained structure, hydrogen.

Microstructural evolution and structure property correlation in Zr-1Nb and Zr-1Nb-1Sn-0.1Fe alloys

International Nuclear Information System (INIS)

Neogy, S.; Srivastava, D.; Chakravartty, J.K.; Dey, G.K.

2005-01-01

This study summarizes the evolution of microstructure and precipitation behavior in binary Zr-1Nb and quaternary Zr-1Nb-1Sn-0.1Fe alloys after different thermo mechanical processing. The processed microstructure and morphology of constituent phases and precipitates have been studied in detail using transmission electron microscopy (TEM). Microstructural studies have revealed the shape, size, size distribution and the nature of precipitate phases. Martensite formation and its tempering behavior have been studied in detail in both the alloys. Recrystallization studies on these alloys have been carried out with a view to understand the recrystallization mechanism. In case of the binary alloy the second phase recipitates were of the β type having composition varying from β I (20 wt% Nb) to β II (85 wt% Nb) depending on the heat treatment temperature and time. The second phase precipitates in the quaternary alloy were intermetallic Zr-Nb-Fe type and also β type rich in Zr. The orientation relationship existing between the precipitating phases and the a matrix were established in case of both the alloys. High resolution electron microscopy (HREM) of the martensitic microstructure and the recrystallized microstructure has revealed the internal structure and the interface structure of the martensite and the precipitating phases respectively. Structure-property correlation studies have been carried out on the heat-treated samples to evaluate the effect of the thermo mechanical processing on the microstructures and hence mechanical properties. (author)

Numerical simulation of the mechanical behavior of ultrafine- and coarse-grained Zr-Nb alloys over a wide range of strain rates

Science.gov (United States)

Serbenta, V. A.; Skripnyak, N. V.; Skripnyak, V. A.; Skripnyak, E. G.

2017-12-01

This paper presents the results on the development of theoretical methods of evaluation and prediction of mechanical properties of Zr-Nb alloys over a range of strain rates from 10-3 to 103 s-1. The mechanical behavior of coarse- and ultrafine-grained Zr-1Nb (E110) was investigated numerically. The ranges of strain rates and temperatures in which the mechanical behavior of Zr-1Nb alloy can be described using modified models of Johnson-Cook and Zerilli-Armstrong were defined. The results can be used in engineering analysis of designed technical systems for nuclear reactors.

Microstructural and mechanical characterization of biomedical Ti-Nb-Zr(-Ta) alloys

International Nuclear Information System (INIS)

Elias, L.M.; Schneider, S.G.; Schneider, S.; Silva, H.M.; Malvisi, F.

2006-01-01

In recent years there has been a significant development of novel implant alloys based on β-Ti such as Ti-Nb-Zr and Ti-Nb-Zr-Ta alloys systems. The purpose of this work is to provide characterization of Ti-35.3Nb-5.1Ta-7.1Zr and Ti-41.1Nb-7.1Zr alloys, in which Nb will substitute the atomic amount of Ta, with emphasis in the property-microstructure-composition relationships. These alloys are produced from commercially pure materials (Ti, Nb, Zr and Ta) by an arc melting method. All ingots were submitted to sequences of heat treatment (1000 deg. C/2 h - WQ), cold working by swaging procedures and other heat treatment (1000 deg. C/2 h - WQ). Specimens, in as cast and heat-treated condition, were examined by light and scanning electron microscopy (SEM). These results suggested the presence of β- and ω-phases. Mechanical properties were based on tensile and hardness tests. These alloys exhibit a lower modulus than that of conventional Ti alloys and the other mechanical properties are suitable for biomedical applications

Corrosion behavior of Zr-x(Nb, Sn and Cu) binary alloys

International Nuclear Information System (INIS)

Kim, M. H.; Lee, M. H.; Park, S. Y.; Jung, Y. H.; We, M. Y.

1999-01-01

For the development of advanced zirconium alloys for nuclear fuel cladding, the corrosion behaviors of zirconium binary alloys were studied on the Zr-xNb, Zr-xSn, and Zr-xCu alloys. The corrosion test were performed in water at 360 deg C, steam at 400 deg C and LiOH at 360 deg C for 45 days. The corrosion behaviors of Zr-xNb was similar to that of Zr-xCu alloys. However, the corrosion behavior of Zr-xSn was different from Zr-xNb and Zr-xCu. The weight gain of Zr-xNb and Zr-xCu was increased with addition of alloying elements. When Sn is added to Zr matrix in range below the solubility limit, the corrosion resistance decrease with increasing Sn-content, while in the range over solubility limit, Sn has an adverse effect on the corrosion resistance. Especially, Zr-xSn alloys showed higher corrosion resistance than Zr-xNb and Zr-xCu alloys in LiOH solution

Thermal stability of the microstructure of an aged Nb-Zr-C alloy

Science.gov (United States)

Uz, Mehmet; Titran, Robert H.

1991-01-01

The effects of thermal aging with and without an applied stress on the microstructure of a Nb-Zr-C alloy containing 0.9 wt percent Zr and 0.06 percent C were studied. Chemical analysis, metallographic examination, energy dispersive X-ray spectra of the bulk material, and chemical and X-ray analyses of the phase-extracted residue were used to characterize the microstructure. The samples examined were from a creep strength study involving hot and cold working, and various combinations of exposure to temperatures ranging from 1350 to 1755 K with and without applied load times as long as 34,000 plus hours. The results showed that the initial microstructure consisted primarily of orthorombic precipitates of Nb sub C which were partially or completely transformed to face-centered cubic carbides of Nb and Zr, (Zr, Nb)C, upon prolonged exposure to elevated temperatures. Furthermore, it was found that the microstructure of the alloy is extremely stable owing to the very finely distributed precipitates throughout its matrix and along the grain boundaries. The lattice parameters of the cubic carbides were determined to vary from 0.458 to 0.465 nm as the Zr/Nb ratio varied from 38/62 to 75/25.

Thermal stability of the microstructure of an aged Nb-Zr-C alloy

International Nuclear Information System (INIS)

Uz, M.; Titran, R.H.

1991-01-01

The effects of thermally aging with and without an applied stress on the microstructure of a Nb-Zr-C alloy containing 0.9 wt % Zr and 0.06 wt % C were studied. Chemical analysis, metallographic examination, energy dispersive x-ray spectra of the bulk material, and chemical and x-ray analyses of the phase-extracted residue were used to characterize the microstructure. The samples examined were from a creep strength study involving hot and cold working, and various combinations of exposure to temperatures ranging from 1350 to 1755 K with and without applied load for times as long as 34,000 plus hours. The results showed that the initial microstructure consisted primarily of orthorhombic precipitates of Nb 2 C which were partially or completely transformed to face-centered cubic carbides of Nb and Zr, (Zr,Nb)C, upon prolonged exposure to elevated temperatures. Furthermore, it was found that the microstructure of the alloy is extremely stable owing to the very finely distributed precipitates throughout its matrix and along the grain boundaries. The lattice parameters of the cubic carbides were determined to vary from 0.458 to 0.465 nm as the Zr/Nb ratio varied from 38/62 to 75/25. 25 refs., 5 figs., 4 tabs

Observations of a Cast Cu-Cr-Zr Alloy

Science.gov (United States)

Ellis, David L.

2006-01-01

Prior work has demonstrated that Cu-Cr-Nb alloys have considerable advantages over the copper alloys currently used in regeneratively cooled rocket engine liners. Observations indicated that Zr and Nb have similar chemical properties and form very similar compounds. Glazov and Zakharov et al. reported the presence of Cr2Zr in Cu-Cr-Zr alloys with up to 3.5 wt% Cr and Zr though Zeng et al. calculated that Cr2Zr could not exist in a ternary Cu-Cr-Zr alloy. A cast Cu-6.15 wt% Cr-5.25 wt% Zr alloy was examined to determine if the microstructure developed would be similar to GRCop-84 (Cu-6.65 wt% Cr-5.85 wt% Nb). It was observed that the Cu-Cr-Zr system did not form any Cr2Zr even after a thermal exposure at 875 C for 176.5 h. Instead the alloy consisted of three phases: Cu, Cu5Zr, and Cr.

Microstructure and mechanical properties of Ti-Zr-Cr biomedical alloys.

Science.gov (United States)

Wang, Pan; Feng, Yan; Liu, Fengchao; Wu, Lihong; Guan, Shaokang

2015-06-01

The Ti-15Zr-xCr (0≤x≤10, wt.%) alloys were investigated to develop new biomedical materials. It was found that the phase constitutions and mechanical properties strongly depended on the Cr content. The Ti-15Zr alloy was comprised of α' phase and a small fraction of β phase was detected with adding 1wt.% Cr. With addition of 5wt.% or more, the β phase was completely retained. In addition, the ω phase was detected in the Ti-15Zr-5Cr alloy and Ti-15Zr-7Cr alloy which exhibited the highest compressive Young's modulus and the lowest ductility. On the other hand, all the Ti-15Zr-xCr alloys without ω phase exhibited high microhardness, high yield strength and superior ductility. Furthermore, the elastic energy of Ti-15Zr-10Cr alloy (5.89MJ/m(3)) with only β phase and that of Ti-15Zr-3Cr alloy (4.04MJ/m(3)) with α' phase and small fraction of β phase was higher than the elastic energy of c.p. Ti (1.25MJ/m(3)). This study demonstrated that Ti-15Zr-3Cr alloy and Ti-15Zr-10Cr alloy with superior mechanical properties are potential materials for biomedical applications. Copyright © 2015. Published by Elsevier B.V.

High-temperature strength of Nb-1%Zr alloy for irradiation-capsules inner-shell

International Nuclear Information System (INIS)

Nomura, Yasushi; Nakata, Hirokatsu; Tanaka, Mitsuo; Fukaya, Kiyoshi.

1978-04-01

Coated fuel particles in capsules will be irradiated at about 1600 0 C in JMTR. Nb-1%Zr alloy was chosen for inner shell material of the capsules because of its sufficient strength at 1000 0 C and low induced radioactivity. Nb-1%Zr ingot produced by electron beam melting was formed into seamless tubes by hollowing and swaging, followed by annealing. Creep test in helium flow and tensile test in vacuum were made to examine mechanical strength of the Nb-1%Zr tubes at 1000 0 C. Following are the results; 1) 0.2% yield stress at 1000 0 C is about 6 kg/mm 2 . 2) 3000 hr creep rupture stress at 1000 0 C is about 6 kg/mm 2 . (auth.)

Aqueous corrosion study on U-Zr alloy

International Nuclear Information System (INIS)

Pal, Titas; Venkatesan, V.; Kumar, Pradeep; Khan, K.B.; Kumar, Arun

2009-01-01

In low power or research reactor, U-Zr alloy is a potential candidate for dispersion fuel. Moreover, Zirconium has a low thermal-neutron cross section and uranium alloyed with Zr has excellent corrosion resistance and dimensional stability during thermal cycling. In the present study aqueous corrosion behavior of U-Zr alloy samples was studied in autoclave at 200 deg C temperature. Corrosion rate was determined from weight loss with time. (author)

Oxidation between 1000 degrees C and 1600 degrees C and limiting criteria for the use of Zr-doped β-NiAl and β/γ alloys

International Nuclear Information System (INIS)

Doychak, J.; Barrett, C.A.; Smialek, J.L.

1989-01-01

This paper reports the isothermal and cyclic oxidation behavior of Zr-doped β-NiAl and β/γ' intermetallic alloys studied over the temperature range 1000 degrees C-1600 degrees C. Isothermal scale growth was governed by γ-Al 2 O 3 growth kinetics. The scale growth rates showed no monotonic trends with alloy aluminum content, although the stoichiometric β-NiAl alloy had the slowest kinetics. Cyclic oxidation at 1200 degrees C for 1000, 1-hr cycles of alloys having less than approximately 40 at %Al was poor due to the formation of martensite and less protective Ni-containing oxides. The cyclic oxidation behavior of Zr-doped stoichiometric β-NiAl was poor beyond 100, 1-hr cycles at 1425 degrees C. Computer modeling of the cyclic oxidation results was performed to arrive at limiting criteria for alloy service life. The limiting criteria were based on alloy aluminum depletion by oxidation that is necessary for less protective Ni-containing oxide formation. The modelling and lifetime criteria were applied to the cyclic oxidation of a Ni-50.2Al-0.04Zr (at%) alloy

Phase analysis and magnetocaloric properties of Zr substituted Gd-Si-Ge alloys

International Nuclear Information System (INIS)

Prabahar, K.; Raj Kumar, D.M.; Manivel Raja, M.; Chandrasekaran, V.

2011-01-01

The structure, microstructure, magneto-structural transition and magnetocaloric effect have been investigated in series of (Gd 5-x Zr x )Si 2 Ge 2 alloys with 0≤x≥0.20. X-ray powder diffraction analysis revealed the presence of orthorhombic structure for Zr containing alloys at room temperature in contrast to the monoclinic structure observed in the parent Gd 5 Si 2 Ge 2 alloy. The microstructural studies reveal that, low Zr addition (x≤0.1) resulted in low volume fraction of detrimental Gd 5 Si 3 -type secondary phase compared to that present in the parent alloy. All the Zr containing alloys have shown the presence of only second order magnetic transition unlike the parent alloy showing both first order structural and second order magnetic transition. A moderate (ΔS) M value of -5.5 J/kg K was obtained for the x=0.05 alloy at an enhanced operating temperature of 292 K compared to -7.8 J/kg K at 274 K of the parent alloy for an applied field of 2 T. The interesting feature of Zr (x=0.05) containing alloy is the wide operating temperature range of ∼25 K than that of ∼10-12 K for the parent, which resulted in enhanced net refrigerant capacity of 103 J/kg compared to that of 53 J/kg for the parent alloy. - Research highlights: → Zr addition in Gd 5 Si 2 Ge 2 alloy has been investigated for the first time to reduce the 5:3-type (Gd 5 Si 3 ) secondary phase formed when using commercial grade elements in Gd 5 Si 2 Ge 2 alloy. → It is interesting to observe that Zr addition decrease the volume fraction 5:3. → The refrigerator capacity and transition temperature of Zr added alloy is greater than the pure Gd 5 Si 2 Ge 2 which makes this alloy promising for room temperature application.

DENSITY-FUNCTIONAL STUDY OF U-Mo AND U-Zr ALLOYS

Energy Technology Data Exchange (ETDEWEB)

Landa, A; Soderlind, P; Turchi, P A

2010-11-01

Density-functional theory previously used to describe phase equilibria in U-Zr alloys [A. Landa, P. Soederlind, P.E.A. Turchi, J. Alloys Comp. 478 (2009) 103-110] is extended to investigate the ground-state properties of U-Mo solid solutions. We discuss how the heat of formation in both alloys correlates with the charge transfer between the alloy components, and how the specific behavior of the density of states in the vicinity of the Fermi level promotes the stabilization of the U{sub 2}Mo compound. Our calculations prove that, due to the existence of a single {gamma}-phase over the typical fuel operation temperatures, {gamma}-U-Mo alloys should indeed have much lower constituent redistribution than {gamma}-U-Zr alloys for which binodal decomposition causes a high degree of constituent redistribution.

Hydrogen storage behavior of ZrCo1-xNix alloys

International Nuclear Information System (INIS)

Jat, Ram Avtar; Parida, S.C.; Agarwal, Renu; Kulkarni, S.G.

2012-01-01

Intermetallic compound ZrCo is proposed as a candidate material for storage, supply and recovery of hydrogen isotopes in International Thermonuclear Experimental Reactor (ITER) Storage and Delivery System (SDS). However, it has been reported that upon repeated hydriding-dehydriding cycles, ZrCo undergoes disproportionation as per the reaction; 2ZrCo + H 2 ↔ ZrH 2 + ZrCO 2 . This results in reduction in hydrogen storage capacity of ZrCo, which is not a desirable property for SDS. Konishi et al. reported that the disproportionation reaction can be suppressed by decreasing the desorption temperature. It is anticipated that suitable ternary alloying of ZrCo can elevated the hydrogen equilibrium pressure and hence decrease the desorption temperature for supply of 100 kPa of hydrogen. In this study, we have investigated the effect of Ni content on the hydrogenation behavior of ZrCo 1-x Ni x alloys

Microstructural characterization of Zr1Nb alloy after hot rolling

Energy Technology Data Exchange (ETDEWEB)

Souza, A.C. [Universidade Estadual do Mato Grosso do Sul (UEMS), MS (Brazil); Rossi, J.L.; Martinez, L.G.; Mucsi, C.S. [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Tsakiropoulos, P. [University of Sheffield (United Kingdom); Ceoni, F.C.; Grandini, C.R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil)

2016-07-01

Full text: The different research lines within the scope in engineering and materials science have developed new materials that can be used in different industrial sectors, such as, energy, health and transportation. For the nuclear industry, for example, the Zr alloys, are of great interest due to its good mechanical properties, excellent corrosion resistance and above all, the high permeability to thermal neutrons. In the health sector, the zirconium poses one of the lowest Young's modulus when compared to other metallic biomaterials, e.g., pure Zr is 68 GPa, bone mineral hydroxyapatite is 80 GPa, for Ti alloys is 90 GPa and above, for Nb is 105 GPa and stainless steels above 189 GPa. This is particularly important for implants in bones, whose elasticity modulus can reach 30 GPa and it is desirable an as close match as possible. However, the zirconium alloys, have great chemical affinity with oxygen and nitrogen. Moreover, oxides and nitrides may form during the melting process, heat treatment and hot rolling, changing the physic-chemical properties of the alloy. This experimental work shows the results of the evolution of the microstructure after hot rolling of the Zr1Nb alloy. It was possible to confirm the absence of formation of oxides and nitrides, thus confirming the of the experimental method of melting and hot rolling of the Zr1Nb alloy. (author)

Enhancement of High Temperature Strength of 2219 Alloys Through Small Additions of Nb and Zr and a Novel Heat Treatment

Science.gov (United States)

Mondol, S.; Makineni, S. K.; Kumar, S.; Chattopadhyay, K.

2018-05-01

This paper presents a detailed investigation on the effect of small amount of Nb and Zr additions to 2219 Al alloy coupled with a novel three-stage heat treatment process. The main aim of the work is to increase the high temperature strength of 2219 alloy by introducing thermally stable L12 type ordered precipitates in the matrix as well as by reducing the coarsening of metastable strengthening θ″ and θ' precipitates. To achieve this, small amounts of Nb and Zr are added to 2219 alloy melt and retained in solid solution by suction casting in a water-cooled copper mould having a cooling rate of 102 to 103 K/s. The suction cast alloy is directly aged at 673 K (400 °C) to form L12 type ordered coherent Al3Zr precipitates. Subsequently, the alloy is solution treated at 808 K (535 °C) for 30 minutes to get supersaturation of Cu in the matrix without significantly affecting the Al3Zr precipitates. Finally, the alloy is aged at 473 K (200 °C), which results in the precipitation of θ″ and θ'. Microstructural characterization reveals that θ″ and θ' are heterogeneously precipitated on pre-existing uniformly distributed Al3Zr precipitates, which leads to a higher number density of these precipitates. This results in a significant increase in strength at room temperature as well as at 473 K (200 °C) as compared to the 2219 alloy. Furthermore, the alloy remains thermally stable after prolonged exposure at 473 K (200 °C), which is attributed to the elastic strain energy minimization by the conjoint Al3Zr/θ' or Al3Zr/θ″ precipitates, and the high Zr and Nb solute-vacancy binding energy, retarding the growth and coarsening of θ″ and θ' precipitates.

Effect of Si and Zr on the Microstructure and Properties of Al-Fe-Si-Zr Alloys

Directory of Open Access Journals (Sweden)

Anna Morozova

2017-11-01

Full Text Available The effects of Si and Zr on the microstructure, microhardness and electrical conductivity of Al-Fe-Si-Zr alloys were studied. An increase in the Zr content over 0.3 wt. % leads to the formation of primary Al3Zr inclusions and also decreases mechanical properties. Therefore, the Zr content should not be more than 0.3 wt. %, although the smaller content is insufficient for the strengthening by the secondary Al3Zr precipitates. The present results indicate that high content of Si significantly affects the hardness and electrical conductivity of the investigated alloys. However, the absence of Si led to the formation of harmful needle-shaped Al3Fe particles in the microstructure of the investigated alloys after annealing. Therefore, the optimum amount of Si was 0.25–0.50 wt. % due to the formation of the Al8Fe2Si phase with the preferable platelet morphology. The maximum microhardness and strengthening effects in Al-1% Fe-0.25% Si-0.3% Zr were observed after annealing at 400–450 °C due to the formation of nanosized coherent Al3Zr (L12 dispersoids. The effect of the increasing of the electrical conductivity can be explained by the decomposition of the solid solution. Thus, Al-1% Fe-0.25% Si-0.3% Zr alloy annealed at 450 °C has been studied in detail as the most attractive with respect to the special focus on transmission line applications.

Thermal decomposition of the b.c.c. β-solid solution of titanium alloy containing 6.7 at% Mo, 3 at% Zr, and 1.8 at% Sn. 1

International Nuclear Information System (INIS)

Zakharova, M.I.; Khundzhua, A.K.; Kertesz, L.; Szasz, A.

1981-01-01

Changes in the crystal structure of the titanium alloy, containing 6.7 at% Mo, 3 at% Zr, and 1.8 at% Sn, during thermal decomposition are followed by means of X-ray and electron diffraction methods. Parallel to these tests the alteration in the electron structure and chemical bonds of the alloy are investigated with the help of the soft-x-ray emission (SXES) method. Attention is focussed on the at room temperature not equilibrated b.c.c. β-solid solution, on the metastable transition phase ω, and on the equilibrium phase α. (author)

Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

Energy Technology Data Exchange (ETDEWEB)

Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24

The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase α and β phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

Niobium alloys production with elements of high steam pressure and high ductilidate Nb46,5%Ti, Nb 1%Zr, Nb 1%Ti and Nb20% Ta

International Nuclear Information System (INIS)

Pinatti, D.G.; Baldan, C.A.; Dainesi, C.R.; Sandim, H.R.Z.

1988-01-01

The melting technology of niobium alloys with high ductilidade and high steam pressure, having the Ti, Zr and Ta as alloying elements is described. The electron beam technique for production of Nb 46,5%Ti, Nb 1%Zr and Nb 20%Ta alloys is analysed, aiming a product with high grade and low cost. (C.G.C.) [pt

Effect of metallurgical factors on the oxidation of Zr - 1% Nb Alloy

International Nuclear Information System (INIS)

Soliman, H.M.

1979-01-01

The importance of study of the oxidation behaviour of zirconium and its niobium alloys arises from their suitability as cladding and structural materials in nuclear reactors and their use in oxidizing conditions. This work includes the oxidation behaviour of Zr - 1%Nb in both air and steam, and to less extent, zirconium was investigated in air. The effect of 1%Nb, oxidizing medium, fluoride ions contamination and thermal cycling on the oxidation behaviour has been investigated using weight gain, plastic deformation generated during oxidation, electron microscopy , metallography and X- ray techniques. The kinetics of oxidation of Zr-1%Nb alloy have been studied in the temperature range 500 - 1200 degree C and 500 - 900 degree C in both air and steam, respectively. The oxidation rate increases with temperature, Initially, the reaction proceeds with a decreasing rate ( mainly parabolic) followed by transition to a linear or acceleration, indicating breakaway. As the oxidation temperature increases, the time to breakaway transition decreases

Creep properties of Nb-1Zr and Nb-1Zr-0.1C

International Nuclear Information System (INIS)

Horak, J.A.; Egner, L.K.

1994-12-01

In the early 1980s a compact, lithium cooled, fast-energy spectrum nuclear reactor was selected for space applications requiring prolonged uninterrupted electrical power. This reactor was to be capable of generating up to 100 kilowatts of electricity for times up to seven years in space and thus was given the acronym SP-100. The material selected for the fuel cladding, reactor heat transport systems and structural components was Nb-1 wt % Zr (Nb-1Zr). In addition to commercial Nb-1Zr, modified alloys containing 100--200 wt ppM each of carbon and nitrogen and 900 ± 150 wt ppM carbon were also included, Type B Nb-1Zr and PWC-11, respectively. The SP-100 reactor was designed to operate at temperatures of 1290--1425 K. At these temperatures the principal mode of deformation for Nb-1Zr is creep, and creep strain of the fuel cladding limits the useful reactor lifetime. To develop a creep data base for design, safety and reliability analyses, uniaxial creep testing of Nb-1Zr, Type B Nb-1Zr and PWC-11 was conducted from 1250--1450 K at stresses from 5.0 MPa to 41.4 MPa. Methodology and test results are presented

Nanotube morphology changes for Ti-Zr alloys as Zr content increases

International Nuclear Information System (INIS)

Kim, Won-Gi; Choe, Han-Cheol; Ko, Yeong-Mu; Brantley, William A.

2009-01-01

Nanotube morphology changes in Ti-Zr alloys as Zr content increases have been investigated. Ti-Zr (10, 20, 30 and 40 wt.%) alloys were prepared by arc melting and heat treated for 24 h at 1000 o C in an argon atmosphere. TiO 2 nanotubes were formed on the Ti-Zr alloys by anodization in H 3 PO 4 containing 0.5 wt.% NaF. Electrochemical experiments were performed using a conventional three-electrode configuration with a platinum counter electrode and a saturated calomel reference electrode. Samples were embedded in epoxy resin, leaving an area of 10 mm 2 exposed to the electrolyte. Anodization was carried out using a scanning potentiostat, and all experiments were conducted at room temperature. Microstructures of the alloys were examined by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and x-ray diffraction (XRD). The Ti-Zr alloy microstructures observed by OM and FE-SEM changed from a lamellar structure to a needle-like structure with increasing Zr content. The microstructures also changed from β phase to increasing amounts of α phase as the Zr content increased. The number of large nanotubes formed by anodization decreased, and the number of small nanotubes increased, as the Zr content increased. The mean inner diameter ranged from approximately 150 to 200 nm with a tube-wall thickness of about 20 nm. The interspace between the nanotubes was approximately 60, 70, 100 and 130 nm for Zr contents of 10, 20, 30 and 40 wt.%, respectively.

Understanding hydride formation in Zr-1Nb alloy through microstructural characterization

International Nuclear Information System (INIS)

Neogy, S.; Srivastava, D.; Tewari, R.; Singh, R.N.; Dey, G.K.; De, P.K.; Banerjee, S.

2003-07-01

In this study the experimental results of hydride formation and their microstructure evolution in Zr-1Nb alloy is presented. This Zr-1Nb binary alloy and other Zr-1 Nb based ternary and quaternary alloys are being used as fuel tube materials and have the potential for meeting the requirement of high burn up fuel. Hydriding of Zr-1Nb alloy having a microstructure comprising equiaxed α grains and a uniform distribution of spherical particles of the β phase has been carried out in this study. The specimens have been hydrided by gaseous charging method to different hydrogen levels. The microstructures of hydrided samples were examined as a function of hydrogen content. The formation of δ hydride in slow cooled specimens and formation of γ hydride in rapidly cooled specimens has been studied with their morphology, habit plane and orientation relationship with the α matrix in view. The habit planes of either type of hydride phase has been determined and compared with those observed in other Zr-Nb alloys. The orientation relationship between the α matrix and the δ hydride was found to be the following: (0001) α // (111) δ and [1120] α // [110] δ . The orientation relationship between the α matrix and the γ hydride was of the following type: (0001) α // (111) γ and [1120] α // [110] γ . The internal structure of both types of hydride has been examined. The effect of the presence of the spherical β phase particles in the a matrix on the growth of the hydride plates has been investigated. (author)

Fabrication by powder metallurgy of the niobium based alloy Nb-1-Zr

International Nuclear Information System (INIS)

Marty, M.; Delaunay, C.; Walder, A.

1989-01-01

The Nb-1Zr alloy has been produced by the powder metallurgy technique. Production of powders was performed by centrifugal atomization with the rotating electrode process (REP) under an inert atmosphere of argon-helium. Alloy powders were characterized by granulometric spectra, oxygen content and the various types of structures which were found. After consolidation by extrusion, materials were evaluated by tensile test under vacuum at ambient temperature, 750 and 900 0 C and compared with the same alloy elaborated by ingot metallurgy. 8 refs., 9 figs. (Author)

TEM study on a new Zr-(Fe, Cu) phase in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe-0.1Cu alloy

Science.gov (United States)

Liu, Yushun; Qiu, Risheng; Luan, Baifeng; Hao, Longlong; Tan, Xinu; Tao, Boran; Zhao, Yifan; Li, Feitao; Liu, Qing

2018-06-01

A new Zr-(Fe, Cu) phase was found in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe- 0.1Cu alloy and alloys aged at 580 °C for 10min, 2 h and 10 h. Electron diffraction experiment shows the crystal structure of this phase to be body-centered tetragonal with unit cell dimensions determined to be a = b = 6.49 Å, c = 5.37 Å. Its possible space groups have been discussed and the reason accounting for its formation is believed to be the addition of Cu according to the atom-level images. In addition, no crystal structural or chemical composition changes were observed throughout the aging process.

Effect of heat treatment on the microstructures and damping properties of biomedical Mg-Zr alloy

Energy Technology Data Exchange (ETDEWEB)

Tsai, Ming-Hung [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Department of Dentistry, Chang Yin dental clinic, No.46-1, Yangming St., Banqiao City, Taipei County 220, Taiwan (China); Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Chen, May-Show [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Lin, Ling-Hung [Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Lin, Ming-Hong [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Wu, Ching-Zong, E-mail: chinaowu@tmu.edu.tw [Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Ou, Keng-Liang, E-mail: klou@tmu.edu.tw [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Graduated Institute of Biomedical Materials and Engineering, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Yu, Chih-Hua [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China)

2011-01-21

Research highlights: > When the as-quenched Mg-1Zr alloy was aged at temperatures ranging from 200 deg. C to 500 deg. C, a microstructural transformation sequence was found to be {alpha}-Mg {yields} ({alpha}-Mg + twin{sub dense}) {yields} ({alpha}-Mg + twin{sub loose}) {yields} ({alpha}-Mg + {alpha}-Zr). > As the as-quenched Mg-1Zr alloy was subjected to aging treatment at 300 deg. C for 16 h, it exhibited the maximum damping properties. > The twin structure plays a crucial role in increasing the damping capacity of the Mg-1Zr alloy. - Abstract: In this study, we elucidated the effect of heat treatment on the microstructures and damping properties of the biomedical Mg-1 wt% Zr (K1) alloy by optical microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and experimental model analysis. The following microstructural transformation occurred when the as-quenched (AQ, i.e., solution heat treated and quenched) K1 alloy was subjected to aging treatment in the temperature range 200-500 deg. C: {alpha}-Mg {yields} ({alpha}-Mg + twin{sub dense}) {yields} ({alpha}-Mg + twin{sub loose}) {yields} ({alpha}-Mg + {alpha}-Zr). This microstructural transformation was accompanied by variations in the damping capacity. The damping properties of the AQ K1 alloy subjected to aging treatment at 300 deg. C for 16 h were the best among those of the alloys investigated in the present study. The presence of twin structures in the alloy matrix was thought to play a crucial role in increasing the damping capacity of the K1 alloy. Hence, we state that a combination of solution treatment and aging is an effective means of improving the damping capacity of biomedical K1 alloys.

Effect of heat treatment on the microstructures and damping properties of biomedical Mg-Zr alloy

International Nuclear Information System (INIS)

Tsai, Ming-Hung; Chen, May-Show; Lin, Ling-Hung; Lin, Ming-Hong; Wu, Ching-Zong; Ou, Keng-Liang; Yu, Chih-Hua

2011-01-01

Research highlights: → When the as-quenched Mg-1Zr alloy was aged at temperatures ranging from 200 deg. C to 500 deg. C, a microstructural transformation sequence was found to be α-Mg → (α-Mg + twin dense ) → (α-Mg + twin loose ) → (α-Mg + α-Zr). → As the as-quenched Mg-1Zr alloy was subjected to aging treatment at 300 deg. C for 16 h, it exhibited the maximum damping properties. → The twin structure plays a crucial role in increasing the damping capacity of the Mg-1Zr alloy. - Abstract: In this study, we elucidated the effect of heat treatment on the microstructures and damping properties of the biomedical Mg-1 wt% Zr (K1) alloy by optical microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and experimental model analysis. The following microstructural transformation occurred when the as-quenched (AQ, i.e., solution heat treated and quenched) K1 alloy was subjected to aging treatment in the temperature range 200-500 deg. C: α-Mg → (α-Mg + twin dense ) → (α-Mg + twin loose ) → (α-Mg + α-Zr). This microstructural transformation was accompanied by variations in the damping capacity. The damping properties of the AQ K1 alloy subjected to aging treatment at 300 deg. C for 16 h were the best among those of the alloys investigated in the present study. The presence of twin structures in the alloy matrix was thought to play a crucial role in increasing the damping capacity of the K1 alloy. Hence, we state that a combination of solution treatment and aging is an effective means of improving the damping capacity of biomedical K1 alloys.

Thermomechanical processing of aluminum micro-alloyed with Sc, Zr, Ti, B, and C

Science.gov (United States)

McNamara, Cameron T.

Critical exploration of the minimalistic high strength low alloy aluminum (HSLA-Al) paradigm is necessary for the continued development of advanced aluminum alloys. In this study, scandium (Sc) and zirconium (Zr) are examined as the main precipitation strengthening additions, while magnesium (Mg) is added to probe the synergistic effects of solution and precipitation hardening, as well as the grain refinement during solidification afforded by a moderate growth restriction factor. Further, pathways of recrystallization are explored in several potential HSLA-Al syste =ms sans Sc. Aluminum-titanium-boron (Al-Ti-B) and aluminum-titanium-carbon (Al-Ti-C) grain refining master alloys are added to a series of Al-Zr alloys to examine both the reported Zr poisoning effect on grain size reduction and the impact on recrystallization resistance through the use of electron backscattered diffraction (EBSD) imaging. Results include an analysis of active strengthening mechanisms and advisement for both constitution and thermomechanical processing of HSLA-Al alloys for wrought or near-net shape cast components. The mechanisms of recrystallization are discussed for alloys which contain a bimodal distribution of particles, some of which act as nucleation sites for grain formation during annealing and others which restrict the growth of the newly formed grains.

Structure, mechanical properties and grindability of dental Ti-10Zr-X alloys

International Nuclear Information System (INIS)

Ho, W.-F.; Cheng, C.-H.; Pan, C.-H.; Wu, S.-C.; Hsu, H.-C.

2009-01-01

This study aimed to investigate the structure, mechanical properties and grindability of a binary Ti-Zr alloy added to a series of alloying elements (Nb, Mo, Cr and Fe). The phase and structure of Ti-10Zr-X alloys were evaluated using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. Three-point bending tests were performed using a desk-top mechanical tester. Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min at each of the four rotational speeds of the wheel (500, 750, 1000 or 1200 m/min). Results were compared with c.p. Ti, which was chosen as a control. Results indicated that the phase/crystal structure, microstructure, mechanical properties and grindability of the Ti-10Zr alloy can be significantly changed by adding small amounts of alloying elements. The alloying elements Nb, Mo, Cr and Fe contributed significantly to increasing the grinding ratio under all grinding conditions, although the grinding rate of all the metals was found to be largely dependent on grinding speed. The Ti-10Zr-1Mo alloy showed increases in microhardness (63%), bending strength (40%), bending modulus (30%) and elastic recovery angle (180%) over those of c.p. Ti, and was also found to have better grindability. The Ti-10Zr-1Mo alloy could therefore be used for prosthetic dental applications if other conditions necessary for dental casting are met

Alloying effects on structural and thermal behavior of Ti1-xZrxC: A first principles study

International Nuclear Information System (INIS)

Chauhan, Mamta; Gupta, Dinesh C.

2016-01-01

The formation energy, equilibrium lattice parameter, bulk modulus, Debye temperature and heat capacity at constant volume have been calculated for TiC, ZrC, and their intermediate alloys (Ti 1-x Zr x C, x = 0,0.25.0.5,0.75,1) using first principles approach. The calculated values of lattice parameter and bulk modulus agree well with the available experimental and earlier theoretical reports. The variation of lattice parameter and bulk modulus with the change in concentration of Zr atom in Ti 1-x Zr x C has also been reported. The heat capacities of TiC, ZrC, and their intermediate alloys have been calculated by considering both vibrational and electronic contributions.

Unusual morphology of the omega phase in a Zr-1.75 At. pct Ni alloy

International Nuclear Information System (INIS)

Srivastava, D.; Mukhopadhyay, P.; Ramadasan, E.; Banerjee, S.

1993-01-01

The observations reported in the present communication were made in the course of a microstructural investigation on dilute Zr-Ni alloys. The alloys were prepared from nuclear-grade sponge zirconium and high-purity nickel by nonconsumable arc melting. Repeated melting was carried out to enhance homogeneity. A master alloy was used in the preparation of very dilute alloys. The observations reported here clearly indicate that the formation of the ω phase on β quenching, can occur in the binary Zr-Ni system at very low solute concentrations, suggesting that nickel is a strong ω stabilizer. Such a situation is known to obtain in the binary Zr-Mo system also. However, the unusual ω morphology observed in the present work has not been reported in the context of dilute Zr-Mo alloys. The appearance of sharp ω reflections and the absence of streaking and diffuse distributions in the selected area electron diffraction (SAD) patterns suggest that the Zr-1.75 at. pct Ni composition lies toward the solute lean end of the composition range associated with the formation of the athermal ω phase in the binary Zr-Ni system. In a more dilute Zr-Ni alloy (Zr-1.30 at. pct Ni), no athermal ω could be observed in β quenched specimens. The absence of streaking is also consistent with the fact that the ω phase in the β quenched Zr-1.75 at. pct Ni alloy did not occur in the form of very fine precipitates. The unusual ω morphology encountered in this work merits further investigation

Microstructure and tensile properties of Fe-40 at. pct Al alloys with C, Zr, Hf, and B additions

Science.gov (United States)

Gaydosh, D. J.; Draper, S. L.; Nathal, M. V.

1989-01-01

The influence of small additions of C, Zr, and Hf, alone or in combination with B, on the microstructure and tensile behavior of substoichiometric FeAl was investigated. Tensile properties were determined from 300 to 1100 K on powder which was consolidated by hot extrusion. All materials possessed some ductility at room temperature, although ternary additions generally reduced ductility compared to the binary alloy. Adding B to the C- and Zr-containing alloys changed the fracture mode from intergranular to transgranular and restored the ductility to approximately 5 percent elongation. Additions of Zr and Hf increased strength up to about 900 K. Fe6Al6Zr and Fe6Al6Hf precipitates, both with identical body-centered tetragonal structures, were identified as the principal second phase in these alloys. Strength decreased steadily as temperature increased above 700 K, as diffusion-assisted mechanisms became operative. Although all alloys had similar strengths at 1100 K, Hf additions significantly improved high-temperature ductility by suppressing cavitation.

LCF behavior of Zr-4 alloy at elevated temperature

International Nuclear Information System (INIS)

Ye Yuming; Cai Lixun

2006-01-01

A series of strain fatigue tests were carried out on small bugle-like slice-specimens of Zr-4 alloy at room temperature and 400 degree C. According to Elastic and Plastic Finite Element Analysis and assumption of local damage equivalence, a strain conversion equation was given to transform the transverse strain of the specimen to the axial strain. Based on the test results of the alloy and the strain conversion equation, fatigue life estimation equations of Zr-4alloy, or M-C (Manson-Coffin) models, were obtained. The results showed that, Zr-4 alloy had obvious cyclic hardening character during high amplitude strain at different temperatures, but showed reverse character during low amplitude strain. Elevated temperature lowered seriously the fatigue life of Zr-4 alloys, ann as the increasing of amplitude strain, temperature effect impaired gradually. Analysis showed that the prediction life by using M-C model based on the traditional strain conversion equation was quite conservative when axial strain amplitude was less than 5000 micro-strain. (authors)

Influence of Temperature to Thermal Properties of U-Zr Alloy With The Zr Content Variation

International Nuclear Information System (INIS)

Aslina-Br-Ginting; Masrukan; M-Husna-Al-Hasa

2007-01-01

Have been done thermal of characteristic covering heat stability, heat capacities, enthalpy and also phase changes from uranium, zirkonium and U-Zr alloy with the Zr content variation of Zr 2 %, 6 %, 10% and 14% weight. Change of the temperature and composition anticipated will cause the characteristic of thermal to uranium metal, zirkonium and also U-Zr alloy. Therefore at this research was conducted using analysis influence of temperature to thermal of characteristic of uranium, zirkonium and U-Zr alloy with the Zr content variation by using DTA and DSC. Result of analysis indicate that the uranium metal at temperature 662 o C stable in phase α. Above at temperature, uranium metal experience of the phase change indicated by formed the thermochemical reaction as much 3 endothermic peak. At temperature 667.16 o C, happened by the phase change of α become the phase β with the enthalpy 2,3034 cal/g, at temperature 773.05 o C happened by the phase change β becoming phase γ 2,8725 cal/g and also at temperature 1125.26 the o C uranium metal experience the phenomenon become to melt with the enthalpy 2,1316 cal/g. (author)

Hydrogen traps in the oxide/alloy interface region of Zr-Nb alloys

International Nuclear Information System (INIS)

Khatamian, D.

1995-03-01

In this study the 1 H( 15 N,αγ) 12 C nuclear reaction has been used to measure hydrogen profiles of anodically oxidized Zr-Nb specimens containing various amounts of niobium. The profiles have been correlated with oxygen profiles, obtained using a Scanning Auger Microprobe (SAM), and with X-ray diffraction patterns. In addition, unoxidized Zr-2.5Nb (Zr-2.5 wt% Nb) samples were implanted with oxygen and hydrogen to study the interaction between these two species when dissolved in the alloy. All the anodically oxidized specimens, except the pure Zr and the single-phase β-Zr (Zr-20Nb) samples, displayed hydrogen peaks beneath the oxide layer. These results, in conjunction with the results from the implanted specimens, indicate that the hydrogen moves under the influence of a stress gradient to the sub-oxide region, where the metal lattice has been expanded due to superficial oxide growth. The results show that dissolved oxygen sites in Zr-2.5Nb alloy do not trap hydrogen. (author). 16 refs., 6 figs

Zr - based alloys as hydride electrodes in Ni-MH batteries

International Nuclear Information System (INIS)

Biris, A.R.; Biris, A.S.; Misan, I.; Lupu, D.

1999-01-01

Hydrogen storage alloys, MH, are already used in Ni-MH alkaline batteries conquering an important share of the rechargeable nickel-cadmium battery market. This remarkable success is due not only to the replacement of the toxic material, cadmium, by metal hydrides but also to an increased specific energy, which makes them attractive for electric vehicles. Many research groups are concerned in the improvement of the hydride electrode characteristics: hydrogen storage capacity, high-rate discharge ability, increased cycle life. These properties can be modified by substitution of the base components of a given alloy. A comparison of two types of alloys suitable for MH electrodes LaNi 5 able to store 1.36 w/o hydrogen with Zr(Ti)-Ni alloys of the AB 2 Laves phase type structure showed that the latter could absorb higher amounts of hydrogen. We report part of studies on Zr-V-Cr-Ni of the 15 C type Laves phase structure using our original procedure for pasted electrodes. The substitution of Cr for V atoms in ZrV 0.5 Ni 1 . 5 did not increase the discharge capacity. However, it proved to have a remarkable effect on the discharge capacity C at low temperatures. C at - 12 deg. C as compared to 20 deg.C increases up to ∼ 65 % for Cr containing alloys. (authors)

Influence of alkali metal hydroxides on corrosion of Zr-base alloys

International Nuclear Information System (INIS)

Jeong, Yong Hwan

1996-01-01

The influence of group-1 alkali hydroxides on different Zr-based alloys have been carried out in static autoclaves at 350 deg C in pressurized water, conditioned in low(0.32 mmol), medium(4.3 mmol) and high(31.5 mmol) equimolar concentration of Li-, Na-, K-, Rb- and Cs-hydroxide. Two types of alloys have been investigated: Zr-Sn-(TRM, Transition metal) and Zr-Sn-Nb-(TRM, Transition metal). From the experiments the cation could be identified as the responsible species for corrosion of Zr alloy in alkalized water. The radius of the cation governs the accelerated corrosion in the pre-transition region of Zr alloy. Incorporation of alkali cation into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significant lower effect for the other bases. Nb containing alloys showed lower corrosion resistance than Zr-Sn-TRM alloys in all alkali solutions. Both types of alloys were corroded significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behavior in the different alkali environments and taking into account the tendency to accelerate the corrosion of Zr alloys, CsOH and KOH are possible alternate alkali for PWR (Pressurized Water Reactor) application. (author)

Corrosion Behaviour of New Zr Alloys

DEFF Research Database (Denmark)

Tolksdorf, E.

1974-01-01

Corrosion studies have indicated that the most promising replacements for Zicaloy-2 are ZrCrFe, ZrVFe and probably ZrNbTa, provided they are in their optimized condition. These alloys are conventionally manufactured alloys. An internally oxidized ZrMgO alloy is even superior, from the corrosion...

Thermal Expansion Property of U-Zr Alloys and U-Zr-Ce Alloys as a Surrogate Metallic Fuel for SFR

International Nuclear Information System (INIS)

Kim, Sun Ki; Lee, Jong Tak; Oh, Seok Jin; Ko, Young Mo; Kim, Ki Hwan; Woo, Youn Myung; Lee, Chan Bock

2010-01-01

Metal fuels was selected for fueling many of the first reactors in the US, including the Experimental Breeder Reactor-I (EBR-I) and the Experimental Breeder Reactor-II (EBR-II) in Idaho, the FERMI-I reactor, and the Dounreay Fast Reactor (DFR) in the UK. Metallic U.Pu.Zr alloys were the reference fuel for the US Integral Fast Reactor (IFR) program. An extensive database on the performance of advanced metal fuels was generated as a result of the operation of these reactors and the IFR program. In this study, the U-Zr binary alloys and U-Zr-Ce ternary alloys as surrogate metallic fuel were fabricated in lower pressure Ar environment by gravity casting. The melt temperature was approximately 1,500 .deg. C. Thermal expansion of the fuel during normal operation is related with fuel performance in a reactor. Therefore, it is necessary to investigate the thermal expansion of the fuel in order to warrant a good prediction the fuel performance

A Novel Zr-1Nb Alloy and a New Look at Hydriding

Energy Technology Data Exchange (ETDEWEB)

Robert D. Mariani; James I. Cole; Assel Aitkaliyeva

2013-09-01

A novel Zr-1Nb has begun development based on a working model that takes into account the hydrogen permeabilities for zirconium and niobium metals. The beta-Nb secondary phase particles (SPPs) in Zr-1Nb are believed to promote more rapid hydrogen dynamics in the alloy in comparison to other zirconium alloys. Furthermore, some hydrogen release is expected at the lower temperatures corresponding to outages when the partial pressure of H2 in the coolant is less. These characteristics lessen the negative synergism between corrosion and hydriding that is otherwise observed in cladding alloys without niobium. In accord with the working model, development of nanoscale precursors was initiated to enhance the performance of existing Zr-1Nb alloys. Their characteristics and properties can be compared to oxide-dispersion strengthened alloys, and material additions have been proposed to zirconium-based LWR cladding to guard further against hydriding and to fix the size of the SPPs for microstructure stability enhancements. A preparative route is being investigated that does not require mechanical alloying, and 10 nanometer molybdenum particles have been prepared which are part of the nanoscale precursors. If successful, the approach has implications for long term dry storage of used fuel and for new routes to nanoferritic and ODS alloys.

Corrosion properties of cladding materials from Zr1Nb alloy

International Nuclear Information System (INIS)

Kloc, K.; Kosler, S.

1975-01-01

The corrosion behaviour was observed of the Zr1Nb alloy in hot water and superheated steam and the effects of impurity content, of the purity of the corrosion environment and of the heat treatment of the alloy were studied on the alloy corrosion resistance. Also studied were the absorption of hydrogen by the alloy and its behaviour in reactor situations. It was ascertained that the alloy has a good corrosion resistance up to a temperature of 350 degC. The corrosion resistance is reduced by the presence of nitrogen above 50 to 70 ppm and of carbon above 50 to 90 ppm. A graphic representation is given of the dependence of corrosion resistance on the temperature of annealing, the nitrogen content of the alloy and the time of the action of hot water or steam, as well as the dependence of the hydrogen content in the alloy on the peripheral tension of the cladding in hot water both in non-active environment and at irradiation with a neutron flux of approximately 10 20 n/cm 2 . (J.B.)

Precipitation in cold-rolled Al-Sc-Zr and Al-Mn-Sc-Zr alloys prepared by powder metallurgy

KAUST Repository

Vlach, Martin

2013-12-01

The effects of cold-rolling on thermal, mechanical and electrical properties, microstructure and recrystallization behaviour of the AlScZr and AlMnScZr alloys prepared by powder metallurgy were studied. The powder was produced by atomising in argon with 1% oxygen and then consolidated by hot extrusion at 350 C. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared with microstructure development observed by transmission and scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. Fine (sub)grain structure developed and fine coherent Al3Sc and/or Al3(Sc,Zr) particles precipitated during extrusion at 350 C in the alloys studied. Additional precipitation of the Al3Sc and/or Al3(Sc,Zr) particles and/or their coarsening was slightly facilitated by the previous cold rolling. The presence of Sc,Zr-containing particles has a significant antirecrystallization effect that prevents recrystallization at temperatures minimally up to 420 C. The precipitation of the Al6Mn- and/or Al 6(Mn,Fe) particles of a size ~ 1.0 μm at subgrain boundaries has also an essential antirecrystallization effect and totally suppresses recrystallization during 32 h long annealing at 550 C. The texture development of the alloys seems to be affected by high solid solution strengthening by Mn. The precipitation of the Mn-containing alloy is highly enhanced by a cold rolling. The apparent activation energy of the Al3Sc particles formation and/or coarsening and that of the Al6Mn and/or Al 6(Mn,Fe) particle precipitation in the powder and in the compacted alloys were determined. The cold deformation has no effect on the apparent activation energy values of the Al3Sc-phase and the Al 6Mn-phase precipitation. © 2013 Elsevier Inc.

Precipitation in cold-rolled Al-Sc-Zr and Al-Mn-Sc-Zr alloys prepared by powder metallurgy

KAUST Repository

Vlach, Martin; Stulí ková , Ivana; Smola, Bohumil; Kekule, Tomá š; Kudrnová , Hana; Daniš, Stanislav; Gemma, Ryota; Očená šek, Vladivoj; Má lek, Jaroslav; Tanprayoon, Dhritti; Neubert, Volkmar

2013-01-01

The effects of cold-rolling on thermal, mechanical and electrical properties, microstructure and recrystallization behaviour of the AlScZr and AlMnScZr alloys prepared by powder metallurgy were studied. The powder was produced by atomising in argon with 1% oxygen and then consolidated by hot extrusion at 350 C. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared with microstructure development observed by transmission and scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. Fine (sub)grain structure developed and fine coherent Al3Sc and/or Al3(Sc,Zr) particles precipitated during extrusion at 350 C in the alloys studied. Additional precipitation of the Al3Sc and/or Al3(Sc,Zr) particles and/or their coarsening was slightly facilitated by the previous cold rolling. The presence of Sc,Zr-containing particles has a significant antirecrystallization effect that prevents recrystallization at temperatures minimally up to 420 C. The precipitation of the Al6Mn- and/or Al 6(Mn,Fe) particles of a size ~ 1.0 μm at subgrain boundaries has also an essential antirecrystallization effect and totally suppresses recrystallization during 32 h long annealing at 550 C. The texture development of the alloys seems to be affected by high solid solution strengthening by Mn. The precipitation of the Mn-containing alloy is highly enhanced by a cold rolling. The apparent activation energy of the Al3Sc particles formation and/or coarsening and that of the Al6Mn and/or Al 6(Mn,Fe) particle precipitation in the powder and in the compacted alloys were determined. The cold deformation has no effect on the apparent activation energy values of the Al3Sc-phase and the Al 6Mn-phase precipitation. © 2013 Elsevier Inc.

Precipitation in cold-rolled Al–Sc–Zr and Al–Mn–Sc–Zr alloys prepared by powder metallurgy

International Nuclear Information System (INIS)

Vlach, M.; Stulikova, I.; Smola, B.; Kekule, T.; Kudrnova, H.; Danis, S.; Gemma, R.; Ocenasek, V.; Malek, J.; Tanprayoon, D.; Neubert, V.

2013-01-01

The effects of cold-rolling on thermal, mechanical and electrical properties, microstructure and recrystallization behaviour of the AlScZr and AlMnScZr alloys prepared by powder metallurgy were studied. The powder was produced by atomising in argon with 1% oxygen and then consolidated by hot extrusion at 350 °C. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared with microstructure development observed by transmission and scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. Fine (sub)grain structure developed and fine coherent Al 3 Sc and/or Al 3 (Sc,Zr) particles precipitated during extrusion at 350 °C in the alloys studied. Additional precipitation of the Al 3 Sc and/or Al 3 (Sc,Zr) particles and/or their coarsening was slightly facilitated by the previous cold rolling. The presence of Sc,Zr-containing particles has a significant antirecrystallization effect that prevents recrystallization at temperatures minimally up to 420 °C. The precipitation of the Al 6 Mn- and/or Al 6 (Mn,Fe) particles of a size ∼ 1.0 μm at subgrain boundaries has also an essential antirecrystallization effect and totally suppresses recrystallization during 32 h long annealing at 550 °C. The texture development of the alloys seems to be affected by high solid solution strengthening by Mn. The precipitation of the Mn-containing alloy is highly enhanced by a cold rolling. The apparent activation energy of the Al 3 Sc particles formation and/or coarsening and that of the Al 6 Mn and/or Al 6 (Mn,Fe) particle precipitation in the powder and in the compacted alloys were determined. The cold deformation has no effect on the apparent activation energy values of the Al 3 Sc-phase and the Al 6 Mn-phase precipitation. - Highlights: • The Mn, Sc and Zr additions to Al totally suppresses recrystallization at 550 °C. • The Sc,Zr-containing particle precipitation is slightly facilitated by

Creep deformation behaviour and microstructural changes in Zr-2.5% Nb alloy

International Nuclear Information System (INIS)

Chaudhuri, S.; Singh, R.; Ghosh, R.N.; Sinha, T.K.; Banerjee, S.

2002-01-01

Cold worked and stress relieved Zr-2.5% Nb alloy is a well-known material used as pressure tubes in Pressurised Heavy Water Reactors. The pressure tubes, made of a typical Zr-alloy, consisting of 2.54% Nb, 0.1175% oxygen and less than 100 ppm impurities, are expected to withstand 9.5 MPa to 12.5 MPa pressure at 250 degC to 310 degC under fast neutron fluxes of 3.5 x 10 17 nm -2 s -1 . These tubes are made by hot extrusion at 780 degC with an extrusion ratio 8.3:1 and 40% cold pilgering followed by annealing at 550 degC for 3 hours and subsequently by 20-30% cold pilgering and stress relieving at 400 degC for 24 hours. The microstructure of such cold worked and stress relieved alloy consists of Β-Zr precipitates in the matrix of elongated Α-Zr grains. Although various factors such as irradiation creep, thermal creep, irradiation growth etc are responsible for limiting the life of pressure tubes; the thermal creep contributes significantly in overall creep deformation. Keeping this in view as well as due to non-availability of adequate published information including creep database on this alloy, an extensive investigation on the thermal creep behaviour of indigenously produced Zr-2.5% Nb alloy was undertaken. The creep tests in air using Mayes' creep testing machines were carried out in the temperature range of 300 degC to 450 degC under stresses in the range of 50 to 550 MPa. Analysis of data revealed that the mechanism of creep deformation remains the same in this range

Mechanical Characterisation and Biomechanical and Biological Behaviours of Ti-Zr Binary-Alloy Dental Implants

Directory of Open Access Journals (Sweden)

Aritza Brizuela-Velasco

2017-01-01

Full Text Available The objective of the study is to characterise the mechanical properties of Ti-15Zr binary alloy dental implants and to describe their biomechanical behaviour as well as their osseointegration capacity compared with the conventional Ti-6Al-4V (TAV alloy implants. The mechanical properties of Ti-15Zr binary alloy were characterised using Roxolid© implants (Straumann, Basel, Switzerland via ultrasound. Their biomechanical behaviour was described via finite element analysis. Their osseointegration capacity was compared via an in vivo study performed on 12 adult rabbits. Young’s modulus of the Roxolid© implant was around 103 GPa, and the Poisson coefficient was around 0.33. There were no significant differences in terms of Von Mises stress values at the implant and bone level between both alloys. Regarding deformation, the highest value was observed for Ti-15Zr implant, and the lowest value was observed for the cortical bone surrounding TAV implant, with no deformation differences at the bone level between both alloys. Histological analysis of the implants inserted in rabbits demonstrated higher BIC percentage for Ti-15Zr implants at 3 and 6 weeks. Ti-15Zr alloy showed elastic properties and biomechanical behaviours similar to TAV alloy, although Ti-15Zr implant had a greater BIC percentage after 3 and 6 weeks of osseointegration.

Precipitation behaviors of cubic and tetragonal Zr–rich phase in Al–(Si–)Zr alloys

Energy Technology Data Exchange (ETDEWEB)

Gao, Tong [Australian Centre for Microscopy & Microanalysis, The University of Sydney, NSW 2006 (Australia); Key Laboratory of Liquid–Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Ceguerra, Anna; Breen, Andrew [Australian Centre for Microscopy & Microanalysis, The University of Sydney, NSW 2006 (Australia); Liu, Xiangfa; Wu, Yuying [Key Laboratory of Liquid–Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Ringer, Simon, E-mail: simon.ringer@sydney.edu.au [Australian Centre for Microscopy & Microanalysis, The University of Sydney, NSW 2006 (Australia)

2016-07-25

The precipitation behaviors of Zr–rich phase in binary Al–0.5Zr and ternary Al–3Si–0.5Zr alloys were investigated by high resolution transmission electron microscopy and atom probe. After the alloys were aged at 525 °C for 24 h, the precipitates in Al–0.5Zr alloy are identified as L1{sub 2}–ZrAl{sub 3}, performing a coherent relationship with the Al matrix. While in Al–3Si–0.5Zr alloy, the precipitates are Si–containing D0{sub 23}–Zr(Al,Si){sub 3}, which has an approximate 90° reversed cube–on–cube orientation relationship with Al. It is regarded that Si accelerates the precipitation of D0{sub 23}–Zr(Al,Si){sub 3}. - Highlights: • L1{sub 2}–ZrAl{sub 3} and D0{sub 23}–Zr(Al, Si){sub 3} particles precipitate in Al–Zr and Al–Si–Zr alloys. • D0{sub 23}–Zr(Al, Si){sub 3} performs an approximate 90° reversed cube–on–cube orientation relationship with Al. • Si accelerates the precipitation process of D0{sub 23}–Zr(Al,Si){sub 3}.

Superconductivity and NMR investigations of amorphous Be-Nb-Zr and Be-Mo-Zr alloys

International Nuclear Information System (INIS)

Goebbels, J.; Lueders, K.; Freyhardt, H.C.; Reichelt, J.

1981-01-01

9 Be NMR investigations and measurements of the superconducting properties and the resistivity are reported for amorphous Besub(32.5)Nbsub(x)Zrsub(67.5-x) and Besub(32.5)Mosub(x)Zrsub(67.5-x) alloys (x = 2.5; 5; 7). Line width analysis suggests an enlarged Nb concentration around the Be sites for the Be-Nb-Zr alloys. Comparing the two types of alloys the Knight shifts are of the same order of magnitude whereas the Tsub(c) and Bsub(c) 2 (0) values are slightly smaller than for the Nb alloys. For Be-Nb-Zr Tsub(c) and K increases with the Nb content. The results are discussed in connection with the density of states N(Esub(F)). (orig.)

Oxide impedance characteristics of the Zr-xNb alloys

International Nuclear Information System (INIS)

Park, S. Y.; Choi, B. K.; Jung, Y. H.; Jung, Y. H.

2002-01-01

To elucidate the correlation between the oxide impedance and corrosion characteristics of the Zr-xNb alloys, the long term corrosion test in high temperature / high pressure aqueous solution and the impedance test in the room temperature sulfate solution were performed. β-quenched plate specimens were heat-treated at 570 .deg. C for 500 hours to get the α+β Nb phase and the at 640 .deg. C for 10 hours to get the α+β Zr phase. The impedance test was conducted in sulfate solution for the initial corrosion test specimen (WG = 30 mg/dm 2 ). To evaluate the impedance date, 4 types of equivalent circuits were constructed by 5 parallel and serial RC elements. By using the equivalent circuits, the thickness of the inner and outer layers were calculated and the electric resistance of each layers were estimated. The corrosion behaviour of Zr-xNb alloys were quite different depending of the annealing condition and Nb-content. The corrosion resistance of the β Nb phase contained high Nb alloys were excellent rather than β Zr phase contained high Nb alloys. The electric resistance of the outer layer of β Zr phase contained high Nb alloy was twice larger than that of β Zr phase contained high Nb alloy, and in the case of outer layer 30% larger. So, the long term corrosion behaviors in high temperature could be estimated well by using the impedance test results

Constitutive Model for Hot Deformation of the Cu-Zr-Ce Alloy

Science.gov (United States)

Zhang, Yi; Sun, Huili; Volinsky, Alex A.; Wang, Bingjie; Tian, Baohong; Liu, Yong; Song, Kexing

2018-02-01

Hot compressive deformation behavior of the Cu-Zr-Ce alloy has been investigated according to the hot deformation tests in the 550-900 °C temperature range and 0.001-10 s-1 strain rate range. Based on the true stress-true strain curves, the flow stress behavior of the Cu-Zr-Ce alloy was investigated. Microstructure evolution was observed by optical microscopy. Based on the experimental results, a constitutive equation, which reflects the relationships between the stress, strain, strain rate and temperature, has been established. Material constants n, α, Q and ln A were calculated as functions of strain. The equation predicting the flow stress combined with these materials constants has been proposed. The predicted stress is consistent with experimental stress, indicating that developed constitutive equation can adequately predict the flow stress of the Cu-Zr-Ce alloy. Dynamic recrystallization critical strain was determined using the work hardening rate method. According to the dynamic material model, the processing maps for the Cu-Zr and Cu-Zr-Ce alloy were obtained at 0.4 and 0.5 strain. Based on the processing maps and microstructure observations, the optimal processing parameters for the two alloys were determined, and it was found that the addition of Ce can promote the hot workability of the Cu-Zr alloy.

Determination of Nb and Zr in U-Nb-Zr alloys by ICP-AES

International Nuclear Information System (INIS)

Wang Cuiping; Dong Shizhe; Li Lin; He Meiying

2003-01-01

The U-Nb-Zr alloy sample is dissolved by HNO 3 , H 2 O 2 and HF, and the contents of Nb and Zr in the sample are determined on the JY-70 II type ICP-AES by using the internal standard synchronous dilution method. The range of determination is 1%-10% and 0.33%-3.33%, respectively for Nb and Zr. The relative standard deviation is better than 3.2% for Nb, and 2.5% for Zr. The method is rapid and convenient for determining Nb and Zr in U-Nb-Zr alloy sample

Structure and properties of Al-Mg-Li-Zr system alloys

International Nuclear Information System (INIS)

Fridlyander, I.N.; Dolzhanskij, Yu.M.; Sandler, V.S.; Tyurin, .V.; Nikol'skaya, T.I.

1977-01-01

Studied were the structure and mechanical properties of the Al-Mg-Li-Zr alloy system (including 01420 alloy) containing 1.6-5.3%Li and 1.0-8.8%Mg). Electron microscopic studies of 01420 alloy conducted after heating at 450 deg C for 4 hours revealed non-uniformly distributed precipitations of a metastable phase ZrAl 3 , having spherical and needle-like configurations. These precipitations, together with zirconium contained in the solid solution, retard recrystallization. The introduction of 0.1-0.2% Zr decreases the limiting solubility of magnesium and lithium in the aluminium solid solution and leads to the formation of disperse equilibrium (S and, possibly, γ) phases with the size of 0.1-0.5 mcm. These phases were observed in the alloys containing (>=) 4% Mg and 1.9-3.5% Li. The method of planned experiment was used to study the principles governing the variation of the mechanical properties of the alloys subjected to water hardening and after aging at 170 deg C for 16 hours. It was established that the strength properties of the hardened alloys become higher, and the relative elongation decreases with the content of lithium and especially magnesium. It would be more proper to assess strengthening in the course of aging according to variation in the yield point and hardness. The effect of aging determined by the yield point depends on the content of lithium and is practically independent of the concentration of magnesium

Hydrogen isotope storage behavior of Zr1-xTixCo alloys

International Nuclear Information System (INIS)

Jat, Ram Avtar; Pati, Subhasis; Parida, S.C.; Agarwal, Renu; Mukerjee, S.K.

2016-01-01

Tritium storage properties similar to uranium make ZrCo as a suitable candidate material for storage, supply and recovery of hydrogen isotopes in various tritium facilities. Beside non-radioactive, nonpyrophoric at room temperature and higher storage capacity (H/f.u. up to 3, f.u. = ZrCo), it has been reported that upon repeated hydriding-dehydriding cycles, ZrCo undergoes dis-proportionation as per the reaction; ZrCo + H 2 ↔ ZrH 2 + ZrCo 2 . The present study is aimed to investigate the effect of Ti content on the hydrogen storage behavior of Zr 1-x Ti x Co alloys and the hydrogen isotope effect

微量TiC对Mo-Ti-Zr-TiC合金性能与显微组织的影响%Effect of Trace TiC on Property and Microstructure of Mo-Ti-Zr-TiC Alloy

Institute of Scientific and Technical Information of China (English)

钱昭; 范景莲; 成会朝; 田家敏

2012-01-01

采用粉末冶金方法制备Mo-Ti-Zr-TiC合金,研究微量TiC的添加对Mo-Ti-Zr-TiC合金的拉伸性能和显微组织的影响.结果表明,在Mo-Ti-Zr合金中添加微量TiC(0.1％～0.5％,质量分数)后,合金的相对密度和室温抗拉强度得到了提高,当TiC添加量为0.4％时,合金强度最高,较Mo-Ti-Zr合金提高了28.1％.微量TiC的添加,阻碍了合金烧结过程中的晶粒长大,合金晶粒尺寸随TiC添加量的增加而降低.添加的细小TiC粒子在高温烧结过程中或与坯体中的微量氧发生反应形成了由Mo、Ti、C及O 4种元素组成的(Mo,Ti)xOyCz细小复合第二相粒子,或发生团聚结成大颗粒,对合金起到净化晶界氧和弥散强化的作用,因而合金的性能相比Mo-Ti-Zr合金有了较明显的提高.%Mo-Ti-Zr-TiC alloy was prepared via powder metallurgy method. The effects of trace TiC additive on the mechanical properties and microstructure of TiC reinforced Mo-Ti-Zr-TiC alloy were studied. The results indicate that the relative density and the tensile strength at room temperature of Mo-Ti-Zr-TiC alloy is effectively enhanced by adding trace TiC (0.1wt%~0.5wt%). The tensile strength achieves the highest value when the content of TiC is 0.4wt%, which is 28.1% higher than that of Mo-Ti-Zr alloy. The adding of trace TiC can inhibit the grain growth during alloy sintering process, which leads to the decrease of grain sizes with the rise of TiC content. A part of the fine TiC particles react with trace oxygen in molybdenum matrix to form (Mo,Ti)xOyC2 compound second phase particles during high temperature sintering, while the other part are agglomerated into large particles, which play a role in grain boundaries purification and dispersion-strengthening.

Phase transition temperature in the Zr-rich corner of Zr-Nb-Sn-Fe alloys

Science.gov (United States)

Canay, M.; Danón, C. A.; Arias, D.

2000-08-01

The influence of small composition changes on the phase transformation temperature of Zr-1Nb-1Sn-0.2(0.7)Fe alloys was studied in the present work, by electrical resistivity measurements and metallographic techniques. For the alloy with 0.2 at.% Fe we have determined Tα↔α+β=741°C and Tα+β↔β=973°C, and for the 0.7 at.% Fe the transformation temperatures were T α↔α+β=712°C and T α+β↔β=961°C. We have verified that the addition of Sn stabilized the β phase.

Precipitation structures and mechanical properties of Al-Li-Zr alloy containing V

International Nuclear Information System (INIS)

Ying, J.K.; Ohashi, T.

1999-01-01

It is known that Al-Li alloys possess high elastic modulus and low density, and the metastable δ' (Al 3 Li) precipitate in these alloys affords considerable strengthening effect. However, with the strengthening resulting from the precipitation of δ' which is coherent with the matrix, these alloys suffer from low ductility and fracture toughness. It seems that the loss of ductility is the slip localization which occurs as a result of slip planes during deformation in connection with the specific hardening mechanism. As a result it indicates typical intergranular fracture. On the one hand, zirconium is used in many aluminum alloys to inhibit recrystallization during alloy processing. When zirconium is present in the alloy grain refinement occurs, which consequently, is considered as a factor that reduces the slip distance, and lowers the stress concentration across grain boundaries and at grain boundary triple points. Nevertheless, if only zirconium is added in Al-Li alloy it still shows intergranular fracture. By Zedaris et al., equilibrium phase Al 3 (Zr,V) in Al-Zr alloy containing V reduces the lattice mismatch along the c-axis with Al and, the L1 2 -structure metastable precipitates Al 3 (Zr,V) in Al-Zr-V alloys are stable at elevated temperature. Therefore, it is interesting to elucidate the effect of V in Al-Li-Zr alloy at the precipitation structures and mechanical properties of these alloys

Influence of oxygen on the interaction of Nb-Zr-C alloy with lithium

International Nuclear Information System (INIS)

Lyutyi, E.M.; Ignativ, M.I.

1980-01-01

This work is devoted to an investigation of the interaction of Nb-1% Zr-0.1% C alloy of different oxygen contents with molten technical-grade lithium. To obtain different oxygen contents in the steel, one lot of samples was annealed at 1400/degree/C for 2 h with a residual gas pressure of 0.1 mPa and the other under the same conditions in a vacuum of 10 mPa, which provided oxygen contents in the samples of 0.015 and 0.019 wt.%, respectively. The small difference between the oxygen contents in the samples of the two lots caused substantial differences in the interaction of the alloy with lithium. The sample with 0.015 wt.% oxygen had practically no corrosion even in holding in lithium for 1000 h. Impregnation of the samples with oxygen during the preliminary anneal leads to intensification of the corrosive action of lithium

Superconducting properties of amorphous Zr-Ge binary alloys

International Nuclear Information System (INIS)

Inoue, A.; Takahashi, Y.; Toyota, N.; Fukase, T.; Masumoto, T.

1982-01-01

A new type of refractory metal-metalloid amorphous alloys exhibiting superconductivity has been found in a binary Zr-Ge system by a modified melt-spinning technique. Specimens are in the form of continuous ribbons 1 to 2 mm wide and 0.02 to 0.03 mm thick. The germanium content in the amorphous alloys is limited to the range of 13 to 21 at%. These amorphous alloys are so ductile that no cracks are observed even after closely contacted bending test. Data are reported for various alloy compositions for the Vickers hardness and crystallization temperature, the tensile fracture strength, superconducting transition temperature Tsub(c), upper critical magnetic field, critical current density in the absence of an applied field, upper critical field gradient at Tsub(c) and the electrical resistivity at 4.2 K. The Ginzburg-Landau (GL) parameter and the GL coherence length were estimated to be 72 to 111 and about 7.9 nm, respectively, from these experimental values by using the Ginzburg-Landau-Abrikosov-Gorkov theory and hence it is concluded that the Zr-Ge amorphous alloys are extremely 'soft' type-II superconductor with high degree of dirtiness which possesses the Tsub(c) values higher than zirconium metal, in addition to high strength combined with good ductility. (author)

Interdiffusion behavior of tungsten or rhenium and group 5 and 6 elements and alloys of the periodic table, part 1. [at dissimilar metal joints

Science.gov (United States)

Arcella, F. G.

1974-01-01

Arc cast W, CVD W, CVD Re, and powder metallurgy Re materials were hot isostatically pressure welded to ten different refractory metals and alloys (Cb, Cb-1Zr, Ta, Ta-10W, T-111, ASTAR-811C, W-25Re, Mo-50Re, W-30Re-20Mo, ect.) and thermally aged at 10 to the minus 8th power torr at 1200, 1500, 1630, 1800, and 2000 C for 100 to 2000 hours. Electron beam microprobe analysis was used to characterize the interdiffusion zone width of each couple system as a function of age time and temperature. Extrapolations of interdiffusion zone thickness to 10,000 hours were made. Classic interdiffusion analysis was performed for several of the systems by Boltzmann-Matano analysis. A method of inhibiting Kirkendall voids from forming during thermal ageing of dissimilar metal junctions was devised and experimentally demonstrated. An electron beam weld study of Cb-1Zr to Re and W-25Re demonstrated the limited acceptability of these welds.

Electrochemical and metallurgical characterization of ZrCr{sub 1-x}NiMo{sub x} AB{sub 2} metal hydride alloys

Energy Technology Data Exchange (ETDEWEB)

Erika, Teliz [Universidad de la República, Facultad de Ciencias, Laboratorio de Electroquímica Fundamental, Núcleo Interdisciplinario Ingeniería Electroquímica, Igua 4225, CP 11400 Montevideo (Uruguay); Ricardo, Faccio [Universidad de la República, Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Centro NanoMat, Polo Tecnológico de Pando, Espacio Interdisciplinario, Facultad de Química, Montevideo (Uruguay); Fabricio, Ruiz [Consejo Nacional de Investigaciones Científicas y Técnicas , CONICET, Av. Rivadavia 1917, C1033AAJ Ciudad de Buenos Aires (Argentina); Centro Atómico Bariloche , Comisión Nacional de Energía Atómica (CAB-CNEA), Av. Bustillo 9500, CP 8400 S.C. de Bariloche, RN (Argentina); Fernando, Zinola [Universidad de la República, Facultad de Ciencias, Laboratorio de Electroquímica Fundamental, Núcleo Interdisciplinario Ingeniería Electroquímica, Igua 4225, CP 11400 Montevideo (Uruguay); and others

2015-11-15

The effects of partial replacement of chromium by molybdenum was studied on the structure and electrochemical kinetic properties of ZrCr{sub 1-x}NiMo{sub x}(x = 0.0, 0.3 and 0.6) metal hydride alloys. The arc-melting prepared alloys were metallurgically characterized by X-ray diffraction and energy dispersive spectroscopy microanalysis, which showed AB{sub 2} (with hexagonal C14 structure) and Zr{sub x}Ni{sub y} (Zr{sub 7}Ni{sub 10}, Zr{sub 9}Ni{sub 11}) phases. After a partial substitution of chromium by molybdenum, secondary phases monotonically increase with the C14 unit cell volume indicating that most of molybdenum atoms locate in the B-site. The alloys were electrochemically characterized using charge/discharge cycling, electrochemical impedance spectroscopy and rate capability experiments that allowed the determination of hydriding reaction kinetic parameters. The presence of molybdenum produces a positive effect for hydrogen diffusion in the alloy lattice, and ZrCr{sub 0.7}NiMo{sub 0.3} alloy depicts the better kinetics associated with a fast activation, lower charge transfer resistance and the best high rate discharge behavior. This fact would be related to a lower diffusion time constant and a bigger value of the product between exchange density current and surface active area. There is a trade-off in the amounts of secondary phase and Laves phases in order to improve the kinetic performance. - Highlights: • Metallurgical characterization evidences the presence of Zr{sub x}Ni{sub y} and C14 phases. • The partial replacement of Cr by Mo promotes the segregation of Zr{sub x}Ni{sub y} phase. • The incorporation of molybdenum improves the kinetics for the hydriding process. • Mo produces a decrease in the diffusion time constant.

Beta decomposition of (Hf/sub x/Zr/sub 1-x/)80Nb20 ternary alloys

International Nuclear Information System (INIS)

Jones, W.B.; Taggart, R.; Polonis, D.H.

1978-01-01

The processes of beta decomposition have been examined in ternary alloys of the form (Hf/sub x/Zr/sub 1-x/) 80 Nb 20 to determine the influence of Hf additions to a basic Zr 80 Nb 20 composition. In the chill cast condition, Hf additions have been found to decrease the temperature coefficient of electrical resistivity from a value of -0.0015%/K for the binary Zr 80 Nb 20 alloy to a value of -0.011%/K for a (Hf 50 Zr 50 ) 80 Nb 20 ternary alloy. This change is explained in terms of the bcc lattice instability typical of Ti, Zr, and Hf alloys. The Hf additions enhance the kinetics of omega-phase precipitation during aging at 648 K. The aging of a (Hf 05 Zr 95 ) 80 Nb 20 alloy for 12 h results in the precipitation of a high volume fraction of cuboidal shaped omega-phase particles. A phase separation which results in the formation of solute lean discs (β/sub l/) occurs together with the precipitation of the omega-phase. These discs formed both randomly within the matrix and heterogeneously along dislocations and at grain boundaries

51Cr diffusion in Zr-Sn alloys

International Nuclear Information System (INIS)

Nicolai, L.I.; Migoni, R.L.; Hojvat de Tendler, Ruth

1982-01-01

The 51 Cr volume diffusion in Zr-Sn alloys is measured in polycrystals with big grains by the thin-film method. The Sn content in the alloys ranges from 0.39% at to 6.66 % at. In the beta-phase the analysed temperature range is 982 deg C-1240 deg C. The Sn dehances the 51 Cr diffusion in beta-Zr, the effect being small but well defined. Assuming the formation of Sn-Cr dimers, the linear dehancement coefficient b and the parameters for the variation of b with temperature were calculated. The parameters Q and D o were calculated for the more diluted alloys and, upon application of the Zener theory for D o , a negative contribution to the activation entropy is found. Three experiments at different temperatures were performed in the alpha-phase. 51 Cr diffuses very fast in alpha-Zr-Sn. No definite correlation is found between the 51 Cr diffusivity and the increasing Sn concentration, probably due to the anisotropy of the alfa-phase. (M.E.L.) [es

Effect of nitrogen addition on superelasticity of Ti-Zr-Nb alloys

International Nuclear Information System (INIS)

Tahara, Masaki; Kim, Hee Young; Miyazaki, Shuichi; Inamura, Tomonari; Hosoda, Hideki

2008-01-01

Recently, the Ti-Zr-Nb alloys have been developed as Ni-free shape memory and superelastic alloys. In this study, the effect of Nb and nitrogen (N) contents on martensitic transformation behavior, shape memory effect and superelasticity in Ti-18Zr-(12-16)Nb-(0-1.0)N (at%) alloys were investigated using tensile tests, optical microscopy and X-ray diffraction. Shape memory effect was observed in Ti-18Zr-(12-13)Nb and Ti-18Zr-12Nb-0.5N alloys at room temperature. The superelastic behavior appeared by the increase of Nb or N content. The Ti-18Zr-(14-15)Nb, Ti-18Zr-(13-14)Nb-0.5N and Ti-18Zr-(12-14)Nb-1.0N alloys exhibited the superelasticity at room temperature. The martensitic transformation start temperature (M s ) decreased by 75 K with 1 at% increase of N content for Ti-18Zr-13Nb alloy. The critical stress for slip deformation and the stress for inducing the martensitic transformation increased with increasing N content. The superelastic recovery strain was also increased by adding N. The maximum recovery strain of 5.0% was obtained in the Ti-18Zr-14Nb-0.5N alloy. (author)

Corrosion resistance of amorphous NiCrZr and NiCrMoZr alloys

International Nuclear Information System (INIS)

Naka, M.; Miyake, M.; Okamoto, I.

1987-01-01

One of the authors has reported that the corrosion resistance of chromium containing amorphous alloys is extremely improved by alloying phosphorus among metalloids. Two factors operate for the improvement of corrosion resistance of the amorphous alloys. First, phosphorus serves for the rapid formation of protective passive film. Second, the compositional and structural homogeneity in amorphous state also account for the formation of protective film. The latter factor has been clearly seen in the high corrosion resistance of CoCrMoZr and CoCrWZr alloys without metalloids. In order to clarify the separately two factors in the corrosion resistance of amorphous alloys, the corrosion resistance of amorphous alloys without metalloids has to be further investigated. This paper also deals with the corrosion resistance and electrochemical behavior of NiCrZr and NiCrMoZr alloys in 1N HCl, and compare them with the corrosion behavior of the crystalline alloys containing the same composition as that of the amorphous alloys

Phase Stability in the Mo-Ti-Zr-C System via Thermodynamic Modeling and Diffusion Multiple Validation

Science.gov (United States)

Kar, Sujoy Kumar; Dheeradhada, Voramon S.; Lipkin, Don M.

2013-08-01

Alloys in the Mo-rich corner of the Mo-Ti-Zr-C system have found broad applications in non-oxidizing environments requiring structural integrity well beyond 1273 K (1000 °C). Alloys such as TZM (Mo-0.5Ti-0.08Zr-0.03C by weight %) and TZC (Mo-1.2Ti-0.3Zr-0.1C by weight) owe much of their high temperature strength and microstructural stability to MC and M2C carbide phases. In turn, the stability of the respective carbides and the subsequent mechanical behavior of the alloys are strongly dependent on the alloying additions and thermal history. A CALPHAD-based thermodynamic modeling approach is employed to develop a quaternary thermodynamic database for the Mo-Ti-Zr-C system. The thermodynamic database thus developed is validated with diffusion multiple experiments and the validated database is exercised to elucidate the effects of alloying and thermal history on the phase equilibrium in Mo-rich alloys.

Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

Energy Technology Data Exchange (ETDEWEB)

Ohishi, Yuji, E-mail: ohishi@see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University (Japan); Kondo, Toshiki [Graduate School of Engineering, Osaka University (Japan); Ishikawa, Takehiko [Japan Aerospace Exploration Agency (Japan); SOKEN-DAI (Graduate University for Advanced Studies) (Japan); Okada, Junpei T. [Institute for Materials Research, Tohoku University (Japan); Watanabe, Yuki [Advanced Engineering Services Co. Ltd. (Japan); Muta, Hiroaki; Kurosaki, Ken [Graduate School of Engineering, Osaka University (Japan); Yamanaka, Shinsuke [Graduate School of Engineering, Osaka University (Japan); Research Institute of Nuclear Engineering, University of Fukui (Japan)

2017-03-15

It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr{sub 1-x}Ni{sub x} (x = 0.12 and 0.24) and Zr{sub 0.77}Cr{sub 0.23}) using the electrostatic levitation technique. - Highlights: • The physical properties of Zr-Ni and Zr-Cr liquid alloys have been measured Zr{sub 1-x}Ni{sub x} (x = 0.12 and 0.24) and Zr{sub 77}Cr{sub 23}. • The measurement was conducted using the electrostatic levitation technique. • The density, viscosity, and surface tension of each liquid alloy were measured.

Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

International Nuclear Information System (INIS)

Ohishi, Yuji; Kondo, Toshiki; Ishikawa, Takehiko; Okada, Junpei T.; Watanabe, Yuki; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

2017-01-01

It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr 1-x Ni x (x = 0.12 and 0.24) and Zr 0.77 Cr 0.23 ) using the electrostatic levitation technique. - Highlights: • The physical properties of Zr-Ni and Zr-Cr liquid alloys have been measured Zr 1-x Ni x (x = 0.12 and 0.24) and Zr 77 Cr 23 . • The measurement was conducted using the electrostatic levitation technique. • The density, viscosity, and surface tension of each liquid alloy were measured.

Damping characteristics of a Ti40.5Ni49.5Zr10 shape memory alloy

International Nuclear Information System (INIS)

Hsieh, S.F.; Wu, S.K.

2005-01-01

Ti 40.5 Ni 49.5 Zr 10 alloy undergoes B2-bar B19' martensitic transformation. Damping capacities of B19' and B2 phases of this alloy are lower than those of Ti 51 Ni 49 alloy due to Zr atoms solid-soluted hardening. Transformation temperatures of this alloy decrease, but transformation peak heights Q max -1 increase with increasing aging time at 300 o C due to the formation of finer (001) M twins for specimens aged longer. The Q max -1 peaks of the slightly cold-rolled Ti 40.5 Ni 49.5 Zr 10 alloy are higher than those of the as-annealed alloy, which may be because the thinner twins are induced by small deformation

Interdiffusion among U-Mo-Zr and alloys of Al to 550oC

International Nuclear Information System (INIS)

Komar Varela, C.L; Arico, S.F; Gribaudo, L.M

2006-01-01

The international community, by means of the project 'Reduced Enrichment for Research and Test Reactors' is interested in the development of a new nuclear fuel of very high density of uranium and low enrichment (≤ 20% de U 235 ) for reactors of investigation and production of radioisotopes, that permit to reach greater neutron flows, with good capacity to be reprocessed One of these assemblies are the alloys of U with Mo contents between 7 and 10% in weight. In the fuels 'dispersed type plate' the particles of U-Mo are mixed with dust of aluminum and are co - laminated between two plates of an alloy of the same material. The existing contact among the particles permits the interdiffusion of the materials with the consequent apparition of new phases. Studies pursuit-irradiation have shown a badly behavior of these new phases. It is for this that is necessary to control the presence of these products of interaction. The aggregate of a third element to the alloys U - Mo has begun to be practiced with this purpose. In this work the modification of the start of the disorder of the phase γU in the alloy U-7%Mo-1%Zr was studied and the interdiffusion between pure aluminum and the same alloy to 550 o C. The results obtained are compared with other obtained for peers U-Mo/Al. The techniques of characterization utilized were: optical microscopy, analysis by diffraction of X-rays and microanalysis quantitative by microprobe electronic. It was observed that the aggregate of Zr refines the grain for a processing of homogenized in composition of Mo to 1000 o C and accelerates the start of the disorder of the phase γU to 550 o C. As for the zone of interaction, was found that the composed identifying do not they differ to them reported in the in peers U-Mo/Al. These are: (U,Mo)Al 4 y UAl 3 (AG)

The Testing of Fuel Rod Models with Zr1Nb Alloy Cladding in Water Vapor at Temperature of Hypothetical Accident Situation in WWER-1000 Type Reactors

International Nuclear Information System (INIS)

Krasnorutsky, V.S.; Petel'guzov, I.A.; Gritsina, V.M.; Rodak, A.G.; Belash, N.N.; Yakovlev, V.K.

2006-01-01

In the article happen to results of testing the fuel rod models, their welded joints, changing the mechanical characteristics of shells of models from experimental parties of pipes from Zr1Nb alloy (Zr+1 mass%Nb) at heating of models, pervaded helium before pressures, using in earned one's living fuel rods (2,2 MPa), before the temperature 770 degree C and above occurs an overblown fuels, but at temperature 820...830 degree C shells can be broken at the expense of pressure of warming gas. Swept away reduction plasticity and embrittlement shells after the heating under temperature of 900...1200 degree C and cooling before room temperature pipes-shells from Zr1Nb alloy and from the staff alloy E110

Alternative Zr alloys with irradiation resistant precipitates for high burnup BWR application

International Nuclear Information System (INIS)

Garzarolli, F.; Ruhmann, H.; Van Swan, L.

2002-01-01

In the core of BWRs, the second-phase particles (SPP) of Zircaloy-2 and Zircaloy-4, the Zr(FeCr) 2 and the Zr 2 (FeNi) phase, release Fe and dissolve. The degree of dissolution depends on initial size and fluence. These SPP, however, are important for the corrosion behavior of Zircaloy. Zircaloy shows an increase of corrosion at a certain burnup, depending on the initial SPP size and fast neutron fluence. Only Zr alloys with irradiation resistant SPP avoid this type of increased corrosion completely. Two types of irradiation resistant materials were considered. One is a Zr-Sn-Fe alloy containing the Zr 3 Fe phase, which is irradiation resistant under BWR conditions. The other material is a Zr-Sn-Nb alloy containing the irradiation resistant β-Nb phase. In-BWR tests have shown that a Sn content of >0.8% is mandatory to minimize the nodular corrosion. Two prototypes of irradiation resistant alloys, Zr1.3Sn0.25-0.3 Fe and Zr1Sn2-3Nb, were irradiated in a BWR for 1372 days to a fast fluence of 9 x 10 21 n/cm 2 (E > 1 MeV). These irradiation tests showed that Zr1.3Sn0.25-0.3 Fe has a little lower resistance against nodular corrosion than optimized LTP (Low Temperature Process) Zircaloy-2/4 and revealed that Zr1Sn2-3Nb is superior to LTP Zircaloy-2/4 with respect to nodular and shadow corrosion resistance. The BWR corrosion resistance of Zr1Sn2-3Nb depends on heat treatment. The lowest corrosion was observed with material fabricated completely in the α-range, but also material manufactured in the lower (α+β)-range exhibits low corrosion. Material fabricated in the upper (α+β)-range showed a somewhat higher corrosion, a corrosion behavior similar to LTP Zircaloy-2/4. As far as final annealing is concerned, a long time annealing at 540 deg C is superior to a standard recrystallization treatment (e.g., at 580 deg C), which still leads to a corrosion behavior that is better than stress relieved Zr1Sn2-3Nb. Zr1Sn2-3Nb is resistant to shadow corrosion, when fabricated

Microstructural evolution of Ni40Zr60 alloy during early stage of mechanical alloying of intermetallic compounds NiZr2 and Ni11Zr9

International Nuclear Information System (INIS)

Lee Peeyew; Koch, C.C.

1994-01-01

The microstructural change of Ni 40 Zr 60 alloy during mechanical alloying of mixtures of the intermetallic compounds NiZr 2 and Ni 11 Zr 9 has been studied by transmission electron microscopy. A specific ''cauliflower'' phase was formed during early stage of mechanical alloying process. It is suggested that the solid state reaction between intermetallic compounds NiZr 2 and Ni 11 Zr 9 is not the only origin for the formation of the ''cauliflower'' phase. ((orig.))

Influence of alloying elements on the dislocation loops created by Zr+ ion irradiation in alpha-zirconium

International Nuclear Information System (INIS)

Hellio, C.; Novion, C.H. de; Boulanger, L.

1987-01-01

Pure zirconium and four (annealed) α - zirconium based alloys (Zr-1760 ppm weight 0, Zr - 1% Nb - 430 ppm 0, Zr-1% Nb-1800 ppm 0, zircaloy 4) have been studied by transmission electron microscopy after 500 keV Zr + ion or 1 MeV electron irradiation performed at high temperature. Type of burgers vectors of the dislocation loops are given; in the case of electron irradiated Zr-1760 ppm 0, the larger loops were found of interstitial type. Alloying elements increase the loop density. The kinetic of loop growth was observed in-situ during 1 MeV electron irradiation between 400 and 700 0 C: oxygen was found to reduce considerably the growth speed of loops. In-situ annealing at 450 or 500 0 C after ion irradiation led to a large coalescence of loops in the case of pure zirconium, but modified only slightly the defect structure of the alloys

Effects of ageing treatment on microstructures and properties of Mg-Gd-Y-Zr alloys with and without Zn additions

International Nuclear Information System (INIS)

Liu, X.B.; Chen, R.S.; Han, E.H.

2008-01-01

Mg-10Gd-3Y-0.5Zr alloys with and without 1% Zn additions have been investigated using optical microscopy, scanning electron microscope and X-ray diffraction. The microstructures, ageing hardening behaviors and mechanical properties of the two alloys are compared. The extruded-T5 specimens exhibit remarkable age hardening responses during ageing from 200 to 250 deg. C. The highest peak hardness and strength of the two alloys are obtained when they are aged at 200 deg. C. Addition of 1% Zn to Mg-10Gd-3Y-0.5Zr alloy results in the greater magnitude ageing effect and better mechanical properties as well as better heat resistance. Furthermore, secondary ageing is carried out at 200 deg. C following preliminary ageing at 250 deg. C for both Mg-10Gd-3Y-0.5Zr and Mg-10Gd-3Y-1Zn-0.5Zr alloys. The ultimate tensile strength values after secondary ageing are slightly lower compared with the highest strength of the two alloys, but secondary ageing offers a better combination of high strength and ductility

Development of Zr alloys - Fabrication of Zr-Nb alloy used in PHWRs

Energy Technology Data Exchange (ETDEWEB)

Lee, Kang In; Kim, Won Baek; Choi, Guk Sun; Lee, Chul Kyung; Jang, Dae Kyu; Seo, Chang Yeol; Sim, Kun Joo; Lee, Jae Cheon [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1996-07-01

The manufacture of Zr-Nb alloy ingot by EB melting process is carried out to meet the chemical composition and mechanical and property specifications and to ensure that the ingots are free of unacceptable defects through this study. It was established that Zr-Nb alloy was made by EB melting technique including the control of adding elements, melting power and melting and cast device. 28 refs., 13 tabs., 26 figs., 23 ills. (author)

Application of thermo-electromotive force and electric resistance measuring methods to researching phase transformations in Zr1Nb alloy

International Nuclear Information System (INIS)

Klimenko, S.P.; Gritsina, V.M.; Petel'guzov, I.A.; Chernyaeva, T.P.

2007-01-01

The paper determines the applicability areas of different methods for the study of structural phase transformations in a Zr+1Nb alloy, which is extensively used in reactor construction; production and fabrication of products from Zr+1Nb is currently developed in Ukraine. Electromotive force and electric resistance were measured to study structural phase transformations of Zr+1Nb fuel rod tubes based on calciumthermal zirconium (Zr1Nb). It was established that changes in electric resistance clearly show the beginning of a massive α → β transition at ∼ 750 degree C and the end of α → β transition at ∼ 950 degree C, whereas measurement of thermo-e.m.f. in the samples subjected to successive 3-hour step annealing in the temperature range from 300 to 700 degree C allows the temperature of monotectoid transformation to be found. For sample Zr1Nb batches the temperature of monotectoid transformation is (620±7) degree C. The measurement results are consistent with the similar studies carried out on Zr+1Nb fuel rod tubes based on electrolytic zirconium (E110), for which the temperature of monotectoid transformation is equal to ∼ 610 degree C

Moessbauer and transport studies of amorphous and icosahedral Zr-Ni-Cu-Ag-Al alloys

International Nuclear Information System (INIS)

Stadnik, Z.M.; Rapp, O.; Srinivas, V.; Saida, J.; Inoue, A.

2002-01-01

The alloy Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 in the amorphous and icosahedral states, and the bulk amorphous alloy Zr 65 Al 7.5 Ni 10 Cu 7.5 Ag 10 , have been studied with 57 Fe Moessbauer spectroscopy, electrical resistance and magnetoresistance techniques. The average quadrupole splitting in both alloys decreases with temperature as T 3/2 . The average quadrupole splitting in the icosahedral alloy is the largest ever reported for a metallic system. The lattice vibrations of the Fe atoms in the amorphous and icosahedral alloys are well described by a simple Debye model, with the characteristic Moessbauer temperatures of 379(29) and 439(28) K, respectively. Amorphous alloys Zr 65 Al 7. )5Ni 10 Cu 7.5 Ag 10 and Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 have been found to be superconducting with the transition temperature, T c , of about 1.7 K. The magnitude of Tc and the critical field slope at Tc are in agreement with previous work on Zr-based amorphous superconductors, while the low-temperature normal state resistivity is larger than typical results for binary and ternary Zr-based alloys. The resistivity of icosahedral Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 is larger than that for the amorphous ribbon of the same composition, as inferred both from direct measurements on the ribbons and from the observed magnetoresistance. However the icosahedral sample is non-superconducting in the measurement range down to 1.5 K. The results for the resistivity and the superconducting T c both suggest a stronger electronic disorder in the icosahedral phase than in the amorphous phase. (author)

Grain Refinement and Mechanical Properties of Cu-Cr-Zr Alloys with Different Nano-Sized TiCp Addition.

Science.gov (United States)

Zhang, Dongdong; Bai, Fang; Wang, Yong; Wang, Jinguo; Wang, Wenquan

2017-08-08

The TiC p /Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiC p /Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiC p -reinforced Cu-Cr-Zr composites. Results show that nano-sized TiC p can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiC p . The grain size decreased from 82 to 28 μm with the nano-sized TiC p content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (σ UCS ) and yield strength (σ 0.2 ) of 4 wt% TiC p -reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiC p -reinforced Cu-Cr-Zr composites decreased with the increasing TiC p content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.

Hydrogen calibration of GD-spectrometer using Zr-1Nb alloy

Science.gov (United States)

Mikhaylov, Andrey A.; Priamushko, Tatiana S.; Babikhina, Maria N.; Kudiiarov, Victor N.; Heller, Rene; Laptev, Roman S.; Lider, Andrey M.

2018-02-01

To study the hydrogen distribution in Zr-1Nb alloy (Э110 alloy) GD-OES was applied in this work. Qualitative analysis needs the standard samples with hydrogen. However, the standard samples with high concentrations of hydrogen in the zirconium alloy which would meet the requirements of the shape, size are absent. In this work method of Zr + H calibration samples production was performed at the first time. Automated Complex Gas Reaction Controller was used for samples hydrogenation. To calculate the parameters of post-hydrogenation incubation of the samples in an inert gas atmosphere the diffusion equations were used. Absolute hydrogen concentrations in the samples were determined by melting in the inert gas atmosphere using RHEN602 analyzer (LECO Company). Hydrogen distribution was studied using nuclear reaction analysis (HZDR, Dresden, Germany). RF GD-OES was used for calibration. The depth of the craters was measured with the help of a Hommel-Etamic profilometer by Jenoptik, Germany.

Microstructure, mechanical property, corrosion behavior, and in vitro biocompatibility of Zr-Mo alloys.

Science.gov (United States)

Zhou, F Y; Wang, B L; Qiu, K J; Li, L; Lin, J P; Li, H F; Zheng, Y F

2013-02-01

In this study, the microstructure, mechanical properties, corrosion behaviors, and in vitro biocompatibility of Zr-Mo alloys as a function of Mo content after solution treatment were systemically investigated to assess their potential use in biomedical application. The experimental results indicated that Zr-1Mo alloy mainly consisted of an acicular structure of α' phase, while ω phase formed in Zr-3Mo alloy. In Zr-5Mo alloy, retained β phase and a small amount of precipitated α phase were observed. Only the retained β phase was obtained in Zr-10Mo alloy. Zr-1Mo alloy exhibited the greatest hardness, bending strength, and modulus among all experimental Zr-Mo alloys, while β phase Zr-10Mo alloy had a low modulus. The results of electrochemical corrosion indicated that adding Mo into Zr improved its corrosion resistance which resulted in increasing the thermodynamic stability and passivity of zirconium. The cytotoxicity test suggested that the extracts of the studied Zr-Mo alloys produced no significant deleterious effect to fibroblast cells (L-929) and osteoblast cells (MG 63), indicating an excellent in vitro biocompatibility. Based on these facts, certain Zr-Mo alloys potentially suitable for different biomedical applications were proposed. Copyright © 2012 Wiley Periodicals, Inc.

Influence of alloying element of corrosion of Zr-Nb-Sn-Fe-Cu alloy and impedance characteristics of its oxide layer

International Nuclear Information System (INIS)

Park, S. Y.; Lee, M. H.; Choi, B. K.; Jung, Y. H.; Jung, Y. H.

2000-01-01

As a part of the advanced Zr fuel cladding development program, the autoclave corrosion test was performed on the series of Zr-0.2Nb-1.1Sn-Fe-Cu and Zr-0.4Nb-0.8Sn-Fe-Cu alloys in 70 ppm LiOH solution at 360 .deg. C. The oxide characteristics were investigated by using the Electrochemical Impedance Spectroscope(EIS) method. The corrosion resistance of the alloys was evaluated from the corrosion rate determined as a function of the concentration of main alloying elements such as Nb, Sn, Fe and Cu. The equivalent circuit was composed as a result of the spectrum from EIS measurements on the oxide layer that formed at pro- and post-transition regions. By using the capacitance characteristics of equivalent circuit, the thickness of impervious layer, it's electrical resistance and characteristics of space charge layer were evaluated. The corrosion characteristics of the Zr-Nb-Sn-Fe-Cu alloys were successfully explained by applying the EIS test results

Hot rolling effect on the characters of Zr-0.6Nb-0.5Fe-0.5Cr alloy

International Nuclear Information System (INIS)

Sungkono; Siti Aidah

2015-01-01

Characters of Zr-0.6Nb-0.5Fe-0.5Cr alloy after hot rolling have been studied. The objective of this research was to obtain of hot rolling effect on the characteristics of microstructures, hardness and phases formed in Zr-0.6Nb-0.5Fe-0.5Cr alloy. The hot rolling process of alloy carried out at temperature of 800 °C with retention time of 1.5 and 2 hours and a thickness reduction between 5 to 25 %. The results of this experiment showed that the Zr-0.6Nb-0.5Fe-0.5Cr alloy has Widmanstaetten structure with microstructure evolving into deformed columnar grains and deformed elongated grains with increasing thickness reduction. Besides, the longer the retention time at temperature of 800 °C is the larger are the grain structures and formation of α-Zr and Zr_3Fe phase. The hardness of Zr-0.6Nb-0.5Fe-0.5Cr alloy has same trends i.e the larger thickness reduction gives higher hardness. The Zr-0.6Nb-0.5Fe-0.5Cr alloy can under go hot rolling deformation at a thickness reduction of 25 % and the formation of α-Zr and Zr_3Fe can increased of hardness and strength of Zr-0.6 Nb-0.5 Fe-0.5 Cr alloy. (author)

Investigation of phase transformations of U2.5Zr7.5Nb and U3Zr9Nb alloys aging at 600 deg C

International Nuclear Information System (INIS)

Cantagalli, Natalia Mattar; Tanure, Leandro Paulo de Almeida Reis; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa

2009-01-01

Investigation has been made of the effects of high-temperature aging (600 deg C) on the phase transformations in the U2.5Zr7.5Nb and U3Zr9Nb alloys. These alloys have been produced with vacuum induction melting (VIM) furnace in cast ingots. The ingots were homogenized at 1000 deg C for 24 hours in vacuum of -4 torr, and cooled to room temperature at a rate of 3 deg C/min. Specimens from these homogeneous materials, cut in 3 mm high and 10 mm diameter, were reheated to γ phase at 850 deg C, for 1 hour, and aging at 600 deg C at different times from 0.5 to 24 hours. The phases decomposition were characterized by X-ray diffraction (XRD), metallographic, micro-probe analyze by energy dispersive spectrometry (EDS) and microhardness methods. It was verified that the decomposition of the δ phase proceeds in two steps. The first is a discontinuous precipitation of a lamellar two-phase aggregate composed of alpha solid solution and a metastable gamma phase. The metastable gamma phase has a constant composition at given temperature. After longer annealing, it decomposes eutectoidally into the equilibrium (α + δ 2 ) phases mixture. During this process a modification of the original lamellar microstructure takes place. The obtained metastable phases of these alloys of different compositions were analyzed in relation to their constitution, heat treatability and micrographic features and the results confronted with available distinct uranium alloys data from literature. (author)

A multi-component Zr alloy with comparable strength and Higher plasticity than Zr-based bulk metallic glasses

International Nuclear Information System (INIS)

Liang, S.X.; Yin, L.X.; Ma, M.Z.; Jing, R.; Yu, P.F.; Zhang, Y.F.; Wang, B.A.; Liu, R.P.

2013-01-01

Zirconium (Zr)-based bulk metallic glass possesses the highest potential as a structural material among metallic glasses. Although Zr-based bulk metallic glass exhibits extremely high strength, its potential application has been restricted by a number of issues, such as fragility, small size, difficult fabrication into different shapes and poisonous beryllium content, among others. In this paper, a Zr-based crystal alloy with comparable strength and higher plasticity than Zr-based bulk metallic glass is presented. The proposed Zr-based alloy has a tensile strength greater than 1600 MPa. That value is comparable to the 1500 MPa to 2000 MPa strength of Zr-based bulk metallic glasses (BMGs). The ductility in terms of elongation reached 6.2%; at the same time, the 1400 MPa tensile strength was retained. This phenomenon is not possible for Zr-based BMGs. XRD results show that the proposed ultrahigh-strength Zr-based crystal alloy has two-phase structures: an hcp-structured α phase and a bcc-structured β phase. The forged specimen exhibits a typical basket-weave microstructure, which is characterised by the interlaced plate α phase separated from the β phase matrix. Fine, short bar-shaped α phases precipitated along the original β grain boundary together with ultrafine dot-shaped α phases that presented inside the original β grain when the ageing temperature was between 500 °C and 525 °C. As the ageing temperature increased, the dot-shaped α phase grew into plate shapes, decreasing the material's strength and increasing its plasticity. The ultrafine dot-shaped and short bar-shaped α phases in the original β phase matrix are the main strengthening mechanisms of the ultrahigh-strength Zr-based crystal alloy.

Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys

International Nuclear Information System (INIS)

Witusiewicz, V.T.; Sommer, F.

2000-01-01

Since the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state, it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously, are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent canaries and ternaries first. In a series of articles, the authors have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni, Cu-Zr, Al-Zr, Al-Cu-Ni, and Al-Cu-Zr alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni 26 Zr 74 . In a subsequent article, the authors will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys

The effect of Zr on the microstructure and properties of Ti-35Nb-XZr alloy

Energy Technology Data Exchange (ETDEWEB)

Málek, Jaroslav, E-mail: malek@ujp.cz [UJP PRAHA a.s., Nad Kamínkou 1345, 156 00 Prague-Zbraslav (Czech Republic); Czech Technical University in Prague, Faculty of Mechanical Engineering, Karlovo náměstí 13, 121 35 Praha 2 (Czech Republic); Hnilica, František, E-mail: hnilica@ujp.cz [UJP PRAHA a.s., Nad Kamínkou 1345, 156 00 Prague-Zbraslav (Czech Republic); Veselý, Jaroslav, E-mail: vesely@ujp.cz [UJP PRAHA a.s., Nad Kamínkou 1345, 156 00 Prague-Zbraslav (Czech Republic); Smola, Bohumil, E-mail: smola@met.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, KeKarlovu 5, 121 16 Prague 2 (Czech Republic); Kolařík, Kamil, E-mail: kamil.kolarik@email.cz [Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Trojanova 339/13, 120 00 Praha 2 (Czech Republic); Fojt, Jaroslav, E-mail: jaroslav.fojt@vscht.cz [Institute of Chemical Technology, Technická 5, 166 28 Prague (Czech Republic); Vlach, Martin, E-mail: martin.vlach@mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, KeKarlovu 5, 121 16 Prague 2 (Czech Republic); Kodetová, Veronika [Charles University in Prague, Faculty of Mathematics and Physics, KeKarlovu 5, 121 16 Prague 2 (Czech Republic)

2016-10-15

The demand for biomaterials with high strength, low modulus, excellent biocompatibility and good corrosion resistance has led to the development of new alloys. Zirconium is known as a biocompatible element that can be used for alloying in titanium alloys. The effect of Zr on the mechanical and structural properties of a titanium alloy is studied in this paper. Binary Ti-35Nb alloy has been alloyed with various amounts of Zr (2, 4, 6 or 8 wt%). The specimens were thermo-mechanically processed (hot forged, solution treated 850 °C/0.5 h/water quenched, cold swaged and finally aged (at 400 °C or 450 °C for various periods). Cold-swaged alloys possess tensile strength of about 800 MPa, along with a low Young's modulus (~50 GPa). The elongation of all the alloys is more than 12%. The hardness increased during 400 °C annealing up to 370 HV10. The addition of Zr stabilized the β-phase and supports recrystallization and recovery processes. Corrosion resistance was also increased by the addition of Zr.

Stabilization effect of Zr and Ti additions on the ageing characteristics of Al-1 wt% Si alloy through a creep study

Energy Technology Data Exchange (ETDEWEB)

Deaf, G.H.; Beshai, M.H.N.; Abd El Khalek, A.M.; Graiss, G. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Kenawy, M.A. [Ain Shams Univ., Cairo (Egypt). Womens Coll.

1997-12-31

Al-1 wt% Si and Al-1 wt% Si-0.1 wt% Zr-0.1 wt% Ti alloys were used to trace the effect of Zr and Ti additions on the behaviour of the steady state creep. After solid solution treatment specimens of both alloys were aged at 623, 673, 723 and 773 K and creep tests were performed at room temperature by applying stresses of 60.0, 62.4, 64.7 and 67.1 MPa. The results showed a sound stabilization effect of Zr and Ti on the ageing characteristics of binary Al-1 wt% Si alloy. Values of the applied stress sensitivity parameter, m, obtained were in the range of (20-34) for Al-Si alloy and (14-19) for Al-Si-Zr-Ti alloy. Time to rupture was found to be strongly increased by Zr and Ti additions. The activation energies of the precipitation process involved were found to be 81.9 kJ/mole and 33.7 kJ/mole of the Al-Si and Al-Si-Zr-Ti alloys respectively. (orig.) 17 refs.

Microstructural investigation of as-cast uranium rich U–Zr alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuting, E-mail: zhangyuting@caep.cn [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); School of Nuclear Science and Technology, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China); Wang, Xin [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Zeng, Gang [Institute of Materials, China Academy of Engineering Physics, Jiangyou 621908, Sichuan (China); Wang, Hui [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Jia, Jianping [Institute of Materials, China Academy of Engineering Physics, Jiangyou 621908, Sichuan (China); Sheng, Liusi [School of Nuclear Science and Technology, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China); Zhang, Pengcheng, E-mail: zpc113@sohu.com [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China)

2016-04-01

The present study evaluates the microstructure in as-cast uranium rich U–Zr alloys, an important subsystem of U–Pu–Zr ternary metallic nuclear reactor fuel, as a function of the Zr content, from 2wt.% to 15wt.%Zr. It has been previously suggested that the unique intermetallic compound δ phase in U–Zr alloys is only present in as-cast U–Zr alloys with a Zr content exceeding 10wt.%Zr. However, our analysis of transmission electron microscopy (TEM) data shows that the δ phase is common to all as-cast alloys studied in this work. Furthermore, specific coherent orientation relationship is found between the α and δ phases, consistent with previous findings, and a third variant is discovered in this paper. - Highlights: • Initially, lattice parameter of as-cast U–Zr alloys decrease with the increasing Zr content, and then increase. • XRD data show the presence of δ-UZr{sub 2} phase in as-cast U–Zr alloys with a Zr content of more than 8wt.% Zr. • Finding δ-UZr{sub 2} phase exists in all as-cast uranium rich U–Zr alloys, even for alloys with a lean Zr content. • Three kinds of preferential orientations of the δ phase grow.

Experimental phases diagram Zr-Fe and Zr-Sn-Fe of the Fe rich zone at a temperature of 1100oC

International Nuclear Information System (INIS)

Nieva, N.; Jimenez, J.; Gomez, A; Granovsky, M.S

2010-01-01

Zr-based alloys are frequently used in the nuclear energy industry; among these are the Zr-based Zircaloys whose main alloys are Sn and Fe. In order to experimentally evaluate part of the diagram of the binary Zr-Fe phases and the ternary Zr-Sn-Fe in the Fe-rich zone, different binary alloys in the area closest to the composition of the ZrFe 2 and Zr 6 Fe 23 compounds were designed as well as a ternary alloy of Zr-Sn-Fe in the Fe-rich region of the ternary system. All the alloys underwent a two month heat treatment at a temperature of 1100 o C. Later the phases that were present were identified using different complementary techniques (mainly X-ray diffraction and microanalysis). The clear presence of the Zr 6 Fe 23 phase was not observed in any of the alloys. A new ternary phase consisting approximately of Zr 2 0Sn 14 Fe 66 was verified in the ternary alloy

Zr inclusions in actinide—Zr alloys: New data and ideas about how they form

International Nuclear Information System (INIS)

Janney, Dawn E.; O'Holleran, Thomas P.

2015-01-01

High-Zr inclusions are common in actinide—Zr alloys despite phase diagrams indicating that these alloys should not contain a high-Zr phase. The inclusions may contain enough Zr to cause significant differences between bulk compositions and those of inclusion-free areas, leading to possible errors in interpreting data if the inclusions are not considered. This paper presents data from high-Zr inclusions in a complex U—Np—Pu—Am—Zr—RE alloy. It is suggested that the high-Zr inclusions nucleated as high-Zr solid solutions at interfaces with high-actinide RE liquids, then unmixed to form nanometer-scale high-actinide sub-inclusions.

Roles of texture of Zr alloys in ZrO{sub 2} film formation and δ-hydride orientation near ZrO{sub 2}/Zr interface

Energy Technology Data Exchange (ETDEWEB)

Qin, W.; Szpunar, J.A., E-mail: weq565@mail.usask.ca, E-mail: jerzy.szpunar@usask.ca [Univ. of Saskatchewan, Dept. of Mechanical Engineering, Saskatoon, SK (Canada); Kozinski, J., E-mail: janusz.kozinski@lassonde.yorku.ca [York Univ., Faculty of Science and Engineering, Toronto, ON (Canada)

2014-07-01

Oxidation and hydrogen embrittlement are related to formation of cracks and failure of Zr alloys used in nuclear reactor applications. An in-depth understanding of the formation of ZrO{sub 2} film and the hydride precipitation and orientation is important for improving the corrosion resistance of zirconium alloys. In this work a theoretical model is developed to analyze the microstructure of ZrO{sub 2} film formed on Zr alloys and the effect of stress that results from ZrO{sub 2} formation on hydride reorientation in the region near oxide/metal interface. Our work shows that the macroscopic stress produced due to Pilling-Bedworth ratio for ZrO{sub 2}/Zr could lead to the hydride re-orientation in the region near ZrO{sub 2}/Zr interface. Whether or not this effect can occur is dependent on the texture of the zirconium alloys. Control of texture of zirconium alloys can affect the microstructure of ZrO{sub 2} film and can be responsible for change of hydride orientation. (author)

Refining U-Zr-Nb alloys by remelting

International Nuclear Information System (INIS)

Aguiar, B.M.; Kniess, C.T.; Riella, H.G.; Ferraz, W.B.

2011-01-01

The high density U-Zr-Nb and U-Nb uranium-based alloys can be employed as nuclear fuel in a PWR reactor due to their high density and nuclear properties. These alloys can stabilize the gamma phase, however, according to TTT diagrams, at the working temperature of a PWR reactor, all gamma phase transforms to α'' phase in a few hours. To avoid this kind of transformation during the nuclear reactor operation, the U-Zr-Nb alloy and U-Nn are used in α'' phase. The stability of α'' phase depends on the alloy composition and cooling rate. The alloy homogenization has to be very effective to eliminate precipitates rich in Zr and Nb to avoid changes in the alloying elements contents in the matrix. The homogenization was obtained by remelting the alloy and keeping it in the liquid state for enough time to promote floating of the precipitates (usually carbides, less dense) and leaving the matrix free of precipitates. However, this floating by density difference may result in segregation between the alloying elements (Nb and Zr, at the top) and uranium (at the bottom). The homogenized alloys were characterized in terms of metallographic techniques, optical microscopy, scanning electronic microscopy, EDS and X-ray diffraction. In this paper, it is shown that the contents of Zr and Nb at the bottom and at the top of the matrix are constant. (author)

High pressure stability analysis and chemical bonding of Ti{sub 1-x}Zr{sub x}N alloy: A first principle study

Energy Technology Data Exchange (ETDEWEB)

Chauhan, Mamta; Gupta, Dinesh C., E-mail: sosfizix@gmail.com, E-mail: mamta-physics@yahoo.co.in [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior – 474 011 (India)

2016-05-23

First-principles pseudo-potential calculations have been performed to analyze the stability of Ti{sub 1-x}Zr{sub x}N alloy under high pressures. The first order phase transition from B1 to B2 phase has been observed in this alloy at high pressure. The variation of lattice parameter with the change in concentration of Zr atom in Ti{sub 1-x}Zr{sub x}N is also reported in both the phases. The calculations for density of states have been performed to understand the alloying effects on chemical bonding of Ti-Zr-N alloy.

X-ray study of rapidly cooled ribbons of Al-Cr-Zr and Al-Ni-Y-Cr-Zr alloys

International Nuclear Information System (INIS)

Betsofen, S.Ya.; Osintsev, O.E.; Lutsenko, A.N.; Konkevich, V.Yu.

2002-01-01

One investigated into phase composition, lattice spacing and structure of rapidly cooled 25-200 μm gauge strips made of Al-4,1Cr-3,2Zr and Al-1,5Cr-1,5Zr-4Ni-3Y alloys, wt. %, produced by melt spinning to a water-cooled copper disk. In Al-4,1Cr-3,2Zr alloy one detected intermetallic phases: Al 3 Zr and two Al 86 Cr 14 composition icosahedral phases apart from aluminium solid solution with 4.040-4.043 A lattice spacing. In Al-1,5Cr-1,5Zr-4Ni-3Y alloy one identified two Al 86 Cr 14 icosahedral phases and two AlNiY and Al 3 Y yttrium-containing ones, lattice spacing of aluminium solid solution was equal to 4.052-4.053 A [ru

Microstructural characterization of laser and electron beam (EB) welds of Nb-1Zr-0.1C alloy

International Nuclear Information System (INIS)

Badgujar, B.P.; Tewari, R.; Dey, G.K.; Samajdar, I.

2015-01-01

Nb-1wt%Zr-0.1wt%C alloy is being considered for the structural applications in proposed Compact High Temperature Reactor (CHTR) on account of its excellent combination of high temperature properties. The applications of this alloy calls for welding, which is a difficult task due to its reactive nature, higher thermal conductivity and melting point. The high energy density techniques like laser and electron beam were employed to produce the welds on sheets of Nb-alloy at various processing parameters in bead-on-plate and square butt joint configurations. The weld joints produced were characterized by studying their optical, Scanning Electron Microscopy (SEM) and Electron Back Scattering Diffraction (EBSD) micro-graphs. The SEM micrograph of EB fusion zone along with the heat affected zone (HAZ) and the base region were studied and abrupt changes in the grain morphology were found in each zone. The fusion zone shows larger grains indicating the rapid grain growth after solidification, whereas the HAZ shows relatively smaller size of the grains but still much larger than the base zone. The SEM micrograph of central part of the same butt weld shows clear grain boundaries with a large variation in the grain size (45-82 micrometer) in the weld region. The heat affected zone (HAZ) and base metal showed fine carbide precipitates along the grain boundaries, whereas carbides were found dissolved in the weld zone. The EBSD micrograph of electron beam fusion zone describing the grain orientation in the weld region are described. The micro-hardness profile across the width of welds was also studied. The detailed results of all these studies are described in this paper. (author)

The Mechanical Properties and In Vitro Biocompatibility of PM-Fabricated Ti-28Nb-35.4Zr Alloy for Orthopedic Implant Applications.

Science.gov (United States)

Xu, Wei; Li, Ming; Wen, Cuie; Lv, Shaomin; Liu, Chengcheng; Lu, Xin; Qu, Xuanhui

2018-03-30

A biocompatible Ti-28Nb-35.4Zr alloy used as bone implant was fabricated through the powder metallurgy process. The effects of mechanical milling and sintering temperatures on the microstructure and mechanical properties were investigated systematically, before in vitro biocompatibility of full dense Ti-28Nb-35.4Zr alloy was evaluated by cytotoxicity tests. The results show that the mechanical milling and sintering temperatures have significantly effects on the density and mechanical properties of the alloys. The relative density of the alloy fabricated by the atomized powders at 1500 °C is only 83 ± 1.8%, while the relative density of the alloy fabricated by the ball-milled powders can rapidly reach at 96.4 ± 1.3% at 1500 °C. When the temperature was increased to 1550 °C, the alloy fabricated by ball-milled powders achieve full density (relative density is 98.1 ± 1.2%). The PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C can achieve a wide range of mechanical properties, with a compressive yield strength of 1058 ± 35.1 MPa, elastic modulus of 50.8 ± 3.9 GPa, and hardness of 65.8 ± 1.5 HRA. The in vitro cytotoxicity test suggests that the PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C has no adverse effects on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties and the net-shape manufacturability makes PM-fabricated Ti-28Nb-35.4Zr alloy a low-cost, highly-biocompatible, Ti-based biomedical alloy.

The Mechanical Properties and In Vitro Biocompatibility of PM-Fabricated Ti-28Nb-35.4Zr Alloy for Orthopedic Implant Applications

Science.gov (United States)

Xu, Wei; Li, Ming; Wen, Cuie; Lv, Shaomin; Liu, Chengcheng; Lu, Xin

2018-01-01

A biocompatible Ti-28Nb-35.4Zr alloy used as bone implant was fabricated through the powder metallurgy process. The effects of mechanical milling and sintering temperatures on the microstructure and mechanical properties were investigated systematically, before in vitro biocompatibility of full dense Ti-28Nb-35.4Zr alloy was evaluated by cytotoxicity tests. The results show that the mechanical milling and sintering temperatures have significantly effects on the density and mechanical properties of the alloys. The relative density of the alloy fabricated by the atomized powders at 1500 °C is only 83 ± 1.8%, while the relative density of the alloy fabricated by the ball-milled powders can rapidly reach at 96.4 ± 1.3% at 1500 °C. When the temperature was increased to 1550 °C, the alloy fabricated by ball-milled powders achieve full density (relative density is 98.1 ± 1.2%). The PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C can achieve a wide range of mechanical properties, with a compressive yield strength of 1058 ± 35.1 MPa, elastic modulus of 50.8 ± 3.9 GPa, and hardness of 65.8 ± 1.5 HRA. The in vitro cytotoxicity test suggests that the PM-fabricated Ti-28Nb-35.4Zr alloy by ball-milled powders at 1550 °C has no adverse effects on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties and the net-shape manufacturability makes PM-fabricated Ti-28Nb-35.4Zr alloy a low-cost, highly-biocompatible, Ti-based biomedical alloy. PMID:29601517

High-temperature air oxidation of E110 and Zr-1%Nb alloys claddings with coatings

International Nuclear Information System (INIS)

Kuprin, A.S.; Belous, V.A.; Voyevodin, V.N.; Bryk, V.V.; Vasilenko, R.L.; Ovcharenko, V.D.; Tolmachova, G.N.; V'yugov, P.N.

2014-01-01

Results of experimental study of the influence of protective vacuum-arc claddings on the base of compounds zirconium-chromium and of its nitrides on air oxidation resistance at temperatures 660, 770, 900, 1020, 1100 deg C during 3600 s. of tubes produced of zirconium alloys E110 and Zr-1%Nb (calcium-thermal alloy of Ukrainian production) are presented. Change of hardness, the width of oxide layer and depth of oxygen penetration into alloys from the side of coating and without coating are investigated by the methods of nanoindentation and by scanning electron microscopy. It is shown that the thickness of oxide layer in zirconium alloys at temperatures 1020 and 1100 deg C from the side of the coating doesn't exceed 5 μm, and from the unprotected side reaches the value of ≥ 120 μm with porous and rough structure. Tubes with coatings save their shape completely independently of the type of alloy; tubes without coatings deform with the production of through cracks

In-situ electrochemical study of Zr1nb alloy corrosion in high temperature Li{sup +} containing water

Energy Technology Data Exchange (ETDEWEB)

Krausová, Aneta [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Macák, Jan, E-mail: macakj@vscht.cz [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Sajdl, Petr [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Novotný, Radek [JRC-IET, Westerduinveg 3, 1755 LE Petten (Netherlands); Renčiuková, Veronika [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Vrtílková, Věra [ÚJP a.s., Nad Kamínkou 1345, 156 10 Prague 5 (Czech Republic)

2015-12-15

Long-term in-situ corrosion tests were performed in order to evaluate the influence of lithium ions on the corrosion of zirconium alloy. Experiments were carried out in a high-pressure high-temperature loop (280 °C, 8 MPa) in a high concentration water solution of LiOH (70 and 200 ppm Li{sup +}) and in a simulated WWER primary coolant environment. The kinetic parameters characterising the oxidation process have been explored using in-situ electrochemical impedance spectroscopy and slow potentiodynamic polarization. Also, a suitable equivalent circuit was suggested, which would approximate the impedance characteristics of the corrosion of Zr–1Nb alloy. The Mott–Schottky approach was used to determine the semiconducting character of the passive film. - Highlights: • Zr1Nb alloy was tested in WWER coolant and in LiOH solutions at 280 °C. • Corrosion rates were estimated in-situ from electrochemical data. • Electrochemical data agreed well with weight gains and metallography data. • Increase of corrosion rate in LiOH appeared after short exposure (300–500 h). • Very high donor densities (1.1–1.2 × 10{sup 20} cm{sup −3}) of Zr oxide grown in LiOH were found.

Alpha and beta stabilizer character of Al in Zr-Nb-Al alloys

International Nuclear Information System (INIS)

Peruzzi Bardella, A.; Bolcich, J.C.

1987-01-01

The T β/α+β of Zr5Nb and Zr5Nb2Al (weight %) were determined in order to observe the alpha-stabilizer character of Al in ternary Zr-Nb-Al alloys. Techniques employed were change of resistivity with temperature in dynamic experiences, and metallography of samples quenched to room temperature after isothermal annealings. The T β/α+β of the ternary resulted 17 ± 8 deg C higher than that of the binary alloy. In addition, taking into account the results of previous investigations of the transformation of beta on quenching Zr-Nb-Al alloys from the beta field to room temperature, it is concluded that the beta-stabilizer character of Nb is stronger than the alpha-stabilizer character of Al in these Zr alloys, and that the Al can have important influence on the mechanical properties by the appearance of TRIP effect. (Author) [es

Excellent superplasticity and deformation mechanism of Al–Mg–Sc–Zr alloy processed via simple free forging

Energy Technology Data Exchange (ETDEWEB)

Duan, Y.L. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Xu, G.F., E-mail: csuxgf660302@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University, Changsha 410083, China. (China); Xiao, D.; Zhou, L.Q. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Deng, Y.; Yin, Z.M. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University, Changsha 410083, China. (China)

2015-01-29

A refined microstructure of Al–Mg–Sc–Zr alloy with an average grain size of ∼3.7 μm and a portion of high angle boundaries of 69.2% was produced by free forging. Excellent superplastic ductility of ≥500% was achieved at a wide temperature range of 450∼500 °C and relatively high strain rate range of 1×10{sup −3}∼5×10{sup −2} s{sup −1} in the Al–Mg–Sc–Zr alloy. A maximum elongation of 1593% was obtained at 475 °C and 1×10{sup −3} s{sup −1}. Moreover, the electron back scattered diffraction (EBSD) and the transmission electron microscopy (TEM) analyses showed that the excellent superplasticity can be attributed to the high fraction of high angle grain boundaries and the presence of Al{sub 3}(Sc,Zr) dispersoids in the Al–Mg–Sc–Zr alloy microstructure. The analyses on the superplastic data revealed the presence of threshold stress, the coefficient of strain rate sensitivity of 0.5, and an activation energy of 83.9 kJ/mol{sup –1}. It indicated that the dominant deformation mechanism was grain boundary sliding. Based on this notion, a constitutive equation for Al–Mg–Sc–Zr alloy has been developed.

Refining U-Zr-Nb alloys by remelting

Energy Technology Data Exchange (ETDEWEB)

Aguiar, B.M.; Kniess, C.T.; Riella, H.G., E-mail: bmaguiar@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ferraz, W.B. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

The high density U-Zr-Nb and U-Nb uranium-based alloys can be employed as nuclear fuel in a PWR reactor due to their high density and nuclear properties. These alloys can stabilize the gamma phase, however, according to TTT diagrams, at the working temperature of a PWR reactor, all gamma phase transforms to {alpha}'' phase in a few hours. To avoid this kind of transformation during the nuclear reactor operation, the U-Zr-Nb alloy and U-Nn are used in {alpha}'' phase. The stability of {alpha}'' phase depends on the alloy composition and cooling rate. The alloy homogenization has to be very effective to eliminate precipitates rich in Zr and Nb to avoid changes in the alloying elements contents in the matrix. The homogenization was obtained by remelting the alloy and keeping it in the liquid state for enough time to promote floating of the precipitates (usually carbides, less dense) and leaving the matrix free of precipitates. However, this floating by density difference may result in segregation between the alloying elements (Nb and Zr, at the top) and uranium (at the bottom). The homogenized alloys were characterized in terms of metallographic techniques, optical microscopy, scanning electronic microscopy, EDS and X-ray diffraction. In this paper, it is shown that the contents of Zr and Nb at the bottom and at the top of the matrix are constant. (author)

Metastable phases in Zr-Excel alloy and their stability under heavy ion (Kr{sup 2+}) irradiation

Energy Technology Data Exchange (ETDEWEB)

Yu, Hongbing, E-mail: 12hy1@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Zhang, Ken; Yao, Zhongwen [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Kirk, Mark A. [Material Science Division Argonne National Laboratory, Argonne, IL, 60439 (United States); Long, Fei; Daymond, Mark R. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada)

2016-02-15

Zr-Excel alloy (Zr-3.5Sn-0.8Nb-0.8Mo, wt.%) has been proposed as a candidate material of pressure tubes in the CANDU-SCWR design. It is a dual-phase alloy containing primary hcp α-Zr and metastable bcc β-Zr. Metastable hexagonal ω-Zr phase could form in β-Zr as a result of aging during the processing of the tube. A synchrotron X-ray study was employed to study the lattice properties of the metastable phases in as-received Zr-Excel pressure tube material. In situ heavy ion (1 MeV Kr{sup 2+}) irradiations were carried out at 200 °C and 450 °C to emulate the stability of the metastable phase under a reactor environment. Quantitative Chemi-STEM EDS analysis was conducted on both un-irradiated and irradiated samples to investigate alloying element redistribution induced by heavy ion irradiation. It was found that no decomposition of β-Zr was observed under irradiation at both 200 °C and 450 °C. However, ω-Zr particles experienced shape changes and shrinkage associated with enrichment of Fe at the β/ω interface during 200 °C irradiation but not at 450 °C. There is a noticeable increase in the level of Fe in the α matrix after irradiation at both 200 °C and 450 °C. The concentrations of Nb, Mo and Fe are increased in the ω phase but decreased in the β phase at 200 °C. The stability of metastable phases under heavy ion irradiation associated with elemental redistribution is discussed.

Safety of some fuel cladding materials, alternative to Zr-alloys

International Nuclear Information System (INIS)

Hache, Georges; Clement, Bernard; Barrachin, Marc

2013-01-01

published by Westinghouse and Fauske with MAAP code, assuming zero kinetics and no physicochemical interactions. SiC is probably tolerant to DBAs and short duration severe accidents (TMI-2 like) but more intolerant than Zr-alloys to long-duration severe accidents (Fukushima Daiichi unit 1 like). Stainless steels (SS) - During SS oxidation by steam, nearly the same number of H 2 moles are produced per cladding length unit at thermochemical equilibrium than for Zr-alloys. - SS oxidation kinetics below 1600 deg. C: According to early tests performed by GE, 304L oxidises faster than Zr-alloys above 1150 deg. C. Recent ORNL tests show that Fe-25 Cr or PM2000 (19% Cr, 5% Al) are similar to SiC at 1200 deg. C. - SS oxidation kinetics above 1600 deg. C (melting point of FeOx): In molten FeOx, oxygen diffusion is very fast; this is known in the literature as 'catastrophic oxidation by molten oxides'. There will be a cliff-edge effect. For un-inerted containments, H 2 recombiners will be saturated, leading to a risk of H 2 explosion in these containments: - The main advantage of SS is the lower heat of reaction produced per cladding length unit at thermochemical equilibrium compared to Zr-alloys. - Molten FeOx will interact with UO 2 to form molten mixtures at temperatures well below UO 2 melting temperature. - Calculations with system codes (ASTEC, MELCOR, MAAP) are necessary and were published by Westinghouse and Fauske with MAAP code, assuming no catastrophic oxidation above 1600 deg. C and no physicochemical interactions. 304L is intolerant to long-duration severe accidents (extended station blackout)

Effects of minor Zr and Sr on as-cast microstructure and mechanical properties of Mg-3Ce-1.2Mn-0.9Sc (wt.%) magnesium alloy

International Nuclear Information System (INIS)

Pan Fusheng; Yang Mingbo; Shen Jia; Wu Lu

2011-01-01

Research highlights: → Minor Zr and/or Sr additions can effectively refine the grains of the Mg-3Ce-1.2Mn-0.9Sc alloy. → Minor Zr and/or Sr additions can improve the tensile properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. → Minor Zr and/or Sr additions can improve the creep properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. - Abstract: The effects of minor Zr and Sr on the as-cast microstructure and mechanical properties of the Mg-3Ce-1.2Mn-0.9Sc (wt.%) alloy were investigated by using optical and electron microscopies, differential scanning calorimetry (DSC) analysis, and tensile and creep tests. The results indicate that adding minor Zr and/or Sr to the Mg-3Ce-1.2Mn-0.9Sc alloy does not cause an obvious change in the morphology and distribution of the Mg 12 Ce phase. However, the grains of the Zr and/or Sr-containing alloys are effectively refined. Among the Zr and/or Sr-containing alloys, the grains of the alloy with the addition of 0.5 wt.%Zr + 0.1 wt.%Sr are the finest, followed by the alloys with the additions of 0.5 wt.%Zr and 0.1 wt.%Sr, respectively. In addition, small additions of Zr and/or Sr can improve the tensile and creep properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. Among the Zr and/or Sr-containing alloys, the alloy with the addition of 0.5 wt.%Zr + 0.1 wt.%Sr obtains the optimum tensile and creep properties.

The structure and mechanical properties of as-cast Zr-Ti alloys

International Nuclear Information System (INIS)

Hsu, H.-C.; Wu, S.-C.; Sung, Y.-C.; Ho, W.-F.

2009-01-01

This study has investigated the structure and mechanical properties of pure Zr and a series of binary Zr-Ti alloys in order to determine their potential application as dental implant materials. The titanium contents of these alloys range from 10 to 40 wt.% and were prepared by arc melting in inert gas. This study evaluated the phase and structure of these Zr-Ti alloys using an X-ray diffraction (XRD) for phase analysis, and an optical microscope for microstructure analysis of the etched alloys. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The experimental results indicated that the pure Zr and Zr-10Ti comprised entirely of an acicular hexagonal structure of α' phase. When the Ti content increased to 20 wt.%, a significant amount of β phase was retained. However, when the Ti content increased to 40 wt.%, only the equi-axed, retained β phase was observed in the cast alloy. Moreover, the hardness values and bending strengths of the Zr-Ti alloys decreased with an increasing Ti content. Among pure Zr and Zr-Ti alloys, the α'-phase Zr-10Ti alloy has the greatest hardness and bending strength. The pure Zr and Zr-Ti alloys exhibit a similar elastic modulus ranging from 68 GPa (Zr-30Ti) to 78 GPa (Zr-40Ti). Based on the results of elastic moduli, pure Zr and Zr-Ti alloys are found to be suitable for implant materials due to lower modulus. Like bending strength, the elastically recoverable angle of Zr-Ti alloys decreased as the concentration of Ti increased. In the current search for a better implant material, the Zr-10Ti alloy exhibited the highest bending strength/modulus ratios as large as 25.3, which are higher than that of pure Zr (14.9) by 70%, and commercially pure Ti (8.7) by 191%. Thus, Zr-Ti alloy's low modulus, ductile property, excellent elastic recovery capability and impressive strength confirm that it is a promising candidate for dental implant materials.

Formation and stability of Fe-rich precipitates in dilute Zr(Fe) single-crystal alloys

International Nuclear Information System (INIS)

Zou, H.; Hood, G.M.; Roy, J.A.; Schultz, R.J.

1993-02-01

The formation and stability of Fe-rich precipitates in two α-Zr(Fe) single-crystal alloys with nominal compositions (I, 50 ppma Fe, and II, 650 ppma Fe) have been investigated (the maximum solid solubility of Fe in α-Zr is 180 ppma - 800 C). Optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been used to examine the characteristics of Fe-rich precipitates. SEM and TEM micrographs show that in as-grown alloy II, Zr 2 Fe precipitates are located at 'stringers'. Precipitates were not observed in as-grown alloy I. During annealing, below the solvus, Fe diffuses to the surfaces to form Zr 3 Fe precipitates in both alloys. The precipitates on the surfaces of alloy I tend to be star-like (0001) or pyramidal (1010), and their distribution is heterogeneous. Dissolution of Zr 3 Fe surface precipitates of alloy I (annealing above the solvus) leaves precipitate-like features on the surfaces. Zr 2 Fe precipitates in as-grown alloy II can be dissolved only by β-phase annealing. (Author) 8 figs., 18 refs

Study of irradiation induced defects and phase instability in β phase of Zr Excel alloy with in-situ heavy ion irradiation

International Nuclear Information System (INIS)

Yu, H.; Yao, Z.; Kirk, M.A.; Daymond, M.R.

2015-01-01

In situ heavy ion irradiation with 1 MeV Kr"2"+ was carried out to study irradiation induced phase change and atomic lattice defects in theβ phase of Zr Excel alloy. No decomposition of β-Zr was observed under irradiation at either 200 "oC or 450 "oC. However, ω-Zr particles experienced shape change and shrinkage associated enrichment of Fe in the β/ω interface at 200 "oC irradiation but not at 450 "oC. The defect evolution in the β-phase was examined with single phase Zr-20Nb alloy. It was found that dislocation loops with Burgers vector 1/2 and both present in β-Zr under room temperature irradiation. (author)

Advanced Corrosion-Resistant Zr Alloys for High Burnup and Generation IV Application

International Nuclear Information System (INIS)

Jeong, Y. H.; Park, S. Y.; Lee, M. H.; Choi, B. K.; Baek, J. H.; Park, J. Y.; Kim, J. H.; Kim, H. G.; Jung, Y. H.; Bang, B. G.

2006-08-01

The systematic study was performed to develop the advanced corrosion-resistant Zr alloys for high burnup and Gen IV application. The corrosion behavior was significantly changed with the alloy composition and the corrosion environment. In general, the model alloys with a higher alloying elements showed a higher corrosion resistance. Among the model alloys tested in this study, Zr-10Cr-0.2Fe showed the best corrosion resistance regardless of the corrosion condition. The oxide on the higher corrosion-resistant alloy such as Zr-1.0Cr-0.2Fe consisted of mainly columnar grains, and it have a higher tetragonal phase stability. In comparison with other alloys being considered for the SCWR, the Zr alloys showed a lower corrosion rate than ferritic-martensitic steels. The results of this study imply that, at least from a corrosion standpoint, Zr alloys deserve consideration as potential cladding or structural materials in supercritical water cooled reactors

Research on aging precipitation in a Cu-Cr-Zr-Mg alloy

International Nuclear Information System (INIS)

Su Juanhua; Dong Qiming; Liu Ping; Li Hejun; Kang Buxi

2005-01-01

The effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy were investigated. Aging precipitation phase was dealt with by transmission electronic microscope (TEM). After solid solution was treated at 920 deg. C and aged at 470 deg. C for 4 h, the fine precipitation of an ordered compound CrCu 2 (Zr, Mg) is found in copper matrix as well as fine Cr and Cu 4 Zr. Along the grain boundary, there are larger chromium. The hardness and electrical conductivity can reach 109 HV and 80% IACS, respectively. Sixty percent cold-rolled deformation prior to aging at 470 deg. C enhances the hardness of the alloy. The coherent precipitates Cr in copper matrix and the dislocations pinned by the fine precipitates are responsible for maximum strengthening of the alloy. So the hardness 165 HV and electrical conductivity 79.2% IACS are available

Study and simulations of quick diffusion in Zr-based alloys

Energy Technology Data Exchange (ETDEWEB)

Corvalán, C., E-mail: corvalan@cnea.gov.ar [UNTREF (Universidad Nacional de Tres de Febrero), General Enrique Mosconi 2736, B1674AHF, Buenos Aires (Argentina); Gerencia de Materiales, CAC, Comisión de Energía Atómica, Av. del Libertador 8250, C1429BNP Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Lucía, A. [UNTREF (Universidad Nacional de Tres de Febrero), General Enrique Mosconi 2736, B1674AHF, Buenos Aires (Argentina); Instituto Sabato, Comisión Nacional de Energía Atómica, Universidad Nacional de San Martín, Buenos Aires (Argentina); Iribarren, M. [Gerencia de Materiales, CAC, Comisión de Energía Atómica, Av. del Libertador 8250, C1429BNP Buenos Aires (Argentina); Instituto Sabato, Comisión Nacional de Energía Atómica, Universidad Nacional de San Martín, Buenos Aires (Argentina); Servant, C. [Laboratoire de Physicochimie de l' Etat Solide, UMR 8182, ICMMO, Université de Paris-Sud XI, 91405 Orsay Cedex (France); Costa e Silva, A. [Universidade Federal Fluminense, Volta Redonda, RJ (Brazil)

2015-11-15

Zirconium and its alloys are widely used in the nuclear industry. Under normal conditions, Zr-alloys are polycrystalline and contain a high density of grain and interphase boundaries. These boundaries function as paths for accelerated matter movement. The movement of fast diffusing elements (Co, Fe, Cr, Ni) in Zr alloys along boundaries produces technologically important changes in the materials in nuclear reactors at normal temperatures (∼550 K) e.g.: segregation, phase precipitation, hydrogen absorption, etc. In this work, diffusion parameters for fast diffusion in Zr at low temperature were assessed for Co and Cr. An improved database for DICTRA (DIffusion-Controlled-TRAnsformation) software for fast diffusion was obtained. The diffusion parameters in grain boundaries of α-Zr for Cr and Co were used from a particular kinetic diffusion model [1]. Simulated profiles were compared with previous experimental work [2]. The results of the comparison and the adequacy of the improved database are discussed. Diffusion profiles on grain boundaries in α-Zr for Cr and Co are presented in the temperature range of 380–460 K. - Highlights: • An improved database for fast diffusion paths was obtained. • The diffusion parameters in type C kinetic on fast paths in α-Zr for Cr and Co were used. • Simulated diffusion profiles were compared with previous experimental results. This comparison and the adequacy of the improved database are discussed. • Diffusion parameters for fast diffusion paths in Zr at low temperature were assessed for Co and Cr. • Diffusion profiles on grain boundaries in α-Zr for Cr and Co are presented in the temperature range of 380–460 K.

Study and simulations of quick diffusion in Zr-based alloys

International Nuclear Information System (INIS)

Corvalán, C.; Lucía, A.; Iribarren, M.; Servant, C.; Costa e Silva, A.

2015-01-01

Zirconium and its alloys are widely used in the nuclear industry. Under normal conditions, Zr-alloys are polycrystalline and contain a high density of grain and interphase boundaries. These boundaries function as paths for accelerated matter movement. The movement of fast diffusing elements (Co, Fe, Cr, Ni) in Zr alloys along boundaries produces technologically important changes in the materials in nuclear reactors at normal temperatures (∼550 K) e.g.: segregation, phase precipitation, hydrogen absorption, etc. In this work, diffusion parameters for fast diffusion in Zr at low temperature were assessed for Co and Cr. An improved database for DICTRA (DIffusion-Controlled-TRAnsformation) software for fast diffusion was obtained. The diffusion parameters in grain boundaries of α-Zr for Cr and Co were used from a particular kinetic diffusion model [1]. Simulated profiles were compared with previous experimental work [2]. The results of the comparison and the adequacy of the improved database are discussed. Diffusion profiles on grain boundaries in α-Zr for Cr and Co are presented in the temperature range of 380–460 K. - Highlights: • An improved database for fast diffusion paths was obtained. • The diffusion parameters in type C kinetic on fast paths in α-Zr for Cr and Co were used. • Simulated diffusion profiles were compared with previous experimental results. This comparison and the adequacy of the improved database are discussed. • Diffusion parameters for fast diffusion paths in Zr at low temperature were assessed for Co and Cr. • Diffusion profiles on grain boundaries in α-Zr for Cr and Co are presented in the temperature range of 380–460 K.

Microstructure and mechanical properties of as-cast Zr-Nb alloys.

Science.gov (United States)

Kondo, Ryota; Nomura, Naoyuki; Suyalatu; Tsutsumi, Yusuke; Doi, Hisashi; Hanawa, Takao

2011-12-01

On the basis of the microstructures and mechanical properties of as-cast Zr-(0-24)Nb alloys the effects of phase constitution on the mechanical properties and magnetic susceptibility are discussed in order to develop Zr alloys for use in magnetic resonance imaging (MRI). The microstructures were evaluated using an X-ray diffractometer, an optical microscope, and a transmission electron microscope; the mechanical properties were evaluated by a tensile test. The α' phase was dominantly formed with less than 6 mass% Nb content. The ω phase was formed in Zr-(6-20)Nb alloys, but disappeared from Zr-22Nb. The β phase dominantly existed in Zr-(9-24)Nb alloys. The mechanical properties as well as the magnetic susceptibility of the Zr-Nb alloys varied depending on the phase constitution. The Zr-Nb alloys consisting of mainly α' phase showed high strength, moderate ductility, and a high Young's modulus, retaining low magnetic susceptibility. Zr-Nb alloys containing a larger volume of ω phase were found to be brittle and, thus, should be avoided, despite their low magnetic susceptibility. When the Zr-Nb alloys consisted primarily of β phase the effect of ω phase weakened the mechanical properties, thereby leading to an increase in ductility, even with an increase in magnetic susceptibility. The minimum value of Young's modulus was obtained for Zr-20Nb, because this composition was the phase boundary between the β and ω phases. However, the magnetic susceptibility of the alloy was half that of Ti-6Al-4V alloys. Zr-Nb alloys consisting of α' or β phase have excellent mechanical properties with low magnetic susceptibility and, thus, these alloys could be useful for medical devices used in MRI. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Shape memory characteristics of Ti-22Nb-(2-8)Zr(at.%) biomedical alloys

International Nuclear Information System (INIS)

Kim, J.I.; Kim, H.Y.; Inamura, T.; Hosoda, H.; Miyazaki, S.

2005-01-01

Shape memory characteristics of Ti-22Nb-(2-8)Zr(at.%) biomedical alloys were investigated by using tensile tests and X-ray diffraction (XRD) measurement. The alloy ingots were fabricated by an arc melting method. The ingots were cold-rolled by a reduction up to 95% in thickness at room temperature. All the alloys were solution-treated at 1173 K for 1.8 ks. The alloys subjected to the solution treatment exhibited large elongations ranging between 28 and 40%. The martensitic transformation temperature decreased by 38 K with 1 at.% increase of Zr content. The maximum recovered strain of 4.3% was obtained in the Ti-22Nb-4Zr(at.%) alloy. Ti-22Nb-(2-4)Zr(at.%) and Ti-22Nb-6Zr(at.%) alloys exhibited stable shape memory effect and superelastic behavior at room temperature, respectively

Effect of thermo-mechanical processing on microstructure and mechanical properties of U - Nb - Zr alloys: Part 2 - U - 3 wt % Nb - 9 wt % Zr and U - 9 wt% Nb - 3 wt% Zr

Science.gov (United States)

Morais, Nathanael Wagner Sales; Lopes, Denise Adorno; Schön, Cláudio Geraldo

2018-04-01

The present work is the second and final part of an extended investigation on Usbnd Nb - Zr alloys. It investigates the effect of mechanical processing routes on microstructure of alloys U - 3 wt % Nb - 9 wt % Zr and U - 9 wt% Nb - 3 wt% Zr, through X-ray diffraction and scanning electron microscopy, completing the investigation, which started with alloy U - 6 wt% Nb - 6 wt% Zr in part 1. Mechanical properties are determined using microhardness and bending tests and correlated with the developed microstructures. The results show that processing sequence, in particular the inclusion of a 1000 °C heat treatment step, affects significantly the microstructure and mechanical properties of these alloys alloy in different ways. Microstructural characterization shows that both alloys present significant volume fraction of precipitates of a body-centered cubic (BCC) γ-Nb-Zr rich phase in addition the uranium-rich matrix. Bending tests show that sample ductility does not correlate necessarily with hardness and that the key factor appears to be the amount of the γ-Nb-Zr precipitates, which controls the matrix microstructure. Samples with a monoclinic α″ cellular microstructure and/or with the tetragonally-distorted BCC phase (γ0), although not strictly ductile, showed the largest allowed strains-before-break and complete elastic recovery of the broken pieces, pointing out to the macroscopic observation of superelasticity.

Study of irradiation induced defects and phase instability in β phase of Zr Excel alloy with in-situ heavy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Yu, H.; Yao, Z., E-mail: 12hy1@queensu.ca [Queen' s University, Department of Mechanical and Materials Engineering, Kingston, ON (Canada); Kirk, M.A. [Argonne National Laboratory, Materials Science Division, Argonne, IL (United States); Daymond, M.R. [Queen' s University, Department of Mechanical and Materials Engineering, Kingston, ON (Canada)

2015-07-01

In situ heavy ion irradiation with 1 MeV Kr{sup 2+} was carried out to study irradiation induced phase change and atomic lattice defects in theβ phase of Zr Excel alloy. No decomposition of β-Zr was observed under irradiation at either 200 {sup o}C or 450 {sup o}C. However, ω-Zr particles experienced shape change and shrinkage associated enrichment of Fe in the β/ω interface at 200 {sup o}C irradiation but not at 450 {sup o}C. The defect evolution in the β-phase was examined with single phase Zr-20Nb alloy. It was found that dislocation loops with Burgers vector 1/2<111> and <001> both present in β-Zr under room temperature irradiation. (author)

Are new TiNbZr alloys potential substitutes of the Ti6Al4V alloy for dental applications? An electrochemical corrosion study.

Science.gov (United States)

Ribeiro, Ana Lúcia Roselino; Hammer, Peter; Vaz, Luís Geraldo; Rocha, Luís Augusto

2013-12-01

The main aim of this work was to assess the electrochemical behavior of new Ti35Nb5Zr and Ti35Nb10Zr alloys in artificial saliva at 37 °C to verify if they are indicated to be used as biomaterials in dentistry as alternatives to Ti6Al4V alloys in terms of corrosion protection efficiency of the material. Electrochemical impedance spectroscopy (EIS) experiments were carried out for different periods of time (0.5-216 h) in a three-electrode cell, where the working electrode (Ti alloys) was exposed to artificial saliva at 37 °C. The near-surface region of the alloys was investigated using x-ray photoelectron spectroscopy (XPS). All alloys exhibited an increase in corrosion potential with the immersion time, indicating the growth and stabilization of the passive film. Ti35Nb5Zr and Ti6Al4V alloys had their EIS results interpreted by a double-layer circuit, while the Ti35Nb10Zr alloy was modeled by a one-layer circuit. In general, the new TiNbZr alloys showed similar behavior to that observed for the Ti6Al4V. XPS results suggest, in the case of the TiNbZr alloys, the presence of a thicker passive layer containing a lower fraction of TiO2 phase than that of Ti6Al4V. After long-term immersion, all alloys develop a calcium phosphate phase on the surface. The new TiNbZr alloys appear as potential candidates to be used as a substitute to Ti6Al4V in the manufacturing of dental implant-abutment sets.

Local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys investigated by EXAFS method

International Nuclear Information System (INIS)

Antonowicz, J.; Pietnoczka, A.; Zalewski, W.; Bacewicz, R.; Stoica, M.; Georgarakis, K.; Yavari, A.R.

2011-01-01

Research highlights: → Coordination number, interatomic distances and mean square atomic displacement in Zr-Cu and Zr-Cu-Al glasses. → Icosahedral symmetry in local atomic structure. → Deviation from random mixing behavior resulting from Al addition. - Abstract: We report on extended X-ray absorption fine structure (EXAFS) study of rapidly quenched Zr-Cu and Zr-Cu-Al glassy alloys. The local atomic order around Zr and Cu atoms was investigated. From the EXAFS data fitting the values of coordination number, interatomic distances and mean square atomic displacement were obtained for wide range of compositions. It was found that icosahedral symmetry rather than that of corresponding crystalline analogs dominates in the local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys. Judging from bonding preferences we conclude that addition of Al as an alloying element results in considerable deviation from random mixing behavior observed in binary Zr-Cu alloys.

Characters of alloy Zr-0.4%Mo-0.5%Fe-0.5%Cr post heat treatment and cold rolling

International Nuclear Information System (INIS)

Sungkono; Siti Aidah

2014-01-01

Research and development of Zr-Mo-Fe-Cr alloys aimed to obtain PWR fuel element structure material with high burn up. In this study of the Zr-0.4%Mo-0.5%Fe-0.5%Cr alloys was prepared from zirconium sponge, molybdenum, iron and chromium powder. The alloy were heat treated at varying temperatures of 650 and 750 °C and retention time of 1, 1.5 and 2 hours. The objectives of this research was to obtain effect of thickness reduction on the character of Zr-0.4%Mo-0.5%Fe-0.5%Cr alloy. The results of this experiment showed that the microstructures of Zr-0.4%Mo-0.5%Fe-0.5%Cr alloy after heat treatment and cold rolling exhibits that the higher of the thickness reduction has applied on the alloy caused the microstructure to evolve from deformed equiaxial grains into flat bar grains and then into deformed flat bar grains. However, the higher of the temperature and the retention time then the larger grain structures so that the cold rolling causes the shape of the grains structure into a flat bar with a relatively larger size which affects the lower hardness. The Zr-0.4%Mo-0.5%Fe-0.5%Cr alloy after heat treatment (650-750°C; 1.5-2 hours) can undergo cold deformation without cracking at a thickness reduction between 5 to 15%. (author)

Evolution of tetragonal phase of ZrO2 in the corrosion of Zry-4 and Zr-2.5Nb at high pressure and temperature

International Nuclear Information System (INIS)

Bordoni, Roberto A.; Olmedo, Ana M.; Villegas, Marina; Maroto, Alberto J. G.; Lin, J.; Szpunar, J. A.

1999-01-01

The corrosion kinetics of Zr-2.5 Nb and Zircaloy-4 was studied at 350 C degrees in lithiated heavy water. The oxides grown on both alloys during the exposures were found to be strongly textured. The pole figures showed that the major orientation components of the oxide formed on Zr-2.5 Nb were (10-3) [0-10] and (10-3)[301] while (10-3) fiber was formed on Zircaloy-4. No significant change in texture was found in either alloy when increasing the thickness of the oxide film. The phases present in the film were determined and their evolution with the exposure time was followed. The results indicated that the tetragonal volume fraction decreased with increasing the thickness of the oxide layers of both materials. The tetragonal volume fraction of Zircaloy-4 was higher than that of Zr-2.5 Nb for the same oxide thickness. (author)

Corrosion Behavior and Oxide Properties of Zr-Nb-Cu and Zr-Nb-Sn Alloy in High Dissolved Hydrogen Primary Water Chemistry

Energy Technology Data Exchange (ETDEWEB)

Lee, Yun Ju; Kim, Tae Ho; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

2016-05-15

The water-metal interface is regarded as rate-controlling site governing the rapid oxidation transition in high burn-up fuel. And the zirconium oxide is made in water-metal interface and its structure and phase do an important role in terms of oxide properties. During oxidation process, the protective tetragonal oxide layer develops at the interface due to accumulated high stress during oxide growth, and it turns into non-protective monoclinic oxide with increasing oxide thickness, thus decreasing the stress. It has been reported that Nb addition was proven to be very beneficial for increasing the corrosion resistance of the zirconium alloys. From a more recent study, Cu addition in Nb containing Zirconium alloy was reported to be effective for increasing corrosion resistance in water containing B and Li. According to the previous research conducted, Zr-Nb-Cu shows better corrosion resistance than Zircaloy-4. The dissolved hydrogen (DH) concentration is the key issue of primary water chemistry, and the effect of DH concentration on the corrosion rate of nickel based alloy has been researched. However, the effect of DH on the zirconium alloy corrosion mechanism was not fully investigated. In this study, the weight gain measurement, FIB-SEM analysis, and Raman spectroscopic measurement were conducted to investigate the effects of dissolved hydrogen concentration and the chemical composition on the corrosion resistance and oxide phase of Zr-Nb-Cu alloy and Zr-Nb-Sn alloy after oxidizing in a primary water environment for 20 d. The corrosion rate of Zr-Nb-Cu alloy is slow, when it is compared to Zr-Nb-Sn alloy. In SEM images, the oxide thickness of Zr-Nb-Cu alloy is measured to be around 1.06 μm it of Zr-Nb-Sn alloy is measured to be 1.15 μm. It is because of the Segregation made by Sn solute element when Sn solute element oxidized. And according to ex situ Raman spectra, Zr-Nb-Cu alloy oxide has more tetragonal zirconium oxide fraction than Zr-Nb-Sn alloy oxide.

Precipitation hardening in dilute Al–Zr alloys

Directory of Open Access Journals (Sweden)

Pedro Henrique Lamarão Souza

2018-01-01

Full Text Available The aim of this study was to investigate the effect of solute content (hipoperitectic Al–0.22 wt.%Zr and hiperperitectic Al–0.32 wt.%Zr on the precipitation hardening and microstructural evolution of dilute Al–Zr alloys isothermally aged. The materials were conventionally cast in a muffle furnace, solidified in a water-cooled Cu mold and subsequently heat-treated at the temperature of 650 K (377 °C for 4, 12, 24, 100 and 400 h. Mechanical characterization was performed at room temperature, using a microhardness tester and microstructural characterization was carried out on a Transmission Electron Microscope – TEM. The observed microhardness values increased during isothermal aging, due to the precipitation of nanometer-scale Al3Zr L12 particles. Peak strength was achieved within 100 h of aging. After aging for 400 h, microhardness values presented a slight decrease for both alloys, thus indicating overaging due to the coalescence of precipitates. Microhardness values increased with solute content, due to the precipitation of a higher number density of finer precipitates. After 400 h of heat-treating, coalescence was higher for the alloy with lower solute content and, also, the presence of antiphase boundaries – APBs, planar faults associated with the L12 to D023 structural transition, were observed. Comparing theoretical calculations of the increment in strength due to precipitation strengthening with experimental results, it was observed that their values are in reasonable agreement. The Orowan dislocation looping mechanism takes place during precipitation hardening for both alloys in the peak hardness condition.

Atomic bonding and mechanical properties of Al-Mg-Zr-Sc alloy

Institute of Scientific and Technical Information of China (English)

高英俊; 班冬梅; 韩永剑; 钟夏平; 刘慧

2004-01-01

The valence electron structures of Al-Mg alloy with minor Sc and Zr were calculated according to the empirical electron theory(EET) in solid. The results show that because of the strong interaction of Al atom with Zr and Sc atom in melting during solidification, the Al3 Sc and Al3 (Sc1-xZrx) particles which act as heterogeneous nuclear are firstly crystallized in alloy to make grains refine. In progress of solidification, the Al-Sc, Al-Zr-Sc segregation regions are formed in solid solution matrix of Al-Mg alloy owing to the strong interaction of Al atom with Zr, Scatoms in bulk of alloy, so in the following homogenization treatment, the finer dispersed Al3 Sc and Al3 (Sc1-x Zrx) second-particles which are coherence with the matrix are precipitated in the segregation region. These finer second particles with the strong Al-Zr, Al-Sc covalent bonds can strengthen the covalent bonds in matrix of the alloy, and also enhance the hardness and strength of Al-Mg alloy. Those finer second-particles precipitated in interface of sub-grains can also strengthen the covalence bonds there, and effectively hinder the interface of sub-grains from migrating and restrain the sub-grains from growing, and cause better thermal stability of Al-Mg alloy.

Improving High-Temperature Tensile and Low-Cycle Fatigue Behavior of Al-Si-Cu-Mg Alloys Through Micro-additions of Ti, V, and Zr

Science.gov (United States)

Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

2015-07-01

High-temperature tensile and low-cycle fatigue tests were performed to assess the influence of micro-additions of Ti, V, and Zr on the improvement of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in the as-cast condition. Addition of transition metals led to modification of microstructure where in addition to conventional phases present in the Al-7Si-1Cu-0.5Mg base, new thermally stable micro-sized Zr-Ti-V-rich phases Al21.4Si4.1Ti3.5VZr3.9, Al6.7Si1.2TiZr1.8, Al2.8Si3.8V1.6Zr, and Al5.1Si35.4Ti1.6Zr5.7Fe were formed. The tensile tests showed that with increasing test temperature from 298 K to 673 K (25 °C to 400 °C), the yield stress and tensile strength of the present studied alloy decreased from 161 to 84 MPa and from 261 to 102 MPa, respectively. Also, the studied alloy exhibited 18, 12, and 5 pct higher tensile strength than the alloy A356, 354 and existing Al-Si-Cu-Mg alloy modified with additions of Zr, Ti, and Ni, respectively. The fatigue life of the studied alloy was substantially longer than those of the reference alloys A356 and the same Al-7Si-1Cu-0.5Mg base with minor additions of V, Zr, and Ti in the T6 condition. Fractographic analysis after tensile tests revealed that at the lower temperature up to 473 K (200 °C), the cleavage-type brittle fracture for the precipitates and ductile fracture for the matrix were dominant while at higher temperature fully ductile-type fracture with debonding and pull-out of cracked particles was identified. It is believed that the intermetallic precipitates containing Zr, Ti, and V improve the alloy performance at increased temperatures.

Corrosion rate transients observed by linear polarization techniques at Zr-1%Nb alloy

International Nuclear Information System (INIS)

Beran, J.; Cerny, K.

1997-01-01

Momentary corrosion rate of Zr-1%Nb alloy during nonisothermal autoclave experiments at temperature up to 328 deg. C in various solutions was determined by T/R p values (T - absolute temperature, R p - polarization resistance), multiplied by temperature independent conversion factor. This factor was found by comparison of conventional corrosion loss evaluation with electrochemical measurements. Corrosion rate transients in boric acid solutions and in lithium hydroxide differed significantly. Great differences were also found in stabilized corrosion rates at the end of experiments. Temperature irregularities caused considerable changes in corrosion rate. (author). 5 refs, 5 figs, 1 tab

Corrosion rate transients observed by linear polarization techniques at Zr-1%Nb alloy

Energy Technology Data Exchange (ETDEWEB)

Beran, J; Cerny, K [ZJS SKODA plc., Pelzen (Czech Republic)

1997-02-01

Momentary corrosion rate of Zr-1%Nb alloy during nonisothermal autoclave experiments at temperature up to 328 deg. C in various solutions was determined by T/R{sub p} values (T - absolute temperature, R{sub p}- polarization resistance), multiplied by temperature independent conversion factor. This factor was found by comparison of conventional corrosion loss evaluation with electrochemical measurements. Corrosion rate transients in boric acid solutions and in lithium hydroxide differed significantly. Great differences were also found in stabilized corrosion rates at the end of experiments. Temperature irregularities caused considerable changes in corrosion rate. (author). 5 refs, 5 figs, 1 tab.

Electric resistivity and thermoelectricity of Ni-Nb-Zr and Ni-Nb-Zr-H glassy alloys

Science.gov (United States)

Fukuhara, Mikio; Inoue, Akihisa

2010-09-01

Electric resistivity ρ and thermoelectric power S of Ni 36Nb 24Zr 40 and (Ni 0.36Nb 0.24Zr 0.4) 90H 10 glassy alloys were investigated in temperature region between 1.5 and 300 K. After resistivity curves of both alloys increase gradually with decreasing temperature down to around 6 K, they dropped suddenly and then reached zero resistivity at 2.1 K, leading to superconductivity. Linear curve with negative TCR of ρ vs T2 and slight increase of S/ T in temperature region down to around 6 K clearly reveal Fermi-liquid phenomenon in electronic state for both alloys independent of hydrogen content.

Electric resistivity and thermoelectricity of Ni-Nb-Zr and Ni-Nb-Zr-H glassy alloys

International Nuclear Information System (INIS)

Fukuhara, Mikio; Inoue, Akihisa

2010-01-01

Electric resistivity ρ and thermoelectric power S of Ni 36 Nb 24 Zr 40 and (Ni 0.36 Nb 0.24 Zr 0.4 ) 90 H 10 glassy alloys were investigated in temperature region between 1.5 and 300 K. After resistivity curves of both alloys increase gradually with decreasing temperature down to around 6 K, they dropped suddenly and then reached zero resistivity at 2.1 K, leading to superconductivity. Linear curve with negative TCR of ρ vs T 2 and slight increase of S/T in temperature region down to around 6 K clearly reveal Fermi-liquid phenomenon in electronic state for both alloys independent of hydrogen content.

Are new TiNbZr alloys potential substitutes of the Ti6Al4V alloy for dental applications? An electrochemical corrosion study

International Nuclear Information System (INIS)

Ribeiro, Ana Lúcia Roselino; Hammer, Peter; Vaz, Luís Geraldo; Rocha, Luís Augusto

2013-01-01

The main aim of this work was to assess the electrochemical behavior of new Ti35Nb5Zr and Ti35Nb10Zr alloys in artificial saliva at 37 °C to verify if they are indicated to be used as biomaterials in dentistry as alternatives to Ti6Al4V alloys in terms of corrosion protection efficiency of the material. Electrochemical impedance spectroscopy (EIS) experiments were carried out for different periods of time (0.5–216 h) in a three-electrode cell, where the working electrode (Ti alloys) was exposed to artificial saliva at 37 °C. The near-surface region of the alloys was investigated using x-ray photoelectron spectroscopy (XPS). All alloys exhibited an increase in corrosion potential with the immersion time, indicating the growth and stabilization of the passive film. Ti35Nb5Zr and Ti6Al4V alloys had their EIS results interpreted by a double-layer circuit, while the Ti35Nb10Zr alloy was modeled by a one-layer circuit. In general, the new TiNbZr alloys showed similar behavior to that observed for the Ti6Al4V. XPS results suggest, in the case of the TiNbZr alloys, the presence of a thicker passive layer containing a lower fraction of TiO 2  phase than that of Ti6Al4V. After long-term immersion, all alloys develop a calcium phosphate phase on the surface. The new TiNbZr alloys appear as potential candidates to be used as a substitute to Ti6Al4V in the manufacturing of dental implant-abutment sets. (paper)

The effect of tungsten on mechanical properties of the Ti-9% Al-3% Zr alloy

International Nuclear Information System (INIS)

Nartova, T.T.; Grigor'ev, I.P.; Stepanov, Yu.N.; Tarasova, O.B.

1979-01-01

The effect of tungsten (from 0 to 10 %) on mechanical properties of the ternary Ti-9 %, Al-3 % Zr alloy, has been studied. The microstructure, tensile properties at 20 and 600 deg C and Vickers hardness in as-forged and as-annealed states have been studied. The experiments have shown that the ultimate strength increases with tungsten content. Titanium alloys with 9 % Al and 3 % Zr in the case of varying tungsten content at 20 deg C fracture by brittle mechanism. The dUctility of the annealed alloy does not rise at 20 deg C, but at the test temperature of 600 deg C the alloy becomes ductile

Devitrification behavior and glass-forming ability of Cu-Zr-Ag alloys

International Nuclear Information System (INIS)

Louzguine-Luzgin, Dmitri V.; Xie, Guoqiang; Zhang, Wei; Inoue, Akihisa

2007-01-01

This paper presents an influence of Ag addition on the glass-forming ability and devitrification behavior of Cu-Zr glassy alloys on heating. The crystallization kinetics and structure changes in Cu 45 Zr 45 Ag 10 and Cu 35 Zr 45 Ag 20 glassy alloys on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Based on the results obtained one can assume that the improvement of the glass-forming ability of the Cu-Zr alloys by the addition of Ag is connected with a particular crystallization mechanism and a higher reduced glass-transition temperature of the Cu 45 Zr 45 Ag 10 ternary alloy compared to the binary Cu 55 Zr 45 counterpart. As observed in the present work crystallization of the Cu-Zr-Ag alloys is found to cause embitterment of the samples and should be avoided as these alloys are considered to be used as structural materials. The Cu 35 Zr 45 Ag 20 alloy shows possible submicron-scale phase separation upon annealing

Study of oxidation behaviour of Zr-based bulk amorphous alloy Zr 65 ...

Indian Academy of Sciences (India)

The oxidation behaviour of Zr-based bulk amorphous alloy Zr65Cu17.5Ni10Al7.5 has been studied in air environment at various temperatures in the temperature range 591–684 K using a thermogravimetric analyser (TGA). The oxidation kinetics of the alloy in the amorphous phase obeys the parabolic rate law for oxidation ...

A DFT study of thermodynamic properties of C36 and C14 Fe2Zr Laves phases

Science.gov (United States)

Ali, Kawsar; Ghosh, P. S.; Arya, A. K.

2018-04-01

Fe-Zr alloys are promising materials for metallic waste immobilization in nuclear industry. C36 and C14 Fe2Zr Laves phases are frequently observed in Fe-Zr alloys that can host radionuclides. The phonon dispersions of C36 and C14 Fe2Zr Laves phases shows that both intermetallics are dynamically stable. The Helmholtz free energy, vibrational entropy, internal energy and specific heat at constant volume has been calculated. The zero point energies of C36 and C14 phases are 9.23 and 9.91 kJ/mole, respectively. The vibrational free energy becomes negative at 250 K and 270 K. The high temperature specific heat at constant volume of both intermetallics is 74 J/K/mole.

Mechanical properties and bio-tribological behaviors of novel beta-Zr-type Zr-Al-Fe-Nb alloys for biomedical applications.

Science.gov (United States)

Hua, Nengbin; Chen, Wenzhe; Zhang, Lei; Li, Guanghui; Liao, Zhenlong; Lin, Yan

2017-07-01

The present study prepares novel Zr 70+x Al 5 Fe 15-x Nb 10 (x=0, 5) alloys by arc-melting for potential biomedical application. The mechanical properties and bio-tribological behaviors of the Zr-based alloys are evaluated and compared with biomedical pure Zr. The as-prepared alloys exhibit a microstructure containing a micrometer-sized dendritic beta-Zr phase dispersed in a Zr 2 Fe-typed matrix. It is found that increasing the content of Zr is favorable for the mechanical compatibility with a combination of low Young's modulus, large plasticity, and high compressive strength. The wear resistance of the Zr-Al-Fe-Nb alloys in air and phosphate buffer saline (PBS) solution is superior to that of pure Zr. The wear mechanism of Zr-based alloys sliding in air is controlled by oxidation and abrasive wear whereas that sliding in PBS is controlled by synergistic effects of the abrasive and corrosive wear. Electrochemical measurements demonstrate that the Zr-based alloys are corrosion resistant in PBS. Their bio-corrosion resistance is improved with the increase in Zr content, which is attributed to the enrichment in Zr and decrease in Al concentration in the surface passive film of alloys. The Zr 75 Al 5 Fe 10 Nb 10 exhibits the best corrosion resistance in PBS, which contributes to its superior wear resistance in a simulated body environment. The combination of good mechanical properties, corrosion resistance, and biotribological behaviors of the Zr-Al-Fe-Nb alloys offers them potential advantages in biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

High-temperature deformation behavior and mechanical properties of rapidly solidified Al-Li-Co and Al-Li-Zr alloys

International Nuclear Information System (INIS)

Sastry, S.M.L.; Oneal, J.E.

1984-01-01

The deformation behavior at 25-300 C of rapidly solidified Al-3Li-0.6Co and Al-3Li-0.3Zr alloys was studied by tensile property measurements and transmission electron microscopic examination of dislocation substructures. In binary Al-3Li and Al-3Li-Co alloys, the modulus normalized yield stress increases with an increase in temperature up to 150 C and then decreases. The yield stress at 25 C of Al-3Li-0.3Zr alloys is 180-200 MPa higher than that of Al-3Li alloys. However, the yield stress of the Zr-containing alloy decreases drastically with increasing temperatures above 75 C. The short-term yield stresses at 100-200 C of the Al-3Li-based alloys are higher than that of the conventional high-temperature Al alloys. The temperature dependences of the flow stresses of the alloys were analyzed in terms of the magnitudes and temperature dependences of the various strengthening contributions in the two alloys. The dislocation substructures at 25-300 C were correlated with mechanical properties. 19 references

Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

Science.gov (United States)

Nishi, Hiroshi; Enoeda, Mikio

2011-10-01

In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 °C. Grain growth occurred on 1045 °C HIP CuCrZr, though slightly on 980 °C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 °C. The low cycle fatigue strength of 1045 °C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

Energy Technology Data Exchange (ETDEWEB)

Nishi, Hiroshi, E-mail: nishi.hiroshi88@jaea.go.jp [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan); Enoeda, Mikio [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan)

2011-10-01

In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 deg. C. Grain growth occurred on 1045 deg. C HIP CuCrZr, though slightly on 980 deg. C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 deg. C. The low cycle fatigue strength of 1045 deg. C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

International Nuclear Information System (INIS)

Nishi, Hiroshi; Enoeda, Mikio

2011-01-01

In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 deg. C. Grain growth occurred on 1045 deg. C HIP CuCrZr, though slightly on 980 deg. C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 deg. C. The low cycle fatigue strength of 1045 deg. C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

Mechanical properties, corrosion, and biocompatibility of Mg-Zr-Sr-Dy alloys for biodegradable implant applications.

Science.gov (United States)

Ding, Yunfei; Lin, Jixing; Wen, Cuie; Zhang, Dongmei; Li, Yuncang

2017-11-28

This study investigates the microstructure, mechanical properties, corrosion behavior, and biocompatibility of magnesium (Mg)-based Mg1Zr2SrxDy (x = 0, 1, 1.63, 2.08 wt %) alloys for biodegradable implant applications. The corrosion behavior of the Mg-based alloys has been evaluated in simulated body fluid using an electrochemical technique and hydrogen evolution. The biocompatibility of the Mg-based alloys has been assessed using SaSO2 cells. Results indicate that the addition of Dy to Mg-Zr-Sr alloy showed a positive impact on the corrosion behavior and significantly decreased the degradation rates of the alloys. The degradation rate of Mg1Zr2Sr1.0Dy decreased from 17.61 to 12.50 mm year -1 of Mg1Zr2Sr2.08Dy based on the hydrogen evolution. The ultimate compressive strength decreased from 270.90 MPa for Mg1Zr2Sr1Dy to 236.71 MPa for Mg1Zr2Sr2.08Dy. An increase in the addition of Dy to the Mg-based alloys resulted in an increase in the volume fraction of the Mg 2 Dy phase, which mitigated the galvanic effect between the Mg 17 Sr 2 phase and the Mg matrix, and led to an increase in the corrosion resistance of the base alloy. The biocompatibility of the Mg-based alloys was enhanced with decreasing corrosion rates. Mg1Zr2Sr2.08Dy exhibited the lowest corrosion rate and the highest biocompatibility compared with the other Mg-based alloys. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

Influence of alkali metal hydroxides on corrosion of Zr-based alloys

International Nuclear Information System (INIS)

Jeong, Y.H.; Ruhmann, H.; Garzarolli, F.

1997-01-01

In this study the influence of group-1 alkali hydroxides on different zirconium based alloys has been evaluated. The experiments have been carried out in small stainless steel autoclaves at 350 deg. C in pressurized 17 MPa water, with in low (0.32 mmol), medium (4.3 mmol) and high (31.5 mmol) equimolar concentrations of Li-, Na-, K-, Rb- and Cs-Hydroxides. Two types of alloys have been investigated: Zr-Sn-(Transition metal) and Zr-Sn-Nb-(Transition metal). The corrosion behaviour was evaluated from weight gain measurements. From the experiments the cation could be identified as the responsible species for zirconium alloy corrosion in alkalized water. The radius of the cation governs the corrosion behaviour in the pre accelerated region of zircaloy corrosion. Incorporating of alkali cations into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significantly lower effect for the other bases. Nb containing alloys show lower corrosion resistance than alloys from the Zr-Sn-TRM system in all alkali solutions. Both types of alloys corrode significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behaviour in the different alkali environments and taking into account the tendency to promote accelerate corrosion, CsOH and KOH are possible alternate alkalis for PWR application. (author). 17 refs, 15 figs, 5 tabs

Influence of alkali metal hydroxides on corrosion of Zr-based alloys

Energy Technology Data Exchange (ETDEWEB)

Jeong, Y H [Korea Atomic Energy Research Inst., Dae Jun (Korea, Republic of); Ruhmann, H; Garzarolli, F [Siemens-KWU, Power Generation Group, Erlangen (Germany)

1997-02-01

In this study the influence of group-1 alkali hydroxides on different zirconium based alloys has been evaluated. The experiments have been carried out in small stainless steel autoclaves at 350 deg. C in pressurized 17 MPa water, with in low (0.32 mmol), medium (4.3 mmol) and high (31.5 mmol) equimolar concentrations of Li-, Na-, K-, Rb- and Cs-Hydroxides. Two types of alloys have been investigated: Zr-Sn-(Transition metal) and Zr-Sn-Nb-(Transition metal). The corrosion behaviour was evaluated from weight gain measurements. From the experiments the cation could be identified as the responsible species for zirconium alloy corrosion in alkalized water. The radius of the cation governs the corrosion behaviour in the pre accelerated region of zircaloy corrosion. Incorporating of alkali cations into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significantly lower effect for the other bases. Nb containing alloys show lower corrosion resistance than alloys from the Zr-Sn-TRM system in all alkali solutions. Both types of alloys corrode significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behaviour in the different alkali environments and taking into account the tendency to promote accelerate corrosion, CsOH and KOH are possible alternate alkalis for PWR application. (author). 17 refs, 15 figs, 5 tabs.

Method of treating Ti--Nb--Zr--Ta superconducting alloys

International Nuclear Information System (INIS)

Horiuchi, T.; Monju, Y.; Tatara, I.; Nagai, N.; Hisata, M.; Matsumoto, K.

1975-01-01

A superconducting alloy is formulated from 10 to 50 at. percent Ti, 20 to 50 at. percent Nb, 10 to 40 at. percent Zr, and 5 to 12 at. percent Ta. A Ti--Nb--Zr--Ta superconducting alloy with a fine, non-homogeneous structure is obtained by forming a β solid solution of Ti--Nb--Zr--Ta alloy by heating to a temperature within the β solid solution range, cooling, and then cold working the heated alloy. The cold worked alloy is heated to a temperature within the (β' + β'') alloy to maintain the peritectoid structure, cold worked, then heated to a temperature within the eutectoid range to form a multiphase alloy structure and then cooled and finally cold worked. (U.S.)

Hot temperature corrosion of a zircon-1%niobium alloy

International Nuclear Information System (INIS)

Muller, Sebastian; Lanzani, Liliana

2010-01-01

The reaction of the Zr-1%Niobium alloy to corrosion is studied in this work, which is used as fuel elements sheath material in Russian VVER reactors. For comparative purposes, the conventional alloys Zircaloy-4 y Zr-2.5%Nb have been tested as well. Autoclave tests were carried out in water and in solutions of LiOH with concentrations of 0-1 to 1M at 343 o C and in water vapor at 400 o C (following ASTM G2/G2M-06). The gain in weight/unit of area of the autoclaved samples was determined in order to evaluate the corrosion, and metallographics were performed to characterize the oxides and hydrides that formed. The results show that for tests of 16 hours, a minimum concentration of 0.65M LiOH is needed to accelerate corrosion in Zr-1%Nb and Zr-2.5%Nb, while acceleration occurs in Zircaloy-4 at a concentration of 0.45M. In solutions of LiOH 1M the hydrogen 'uptake' in Zr-1Nb and Zr-2,5Nb is considerably lower in Zircaloy-4. The lesser amount of β-Zr phase present in the Zr-1Nb alloy produces thinner and more compact oxides, with better visual characteristics than for those formed in Zr-2.5Nb

The effect of aging on the critical current density in superconducting Nb-Ti-Zr alloys

International Nuclear Information System (INIS)

Ishida, Fumihiko; Doi, Toshio

1979-01-01

The effect of aging temperature, cold-reduction prior to aging, O 2 content and composition on the variation in the critical current density, J sub(c), by isothermal aging was investigated in heavily cold-worked Nb-Ti-Zr alloys on the Nb-Ti side. The results are summarized as follows: (1) When these alloys are aged isothermally at temperatures from 350 to 500 0 C, J sub(c) increases initially, reaches a maximum value and then decreases. Increase in J sub(c) of three orders of magnitude is possible as a result of aging. (2) The maximum value of J sub(c) on the isothermal aging curve becomes higher at a lower aging temperature, at a less cold-reduction prior to aging or with a higher O 2 content. (3) The J sub(c) of aged alloy becomes a maximum in composition containing 35 at%Nb, 60 to 65 at%Ti and less than 5 at%Zr. (4) The maximum value of J sub(c) was obtained for Nb-60.0 at%Ti-5.0 at%Zr alloy containing 1200 wt ppm O 2 , aged at 350 0 C for 330 h after 98.44% cold-reduction. The values of J sub(c) at 4.2 K were 2.4 x 10 9 A/m 2 at 5.0 T, 1.1 x 10 9 A/m 2 at 7.0 T and 3.0 x 10 8 A/m 2 at 9.0 T, respectively. The upper critical field of this specimen was 11.3 T at 4.2 K and its critical temperature was 8.6 K. (author)

The distribution trends and site preferences of alloying elements in precipitates within a Zr alloy: A combined first-principles and experimental study

Energy Technology Data Exchange (ETDEWEB)

Luan, B.F., E-mail: bfluan@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Wang, J.M.; Qiu, R.S.; Tao, B.R.; He, W.J. [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Zhang, X.Y.; Liu, R.P. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, Q., E-mail: qingliu@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China)

2016-09-05

Energy dispersive X-ray spectroscopy in scanning transmission electron microscope (STEM-EDS) technique and first-principles calculation are jointly utilized to investigate the distribution trends and site preferences of alloying elements in the precipitates within Zr-1.0Cr-0.4Fe-0.4Mo-0.4Bi alloy. Based on selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS) results, the precipitates within the studied alloy are confirmed to be ZrCr{sub 2}-based Laves phase with FCC (C15) type structure. The STEM-EDS elemental mapping is acquired to clarify the distribution trends of alloying elements in precipitates, i.e. Fe>Mo>Bi. To better verify this distribution behavior, substitutional formation energies and equilibrium concentrations of ternary alloying elements in ZrCr{sub 2} Laves phase are calculated by first-principles. The calculated results show a good consistence with the STEM-EDS results. In addition, the site preferences of ternary alloying elements in ZrCr{sub 2} Laves phase are predicted by the calculation of transfer energies. Finally, the reasons accounting for different distribution trends and site preferences of alloying elements in ZrCr{sub 2} Laves phase are discussed in terms of density of states, which attributed to the pseudogap effect and hybridizations between atoms. - Highlights: • Clarified the distribution trends of Fe>Mo>Bi in precipitates by STEM-EDS. • Verified the experimental results by first-principles calculation. • Predicted the site preferences of alloying elements by first-principles calculation. • Hybridization and pseudogap lead to the strong distribution and site preferences.

Diffusion of hydrogen interstitials in Zr based AB2 and mischmetal based AB5 alloys

International Nuclear Information System (INIS)

Mani, N; Ravi, N; Ramaprabhu, S

2005-01-01

The Zr based AB 2 alloys ZrMnFe 0.5 Ni 0.5 , ZrMnFe 0.5 Co 0.5 and mischmetal (Mm) based AB 5 alloy MmNi 3.5 Al 0.5 Fe 0.5 Co 0.5 have been prepared and characterized by means of powder x-ray diffractograms. The hydrogen absorption kinetics of these alloys have been studied in the temperature and pressure ranges 450-650 0 C and 10-100 mbar respectively with a maximum H to host alloy formula unit ratio of 0.01, using a pressure reduction technique. The diffusion coefficient of the hydrogen interstitials has been determined from hydrogen absorption kinetics experiments. The dependence of the diffusion coefficient on the alloy content has been discussed. For Mm based MmNi 3.5 Al 0.5 Fe 0.5 Co 0.5 alloy, the diffusion coefficient is about an order of magnitude higher than that of the Zr based alloys

The Method of Measured Electrical Resistivity in Studying Phase Transformations in Zr1Nb Alloy

International Nuclear Information System (INIS)

Gritsina, V.M.; Klimenko, S.P.; Chernyaeva, T.P.

2006-01-01

The paper systematically arranges and analyzes the data on the methods of research into α ↔ β transformation process in zirconium alloys, as well as capabilities and information provided by each method. A special emphasis is put on the method of measured electrical resistivity. The authors also present the results of their own research into α ↔ β transformation process in Zr1Nb alloy (in the material of Zr+1% Nb tubing produced in Ukraine from calciothermal zirconium). The ρ →T curve was used to define the maximum and minimum values for transformation temperatures. Combined processing of the phase data on Zr+1% Nb found in literature and obtained from measured resistivity suggests that transformation process happens in several stages. The maximum value on the ρ → T curve corresponds to the beginning of stage 3, whereas the minimum - to its completion; as suggested by the pooled data, accounts for over 95% of the total volume of the material

Effects of molybdenum content on the structure and mechanical properties of as-cast Ti-10Zr-based alloys for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Ho, Wen-Fu, E-mail: fujiiwfho@yahoo.com.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua, Taiwan (China); Wu, Shih-Ching; Hsu, Shih-Kuang [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Li, Yu-Chi [Department of Materials Science and Engineering, Da-Yeh University, Changhua, Taiwan (China); Hsu, Hsueh-Chuan, E-mail: hchsu@ctust.edu.tw [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China)

2012-04-01

The effects of molybdenum on the structure and mechanical properties of a Ti-10Zr-based system were studied with an emphasis on improving the strength/modulus ratio. Commercially pure titanium (c.p. Ti) was used as a control. As-cast Ti-10Zr and a series of Ti-10Zr-xMo (x = 1, 3, 5, 7.5, 10, 12.5, 15, 17.5 and 20 wt.%) alloys prepared using a commercial arc-melting vacuum pressure casting system were investigated. X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The experimental results indicated that these alloys had different structures and mechanical properties when various amounts of Mo were added. The as-cast Ti-10Zr has a hexagonal {alpha} Prime phase, and when 1 wt.% Mo was introduced into the Ti-10Zr alloy, the structure remained essentially unchanged. However, with 3 or 5 wt.%, the martensitic {alpha} Double-Prime structure was found. When increased to 7.5 wt.% or greater, retention of the metastable {beta} phase began. The {omega} phase was observed only in the Ti-10Zr-7.5Mo alloy. Among all Ti-10Zr-xMo alloys, the {alpha} Double-Prime -phase Ti-10Zr-5Mo alloy had the lowest elastic modulus. It is noteworthy that all the Ti-10Zr and Ti-10Zr-xMo alloys had good ductility. In addition, the Ti-10Zr-5Mo and Ti-10Zr-12.5Mo alloys exhibited higher bending strength/modulus ratios at 20.1 and 20.4, respectively. Furthermore, the elastically recoverable angles of these two alloys (26.4 Degree-Sign and 24.6 Degree-Sign , respectively) were much greater than those of c.p. Ti (2.7 Degree-Sign ). Given the importance of these properties for implant materials, the low modulus, excellent elastic recovery capability and high strength/modulus ratio of {alpha} Double-Prime phase Ti-10Zr-5Mo and {beta} phase Ti-10Zr-12.5Mo alloys appear to make them promising candidates. - Highlights: Black-Right-Pointing-Pointer The effects of Mo on the structure

The effect of Zr content on the microstructure, mechanical properties and cell attachment of Ti-35Nb-xZr alloys

International Nuclear Information System (INIS)

Ning Congqin; Zhai Wanyin; Chen Lei; Ding Dongyan; Dai Kerong

2010-01-01

β-type low elastic modulus alloys of the Ti-Nb-Zr system have recently attracted much attention for both orthopedic and dental applications. In the present study, meta-stable β alloys of Ti-35Nb-xZr with different Zr contents were developed. The effect of Zr content on the microstructure, mechanical properties and cell attachment was investigated. It was found that the addition of Zr improved the tensile strength and elongation of Ti-35Nb-xZr alloys, and simultaneously reduced the elastic modulus. Moreover, the Zr element helped to stabilize the β phase. Cell culture work indicated that the addition of Zr enhanced the attachment and spreading of bone marrow stem cells. Cell attachment and spreading on the surface of titanium alloys were dominated not only by the wettability but also by the inherent biocompatibility of alloying elements. The peak-aged alloy with 5 wt% Zr had a highest tensile strength of 874 MPa, while its elastic modulus was only 65 GPa, presenting a much higher strength/modulus ratio than Ti-6Al-4V. The Ti-35Nb-5Zr alloy exhibited a great potential for orthopedic and dental applications.

Study on direct dissolution of U-10Zr alloy and distribution of uranium and zirconium in liquid cadmium

International Nuclear Information System (INIS)

Ye Yuxing; Gao Yuan

1997-09-01

The effect of dissolution time, temperature, total surface area of U-10Zr alloy pellets and stirring on the dissolution and dissolution rate of uranium in liquid cadmium were studied. Cadmium containing U and Zr dissolved from U-10Zr alloy at 475 degree C and 500 degree C respectively was analyzed with electron microanalyzer. The experimental results show that at 400 degree and 500 degree C with the stirring rate of some 150 r/min, the solubilities of uranium in liquid cadmium are 0.4% and 2.2%, respectively. At the first 30 min, the dissolution rates of U-10Zr alloy pellets are 0.05 g/(cm 2 ·h) and 0.32 g/(cm 2 ·h), respectively. The suitable dissolution conditions for U-10Zr alloy pellets in liquid cadmium (the ratio of the mass of liquid cadmium to that of the pellets ≅7) are: temperature, about 480 degree C; stirring rate, about 150 r/min; dissolution time, 4 h. The distribution of uranium and zirconium in cadmium is homogeneous

Evidence of icosahedral short-range order in Zr70Cu30 and Zr70Cu29Pd1 metallic glasses

DEFF Research Database (Denmark)

Saksl, K.; Franz, H.; Jovari, P.

2003-01-01

Change in local atomic environment during crystallization of Zr-based glassy alloys was studied by extended x-ray absorption fine structure (EXAFS) spectroscopy. The formation of icosahedral quasicrystalline phase followed by crystallization of tetragonal CuZr2 has been observed in the Zr70Cu29Pd1...... glassy alloy during annealing up to 850 K. On the other hand, the binary Zr70Cu30 alloy shows a single glassy to crystalline CuZr2 phase transformation. The local atomic environment of as-quenched Zr70Cu30 alloy is matched to an icosahedral local atomic configuration, which is similar to that of the as......-quenched Zr70Cu29Pd1 alloy and the alloy annealed at 593 K containing icosahedral phase. Considering that the supercooled liquid region appears prior to crystallization in the Zr70Cu30 glassy alloy, the observed results support the theory claiming a strong correlation between the existence of local...

The role of Zr and T6 heat treatment on microstructure evolution and hardness of AlSi9Cu3(Fe diecasting alloy

Directory of Open Access Journals (Sweden)

Vončina M.

2017-01-01

Full Text Available The microstructure features and hardness of AlSi9Cu3(Fe die casting alloy was investigated in the presence of Zr addition. The cast alloys were undergone the solutionizing treatment 2 h at 500°C followed by artificial aging at 180°C for 5 h. Optical microscopy and electron micro-analyzer were used to study the formation of different intermetallic phases. The hardness was tested for all samples at 25°C. The results revealed that the intermetallic phase, based on (Al,Si(Zr,Ti, forms when Zr is added in the investigated alloy, while the T6 heat treatment does not influence on the formation of Zr-bearing phase. Results also indicate that the hardness slightly increases in the AlSi9Cu3 alloy in as-cast state when Zr is added, while after T6 heat treatment increases by 50% in the alloy without Zr and by 61% in the alloy with Zr addition.

Microstructural and thermophysical properties of U–6 wt.%Zr alloy for fast reactor application

International Nuclear Information System (INIS)

Kaity, Santu; Banerjee, Joydipta; Nair, M.R.; Ravi, K.; Dash, Smruti; Kutty, T.R.G.; Kumar, Arun; Singh, R.P.

2012-01-01

Highlights: ► Characterization of U–6%Zr alloy prepared by injection casting route. ► Martensitic to non-martensitic transformation of U–6%Zr alloy occurs at 843 K. ► Specific heat versus temperature curve shows a phase transition at 845 K. ► Average coefficient of thermal expansion is 18.28 × 10 −6 K −1 (298–823 K). ► Hardness versus temperature plot shows a transition at 748 K. - Abstract: The microstructural and high temperature behavior of U–6 wt.%Zr alloy has been investigated in this study. U–6 wt.%Zr alloy sample for this study was prepared by following injection casting route. The thermophysical properties like coefficient of thermal expansion, specific heat, thermal conductivity of the above alloy were determined. The hot-hardness data of the U–6 wt.%Zr alloy was also generated from room temperature to 973 K. Apart from that, the fuel-clad chemical compatibility with T91 grade steel was also studied by diffusion couple experiment. No studies have been reported on U–6 wt.%Zr alloy. This paper aims at filling up the gap on characterization and thermophysical property evaluation of U–6 wt.%Zr alloy.

Grain size stability and hardness in nanocrystalline Cu–Al–Zr and Cu–Al–Y alloys

Energy Technology Data Exchange (ETDEWEB)

Roy, D., E-mail: droy2k6@gmail.com [Material Science and Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States); Materials and Metallurgical Engineering Department, NIFFT, Ranchi 834003 (India); Mahesh, B.V. [Department of Mechanical and Aerospace Engineering, Monash University (Australia); Atwater, M.A. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, RDRL-WMM-F, Aberdeen Proving Ground, MD 21005-5069 (United States); Chan, T.E.; Scattergood, R.O.; Koch, C.C. [Material Science and Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States)

2014-03-01

Cryogenic high energy ball milling has been used to synthesize nanocrystalline Cu–14Al, Cu–12Al–2Zr and Cu–12Al–2Y alloys by mechanical alloying. The alloys were studied with the aim of comparing the effect of substituting Y and Zr in place of Al, in Cu–Al alloys, on the grain size stability at elevated temperatures. The as-milled alloys were subjected to annealing at various temperatures between 200 and 900 °C and the resulting grain morphology has been studied using X-ray diffraction and transmission electron microscopy. The addition of Y results in significantly reduced susceptibility to grain growth whereas in case of CuAl and CuAlZr alloys, the susceptibility to grain growth was much higher. The hardness is substantially increased due to Zr and Y addition in the as-milled CuAl powders. However, the hardness of Cu–12Al–2Zr gradually decreases and approaches that of Cu–14Al alloy after the annealing treatment whereas in case of Cu–12Al–2Y alloy, the relative drop in the hardness is much lower after annealing. Accordingly, the efficacy of grain size stabilization by Y addition at high homologous temperatures has been explained on the basis of a recent thermodynamic stabilization models.

Grain size stability and hardness in nanocrystalline Cu–Al–Zr and Cu–Al–Y alloys

International Nuclear Information System (INIS)

Roy, D.; Mahesh, B.V.; Atwater, M.A.; Chan, T.E.; Scattergood, R.O.; Koch, C.C.

2014-01-01

Cryogenic high energy ball milling has been used to synthesize nanocrystalline Cu–14Al, Cu–12Al–2Zr and Cu–12Al–2Y alloys by mechanical alloying. The alloys were studied with the aim of comparing the effect of substituting Y and Zr in place of Al, in Cu–Al alloys, on the grain size stability at elevated temperatures. The as-milled alloys were subjected to annealing at various temperatures between 200 and 900 °C and the resulting grain morphology has been studied using X-ray diffraction and transmission electron microscopy. The addition of Y results in significantly reduced susceptibility to grain growth whereas in case of CuAl and CuAlZr alloys, the susceptibility to grain growth was much higher. The hardness is substantially increased due to Zr and Y addition in the as-milled CuAl powders. However, the hardness of Cu–12Al–2Zr gradually decreases and approaches that of Cu–14Al alloy after the annealing treatment whereas in case of Cu–12Al–2Y alloy, the relative drop in the hardness is much lower after annealing. Accordingly, the efficacy of grain size stabilization by Y addition at high homologous temperatures has been explained on the basis of a recent thermodynamic stabilization models

Microstructure, mechanical property and in vitro biocorrosion behavior of single-phase biodegradable Mg–1.5Zn–0.6Zr alloy

Directory of Open Access Journals (Sweden)

Tao Li

2014-06-01

Full Text Available The microstructure, mechanical property, and in vitro biocorrosion behavior of as-cast single-phase biodegradable Mg–1.5Zn–0.6Zr alloy were investigated and compared with a commercial as-cast AZ91D alloy. The results show that the Mg–1.5Zn–0.6Zr alloy had a single-phase solid solution structure, with an average grain size of 34.7 ± 13.1 μm. The alloy exhibited ultimate tensile strength of 168 ± 2.0 MPa, yield strength of 83 ± 0.6 MPa, and elongation of 9.1 ± 0.6%. Immersion tests and electrochemical measurements reveal that the alloy displayed lower biocorrosion rate and more uniform corrosion mode than AZ91D in Hank's solution. The elimination of intensive galvanic corrosion reactions and the formation of a much more compact and uniform corrosion film mainly account for the better biocorrosion properties of the Mg–1.5Zn–0.6Zr alloy than AZ91D.

Mechanism of abnormally slow crystal growth of CuZr alloy

International Nuclear Information System (INIS)

Yan, X. Q.; Lü, Y. J.

2015-01-01

Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed

Structural investigation of Fe(Cu)ZrB amorphous alloy

International Nuclear Information System (INIS)

Duhaj, P.; Janickovic, D.

1996-01-01

The crystallization process in Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 alloys. In both alloys the first crystallization begins with the formation of nanocrystalline α-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of α-Fe and dispersed Fe 23 Zr 6 phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

Glass-forming ability and stability of ternary Ni-early transition metal (Ti/Zr/Hf) alloys

Energy Technology Data Exchange (ETDEWEB)

Basu, Joysurya [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India); Ranganathan, S. [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India)]. E-mail: rangu@met.iisc.ernet.in

2006-08-15

Four Ni-bearing Ti, Zr and Hf ternary alloys of nominal composition Zr{sub 41.5}Ti{sub 41.5}Ni{sub 17}, Zr{sub 25}Ti{sub 25}Ni{sub 50}, Zr{sub 41.5}Hf{sub 41.5}Ni{sub 17} and Ti{sub 41.5}Hf{sub 41.5}Ni{sub 17} were rapidly solidified in order to produce ribbons. The Zr-Ti-Ni and Ti-Hf-Ni alloys become amorphous, whereas the Zr-Hf-Ni alloy shows precipitation of a cubic phase. The devitrification of all three alloys was followed and the relative tendency to form nanoquasicrystals and cF96 phases analysed. The relative glass-forming ability of the alloys can be explained by taking into account their atomic size difference. Addition of Ni often leads to quasicrystallisation or quasicrystal-related phases. This can be explained by the atomic radius and heat of mixing of the constituent elements. The phases precipitated at the initial stages of crystallisation indicate the possible presence of Frank-Kasper polyhedral structure in the amorphous alloys. Structural analysis reveals that the Laves and the anti-Laves phases have the same polyhedral structural unit, which is similar to the structural characteristics of glass.

Interdiffusion between U(Mo,Pt) or U(Mo,Zr) and Al or Al A356 alloy

International Nuclear Information System (INIS)

Komar Varela, C.; Mirandou, M.; Arico, S.; Balart, S.; Gribaudo, L.

2009-01-01

Solid state reactions in chemical diffusion couples U-7 wt.%Mo-0.9 wt.%Pt/Al at 580 deg. C and U-7 wt.%Mo-0.9 wt.%Pt/Al A356 alloy, U-7 wt.%Mo-1 wt.%Zr/Al and U-7 wt.%Mo-1 wt.%Zr/Al A356 alloy at 550 deg. C were characterized. Results were obtained from optical and scanning electron microscopy, electron probe microanalysis and X-ray diffraction. The UAl 3, UAl 4 and Al 20 Mo 2 U phases were identified in the interaction layers of γU(Mo,Pt)/Al and γU(Mo,Zr)/Al diffusion couples. Al 43 Mo 4 U 6 ternary compound was also identified in γU(Mo,Zr)/Al due to the decomposition of γU(Mo,Zr) phase. The U(Al,Si) 3 and U 3 Si 5 phases were identified in the interaction layers of γU(Mo,Pt)/Al A356 and γU(Mo,Zr)/Al A356 diffusion couples. These phases are formed due to the migration of Si to the interaction layer. In the diffusion couple U(Mo,Zr)/Al A356, Zr 5 Al 3 phase was also identified in the interaction layer. The use of synchrotron radiation at Brazilian Synchrotron Light Laboratory (LNLS, CNPq, Campinas, Brazil) was necessary to achieve a complete crystallographic characterization.

Formation of ω-phase in Zr-4 at.% Cr alloy

International Nuclear Information System (INIS)

Dobromyslov, A.V.; Kazantseva, N.V.

1996-01-01

The ω-phase has been discovered in zirconium-base alloys with the transition metals of Period 4 of the Periodic Table only in Zr-V, Zr-Cr, and Zr-Cu alloys. The first mention about the ω-phase formation in Zr-Cr alloys was given for Zr-4.5 at.%. However, there were no experimental data that confirmed this fact. W.M. Rumball and F.G. Elder presented the X-ray results on the ω-phase formation in Zr-3.9 at.%Cr, but at the present time there are no electron microscope studies of the structure of the ω-phase in this system. Investigations of the features of the ω-phase formation, morphology of the ω-phase and the mechanism of its formation in the different zirconium-base alloys are necessary to establish the common features of the formation of structures with the metastable phases. The task of the present work is to study the conditions and features of the ω-phase formation in the Zr-Cr alloys and the effect of the eutectoid decomposition on the formation of ω-phase. This article is part of the detailed investigations of the feature and condition of the ω-phase formation in zirconium-base alloys with the transition metals of the groups I and V to VIII of the Periodic Table

The ambient and high temperature deformation behavior of Al–Si–Cu–Mg alloy with minor Ti, Zr, Ni additions

International Nuclear Information System (INIS)

Hernandez-Sandoval, J.; Garza-Elizondo, G.H.; Samuel, A.M.; Valtiierra, S.; Samuel, F.H.

2014-01-01

Highlights: • Characterization on the precipitation of Ni- and Zr-based intermetallics. • High temperature tensile properties of 354 alloy containing Zr and Ni below 0.5%. • Quality index charts as a function of heat treatment. • Yield strength and ductility color contours as a function of aging temperature and aging time. - Abstract: The principal aim of the present work was to investigate the effects of minor additions of nickel and zirconium on the strength of cast aluminum alloy 354 at ambient and high temperatures. Tensile properties of the as-cast and heat-treated alloys were determined at room temperature and at high temperatures (190 °C, 250 °C, 350 °C). The results show that Zr reacts only with Ti, Si and Al. From the quality index charts constructed for these alloys, the quality index attains minimum and maximum values of 259 MPa and 459 MPa, in the as-cast and solution-treated conditions; also, maximum and minimum values of yield strength are observed at 345 MPa and 80 MPa, respectively, within the series of aging treatments applied. A decrease in tensile properties of ∼10% with the addition of 0.4 wt.% nickel is attributed to a nickel–copper reaction. The reduction in mechanical properties due to addition of different elements is attributed principally to the increase in the percentage of intermetallic phase particles formed during solidification; such particles act as stress concentrators, decreasing the alloy ductility. Tensile test results at ambient temperatures show a slight increase (∼10%) in alloys with Zr and Zr/Ni additions, particularly at aging temperatures above 240 °C. Additions of Zr and Zr + Ni increase the high temperature tensile properties, in particular for the alloy containing 0.2 wt.% Zr + 0.2 wt.% Ni, which exhibits an increase of more than 30% in the tensile properties at 300 °C compared with the base 354 alloy

The Structure–Function Relationships of Classical Cannabinoids: CB1/CB2 Modulation

Science.gov (United States)

Bow, Eric W.; Rimoldi, John M.

2016-01-01

The cannabinoids are members of a deceptively simple class of terpenophenolic secondary metabolites isolated from Cannabis sativa highlighted by (−)-Δ9-tetrahydrocannabinol (THC), eliciting distinct pharmacological effects mediated largely by cannabinoid receptor (CB1 or CB2) signaling. Since the initial discovery of THC and related cannabinoids, synthetic and semisynthetic classical cannabinoid analogs have been evaluated to help define receptor binding modes and structure–CB1/CB2 functional activity relationships. This perspective will examine the classical cannabinoids, with particular emphasis on the structure–activity relationship of five regions: C3 side chain, phenolic hydroxyl, aromatic A-ring, pyran B-ring, and cyclohexenyl C-ring. Cumulative structure–activity relationship studies to date have helped define the critical structural elements required for potency and selectivity toward CB1 and CB2 and, more importantly, ushered the discovery and development of contemporary nonclassical cannabinoid modulators with enhanced physicochemical and pharmacological profiles. PMID:27398024

Extraordinary high strength Ti-Zr-Ta alloys through nanoscaled, dual-cubic spinodal reinforcement.

Science.gov (United States)

Biesiekierski, Arne; Ping, Dehai; Li, Yuncang; Lin, Jixing; Munir, Khurram S; Yamabe-Mitarai, Yoko; Wen, Cuie

2017-04-15

While titanium alloys represent the current state-of-the-art for orthopedic biomaterials, concerns still remain over their modulus. Circumventing this via increased porosity requires high elastic admissible strains, yet also limits traditional thermomechanical strengthening techniques. To this end, a novel β-type Ti-Zr-Ta alloy system, comprised of Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta, was designed and characterized mechanically and microstructurally. As-cast, this system displayed extremely high yield strengths and elastic admissible strains, up to 1.4GPa and potentially 1.48%, respectively. This strength was attributed to a nanoscaled, cuboidal structure of semi-coherent, dual body-centered cubic (BCC) phases, arising from the thermodynamics of interaction between Ta and Zr; this morphology occurring with dual BCC-phases is heretofore unreported in Ti-based alloys. Further, cell proliferation investigated by MTS assay suggests this was achieved without sacrificing biocompatibility, with no significant difference to either empty-well or commercially-pure Ti controls noted. The current research details microstructural, mechanical, and biological investigations into four novel biomedical alloys in a hitherto uninvestigated region of the Ti-Zr-Ta alloy system; Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta. We find that the investigated alloys display 0.2% yield strengths of up to 1.40GPa and elastic admissible strains of up to 1.48%, along with biological properties comparable to that seen in the conventional metallic biomaterial ASTM Grade-2 CP-Ti, achieved in the complete absence of traditional thermomechanical processing techniques. This is attributed to the presence of a dual-BCC cuboidal nanostructure, achieved via spinodal decomposition; while similar structures have been reported in e.g. Ni-based superalloys, we believe this is the first such structure investigated in a Ti-based material. As such, this work is felt to be of

An XRD technique for quantitative phase analysis of Al-U-Zr alloy

International Nuclear Information System (INIS)

Khan, K.B.; Kulkarni, N.K.; Jain, G.C.

2003-01-01

In several nuclear research reactors all over the world, Al-U alloy is used as fuel. To stabilise less brittle phase UAl 3 in Al-U alloy, a small amount of Zr (1 to 3 wt% ) is added. A rapid, non destructive and simple x-ray diffraction technique has been developed for quantitative phase analysis Al-U-Zr alloy system containing UAl 4 , UAl 3 and Al. (author)

Structural and Mechanical Properties of the ZrC/Ni-Nanodiamond Coating Synthesized by the PVD and Electroplating Processes for the Cutting Knifes

Science.gov (United States)

Chayeuski, V.; Zhylinski, V.; Cernashejus, O.; Visniakov, N.; Mikalauskas, G.

2018-04-01

In this work, combined gradient ZrC/Ni-nanodiamond ultradispersed diamonds (UDD) coatings were synthesized on the surface of knife blades made of hard alloy WC-2 wt.% Co by electroplating and cathode arc evaporation PVD techniques to increase the durability period of a wood-cutting milling tool. The microstructure, phase and elemental composition, microhardness, and adhesion strength of the coatings were investigated. Ni-UDD layer is not mixed with the ZrC coating and hard alloy substrate. Cobalt is present in Ni-UDD layer after deposition of ZrC. The ZrC/Ni-nanodiamond coating consists of separate phases of zirconium carbide (ZrC), α-Ni, and Ni-UDD. The maximum value of microhardness of the Ni-nanodiamond coating is 5.9 GPa. The microhardness value of the ZrC/Ni-nanodiamond coatings is 25 ± 6 GPa, which corresponds to the microhardness of the hard alloy substrate and ZrC coating. The obtained high values of the critical loads on the scratch track of the ZrC/Ni-nanodiamond coating in 24 N prove a sufficiently high value of the adhesion strength of the bottom Ni-UDD layer with WC-Co substrate. Pilot testing of ZrC/Ni-nanodiamond-coated cutting tools proved their increasing durability period to be 1.5-1.6 times higher than that of bare tools, when milling laminated chipboard.

Effect of V or Zr addition on the mechanical properties of the mechanically alloyed Al-8wt%Ti alloys

International Nuclear Information System (INIS)

Moon, I.H.; Lee, J.H.; Lee, K.M.; Kim, Y.D.

1995-01-01

Mechanical alloying (MA) of Al-Ti alloy, being a solid state process, offers the unique advantage of producing homogeneous and fine dispersions of thermally stable Al 3 Ti phase, where the formation of the fine Al 3 Ti phase by the other method is restricted from the thermodynamic viewpoint. The MA Al-Ti alloys show substantially higher strength than the conventional Al alloys at the elevated temperature due to the presence of Al 3 Ti as well as Al 4 C 3 and Al 2 O 3 , of which the last two phases were introduced during MA process. The addition of V or Zr to Al-Ti alloy was known to decrease the lattice mismatch between the intermetallic compound and the aluminum matrix, and such decrease in lattice mismatching can influence positively the high temperature mechanical strength of the MA Al-Ti by increasing the resistance to dispersoid coarsening at the elevated temperature. In the present study, therefore, the mechanical behavior of the MA Al-Ti-V and Al-Ti-Zr alloys were investigated in order to evaluate the effect of V or Zr addition on the mechanical properties of the MA Al-8Ti alloy at high temperature

Crystallization behavior and the thermal properties of Zr63Al7.5Cu17.5Ni10B2 bulk amorphous alloy

International Nuclear Information System (INIS)

Jang, J.S.C.; Chang, L.J.; Jiang, Y.T.; Wong, P.W.

2003-01-01

The ribbons of amorphous Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloys with 0.1 mm thickness were prepared by melt spinning method. The thermal properties and micro structural development during the annealing of amorphous alloy have been investigated by a combination of differential thermal analysis, differential scanning calorimetry, high-temperature optical microscope, X-ray diffractometry and TEM. The glass transition temperature for the Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloys are measured about 645 K (372 C). This alloy also obtains a large temperature interval ΔT x about 63 K. Meanwhile, the calculated T rg for Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloy presents the value of 0.57. The activation energy of crystallization for the alloy Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 was about 370± 10 kJ/mole as determined by the Kissinger and Avrami plot, respectively. These values are about 20% higher than the activation energy of crystallization for the Zr 65 Al 7.5 Cu 17.5 Ni 10 alloy (314 kJ/mol.). This implies that the boron additions exhibit the effect of improving the thermal stability for the Zr-based alloy. The average value of the Avrami exponent n were calculated to be 1.75±0.15 for Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloy. This indicates that this alloy presents a crystallization process with decreasing nucleation rate. (orig.)

Corrosion and deuterium uptake of Zr-based alloys in supercritical water

International Nuclear Information System (INIS)

Khatamian, D.

2010-01-01

To increase the thermodynamic efficiency above 40% in nuclear power plants, the use of supercritical water as the heat transport fluid has been suggested. Zircaloy-2, -4, Zr-Cr-Fe, Zr-1Nb and Zr-2.5Nb were tested as prospective fuel cladding materials in 30 MPa D 2 O at 500 o C. Zircaloy-2 showed the highest rates of corrosion and hydriding. Although Zr-Cr-Fe initially showed a very low corrosion rate, it displayed breakaway corrosion kinetics after 50 h exposure. The best-behaved material both from a corrosion and hydrogen uptake point of view was Zr-2.5Nb. However, the Zr-2.5Nb oxide growth rate was still excessive and beyond the current CANDU design allowance. Similar coupons, coated with Cr, were also tested. The coated layer effectively prevented oxidation of the coupons except on the edges, where the coating was thinner and had some flaws. In addition, the Cr-coated Zr-2.5Nb coupons had the lowest deuterium pickup of all the alloys tested and showed no signs of accelerated or nonuniform corrosion. (author)

Internal friction and mechanical properties of Zr - 2.5% Nb alloy after programme loading

International Nuclear Information System (INIS)

Gindin, I.A.; Chirkina, L.A.; Okovit, V.S.; Netesov, V.M.

1984-01-01

Temperature dependence of internal friction in the range 20-600 deg C of the alloy Zr-2.5% Nb in the initial state after programmed loading up to 0.1% of residual elongation and static deformation to the same deformation degree has been studied. It is shown, that the programmed loading promotes the decrease in relaxation rate at 20 and 200 deg C and the increase of strength characteristics of the alloy without the decrease in plasticity margin to fracture in the range 20-400 deg C

Structural investigation of Fe(Cu)ZrB amorphous alloy

Energy Technology Data Exchange (ETDEWEB)

Duhaj, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Matko, I. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Svec, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Sitek, J. [Department of Nuclear Physics and Technology, Slovak Technical University, 81219 Bratislava (Slovakia); Janickovic, D. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav

1996-07-01

The crystallization process in Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} alloys. In both alloys the first crystallization begins with the formation of nanocrystalline {alpha}-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of {alpha}-Fe and dispersed Fe{sub 23}Zr{sub 6} phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

Science.gov (United States)

Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

2013-10-01

A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

Stability study of the γ phase in U-Nb-Zr alloys

International Nuclear Information System (INIS)

Arico, S.F; Hermida, J.D; Gribaudo, L.M

2006-01-01

The development of new low enrichment nuclear fuels for research and radioisotope production reactors imposes the knowledge of properties and behaviors about a series of alloys which the reducing of U 235 (fissionable) concentration is compensated with a greater density of this element inside the fuel. One of these series is composed by U alloys with different contents of alloying, that allow to retain the body centered cubic structure solid solution recognized as phase α in metastable condition at low temperatures. For the present work 10 U based alloys were manufactured with different concentrations containing up to 43,7 % zirconium weight and up to 7,3 % niobium weight. An arch oven was utilized with argon atmosphere. The identification of the present phases in massive samples from the melting was carried out through X-rays diffraction analysis. The results obtained in this work are compared with others results published since the year 1957. In the samples melted the intermetallic UZr 2 diminishes in quantity with the reduction of the composition of Zr in the alloys. In all of them were identified, besides, Zr 6 Fe 3 O, ZrO 0,35 , α and U 3 O 8 present in quantities reduced. The quantity of the two last phases diminishes at the same time with the content in Zr. The parameter of network of the cubic phase γU in these alloys can be represented for the equation: α=(3,5796 -0,1616.x Nb +0,1155.x Zr )/(1.0306+0,003.x Nb -0,0068.x Zr . The parameter of network of the γ phase was measured. Comparing it measured with the value calculated, for eight alloys, the proposed equation showed a very good adjustment (HC)

The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys

Directory of Open Access Journals (Sweden)

Kwo-Hsiung Young

2016-07-01

Full Text Available Effects of substitutions of rare earth (RE elements (Y, La, Ce, and Nd to the Zr-based AB2 multi-phase metal hydride (MH alloys on the structure, gaseous phase hydrogen storage (H-storage, and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15 are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation and is recommended for all the AB2 MH alloys for electrochemical applications.

Ceramic Coatings for Clad (The C³ Project): Advanced Accident-Tolerant Ceramic Coatings for Zr-Alloy Cladding

Energy Technology Data Exchange (ETDEWEB)

Sickafus, Kurt E. [Univ. of Tennessee, Knoxville, TN (United States); Wirth, Brian [Univ. of Tennessee, Knoxville, TN (United States); Miller, Larry [Univ. of Tennessee, Knoxville, TN (United States); Weber, Bill [Univ. of Tennessee, Knoxville, TN (United States); Zhang, Yanwen [Univ. of Tennessee, Knoxville, TN (United States); Patel, Maulik [Univ. of Tennessee, Knoxville, TN (United States); Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Wolfe, Doug [Pennsylvania State Univ., University Park, PA (United States); Fratoni, Max [Univ. of California, Berkeley, CA (United States); Raj, Rishi [Univ. of Colorado, Boulder, CO (United States); Plunkett, Kenneth [Univ. of Colorado, Boulder, CO (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Hollis, Kendall [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nelson, Andy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stanek, Chris [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Comstock, Robert [Westinghouse Electric Corporation, Pittsburgh, PA (United States); Partezana, Jonna [Westinghouse Electric Corporation, Pittsburgh, PA (United States); Whittle, Karl [Univ. of Sheffield (United Kingdom); Preuss, Michael [Univ. of Manchester (United Kingdom); Withers, Philip [Univ. of Manchester (United Kingdom); Wilkinson, Angus [Univ. of Oxford (United Kingdom); Donnelly, Stephen [Univ. of Huddersfield (United Kingdom); Riley, Daniel [Australian Nuclear Science and Technology Organisation, Syndney (Australia)

2017-02-14

The goal of this NEUP-IRP project is to develop a fuel concept based on an advanced ceramic coating for Zr-alloy cladding. The coated cladding must exhibit demonstrably improved performance compared to conventional Zr-alloy clad in the following respects: During normal service, the ceramic coating should decrease cladding oxidation and hydrogen pickup (the latter leads to hydriding and embrittlement). During a reactor transient (e.g., a loss of coolant accident), the ceramic coating must minimize or at least significantly delay oxidation of the Zr-alloy cladding, thus reducing the amount of hydrogen generated and the oxygen ingress into the cladding. The specific objectives of this project are as follows: To produce durable ceramic coatings on Zr-alloy clad using two possible routes: (i) MAX phase ceramic coatings or similar nitride or carbide coatings; and (ii) graded interface architecture (multilayer) ceramic coatings, using, for instance, an oxide such as yttria-stabilized zirconia (YSZ) as the outer protective layer. To characterize the structural and physical properties of the coated clad samples produced in 1. above, especially the corrosion properties under simulated normal and transient reactor operating conditions. To perform computational analyses to assess the effects of such coatings on fuel performance and reactor neutronics, and to perform fuel cycle analyses to assess the economic viability of modifying conventional Zr-alloy cladding with ceramic coatings. This project meets a number of the goals outlined in the NEUP-IRP call for proposals, including: Improve the fuel/cladding system through innovative designs (e.g. coatings/liners for zirconium-based cladding) Reduce or eliminate hydrogen generation Increase resistance to bulk steam oxidation Achievement of our goals and objectives, as defined above, will lead to safer light-water reactor (LWR) nuclear fuel assemblies, due to improved cladding properties and built-in accident resistance, as well as

Low in reactor creep Zr-base alloy tubes

International Nuclear Information System (INIS)

Cheadle, B.A.; Holt, R.A.

1984-01-01

This invention relates to zirconium alloy tubes especially for use in nuclear power reactors. More particularly it relates to quaternary 3.5 percent Sn, 1 percent Mo, 1 percent Nb, balance Zr alloy tubes which have been extruded, cold worked and heat treated to lower their dislocation density. In one embodiment the alloys are cold worked less than 5 percent and stress relieved to produce a low dislocation density and in another embodiment the alloys are cold worked up to about 50 percent and annealed to produce a very low dislocation density and also small equiaxed β grains

Synergetic effects of Sc and Zr microalloying and heat treatment on mechanical properties and exfoliation corrosion behavior of Al-Mg-Mn alloys

International Nuclear Information System (INIS)

Peng, Yongyi; Li, Shu; Deng, Ying; Zhou, Hua; Xu, Guofu; Yin, Zhimin

2016-01-01

Mechanical properties, exfoliation corrosion behavior and microstructure of Al-5.98Mg-0.47Mn and Al-6.01Mg-0.45Mn-0.25Sc-0.10Zr (wt%) alloy sheets under various homogenizing and annealing processes were investigated comparatively by tensile tests, electrochemical measurements, X-ray diffraction technique and microscopy methods. The as-cast alloys mainly consist of Fe and Mn enriched impurity phases, Mg and Mn enriched non-equilibrium aluminides and Mg 3 Al 2 phases. During homogenization treatment, solvable intermetallics firstly precipitate and then dissolve into matrix. The optimized homogenization processes for removing micro-segregation and obtaining maximum precipitation strengthening of secondary Al 3 (Sc, Zr) particles are 440 °C×8 h and 300 °C×8 h, respectively. Sc and Zr additions can make the yield strength of Al-Mg-Mn alloy increase by 21 MPa (6.9%), 120 MPa (61.2%) and 127 MPa (68.3%), when annealed at 270 °C, 300 °C and 330 °C, respectively, indicating that Orowan precipitation strengthening caused by secondary Al 3 (Sc, Zr) nano-particles is much greater than grain boundary strengthening from primary Al 3 (Sc, Zr) micro-particles. Increasing homogenization and annealing degrees and adding Sc and Zr all can decrease corrosion current density and improve exfoliation corrosion resistance. The exfoliation corrosion behavior is dominant by anodic dissolution occurring at the interface between intermetallics and α(Al) matrix. After homogenizing at 440 °C for 8 h and annealing at 300 °C for 1 h, yield strength, ultimate strength, elongation to failure and exfoliation corrosion rank are 196 MPa, 360 MPa, 20.2% and PA (slight pitting corrosion) in Al-Mg-Mn alloy, and reach to 316 MPa, 440 MPa, 17.0% and PA in Al-Mg-Mn-Sc-Zr alloy, respectively, revealing that high strength, high ductility and admirable corrosion resistance of Al-Mg-Mn alloys can be achieved by the synergetic effects of Sc and Zr microalloying and heat treatment.

Microstructure, mechanical property and in vitro biocorrosion behavior of single-phase biodegradable Mg–1.5Zn–0.6Zr alloy

OpenAIRE

Tao Li; Yong He; Hailong Zhang; Xitao Wang

2014-01-01

The microstructure, mechanical property, and in vitro biocorrosion behavior of as-cast single-phase biodegradable Mg–1.5Zn–0.6Zr alloy were investigated and compared with a commercial as-cast AZ91D alloy. The results show that the Mg–1.5Zn–0.6Zr alloy had a single-phase solid solution structure, with an average grain size of 34.7 ± 13.1 μm. The alloy exhibited ultimate tensile strength of 168 ± 2.0 MPa, yield strength of 83 ± 0.6 MPa, and elongation of 9.1 ± 0.6%. Immersion tests and electroc...

Comparison of results analysis of chemical composition of alloys inside the U-Zr-Nb by XRF and AAS techniques

International Nuclear Information System (INIS)

Masrukan; Tri Yulianto; Anwar Muchsin

2011-01-01

U-Zr-Nb alloy chemical composition analysis using X Ray Fluorescence (XRF) and Atomic Absorption Spectroscopy (AAS) techniques have been conducted, where U-Zr- Nb alloy was chosen as candidates for new high-density fuel for future research reactors . Composition analysis is necessary because the composition of elements in the fuel will determine the characteristics of fuel during the fabrication process and in the reactor. The use of two kinds of analysis techniques were designed to obtain accurate analysis results. The experiment was conducted to determine the major element composition and impurities in the alloy U-Zr-Nb. First U-Zr-Nb varying alloy composition Nb were respectively 1%, 4%, 7% (U10% Zr1% Nb, U10% Zr4% Nb and U10% 7% Nb) as results of the melting process of measuring the diameter of 120 mm crushed on the surface bottom. Once on the bottom surface is smooth, then analyzed using XRF techniques. To analyze the elements using AAS techniques, alloy U-Zr-Nb cut into 10 mm x 5 mm then dissolved using HF and nitric acid. Solution that occurred were analyzed using AAS technique. From the analysis using the XRF technique is obtained the alloy U-10% Zr-1% Nb, U-10% Zr-4% Nb and Zr-10% U-7% Nb) had a content of each element as follows: U (87.8858%), Zr (2.6097%) and Nb (0.2206%), U (87.8556%), Zr (2.6302%), and Nb (0.6573%); U (84.6334%), Zr (2.5773%), and Nb (1.0940) weight. Results of analysis using AAS techniques on samples obtained third consecutive Zr content of 9.25%, 8.90% and 9.80% while the content of Nb was not detected. Meanwhile, the results of elemental analysis of impurities in all three samples showed that almost all the elements are still qualify as fuel except Zn element. Element Zn at the three samples of each alloys U-10% Zr-1% Nb, U-10% Zr-4% Nb and U-10% Zr-7%Nb is 1.3266%, 3.2756% and 1.0927% weight. It could be concluded that the results of analysis of elemental content and impurities in the alloy U-Nb-Zr using both XRF and AAS visible

Microstructures and phase transformations of Ti-30Zr-xNb (x = 5, 7, 9, 13 at.%) shape memory alloys

Energy Technology Data Exchange (ETDEWEB)

Qu, Wentao; Sun, Xuguang; Yuan, Bifei [School of Mechanical Engineering, Xi' an Shiyou University, Xi' an 710065 (China); Xiong, Chengyang; Zhang, Fei [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Yan, E-mail: liyan@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Sun, Baohui [Lanzhou Seemine SMA Co. Ltd., Lanzhou 730010 (China)

2016-12-15

The microstructures, phase transformations and shape memory properties of Ti-30Zr-xNb (x = 5, 7, 9, 13 at.%) alloys were investigated. The X-ray diffraction and transmission electron microscopy observations showed that the Ti-30Zr-5Nb, Ti-30Zr-7/9Nb and Ti-30Zr-13Nb alloys were composed of the hcp α′-martensite, orthorhombic α″-martensite and β phases, respectively. The results indicated the enhanced β-stabilizing effect of Nb in Ti-30Zr-xNb alloys than that in Ti-Nb alloys due to the high content of Zr. The differential scanning calorimetry test indicated that the Ti-30Zr-5Nb alloy displayed a reversible transformation with a high martensitic transformation start temperature of 776 K and a reverse martensitic transformation start temperature (A{sub s}) of 790 K. For the Ti-30Zr-7Nb and Ti-30Zr-9Nb alloys, the martensitic transformation temperatures decreased with the increasing Nb content. Moreover, an ω phase transformation occurred in the both alloys upon heating at a temperature lower than the corresponding A{sub s}, which is prompted by more addition of Nb. Although the critical stress in tension of the three martensitic alloys decreased with increasing Nb content, the Ti-30Zr-9Nb alloy showed a critical stress of as high as 300 MPa. Among all the alloys, the Ti-30Zr-9Nb alloy exhibited the maximum shape memory effect of 1.61%, due to the lowest critical stress for the martensite reorientation. - Highlights: •Ti-30Zr-5Nb alloy is composed of hcp α′-martensite with the M{sub s} of 776 K. •Ti-30Zr-7Nb and Ti-30Zr-9Nb alloys are predominated by orthorhombic α″-martensite. •Ti-30Zr-13Nb alloy consists of a single β phase due to the β-stabilizing effect of Nb. •The martensitic transformation temperatures decrease with increasing Nb content. •Ti-30Zr-9Nb alloy shows the maximum shape memory effect of 1.61%.

Encapsulation of Mg-Zr alloy in metakaolin-based geo-polymer

International Nuclear Information System (INIS)

Rooses, Adrien; Steins, Prune; Dannoux-Papin, Adeline; Lambertin, David; Poulesquen, Arnaud; Frizon, Fabien

2013-01-01

Investigations were carried out to propose a suitable material for the encapsulation of Mg-Zr alloy wastes issued from fuel cladding of the first generation nuclear reactors. Stability over time, good mechanical properties and low gas production are the main requirements that embedding matrices must comply with in order to be suitable for long run storage. One of the main issues encapsulating Mg-Zr alloy in mineral binder is the hydrogen production related to Mg-Zr alloys corrosion and water radiolysis process. In this context, metakaolin geo-polymers offer an interesting outlook: corrosion densities of Mg-Zr alloys are significantly lower than in Portland cement. This work firstly presents the hydrogen production of Mg-Zr alloy embedded in geo-polymers prepared from different the activation solution (NaOH or KOH). The effect of addition of fluorine on the magnesium corrosion in geo-polymer has been investigated too. The results point out that sodium geo-polymer is a suitable binder for Mg-Zr alloy encapsulation with respect to magnesium corrosion resistance. Furthermore the presence of fluorine reduces significantly the hydrogen release. Then, the impact of fluorine on the geo-polymer network formation was studied by rheological, calorimetric and 19 F NMR measurements. No direct effect resulting from the addition of fluorine has been shown on the geo-polymer binder. Secondly, the formulation of the encapsulation matrix has been adjusted to fulfil the expected physical and mechanical properties. Observations, dimensional evolutions and compressive strengths demonstrated that addition of sand to the geo-polymer binder is efficient to meet the storage criteria. Consequently, a matrix formulation compatible with Mg-Zr alloy encapsulation has been proposed. Finally, irradiation tests have been carried out to assess the hydrogen radiolytic yield of the matrix under exposure to γ radiation. (authors)

Change of Composition in Metallic Fuel Slug of U-Zr Alloy from High-Temperature Annealing

Energy Technology Data Exchange (ETDEWEB)

Youn, Young Sang; Lee, Jeong Mook; Kim, Jong Yun; Kim, Jong Hwan; Song, Hoon [KAERI, Daejeon (Korea, Republic of)

2016-09-15

The U–Zr alloy is a candidate for fuel to be used as metallic fuel in sodium-cooled fast reactors (SFRs). Its chemical composition before and after annealing at the operational temperature of SFRs (610 .deg. C) was investigated using X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray diffraction. The original alloy surface contained uranium oxides with the U(IV) and U(VI) oxidation states, Zr{sub 2}O{sub 3}, and a low amount of uranium metal. After annealing at 610 .deg. C, the alloy was composed of uranium metal, uranium carbide, uranium oxide with the U(V) valence state, zirconium metal, and amorphous carbon. Meanwhile, X-ray diffraction data indicate that the bulk composition of the alloy remained unchanged.

Change of Composition in Metallic Fuel Slug of U-Zr Alloy from High-Temperature Annealing

International Nuclear Information System (INIS)

Youn, Young Sang; Lee, Jeong Mook; Kim, Jong Yun; Kim, Jong Hwan; Song, Hoon

2016-01-01

The U–Zr alloy is a candidate for fuel to be used as metallic fuel in sodium-cooled fast reactors (SFRs). Its chemical composition before and after annealing at the operational temperature of SFRs (610 .deg. C) was investigated using X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray diffraction. The original alloy surface contained uranium oxides with the U(IV) and U(VI) oxidation states, Zr 2 O 3 , and a low amount of uranium metal. After annealing at 610 .deg. C, the alloy was composed of uranium metal, uranium carbide, uranium oxide with the U(V) valence state, zirconium metal, and amorphous carbon. Meanwhile, X-ray diffraction data indicate that the bulk composition of the alloy remained unchanged

Mechanical properties and biocorrosion resistance of the Mg-Gd-Nd-Zn-Zr alloy processed by equal channel angular pressing.

Science.gov (United States)

Zhang, Junyi; Kang, Zhixin; Wang, Fen

2016-11-01

A Mg-Gd-Nd-Zn-Zr alloy was processed by equal channel angular pressing (ECAP) at 375°C. The grain size of Mg-Gd-Nd-Zn-Zr alloy was refined to ~2.5μm with the spherical precipitates (β1 phase) distributing in the matrix. The mechanical properties of ECAPed alloy were significantly improved as a result of the grain refinement and precipitation strengthening. The corrosion rate of the ECAPed magnesium alloy in simulated body fluid dramatically decreased from 0.236mm/a to 0.126mm/a due to the strong basal texture and refined microstructure. This wrought magnesium alloy shows potentials in biomedical application. Copyright © 2016 Elsevier B.V. All rights reserved.

Crystallization-induced plasticity of Cu-Zr containing bulk amorphous alloys

International Nuclear Information System (INIS)

Lee, Seok-Woo; Huh, Moo-Young; Fleury, Eric; Lee, Jae-Chul

2006-01-01

This study examined the parameter governing the plasticity observed in various Cu-Zr containing monolithic amorphous alloys. All the alloys were fully amorphous in their as-cast condition but exhibited different plastic strains. Microscopic observations of the quasi-statically compressed alloys showed abundant nanocrystallites in the amorphous matrices in the alloys that exhibited pronounced plasticity. On the other hand, insignificant changes in the microstructure were observed in the alloy that did not show plasticity. The mechanism for the formation of these deformation-induced nanocrystallites was examined from the viewpoints of thermodynamics and kinetics. The role of the deformation-induced nanocrystallites on the plasticity of the amorphous alloy was examined using high-resolution transmission electron microscopy. The results demonstrate that compressive loading facilitates nanocrystallization in monolithic Cu-Zr containing amorphous alloys, resulting in plasticity. The parameter governing the plasticity in these monolithic Cu-Zr containing amorphous alloys lies in the activation energy for the overall crystallization process

Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment

International Nuclear Information System (INIS)

Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa

2011-01-01

Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the α and γ phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)

Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment

Energy Technology Data Exchange (ETDEWEB)

Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa, E-mail: ferrazw@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG) Belo Horizonte, MG (Brazil)

2011-07-01

Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the {alpha} and {gamma} phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)

Dendritic solidification and thermal expansion of refractory Nb-Zr alloys investigated by electrostatic levitation

Energy Technology Data Exchange (ETDEWEB)

Yang, S.J.; Hu, L.; Wang, L.; Wei, B. [Northwestern Polytechnical University, Department of Applied Physics, Xi' an (China)

2017-05-15

The dendritic growth and thermal expansion of isomorphous refractory Nb-5%Zr, Nb-10%Zr, and Nb-15%Zr alloys were studied by electrostatic levitation technique. The obtained maximum undercoolings for the three alloys were 534 (0.2T{sub L}), 498 (0.19T{sub L}), and 483 K (0.18T{sub L}), respectively. Within these undercooling ranges, the dendritic growth velocities of the three alloys all exhibited power laws, and achieved 38.5, 34.0, and 27.1 m s{sup -1} at each maximum undercooling. The microstructures were characterized by coarse dendrites at small undercooling, while they transformed into refined dendrites under large undercooling condition. In addition, the measured thermal expansion coefficients of solid Nb-Zr alloys increased linearly with temperature. The values at liquid state were more than double of those at solid state, which also displayed linear dependence on temperature. (orig.)

Potentiodynamic polarization studies of bulk amorphous alloy Zr57Cu15.4Ni12.6Al10Nb5 and Zr59Cu20Ni8Al10Ti3 in aqueous HNO3 media

International Nuclear Information System (INIS)

Sharma, Poonam; Dhawan, Anil; Jayraj, J.; Kamachi Mudali, U.

2013-01-01

The potentiodynamic polarization studies were carried out on Zr based bulk amorphous alloy Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 and Zr 59 Cu 20 Ni 8 Al 10 Ti 3 in solutions of 1 M, 6 M and 11.5 M HNO 3 aqueous media at room temperature. As received specimens of Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 (5 mm diameter rod) and Zr 59 Cu 20 Ni 8 Al 10 Ti 3 (3 mm diameter rod) were polished with SiC paper before testing them for potentiodynamic polarization studies. The amorphous nature of the specimens was checked by X-ray diffraction. The bulk amorphous alloy Zr 59 Cu 20 Ni 8 Al 10 Ti 3 shows the better corrosion resistance than Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 alloy in the aqueous HNO 3 media as the value of the corrosion current density (I corr ) for Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 alloy were found to be more than Zr 59 Cu 20 Ni 8 Al 10 Ti 3 alloy in aqueous HNO 3 media. The improved corrosion resistance of Zr 59 Cu 20 Ni 8 Al 10 Ti 3 alloy is possibly due to the presence of Ti and formation of TiO 2 during anodic oxidation. Both Zr based bulk amorphous alloys shows wider passive range at lower concentration of nitric acid and the passive region gets narrowed down with the increase in concentration. A comparison of data obtained from both the Zr-based bulk amorphous alloys is made and results are discussed in the paper. (author)

Obtaining of U-2.5Zr7.5Nb and U-3Zr-9Nb alloys by sintering process

International Nuclear Information System (INIS)

Mazzeu, Thiago de Oliveira; Paula, Joao Bosco de; Ferraz, Wilmar Barbosa; Santos, Ana Maria Matildes dos; Brina, Jose Giovanni Mascarenhas

2011-01-01

The development of metallic fuels with low enrichment to be used in research and test reactors, as well in the future pressurized water reactors, focuses on the search for uranium alloys of high density. Alloying elements such as Zr, Nb and Mo are added to uranium to improve fuel performance in reactors. In this context, the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) in Belo Horizonte is developing the U-2.5Zr-7.5Nb and U- 3Zr-9Nb (weight %) alloys by the innovative process of sintering that utilizes raw materials in the form of powders. The powders were pressed at 400MPa and then sintered under a vacuum of about 5 x 10-6 Torr at temperatures ranging from 1050 deg to 1300 deg C. The densities of the alloys were measured geometrically and by hydrostatic method using water. The microstructures of the pellets were observed by scanning electron microscopy (SEM) and the elements of alloying were identified by energy dispersive X-ray spectroscopy (SEM/EDS) analysis. The obtained results showed a small increasing density with rising sintering temperature. The highest density achieved was approximately 80% of theoretical density. It was also qualitatively observed that the superficial oxidation of the pellets increased with increasing sintering temperature thus avoiding the fusion of the alloys at higher temperatures. (author)

Biological Properties of Ti-Nb-Zr-O Nanostructures Grown on Ti35Nb5Zr Alloy

Directory of Open Access Journals (Sweden)

Zhaohui Li

2012-01-01

Full Text Available Surface modification of low modulus implant alloys with oxide nanostructures is one of the important ways to achieve favorable biological behaviors. In the present work, amorphous Ti-Nb-Zr-O nanostructures were grown on a peak-aged Ti35Nb5Zr alloy through anodization. Biological properties of the Ti-Nb-Zr-O nanostructures were investigated through in vitro bioactivity testings, stem cell interactions, and drug release experiments. The Ti-Nb-Zr-O nanostructures demonstrated a good capability of inducing apatite formation after immersion in simulated body fluids (SBFs. Drug delivery experiment based on gentamicin and the Ti-Nb-Zr-O nanostructures indicated that a high drug loading content could result in a prolonged release process and a higher quantity of drug residues in the oxide nanostructures after drug release. Quick stem cell adhesion and spreading, as well as fast formation of extracellular matrix materials on the surfaces of the Ti-Nb-Zr-O nanostructures, were found. These findings make it possible to further explore the biomedical applications of the Ti-Nb-Zr-O nanostructure modified alloys especially clinical operation of orthopaedics by utilizing the nanostructures-based drug-release system.

Zirconium hydrides and Fe redistribution in Zr-2.5%Nb alloy under ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Idrees, Y.; Yao, Z. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, Canada, K7L 3N6 (Canada); Cui, J.; Shek, G.K. [Kinetrics, Mississauga, ON (Canada); Daymond, M.R., E-mail: daymond@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, Canada, K7L 3N6 (Canada)

2016-11-15

Zr-2.5%Nb alloy is used to fabricate the pressure tubes of the CANDU reactor. The pressure tube is the primary pressure boundary for coolant in the CANDU design and is susceptible to delayed hydride cracking, reduction in fracture toughness upon hydride precipitation and potentially hydride blister formation. The morphology and nature of hydrides in Zr-2.5%Nb with 100 wppm hydrogen has been investigated using transmission electron microscopy. The effect of hydrides on heavy ion irradiation induced decomposition of the β phase has been reported. STEM-EDX mapping was employed to investigate the distribution of alloying elements. The results show that hydrides are present in the form of stacks of different sizes, with length scales from nano- to micro-meters. Heavy ion irradiation experiments at 250 °C on as-received and hydrided Zr-2.5%Nb alloy, show interesting effects of hydrogen on the irradiation induced redistribution of Fe. It was found that Fe is widely redistributed from the β phase into the α phase in the as-received material, however, the loss of Fe from the β phase and subsequent precipitation is retarded in the hydrided material. This preliminary work will further the current understanding of microstructural evolution of Zr based alloys in the presence of hydrogen. - Graphical abstract: STEM HAADF micrographs at low magnification showing the hydride structure in Zr-2.5Nb alloy.

Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

KAUST Repository

Kanoun, Mohammed; Goumri-Said, Souraya

2014-01-01

We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

KAUST Repository

Kanoun, Mohammed

2014-09-01

We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young\\'s modulus, and Poisson\\'s ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

Compositional optimization for nanocrystalline hard magnetic MRE–Fe–B–Zr alloys via modifying RE and B contents

Energy Technology Data Exchange (ETDEWEB)

Qian, D.Y.; Hussain, M.; Zheng, Z.G.; Zhong, X.C. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Gao, X.X. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Z.W., E-mail: zwliu@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

2015-06-15

To reduce the rare earth content and maintain good magnetic properties for NdFeB based alloys, the effects of RE and B contents on the micro-structure and magnetic properties of nanocrystalline MRE{sub 11−y}Fe{sub 79.5}B{sub 8+y}Zr{sub 1.5} (MRE=Nd{sub 0.8}(Dy{sub 0.5}Y{sub 0.5}){sub 0.2}, y=0–3) alloys have been investigated. Increasing B concentration leads to the appearance and increase of soft magnetic Fe{sub 3}B phase and reduced grain size. With decreasing MRE and increasing B concentrations, the coercivity decreased from 1159.8 kA/m for y=0 to 619.0 kA/m for y=3. The saturation magnetization and remanence increased with B content until y=2 then decreases. The B content also has effects on the exchange coupling, microstructure and thermal stability. While comparing MRE{sub 10}Fe{sub 82.5}B{sub 6}Zr{sub 1.5} alloy with MRE{sub 11−y}Fe{sub 79.5}B{sub 8+y}Zr{sub 1.5} (y=1 and 2) alloys, the alloy with 9 at% MRE can achieve similar magnetic properties as that with 10 at% MRE. The magnetic properties with coercivity of 792.2 kA/m, (BH){sub max} of 128 kJ/m{sup 3} and good thermal stability have been obtained for MRE{sub 9}Fe{sub 79.5}B{sub 10}Zr{sub 1.5} alloy. - Highlights: • Nanocomposite NdFeB composition is optimized to reduce RE from 10 to 9 at.%. • Increasing B content benefits microstructure, exchange coupling, thermal stability. • Alloy with 9% RE has H{sub c}=792kA/m, (BH){sub max}=128kJ/m{sup 3} and low temperature coefficients.

Effect of TiC Additions on the Formation and Microstructural Evolution of Zr66.7Ni33.3Amorphous Alloys%TiC掺杂对Zr66.7Ni33.3非晶形成及结构演化影响的研究

Institute of Scientific and Technical Information of China (English)

耿浩然; 王艳; 王英姿; 夏琳燕

2012-01-01

We used Zr66.7 Ni33.3 binary alloys as base alloys and selected the intermetallic compound TiC as additional particles. The influence of TiC addition on the microstructural evolution induced by mechanical alloying has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The experimental results show that the proper addition of TiC (5wt%) not only shortens the starting time of the amarphization reaction, but also improves the glass forming ability (GFA) of Zr-Ni alloy powders and greatly enhances the mechanical stability of the amorphous composites. Based upon the EDX analysis, we have found that the diffusion of TiC among the atoms of Zr and Ni is inhomogeneous, leading to the increase of the disorder degree of atoms in local regions. Therefore, the TiC addition improves the GFA and stability of the Zr-Ni alloys. The DSC results demonstrate that the effect of the addition of 3 wt% TiC is better than that of the addition of 5 wt% TiC on the improvement of thermal stability of the amorphous phase, suggesting that there is no correlation between thermal stability and mechanical stability of MA induced Zr-Ni-based amorphous alloys.%利用机械合金化法,以Zr66.7Ni33.3合金粉末作为基体,选择TiC作为掺杂物,研究其对机械合金化诱导合金粉末显微结构演化行为的影响.研究发现,掺杂适量的TiC粉末可使Ti和C原子在Zr-Ni间发生不均匀扩散,导致局域范围内原子排列的无序度增大,从而提高非晶形成能力和机械稳定性,其中5wt％ TiC的掺杂效果最佳.此外,3wt％TiC掺杂导致非晶相的热稳定性优于5wt％TiC的掺杂效果,说明机械合金化合成Zr-Ni基非晶合金粉末的机械稳定性和其热稳定性之间无相关性.

Corrosion of clean Mg-Zr alloys in various basic media for waste encapsulation

International Nuclear Information System (INIS)

Lambertin, D.; Frizon, F.; Blachere, A.; Bart, F.

2012-01-01

The dismantling of UNGG nuclear reactor generates a large volume of fuel decladding. These materials are based on Mg-Zr alloy. The strategy could be to encapsulate these wastes into an ordinary Portland cement (OPC) or geo-polymer (aluminosilicate material) in a form suitable for storage. Studies have been performed on Mg or Mg-Al alloy in basic media but no data are available on Mg-Zr behaviour. The influence of representative pore solution of OPC and geo-polymer with Mg-Zr alloy has been studied on corrosion behaviour. Electrochemical methods have been used to determine the corrosion densities at room temperature. Results show that the corrosion densities of Mg-Zr alloy in OPC solution is one order of magnitude more important than in geo-polymer solution environment and effect of inhibiting agent has been undertaken with Mg-Zr alloy. The evaluation of encapsulation of Mg-Zr alloy in OPC and geo-polymer has been done in term of corrosion hydrogen production. (authors)

Desorption dynamics of deuterium in CuCrZr alloy

Science.gov (United States)

Thi Nguyen, Lan Anh; Lee, Sanghwa; Noh, S. J.; Lee, S. K.; Park, M. C.; Shu, Wataru; Pitcher, Spencer; Torcy, David; Guillermain, David; Kim, Jaeyong

2017-12-01

Desorption behavior of deuterium (D2) in CuCrZr alloy was investigated considering sample thickness, loading and baking temperature of deuterium followed by the ITER scopes. Cylindrical specimens of 1, 3, 5 mm thick with 4 mm diameter were exposed to deuterium at a pressure of 25 bar at 120, 240 and 350 °C for 24 h, then baked at 800 °C in a vacuum chamber maintained at a pressure lower than 10-7 Torr. Deuterium desorption characteristics such as desorption rate and amount of deuterium in the sample were estimated by analyzing the desorption peaks monitored with a residual gas analyzer (RGA), and the trapping energy of deuterium was calculated using thermal desorption spectroscopy (TDS). Secondary ion mass spectroscopy (SIMS) results showed that deuterium atoms embedded in the sample at a depth of less than 15 μm and desorbed as low as 400 °C. All absorbed deuterium atoms in the specimen were completely retrieved by dynamic pumping at 800 °C in 15 min. The desorption rate of deuterium per unit area was inversely proportional to the increment of the thickness of the sample, and was proportional to the loading temperature. Based on the assumption that a uniform distribution of interstitial sites for deuterium follows the Femi-Dirac statistics, the result of TDS demonstrated that the CuCrZr alloy has two types of trapping energies, which were estimated to be 62 and 79 kJ/mol.

FRACTIONAL RECRYSTALLIZATION KINETICS IN DIRECTLY COLD ROLLED Al-Mg, Al-Mg-Sc AND Al-Mg-Sc-Zr ALLOY

Directory of Open Access Journals (Sweden)

M. S. Kaiser

2014-12-01

Full Text Available The evaluation of texture as a function of recrystallization has been characterized for directly cold rolled Al-6Mg, Al-6Mg-0.4Sc and Al-6Mg-0.4Sc-0.2Zr alloys. Samples were annealed isothermally at 400 °C for 1 to 240 minutes to allow recrystallization. Recrystallization kinetics of the alloys is analyzed from the micro-hardness variation. Isothermally annealed samples of aluminum alloys were also studied using JMAK type analysis to see if there exists any correlation between the methods. Recrystallization fraction behavior between two methods the scandium added alloys show the higher variation due to precipitation hardening and higher recrystallization behavior. The scandium and zirconium as a combined shows the more variation due to formation of Al3(Sc, Zr precipitate. From the microstructure it is also observed that the base Al-Mg alloy attained almost fully re-crystallized state after annealing at 400 °C for 60 minutes

The Thermodynamic Characterization of ZrCo–H, HfCo−H, HfNi−H and Zr{sub 1–x}HfxNi(Co) Alloy–H Systems

Energy Technology Data Exchange (ETDEWEB)

Flanagan, Ted B., E-mail: ted.flanagan@uvm.edu; Noh, Hak; Luo, Suifang

2016-08-25

ZrCo and HfCo intermetallic compounds have the same cubic (CsCl-type) structure and their ternary (Zr{sub 1−x}Hf{sub x})Co alloys are also cubic. ZrNi and HfNi intermetallic compounds have the orthorhombic structure (CrB-type) and the ternary (Zr{sub 1−x}Hf{sub x})Ni alloys also have this structure. Thermodynamic data for hydride formation and decomposition in ZrCo, HfCo and HfNi intermetallic compounds have been determined from reaction calorimetry and from pressure-composition isotherms. Thermodynamic data have been determined for the three ternary alloys: (Zr{sub 0.75}Hf{sub 0.25})Co, (Zr{sub 0.50}Hf{sub 0.50})Co, and (Zr{sub 0.25}Hf{sub 0.75})Co and the four ternary alloys: (Zr{sub 0.875}Hf{sub 0.125})Ni, (Zr{sub 0.75}Hf{sub 0.25})Ni, (Zr{sub 0.50}Hf{sub 0.50})Ni, and (Zr{sub 0.25}Hf{sub 0.75})Ni. This offers the opportunity to learn how the thermodynamic properties of the ternary alloy-H systems change with the stoichiometry of alloys with the same structure. - Highlights: • Calorimetric enthalpies determined for H absorption by ZrCo, HfCo, HfNi are determined. • Ternary alloys, e.g., Zr{sub 1−x}Hf{sub x}Ni, prepared and characterized by x-ray diffraction. • Isotherms for the ternary alloys give thermodynamic parameters for H solution.

Correlation between zirconium oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys

International Nuclear Information System (INIS)

Park, Sang Yoon; Lee, Myung Ho; Choi, Byoung Kwon; Jeong, Yong Hwan; Jung, Youn Ho

2001-01-01

To evaluate the correlation of Zr oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys, the corrosion behavior of the alloys was tested in the autoclave containing 70 ppm LiOH solution at 360 .deg. C. The characteristics of the oxide on the alloys were investigated by using the electrochemical impedance spectrosocpy (EIS) method. The corrosion resistance of the alloys was evaluated from the corrosion rate determined as a function of the concentration of Nb. The equivalent circuit of the oxide was composed on the base of the spectrum from EIS measurements on the oxide layers that had formed at pre-and post-transition regions on the curve of corrosion rate. By using the capacitance characteristics of the equivalent circuit, the thickness of impervious layer, it's electrical resistance and characteristics of space charge layer were evaluated. The corrosion characteristics of the Zr-Nb-Sn-Fe-Cu alloys were successfully explained by applying the EIS test results

Development in corrosion resistance by microstructural refinement in Zr-16 SS 304 alloy using suction casting technique

Energy Technology Data Exchange (ETDEWEB)

Das, N., E-mail: nirupamd@barc.gov.in; Sengupta, P.; Abraham, G.; Arya, A.; Kain, V.; Dey, G.K.

2016-08-15

Highlights: • Grain refinement was made in Zr–16 wt.% SS alloy while prepared by suction casting process. • Distribution of Laves phase, e.g., Zr{sub 2}(Fe, Cr) was raised in suction cast (SC) Zr–16 wt.% SS. • Corrosion resistance was improved in SC alloy compared to that of arc-melt-cast alloy. • Grain refinement in SC alloy assisted for an increase in its corrosion resistance. - Abstract: Zirconium (Zr)-stainless steel (SS) hybrid alloys are being considered as baseline alloys for developing metallic-waste-form (MWF) with the motivation of disposing of Zr and SS base nuclear metallic wastes. Zr–16 wt.% SS, a MWF alloy optimized from previous studies, exhibit significant grain refinement and changes in phase assemblages (soft phase: Zr{sub 2}(Fe, Cr)/α-Zr vs. hard phase: Zr{sub 3}(Fe, Ni)) when prepared by suction casting (SC) technique in comparison to arc-cast-melt (AMC) route. Variation in Cr-distribution among different phases are found to be low in suction cast alloy, which along with grain refinement restricted Cr-depletion at the Zr{sub 2}(Fe, Cr)/Zr interfaces, prone to localized attack. Hence, SC alloy, compared to AMC alloy, showed lower current density, higher potential at the breakdown of passivity and higher corrosion potential during polarization experiments (carried out under possible geological repository environments, viz., pH 8, 5 and 1) indicating its superior corrosion resistance.

Effects of phase constitution of Zr-Nb alloys on their magnetic susceptibilities

International Nuclear Information System (INIS)

Nomura, Naoyuki; Tanaka, Yuko; Suyalatu; Kondo, Ryota; Doi, Hisashi; Tsutsumi, Yusuke; Hanawa, Takao

2009-01-01

The magnetic susceptibilities and microstructures of Zr-Nb binary alloys were investigated to develop a new metallic biomaterial with a low magnetic susceptibility for magnetic resonance imaging (MRI). The magnetic susceptibility was measured with a magnetic susceptibility balance, and the microstructure was evaluated with an X-ray diffractometer (XRD), an optical microscope (OM), and a transmission electron microscope (TEM). Zr-Nb alloys as-cast showed a minimum value of magnetic susceptibility between 3 and 9 mass% Nb, and the value abruptly increased up to 20 mass% Nb, followed by a gradual increase with the increase of the Nb content. XRD, OM, and TEM revealed that the minimum value of the susceptibility was closely related to the appearance of the athermal ω phase in the β phase. Since the magnetic susceptibility of Zr-3Nb alloy consisting of an α' phase was as low as that of Zr-9Nb alloy consisting of the β and ω phases, that of the ω phase was lower than that of the α' and β phases. When Zr-16Nb alloy was heat-treated, the isothermal ω phase appeared, and, simultaneously, the magnetic susceptibility decreased. Therefore, the ω phase contributes to the decrease of the magnetic susceptibility, independently of the formation process of the ω phase. The magnetic susceptibility of the Zr-3Nb alloy as-cast was almost one-third that of Ti-6Al-4V alloy, which is commonly used for medical implant devices. Zr-Nb alloys are useful for medical devices used under MRI. (author)

A superplastic Al-Li-Cu-Mg-Zr powder alloy with high hardness and modulus

International Nuclear Information System (INIS)

Phillips, V.A.

1986-01-01

Structure/property studies were made on an experimental Al-3.18% Li-4.29% Cu-1.17% Mg-0.18% Zr powder alloy, which is of the low density/high modulus type. Alloy powder was made by the P and W/GPD rapid solidification rate (RSR) process, canned, and extruded to bar. The density was 2.458 x 10/sup 6/ g/m/sup 3/. The material was solution-treated, and aged at 149 0 C(300 0 F), 171 0 C(340 0 F), and 193 0 C(380 0 F), using hardness tests to determine the aging curves. Testpieces solution-treated at 516 0 C(961 0 F) showed an average yield strength (0.2% offset) of 43.3 ksi (299 MPa) and ultimate tensile strength of 50.0 ksi (345 MPa), with 1% elongation, which increased to 73.0 ksi (503 MPa) and 73.1 ksi (504 MPa), respectively, with only 0.2% elongation, on peak aging at 193 0 C(380 0 F), with a modulus of elasticity of 11.4 x 10/sup 6/ psi (78.3 GPa). Hardness values reached 90-92 R/sub B/ on aging at 149-193 0 C(300-380 0 F). The as-extruded alloy showed superplastic behavior at 400-500 0 C(752-932 0 F) with elongations of 80-185% on 25.6 mm, peaking at 450 0 C(842 0 F). An RSR Al-2.53% Li-2.82% Mn-0.02% Zr extruded allow showed only 18-23% elongation at 400-500 0 C(752-932 0 F)

Microstructure, mechanical properties and stress corrosion cracking of Al–Zn–Mg–Zr alloy sheet with trace amount of Sc

Energy Technology Data Exchange (ETDEWEB)

Huang, Xing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Pan, Qinglin, E-mail: pql1964@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiming; Huang, Zhiqi [Guangdong Fenglu Aluminum Co., Ltd, Foshan 528133 (China); Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

2015-11-25

Microstructural and property evolution of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy sheet during its preparation were investigated in detail by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Vickers micro-hardness test and room temperature tensile test. Stress corrosion cracking (SCC) behavior of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy under different heat treatments was studied using slow strain rate test. The results showed that serious dendritic segregation existed in as-cast condition. The suitable homogenization treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was 470 °C/24 h. After homogenization treatment, dissoluble Zn and Mg enriched non-equilibrium phases dissolved into α-Al matrix completely. The suitable solid solution-aging treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was solution treated at 470 °C for 60 min, followed by water quenching and then aged at 120 °C for 24 h. Under this aging temper, the grain structures were composed of sub-grains, η′ phases and nanometer-sized, spherical Al{sub 3}(Sc, Zr) particles. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The improved corrosion resistance from increasing aging temperature or prolonging aging time was due to the discontinuous η precipitates along the grain boundary and the high area fraction of GBPs. The main strengthening mechanisms of Al–Zn–Mg–0.10%Sc–0.10%Zr alloy are precipitation strengthening derived from η′ precipitates, dispersion strengthening, sub-grain strengthening and grain refinement caused by coherent Al{sub 3}(Sc, Zr) particles. - Highlights: • The suitable homogenization treatment of the alloy has been identified. • Evolution of microstructure and mechanical properties is investigated. • Strengthening mechanisms of the alloy has been established. • The basic mechanism has

Structure and mechanical properties of TiZr binary alloy after Al addition

International Nuclear Information System (INIS)

Jiang, X.J.; Jing, R.; Liu, C.Y.; Ma, M.Z.; Liu, R.P.

2013-01-01

Microstructure and mechanical properties of hot-rolled TiZrAl alloys were studied. The results showed that the microstructure of all alloys mainly consisted of lamellar α phase. The thickness of the lamellar α phase gradually increased with increasing aluminum content. Moreover, large numbers of stacking faults was observed in Ti–25Zr–15Al (at%) alloy. The aluminum addition strongly affected the mechanical properties of the TiZrAl alloys. With increased aluminum contents, the strength increased evidently, whereas, the elongation decreased. Ti–25Zr–15Al (at%) with the highest aluminum contents in all alloys, possessed the highest tensile strength (σ b =1319 MPa), i.e. strengthened by 41% compared with Ti–25Zr (at%) alloy, and still retained the elongation of 5.5%. According to the classical size and/or modulus misfits model, the effect of aluminum addition was significant in TiZr alloys because of the considerable misfits between aluminum and zirconium

Carbides precipitated from the melt in a Zr-2.5 Nb alloy

International Nuclear Information System (INIS)

Piotrkowski, R.; Garcia, E.A.; Vigna, G.L.; Bermudez, S.E.

1993-01-01

An experimental method is presented which leads to the formation of carbides similar in size (3 to 8 microns) and composition to those observed in some pressure tubes of CANDU type reactors. The method is based on melting the Zr-2.5 Nb alloy in a graphite crucible, where isothermal C diffusion in the Zr-Nb melt took place. It can be inferred that the carbides observed in pressure tubes could be originated in high temperature stages of the manufacture process. Otherwise, they could have been incorporated in the Zr sponge. As a result of the diffusion couple Liquid Zr-2.5 Nb/Solid Graphite, a carbide layer, up to 100μm thick, grew attached to the crucible wall, together with carbide particles whose size was in the some microns range. The smallest particles were arranged in rows determined by the prior β phase grains. The main carbide phase detected was the cubic MC 1-x ; the hexagonal M 2 C was also detected; M for metal. (Author)

Experimental determination of the constitution and the phase relationships in Zr (2.5-8.0)at.%Nb (0-6.7)at.%Al alloys with 750at.ppm0 and 250at.ppmN, between 730-900 deg C

International Nuclear Information System (INIS)

Peruzzi Bardella, A.; Bolcich, J.C.

1990-01-01

Zr alloys with 2.5 to 8.0 at%Nb and 0 to 6.7 at%Al, were subjected to dynamic and static treatments between 730-900 deg C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zr-Nb-Al alloys with 750 at.ppm0 and 250 at.ppmN are the following: a) Equilibrium relationships are established between α (hcp), β (bcc) and Zr 3 Al (Cu 3 Au) phases along isothermal sections at 730, 771 and 800 deg C. b) β/α+β boundaries are determined along iso-aluminium vertical sections at 6.7, 3.3 and 0 at%Al. As for the first two iso-aluminium sections, the β/α+β equilibrium boundary corresponding to the binary Zr-Nb system is found to have a positive curvature, which is contrary to what has been reported in the literature. The increase in the Al content shifts the T β/α+β at a rate of 5.1 to 8.5 deg C/at.%Al, depending on Nb content. c) The addition of Al to Zr-Nb alloys increases the partial solubility of Nb in the α phase, its maximum value at 730 deg C being about 0.7-0.8 at% for 4 at%Al. d) Solubility values for Al in α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy on the Zr-Al system. (Author)

The role of Zr and Nb in oxidation/sulfidation behavior of Fe-Cr-Ni alloys

Energy Technology Data Exchange (ETDEWEB)

Natesan, K. (Argonne National Lab., IL (USA)); Baxter, D.J. (Argonne National Lab., IL (USA) INCO Alloy Ltd., Hereford, England (UK))

1990-11-01

05Structural Fe-Cr-Ni alloys may undergo rapid degradation at elevated temperatures unless protective surface oxide scales are formed and maintained. The ability of alloys to resist rapid degradation strongly depends on their Cr content and the chemistry of the exposure environment. Normally, 20 wt % Cr is required for service at temperatures up to 1000{degree}C; the presence of sulfur, however, inhibits formation of a protective surface oxide scale. The oxidation and sulfidation behavior of Fe-Cr-Ni alloys is examined over a wide temperature range (650 to 1000{degree}C), with particular emphasis on the effects of alloy Cr content and the radiation of reactive elements such as Nb and Zr. Both Nb and Zr are shown to promote protective oxidation behavior on the 12 wt % Cr alloy in oxidizing environments and to suppress sulfidation in mixed oxygen/sulfur environments. Additions of Nb and Zr at 3 wt % level resulted in stabilization of Cr{sub 2}O{sub 3} scale and led to a barrier layer of Nb- or Zr-rich oxide at the scale/metal interface, which acted to minimize the transport of base metal cations across the scale. Oxide scales were preformed in sulfur-free environments and subsequently exposed to oxygen/sulfur mixed-gas atmospheres. Preformed scales were found to delay the onset of breakaway corrosion. Corrosions test results obtained under isothermal and thermal cycling conditions are presented. 58 refs., 55 figs., 8 tabs.

A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

International Nuclear Information System (INIS)

Huang, Y.J.; Shen, J.; Sun, J.F.; Yu, X.B.

2007-01-01

The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti 41.5 Zr 2.5 Hf 5 Cu 42.5-x Ni 7.5 Si 1 Sn x (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy. The activation energies for glass transition and crystallization for Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy also possesses superior mechanical properties

Molecular basis of cannabinoid CB1 receptor coupling to the G protein heterotrimer Gαiβγ: identification of key CB1 contacts with the C-terminal helix α5 of Gαi.

Science.gov (United States)

Shim, Joong-Youn; Ahn, Kwang H; Kendall, Debra A

2013-11-08

The cannabinoid (CB1) receptor is a member of the rhodopsin-like G protein-coupled receptor superfamily. The human CB1 receptor, which is among the most expressed receptors in the brain, has been implicated in several disease states, including drug addiction, anxiety, depression, obesity, and chronic pain. Different classes of CB1 agonists evoke signaling pathways through the activation of specific subtypes of G proteins. The molecular basis of CB1 receptor coupling to its cognate G protein is unknown. As a first step toward understanding CB1 receptor-mediated G protein signaling, we have constructed a ternary complex structural model of the CB1 receptor and Gi heterotrimer (CB1-Gi), guided by the x-ray structure of β2-adrenergic receptor (β2AR) in complex with Gs (β2AR-Gs), through 824-ns duration molecular dynamics simulations in a fully hydrated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer environment. We identified a group of residues at the juxtamembrane regions of the intracellular loops 2 and 3 (IC2 and IC3) of the CB1 receptor, including Ile-218(3.54), Tyr-224(IC2), Asp-338(6.30), Arg-340(6.32), Leu-341(6.33), and Thr-344(6.36), as potential key contacts with the extreme C-terminal helix α5 of Gαi. Ala mutations of these residues at the receptor-Gi interface resulted in little G protein coupling activity, consistent with the present model of the CB1-Gi complex, which suggests tight interactions between CB1 and the extreme C-terminal helix α5 of Gαi. The model also suggests that unique conformational changes in the extreme C-terminal helix α5 of Gα play a crucial role in the receptor-mediated G protein activation.

Effect of processing variables on microstructure and properties of two Al-Li-Cu-Mg-Zr alloys

International Nuclear Information System (INIS)

Palmer, I.G.; Lewis, R.E.; Crooks, D.D.

1984-01-01

Two Al-Li-Cu-Mg-Zr alloys have been prepared in the form of both powder metallurgy (PM) and ingot metallurgy (IM) alloys. The compositions were selected to meet certain program goals based on the results of an alloy development phase, the details of which have been previously published. The target compositions were Al-3Li-1.5Cu-1Mg-0.2Zr and Al-3Cu-2Li-1Mg-0.2Zr. The PM alloys were prepared from chill cast remelt stock by centrifugal atomization in helium, followed by screening, degassing, and extrusion. The IM alloys were prepared by direct chill (DC) casting, homogenization and extrusion. Full details of the production of the alloys are given. The effects of various processing conditions on microstructure and properties were evaluated, including different heat treatments and stretching conditions. These effects are described in detail with particular emphasis on a comparison of the PM and IM alloys. 10 references

Diffusion and chemical activity of Zr-Sn and Zr-Ti systems

International Nuclear Information System (INIS)

Zee, R.H.; Watters, J.F.; Davidson, R.D.

1986-01-01

A modified evaporation method was used to determine the diffusion coefficients and the emission rates of Sn and Ti in Zr-Sn and Zr-Ti, respectively, at temperatures between 1605 and 1970 K. Results show that both Sn and Ti diffuse in their respective alloys via a vacancy mechanism. Comparison with data in the literature reveals that the activation energy for diffusion of Sn in Zr-Sn, with Sn content between 3 and 5 at.X is relatively constant from 1200 to 1970 K. From the measured emission rates, values of 103 and 98 kcal/mol were obtained for the enthalpies of sublimation for Sn and Ti in their alloys. With a comparison of the solute vapor pressures with those of the pure elements, partial molar free energies, entropies, and enthalpies for the two systems were determined in the temperature range investigated. The Zr-Sn system shows a very large negative heat of formation (-33 kcal/mol) whereas the Zr-Ti system behaves quite ideally, in agreement with phase-diagram predictions

Magnetoimpedance effect in Nanoperm alloys

International Nuclear Information System (INIS)

Hernando, B.; Alvarez, P.; Santos, J.D.; Gorria, P.; Sanchez, M.L.; Olivera, J.; Perez, M.J.; Prida, V.M.

2006-01-01

The influence of isothermal annealing (1 h at 600 deg. C in Ar atmosphere) on the soft magnetic properties and magnetoimpedance (MI) effect has been studied in ribbons of the following Nanoperm alloys: Fe 91 Zr 7 B 2 , Fe 88 Zr 8 B 4 , Fe 87 Zr 6 B 6 Cu 1 and Fe 8 Zr 1 B 1 . A maximum MI ratio of about 27% was measured for the nanocrystalline alloy Fe 87 Zr 6 B 6 Cu 1 at a driving frequency of 0.2 MHz. The thermal annealing led to magnetic softening for this alloy, while a hardening is observed for the Fe 8 Zr 1 B 1 alloy

Effect of Zr Purity and Oxygen Content on the Structure and Mechanical Properties of Melt-Spun and Suction-Cast Cu46Zr42Al7Y5 Alloy

Directory of Open Access Journals (Sweden)

Kozieł T.

2016-06-01

Full Text Available The effect of oxygen content in zirconium on the structure and mechanical properties of the Cu46Zr42Al7Y5 alloy, in the form of melt-spun ribbons and suction-cast rods, was investigated. Two types of Zr, rod and crystal bar of different nominal purities and oxygen contents, were used to synthesize the alloy by arc melting. Rapidly solidified ribbons were produced by melt spinning and their amorphous structures were confirmed by X-ray diffractometry (XRD and differential scanning calorimetry (DSC. Bulk samples in the form of rods were cast using a special water-cooled suction casting unit attached to the arc melting system. XRD and DSC studies proved the amorphous structure of the bulk alloy synthesized from low-oxygen Zr and partial crystallization of the same alloy for high-oxygen Zr. In both bulk samples, uniformly distributed crystalline particles were identified as yttrium oxides. Higher mean compressive strength of amorphous alloy was observed. The hardness of amorphous phase was close to 500 HV1 in both bulk alloys, while the hardness of crystalline dendritic areas, observed in the alloy synthesized from high oxygen Zr, was lower by about 50 HV1.

Effects of homogenization on microstructures and properties of a new type Al-Mg-Mn-Zr-Ti-Er alloy

International Nuclear Information System (INIS)

He, L.Z.; Li, X.H.; Liu, X.T.; Wang, X.J.; Zhang, H.T.; Cui, J.Z.

2010-01-01

Research highlights: These new type alloys are very potential for increased use in aerospace and automobile industries. However, most of published reports have focused on the effects of Cu, Sc, Zr, Ag, rare metals and Si additions, Portevin-LeChatelier effect, corrosion properties, friction stir welding and superplasticity in 5000-series aluminum alloy, few investigated on Er and stepped homogenization on the precipitation of dispersoids in Al-Mg-Mn alloy. The purpose of this work was to study the effects of Er and homogenization treatment on mechanical properties and microstructural evolution in new type Al-Mg-Mn-Er alloy. - Abstract: Microstructural evolutions and mechanical properties of Al-Mg-Mn-Zr-Ti-Er alloy after homogenization were investigated in detail by optical microscope (OM), scanning electronic microscope (SEM), transmission electronic microscope (TEM), energy dispersive spectrum (EDS) and tensile test. A maximum tensile strength is obtained when the alloy homogenized at 510 deg. C for 16 h. With increasing preheating temperature (200-400 deg. C), the strength of the alloy finial homogenized at 490 deg. C for 16 h increases. When the preheating temperature is ≥300 deg. C, the strengths of the two-step homogenized alloys are higher than those of the single homogenized alloys. The preheating stage plays an important role in the microstructures and properties of the final homogenized alloy. Many fine (Mn,Fe)Al 6 precipitates when the preheating temperature is 400 deg. C. ErAl 3 phase cannot be observed during preheating stage. Plenty of fine (Mn,Fe)Al 6 and ErAl 3 precipitate in finial homogenized alloy when the preheating temperature is ≥300 deg. C. The Al-Mg-Mn-Zr-Ti-Er alloy is effectively strengthened by substructure and dispersoids of (Mn,Fe)Al 6 and ErAl 3 .

Mechanical properties and corrosion behavior of Mg-Gd-Ca-Zr alloys for medical applications.

Science.gov (United States)

Shi, Ling-Ling; Huang, Yuanding; Yang, Lei; Feyerabend, Frank; Mendis, Chamini; Willumeit, Regine; Ulrich Kainer, Karl; Hort, Norbert

2015-07-01

Magnesium alloys are promising candidates for biomedical applications. In this work, influences of composition and heat treatment on the microstructure, the mechanical properties and the corrosion behavior of Mg-Gd-Ca-Zr alloys as potential biomedical implant candidates were investigated. Mg5Gd phase was observed at the grain boundaries of Mg-10Gd-xCa-0.5Zr (x=0, 0.3, 1.2wt%) alloys. Increase in the Ca content led to the formation of additional Mg2Ca phase. The Ca additions increased both the compressive and the tensile yield strengths, but reduced the ductility and the corrosion resistance in cell culture medium. After solution heat treatment, the Mg5Gd particles dissolved in the Mg matrix. The compressive strength decreased, while the corrosion resistance improved in the solution treated alloys. After ageing at 200°C, metastable β' phase formed on prismatic planes and a new type of basal precipitates have been observed, which improved the compressive and tensile ultimate strength, but decreased the ductility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microstructure, mechanical properties, in vitro degradation and cytotoxicity evaluations of Mg-1.5Y-1.2Zn-0.44Zr alloys for biodegradable metallic implants.

Science.gov (United States)

Fan, Jun; Qiu, Xin; Niu, Xiaodong; Tian, Zheng; Sun, Wei; Liu, Xiaojuan; Li, Yangde; Li, Weirong; Meng, Jian

2013-05-01

Mg-1.5Y-1.2Zn-0.44Zr alloys were newly developed as degradable metallic biomaterials. A comprehensive investigation of the microstructure, mechanical properties, in vitro degradation assessments and in vitro cytotoxicity evaluations of the as-cast state, as-heat treated state and as-extruded state alloys was done. The microstructure observations show that the Mg-1.5Y-1.2Zn-0.44Zr alloys are mainly composed of the matrix α-Mg phases and the Mg12ZnY secondary phases (LPS structure). The hot extrusion method significantly refined the grains and eliminated the defects of both as-cast and heat treated alloys and thereby contributed to the better mechanical properties and biodegradation resistance. The values of tensile strength and tensile yield strength of the alloy in the as-extruded condition are about 236 and 178 MPa respectively, with an excellent elongation of 28%. Meanwhile, the value of compressive strength is about 471 MPa and the value of bending strength is about 501 MPa. The superior bending strength further demonstrates the excellent ductility of the hot extruded alloys. The results of immersion tests and electrochemical measurements in the SBF indicate that a protective film precipitated on the alloy's surface with the extension of degradation. The protective film contains Mg(OH)2 and hydroxyapatite (HA) which can reinforce osteoblast activity and promote good biocompatibility. No significant cytotoxicity towards L-929 cells was detected and the immersion extracts of alloy samples could enhance the cell proliferation with time in the cytotoxicity evaluations, implying that the Mg-1.5Y-1.2Zn-0.44Zr alloys have the potential to be used for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

The formation of FHA coating on biodegradable Mg-Zn-Zr alloy using a two-step chemical treatment method

International Nuclear Information System (INIS)

Jiang, S.T.; Zhang, J.; Shun, S.Z.; Chen, M.F.

2016-01-01

Highlights: • Use a two-step chemical treatment method for formation of FHA coating on biodegradable Mg-Zn-Zr alloy;. • We reported the formation mechanism of FHA coating on Mg-Zn-Zr alloy and achieved optimum properties;. • The MgF_2 coating and FHA coating provide effective protection for the Mg alloy substrate and the FHA coating showed better corrosion resistance. - Abstract: To improve the corrosion resistance of the biomedical magnesium alloy, a two-step chemical treatment method has been employed to prepare an FHA coating on the alloy surface. Prior to forming an FHA layer, the samples of Mg-3 wt% Zn-0.5 wt% Zr alloy were soaked in HF with concentration of 20% (v/v) at 37 °C temperature for 2 h, and were then placed into an aqueous solution with 0.1 mol/L Ca(NO_3).4H_2O and 0.06 mol/L NH_4H_2PO_4 at 90 °C to prepare the Ca-P coating. The concentrations of Mg"2"+, F"− ions, and pH variation with immersing time in the solution were investigated to explore the growth mechanism of FHA. The surface morphologies and compositions of the coatings were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results showed that the alloy surface treated with acid formed a layer of MgF_2 nanoparticles with a thickness of 0.7 μm. The corrosion resistance of coatings in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results showed that the substrate with FHA coating had good corrosion resistance. After immersing into the calcium phosphate solution, some small spherical particles were first formed on the surface; these then cover the surface completely after 20 min. Some clusters consisting of needle-like crystal were observed in the spherical particles covering the surface, and the Ca/P ratio of the needle-like crystal was 1.46, clearly growing along the c axis preferred orientation growth. After immersion for 60 min, the FHA coating with

Electron microscopy investigations of rapidly solidified Fe-Zr-B-Cu alloys

International Nuclear Information System (INIS)

Majumdar, B.; Arvindha Babu, D.; Akhtar, D.

2010-01-01

Rapidly solidified Fe-based nanocrystalline soft magnetic materials possess a unique combination of properties i,e high permeability, saturation and Curie temperature and very low coercivity which are otherwise not attainable in conventional soft magnetic materials. The alloys are processed by producing amorphous phase through melt spinning route followed by a partial devitrification for incorporation of nanocrystalline phase in the amorphous matrix. In this paper, detailed electron microscopic investigations of melt spun Fe-Zr-B-Cu alloys are presented. Melt spun ribbons of Fe 99-x-y Zr x BCu 1 alloys with x+y = 11 and x+y = 13 were prepared under different wheel speed conditions and then vacuum annealed for 1 h at different temperatures. The microstructure changes from completely amorphous to a cellular/dendritic bcc solid solution coexisting with the amorphous phase at intercellular/dendritic regions when Zr/B ratio or the process parameters are varied. Annealing leads to the precipitation of nanocrystalline bcc-Fe phase from both amorphous phase and already existing bcc solid solution. (author)

Ternary ceramic alloys of Zr-Ce-Hf oxides

Science.gov (United States)

Becher, P.F.; Funkenbusch, E.F.

1990-11-20

A ternary ceramic alloy is described which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce[sub x]Hf[sub y]Zr[sub 1[minus]x[minus]y]O[sub 2], is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites. 1 fig.

Grain refining efficiency of Al-Ti-C alloys

International Nuclear Information System (INIS)

Birol, Yuecel

2006-01-01

The problems associated with boride agglomeration and the poisoning effect of Zr in Zr-bearing alloys have created a big demand for boron-free grain refiners. The potential benefits of TiC as a direct nucleant for aluminium grains have thus generated a great deal of interest in TiC-bearing alloys in recent years. In Al-Ti-C grain refiners commercially available today, Al 3 Ti particles are introduced into the melt along with the TiC particles. Since the latter are claimed to nucleate α-Al directly, it is of great technological interest to see if reducing the Ti:C ratio further, i.e., increasing the C content of the grain refiner, will produce an increase in the grain refining efficiency of these alloys. A series of grain refiner samples with the Ti concentration fixed at 3% and a range of C contents between 0 and 0.75 were obtained by appropriately mixing an experimental Al-3Ti-0.75C alloy with Al-10Ti alloy and commercial purity aluminium. The grain refining efficiency of these grain refiners was assessed to investigate the role of the insoluble TiC and the soluble Al 3 Ti particles. The optimum chemistry for the Al-Ti-C grain refiners was also identified

Grain refining efficiency of Al-Ti-C alloys

Energy Technology Data Exchange (ETDEWEB)

Birol, Yuecel [Materials Institute, Marmara Research Center, TUBITAK, 41470 Gebze, Kocaeli (Turkey)]. E-mail: yucel.birol@mam.gov.tr

2006-09-28

The problems associated with boride agglomeration and the poisoning effect of Zr in Zr-bearing alloys have created a big demand for boron-free grain refiners. The potential benefits of TiC as a direct nucleant for aluminium grains have thus generated a great deal of interest in TiC-bearing alloys in recent years. In Al-Ti-C grain refiners commercially available today, Al{sub 3}Ti particles are introduced into the melt along with the TiC particles. Since the latter are claimed to nucleate {alpha}-Al directly, it is of great technological interest to see if reducing the Ti:C ratio further, i.e., increasing the C content of the grain refiner, will produce an increase in the grain refining efficiency of these alloys. A series of grain refiner samples with the Ti concentration fixed at 3% and a range of C contents between 0 and 0.75 were obtained by appropriately mixing an experimental Al-3Ti-0.75C alloy with Al-10Ti alloy and commercial purity aluminium. The grain refining efficiency of these grain refiners was assessed to investigate the role of the insoluble TiC and the soluble Al{sub 3}Ti particles. The optimum chemistry for the Al-Ti-C grain refiners was also identified.

Effect of hydrogen and oxygen content on the embrittlement of Zr alloys

International Nuclear Information System (INIS)

Griger, A.; Hozer, Z.; Matus, L.; Vasaros, L.; Horvath, M.

2001-01-01

An experimental study is carried out in the KFKI Atomic Energy Research Institute in order to clear up the role of oxidation and hydrogen uptake in the embrittlement process. Russian E110 type Zr1%Nb and Zircaloy-4 claddings are used as test materials. The differences between the properties of two alloys are examined. The sample preparation covered the following cases: oxidation in Ar+O 2 atmosphere; hydrogen uptake of as received and pre-oxidised samples (in Ar+O 2 atmosphere); oxidation in steam. The oxidation in Ar+O 2 and the subsequent hydrogen uptake procedure make possible the production of samples with well-characterized hydrogen and oxygen content. Corrosion treated ring samples of 8 mm height are examined in ring compression tests. The force-deformation curves are recorded and the crushing force and deformation are determined. The relative deformation is used for the characterisation of embrittlement level. The results of experiments provide detailed information about the effect of hydrogen and oxygen content on the embrittlement of zirconium alloys. The conclusions are: 1) hydrogen seems to play a more important role in the embrittlement of zirconium alloys than oxygen; 2) the Zircaloy-4 alloy becomes brittle at lower hydrogen content than the Zr1%Nb; 3) under steam oxidation conditions the Zr1%Nb alloy takes up much more hydrogen and becomes more brittle than the Zircaloy-4

Interdiffusion and reactions between U-Mo and Zr at 650 °C as a function of time

Science.gov (United States)

Park, Y.; Keiser, D. D.; Sohn, Y. H.

2015-01-01

Development of monolithic U-Mo alloy fuel (typically U-10 wt.%Mo) for the Reduced Enrichment for Research and Test Reactors (RERTR) program entails a use of Zr diffusion barrier to eliminate the interdiffusion-reactions between the fuel alloy and Al-alloy cladding. The application of Zr barrier to the U-Mo fuel system requires a co-rolling process that utilizes a soaking temperature of 650 °C, which represents the highest temperature the fuel system is exposed to during both fuel manufacturing and reactor application. Therefore, in this study, development of phase constituents, microstructure and diffusion kinetics of U-10 wt.%Mo and Zr was examined using solid-to-solid diffusion couples annealed at 650 °C for 240, 480 and 720 h. Phase constituents and microstructural development were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Concentration profiles were mapped as diffusion paths on the isothermal ternary phase diagram. Within the diffusion zone, single-phase layers of β-Zr and β-U were observed along with a discontinuous layer of Mo2Zr between the β-Zr and β-U layers. In the vicinity of Mo2Zr phase, islands of α-Zr phases were also found. In addition, acicular α-Zr and U6Zr3Mo phases were observed within the γ-U(Mo) terminal alloy. Growth rate of the interdiffusion-reaction zone was determined to be 7.75 (± 5.84) × 10-16 m2/s at 650 °C, however with an assumption of a certain incubation period.

Enhancement of wear and corrosion resistance of low modulus β-type Zr-20Nb-xTi (x=0, 3) dental alloys through thermal oxidation treatment.

Science.gov (United States)

Zhang, Jianfeng; Gan, Xiaxia; Tang, Hongqun; Zhan, Yongzhong

2017-07-01

In order to obtain material with low elastic modulus, good abrasion resistance and high corrosion stability as screw for dental implant, the biomedical Zr-20Nb and Zr-20Nb-3Ti alloy with low elastic modulus were thermal oxidized respectively at 700°C for 1h and 600°C for 1.25h to obtain the compact oxidized layer to improve its wear resistance and corrosion resistance. The results show that smooth compact oxidized layer (composed of monoclinic ZrO 2 , tetragonal ZrO 2 and 6ZrO 2 -Nb 2 O 5 ) with 22.6μm-43.5μm thickness and 1252-1306HV hardness can be in-situ formed on the surface of the Zr-20Nb-xTi (x=0, 3). The adhesion of oxidized layers to the substrates is determined to be 58.35-66.25N. The oxidized Zr-20Nb-xTi alloys reveal great improvement of the pitting corrosion resistance in comparison with the un-oxidized alloys. In addition, the oxidized Zr-20Nb-3Ti exhibits sharply reduction of the corrosion rates and the oxidized Zr-20Nb shows higher corrosion rates than un-oxidized alloys, which is relevant with the content of the t-ZrO 2 . Wear test in artificial saliva demonstrates that the wear losses of the oxidized Zr-20Nb-xTi (x=0, 3) are superior to pure Ti. All of the un-oxidized Zr-20Nb-xTi (x=0, 3) alloys suffer from serious adhesive wear due to its high plasticity. Because of the protection from compact oxide layer with high adhesion and high hardness, the coefficients of friction and wear losses of the oxidized Zr-20Nb-xTi (x=0, 3) alloys decrease 50% and 95%, respectively. The defects on the oxidized Zr-20Nb have a negative effect on the friction and wear properties. In addition, after the thermal oxidation, compression test show that elastic modulus and strength of Zr-20Nb-xTi (x=0, 3) increase slightly with plastic deformation after 40% of transformation. Furthermore, stripping of the oxidized layer from the alloy matrix did not occur during the whole experiments. As the surface oxidized Zr-20Nb-3Ti alloy has a combination of excellent performance

Microstructure and mechanical properties of Ti-15Zr alloy used as dental implant material.

Science.gov (United States)

Medvedev, Alexander E; Molotnikov, Andrey; Lapovok, Rimma; Zeller, Rolf; Berner, Simon; Habersetzer, Philippe; Dalla Torre, Florian

2016-09-01

Ti-Zr alloys have recently started to receive a considerable amount of attention as promising materials for dental applications. This work compares mechanical properties of a new Ti-15Zr alloy to those of commercially pure titanium Grade4 in two surface conditions - machined and modified by sand-blasting and etching (SLA). As a result of significantly smaller grain size in the initial condition (1-2µm), the strength of Ti-15Zr alloy was found to be 10-15% higher than that of Grade4 titanium without reduction in the tensile elongation or compromising the fracture toughness. The fatigue endurance limit of the alloy was increased by around 30% (560MPa vs. 435MPa and 500MPa vs. 380MPa for machined and SLA-treated surfaces, respectively). Additional implant fatigue tests showed enhanced fatigue performance of Ti-15Zr over Ti-Grade4. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Zr on the Corrosion Properties of Mg-Li-Al Alloy

International Nuclear Information System (INIS)

Kim, Soon Ho; Choi, Sang Hyun; Kim, In Bae; Kim, Kyung Hyun

1994-01-01

Effect of Zr on the electrochemical corrosion characteristics of Mg-Li-Al alloy has been investigated by means of potentiodynamic polarization study. The electrochemical behaviors were evaluated in 0.03% NaCl solution and the solution buffered with KH 2 PO 5 · NaOH at room temperature. It was found that the addition of very small quantity of Zr (0.03wt%) in Mg-Li-Al alloy increased corrosion rates and amount of corrosion products and decreased the pitting resistance of the alloy. From the results it was concluded that Zr which is added to increase the strength of Mg-Li-Al alloy is harmful to corrosion properties of the alloy

Effects of TiN coating on the corrosion of nanostructured Ti-30Ta-xZr alloys for dental implants

Science.gov (United States)

Kim, Won-Gi; Choe, Han-Cheol

2012-01-01

Electrochemical characteristics of a titanium nitride (TiN)-coated/nanotube-formed Ti-Ta-Zr alloy for biomaterials have been researched by using the magnetic sputter and electrochemical methods. Ti-30Ta-xZr (x = 3, 7 and 15 wt%) alloys were prepared by arc melting and heat treated for 24 h at 1000 °C in an argon atmosphere and then water quenching. The formation of oxide nanotubes was achieved by anodizing a Ti-30Ta-xZr alloy in H3PO4 electrolytes containing small amounts of fluoride ions at room temperature. Anodization was carried out using a scanning potentiostat, and all experiments were conducted at room temperature. The microstructure and morphology of nanotube arrays were characterized by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The TiN coatings were obtained by the radio-frequency (RF) magnetron sputtering technique. The depositions were performed from pure Ti targets on Ti-30Ta-xZr alloys substrates. The corrosion properties of the specimens were examined using potentiodynamic test in a 0.9% NaCl solution by using potentiostat. The microstructures of Ti-30Ta-xZr alloys were changed from an equiaxed to a needle-like structure with increasing Zr content. The interspace between the nanotubes was approximately 20, 80 and 200 nm for Zr contents of 3, 7 and 15 wt%, respectively. The corrosion resistance of the TiN-coated on the anodized Ti-30Ta-xZr alloys was higher than that of the untreated Ti alloys, indicating a better protective effect.

Effect of Fe and Zr additions on ω phase formation in β-type Ti-Mo alloys

International Nuclear Information System (INIS)

Min, X.H.; Emura, S.; Zhang, L.; Tsuzaki, K.

2008-01-01

The effect of 1% Fe and/or 5% Zr (mass%) additions on ω phase formation was investigated for the Ti-15Mo alloy by means of X-ray diffraction analysis and hardness testing. Upon water quenching following solution treatment in the β phase region, the athermal ω phase formation could not be observed in all the alloys, regardless of Fe and Zr additions. The lattice parameter of the β phase decreases with Fe addition, while it increases with Zr addition. Solid solution strengthening by Fe and Zr is not recognized for the β phase. The isothermal ω phase formed after aging at 723 K and 773 K for 3.6 ks, which results in a decrease in the lattice parameter of the β phase and an increase in the hardness. The isothermal ω phase formation is suppressed with Fe and/or Zr additions. This is interpreted as the consequence of the increase in the average value of the bond order (Bo) for the Ti-15Mo-5Zr and Ti-15Mo-5Zr-1Fe alloys, and of the decrease in the average value of the metal d-orbital energy level (Md) for the Ti-15Mo-1Fe alloy. In addition, the degree of the suppression of isothermal ω phase can be predicted by the average values of Bo and Md

Ti-25Ta-Zr alloys for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Kuroda, Pedro Akira Bazaglia; Quadros, Fernanda Freitas; Grandini, Carlos Roberto, E-mail: pedro@fc.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Bauru, SP (Brazil). Faculdade de Ciencias

2016-07-01

Full text: The most widely used titanium alloy for biomedical applications is Ti-6Al-4V, however, previous studies showed that vanadium cause allergic reactions in human tissue and aluminum has been associated with neurological disorders. Then, to solve this problem, new titanium alloys without the presence of these elements are being developed, with the addition of different elements, usually the β-stabilizers, which can change its microstructure and mechanical properties, and may make the titanium and its alloys, most promising for use as biomaterial. In this paper the development and characterization of Ti-25Ta-(10-40)Zr alloys, for biomedical applications are discussed. X-ray diffraction results show the coexistence of α', α” and β phases, which are corroborated by SEM results. The results of microhardness and elastic modulus present an anomaly for the alloy with 10 wt% Zr, due, probably the presence of ω phase. (author)

Electrochemical and surface behavior of hydyroxyapatite/Ti film on nanotubular Ti-35Nb-xZr alloys

International Nuclear Information System (INIS)

Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

2012-01-01

In this paper, we investigated the electrochemical and surface behavior of hydroxyapatite (HA)/Ti films on the nanotubular Ti-35Nb-xZr alloy. The Ti-35Nb-xZr ternary alloys with 3-10 wt.% Zr content were made by an arc melting method. The nanotubular oxide layers were developed on the Ti-35Nb-xZr alloys by an anodic oxidation method in 1 M H 3 PO 4 electrolyte containing 0.8 wt% NaF at room temperature. The HA/Ti composite films on the nanotubular oxide surfaces were deposited by a magnetron sputtering method. Their surface characteristics were analyzed by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and an X-ray diffractometer (XRD). The corrosion behavior of the specimens was examined through potentiodynamic and AC impedance tests in 0.9% NaCl solution. From the results, the Ti-35Nb-xZr alloys showed a solely β phase microstructure that resulted from the addition of Zr. The nanotubular structure formed with a diameter of about 200 nm, and the HA/Ti thin film was deposited on the nanotubular structure. The HA/Ti thin film-coated nanotubular Ti-35Nb-xZr alloys showed good corrosion resistance in 0.9% NaCl solution.

Investigation of the structure and properties of the titanium alloy of the Ti-Al-Mo-V-Fe-Cu-Zr-Sn system

International Nuclear Information System (INIS)

Moiseev, V.N.; Dolzhanskij, Yu.M.; Zakharov, Yu.I.; Znamenskaya, E.V.

1979-01-01

The alloys of martensitic type in the Ti-Al-Mo-V-Fe-Cu-Zr-Sn system after heat treatment are investigated. To determine the composition of the titanium alloy methods of mathematical planning of the experiment are applied. Results of mechanical tests of the alloys are presented, as well as coefficients of models for the properties, calculated according to these data. The investigation establishes the composition of a high-strength titanium alloy of a martensitic type, containing 4.5-60 % Al, 2.0-4.0 % Mo, 0.5-1.9 % V, 0.3-1.5 % Fe, 0.3-1.5 % Cu, 1.5-3.0 % Sn, 2.0-4.0 % Zr. The semiproducts, produced by deformation in β-field, after heat treatment have an ultimate strength >=120 kg/mm 2 , satisfactory ductility and reliability. The alloy possesses rather a high heat resistance and can be operated at 400-500 deg C

Effect of minor Er and Zr on microstructure and mechanical properties of Al–Mg–Mn alloy (5083) welded joints

International Nuclear Information System (INIS)

Dongxia, Yang; Xiaoyan, Li; Dingyong, He; Hui, Huang

2013-01-01

Samples of Al–Mg–Mn and Al–Mg–Mn–Er–Zr alloys were welded using the method of laser welding. The influence of Er and Zr on microstructure, microhardness and mechanical properties of the Al–Mg–Mn alloy welded joints were investigated. It has been found that addition of Er and Zr refines the grain size in the fusion zone, due to the formation of primary Al 3 Zr and Al 3 Er. Fine equiaxed grains are dominated near the fusion boundary of the Al–Mg–Mn–Er–Zr alloy joint, which is contrary with the columnar crystal in the Al–Mg–Mn alloy joint. Microhardness of the center of the fusion zone rises from 74HV 0.1 to 84HV 0.1 owing to the grain refinement by Er and Zr. The tensile test result shows that the ultimate tensile strength and yield strength are improved by adding Er and Zr. The main reason for this is related to grain refining strengthening.

3D-AP and positron annihilation study of precipitation behavior in Cu-Cr-Zr alloy

DEFF Research Database (Denmark)

Hatakeyama, M.; Toyama, T.; Yang, J.

2009-01-01

Precipitation behavior in a Cu-0.78%Cr-0.13%Zr alloy during aging and reaging has been studied by laser-assisted local electrode three-dimensional atom probe (Laser-LEAP) and positron annihilation spectroscopy (PAS). After the prime aging at 460 degrees C, Cr clusters enriched with Zr were observed...

Microstructural studies of suck cast (Zr-SS)-3 and 5 AI alloys for nuclear metallic waste form

International Nuclear Information System (INIS)

Kumar, P.; Das, N.; Sengupta, P.; Arya, A.; Dey, G.K.

2015-01-01

Management of radioactive metallic waste using 'alloy melting route' is currently being investigated. For disposal of Zr and SS base nuclear metallic wastes, Zr-stainless steel (SS) hybrid alloys are being considered as baseline alloys for developing metallic-waste-form (MWF) alloys. In this context Zr-16 wt. %55 has been selected for MWF alloy in our previous study. In present study, to include amorphous phase in this alloy, 3 and 5 wt. % Al has been added in order to improve desirable properties and useful features of MWF and the two alloys have been prepared by suck casting techniques. Microstructure of these alloys have been investigated by optical and electron microscopy which shows occurrence of two different phases, e.g. dark grey and white phases, in (Zr-16 SS)-3 Al and three different phases, e.g. grey, dark grey and white phases in (Zr-16 SS)-5 AI. Electron diffraction and X-ray diffraction (XRD) analyses of these two alloy specimens revealed the occurrence of Zr (Fe, Cr, AI) (dark grey) and Zr 2 (Fe, Cr, AI) (white) phases in (Zr-16 SS)-3 Al whereas, Zr (Fe, Cr, AI) (dark grey), Zr 2 (Fe, Cr, AI) (grey) and Zr 3 (Fe, Cr, AI) (white) phases were found in (Zr-16 SS)-5 AI. In addition, presence of amorphous phase was indicated by XRD analysis that could be confirmed by transmission electron microscopy of these two alloys. (author)

Corrosion resistance of ZrTi alloys with hydroxyapatite-zirconia-silver layer in simulated physiological solution containing proteins for biomaterial applications

Energy Technology Data Exchange (ETDEWEB)

Mareci, D., E-mail: danmareci@yahoo.com [Technical University “Gheorghe Asachi” of Iasi, Faculty of Chemical Engineering and Environmental Protection, D. Mangeron, Iasi, 700050 (Romania); Trincă, L.C. [“Ion Ionescu de la Brad” University of Agricultural Science and Veterinary Medicine, Faculty of Horticulture, Science Department, 3, Mihail Sadoveanu Alley, Iaşi, 700490 (Romania); Căilean, D. [Technical University “Gheorghe Asachi” of Iasi, Faculty of Chemical Engineering and Environmental Protection, D. Mangeron, Iasi, 700050 (Romania); Souto, R.M., E-mail: rsouto@ull.es [Department of Chemistry, Universidad de La Laguna, E-38200 La Laguna (Tenerife, Canary Islands) (Spain); Institute of Material Science and Nanotechnology, Universidad de La Laguna, E-38200 La Laguna (Tenerife, Canary Islands) (Spain)

2016-12-15

Highlights: • Hydroxyapatite-zirconia coated ZrTi alloys were characterized for biocompatibility. • Silver nanoparticles added for antimicrobial activity. • Electrochemical behaviour consistent with surface layer of duplex structure. • Porous coating forms on passivating oxide layer. • HA-ZrO{sub 2}-Ag coated Zr45Ti exhibits high potential for implant application. - Abstract: The degradation characteristics of hydroxyapatite-zirconia-silver films (HA-ZrO{sub 2}-Ag) coatings on three ZrTi alloys were investigated in Ringer’s solution containing 10% human albumin protein at 37 °C. Samples were immersed for 7 days while monitored by electrochemical impedance spectroscopy (EIS) and linear potentiodynamic polarization (LPP). The electrochemical analysis in combination with surface analytical characterization by scanning electron microscopy (SEM/EDX) reveals the stability and corrosion resistance of the HA-ZrO{sub 2}-Ag coated ZrTi alloys. The characteristic feature that describes the electrochemical behaviour of the coated alloys is the coexistence of large areas of the coating presenting pores in which the ZrTi alloy substrate is exposed to the simulated physiological environment. The EIS interpretation of results was thus performed using a two-layer model of the surface film. The blocking effect in the presence the human albumin protein produces an enhancement of the corrosion resistance. The results disclose that the Zr45Ti alloy is a promising material for biomedical devices, since electrochemical stability is directly associated to biocompatibility.

Microstructural and thermodynamic evaluation of as-cast U-rich U-Zr alloys

International Nuclear Information System (INIS)

Basak, Chandrabhanu; Prasad, G.J.; Kamath, H.S.

2009-01-01

The present study involves evaluation of microstructures and some basic properties of as-cast uranium rich U-Zr alloys; i.e. uranium alloys containing 2wt%, 5wt%, 7wt% and 10 wt% zirconium. Microstructural evaluation, both optical and SEM, with hardness values are reported. It was shown that a definite correlation exists between the microstructure and the hardness of the alloy. Lattice parameter and densities are determined with the help of XRD analysis. Also the phase transformation mechanism is proposed based on the microstructures and XRD analysis. Thermodynamic analysis coupled with the experimental observation reveals that the lamellar structure found in the as-cast U-rich U-Zr alloys originates from the monotectoid reaction (γ→β + γ'). As Zr concentration increases in the alloy the gamma phase can remain in the metastable state even at lower T. So, with increasing Zr content the monotectoid reaction takes place at lower temperature causing generation of finer lamellae. (author)

The Zr-Ti-Cr system. Equilibria at 900 and 1100 C degrees

International Nuclear Information System (INIS)

Arico, Sergio F.; Gribaudo, Luis M.

2003-01-01

Main contributions to the knowledge of the ternary system Zr-Ti-Cr were published in the sixties. Stability domains of phases at temperatures between 500 and 1400 C degrees were there presented. Here, results related to the phase diagram at 900 and 1100 C degrees are informed. Three alloys with 40 at.% Cr and different Zr/Ti ratios and one more, richer in Cr, were elaborated. Specimens of the alloys were heat treated 1000 and 800 h at 900 and 1100 C degrees respectively. Phase characterizations were performed by optic metallography and X-ray diffraction analysis. Compositions were determined by microprobe. Alloys with 40 at.% Cr at both temperatures have biphasic equilibria between the intermetallic Laves phase AB 2 and the body-centered cubic solid solution containing principally zirconium and titanium. The Cr-rich alloy presents equilibrium of the AB 2 compound and the Cr-rich solid solution. Results of the present and previous works are used in order to propose new isothermal sections at 900 and 1100 C degrees. (author)

Effect of nitrogen addition and annealing temperature on superelastic properties of Ti-Nb-Zr-Ta alloys

Energy Technology Data Exchange (ETDEWEB)

Tahara, Masaki [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Kim, Hee Young, E-mail: heeykim@ims.tsukuba.ac.jp [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Hosoda, Hideki [Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Nam, Tae-hyun [School of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Miyazaki, Shuichi, E-mail: miyazaki@ims.tsukuba.ac.jp [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); School of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

2010-10-15

Research highlights: In this study, the effects of composition and annealing temperature on microstructure, shape memory effect and superelastic properties were investigated in Ti-Nb-4Zr-2Ta-N alloys by measuring stress-strain curves at various temperatures and using transmission electron microscopy. Dissolution of {alpha} phase increases M{sub s} and decreases the critical stress for slip for the Ti-22Nb-4Zr-2Ta alloy while it causes the decrease of M{sub s} and the increase of the critical stress for slip for the Ti-20Nb-4Zr-2Ta-0.6N alloy. The different effect of dissolution of {alpha} phase can be attributed to the fact that N is absorbed in {alpha} phase. - Abstract: The composition dependence of the mechanical properties and martensitic transformation behavior of Ti-Nb-4Zr-2Ta-N alloys is investigated. The effect of annealing temperature on the microstructural evolution and superelastic properties in the N-added and N-free alloys is compared. The addition of N decreases M{sub s} of Ti-Nb-4Zr-2Ta alloys by about 200 K per 1 at.%N and improves the superelastic properties of Ti-Nb-4Zr-2Ta alloys. The dissolution of {alpha} phase increases the martensitic transformation start temperature and decreases the superelastic recovery strain for the N-free alloy, whereas it causes opposite effects for the N-added alloy. The different annealing temperature dependences of superelastic properties are discussed on the basis of microstructure observation.

Effect of nitrogen addition and annealing temperature on superelastic properties of Ti-Nb-Zr-Ta alloys

International Nuclear Information System (INIS)

Tahara, Masaki; Kim, Hee Young; Hosoda, Hideki; Nam, Tae-hyun; Miyazaki, Shuichi

2010-01-01

Research highlights: In this study, the effects of composition and annealing temperature on microstructure, shape memory effect and superelastic properties were investigated in Ti-Nb-4Zr-2Ta-N alloys by measuring stress-strain curves at various temperatures and using transmission electron microscopy. Dissolution of α phase increases M s and decreases the critical stress for slip for the Ti-22Nb-4Zr-2Ta alloy while it causes the decrease of M s and the increase of the critical stress for slip for the Ti-20Nb-4Zr-2Ta-0.6N alloy. The different effect of dissolution of α phase can be attributed to the fact that N is absorbed in α phase. - Abstract: The composition dependence of the mechanical properties and martensitic transformation behavior of Ti-Nb-4Zr-2Ta-N alloys is investigated. The effect of annealing temperature on the microstructural evolution and superelastic properties in the N-added and N-free alloys is compared. The addition of N decreases M s of Ti-Nb-4Zr-2Ta alloys by about 200 K per 1 at.%N and improves the superelastic properties of Ti-Nb-4Zr-2Ta alloys. The dissolution of α phase increases the martensitic transformation start temperature and decreases the superelastic recovery strain for the N-free alloy, whereas it causes opposite effects for the N-added alloy. The different annealing temperature dependences of superelastic properties are discussed on the basis of microstructure observation.

Effect of the Size of Al3(Sc,Zr) Precipitates on the Structure of Multi-Directionally Isothermally Forged Al-Mg-Sc-Zr Alloy

Science.gov (United States)

Sitdikov, O. Sh.; Avtokratova, E. V.; Mukhametdinova, O. E.; Garipova, R. N.; Markushev, M. V.

2017-12-01

The effect of Al3(Sc,Zr) dispersoids on the evolution of the cast Al-Mg-Sc-Zr alloy structure under multi-directional isothermal forging (MIF) has been investigated. The alloy, which has an equiaxed grain structure with a grain size of 25 μm and contains dispersoids 5-10 and 20-50 nm in size after onestage (at 360°C for 6 h) and two-stage (360°C for 6 h + 520°C for 1 h) annealing, respectively, was deformed at 325°C ( 0.65 T m) up to cumulative strains of e = 8.4. In the initial stages of MIF, new fine (sub)grains surrounded by low-angle and high-angle boundaries (HABs) were formed near the initial grain boundaries. With increasing strain, the volume fraction and misorientation of these crystallites increased, which led to the replacement of a coarse-grained structure with a fine-grained one with a grain size of 1.5-2.0 μm. Dynamic recrystallization occurred in accordance to a continuous mechanism and was controlled by the interaction of lattice dislocations and/or (sub)grain boundaries with dispersoids that effectively inhibited the migration of boundaries, as well as the rearrangement of lattice dislocations and their annihilation. The particle size and the density of their distribution significantly affected the parameters of the evolved structure; in an alloy with smaller particles, a structure with a smaller grain size and a larger HAB fraction developed.

High thermal shock resistance of the hot rolled and swaged bulk W–ZrC alloys

Energy Technology Data Exchange (ETDEWEB)

Xie, Z.M.; Liu, R.; Miao, S.; Yang, X.D. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Science Center, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Zhang, T., E-mail: zhangtao@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Science Center, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Fang, Q.F.; Wang, X.P. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Science Center, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Liu, C.S., E-mail: csliu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Science Center, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Lian, Y.Y. [Southwestern Institute of Physics, Chengdu (China); Liu, X., E-mail: xliu@swip.ac.cn [Southwestern Institute of Physics, Chengdu (China); Luo, G.N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2016-02-15

The thermal shock (single shot) resistance and mechanical properties of the W–0.5wt% ZrC (WZC) alloys manufactured by ordinary sintering followed by swaging or rolling process were investigated. No cracks or surface melting were detected on the surface of the rolled WZC alloy plates after thermal shock at a power density of 0.66 GW/m{sup 2} for 5 ms, while primary intergranular cracks appear on the surface of the swaged WZC samples after thermal shock at a power density of 0.44 GW/m{sup 2} for 5 ms. Three point bending tests indicate that the rolled WZC alloy has a flexural strength of ∼2.4 GPa and a total strain of 1.8% at room temperature, which are 100% and 260% higher than those of the swaged WZC, respectively. The fracture energy density of the rolled WZC alloy is 3.23 × 10{sup 7} J/m{sup 3}, about 10 times higher than that of the swaged WZC (2.9 × 10{sup 6} J/m{sup 3}). The high thermal shock resistance of the rolled WZC alloys can be ascribed to their extraordinary ductility and plasticity. - Graphical abstract: (Left panel) surface morphology observed by optical microscope after a single pulse for 5 ms with various absorbed power densities at RT on the rolled WZC. (Right panel) curves of flexural stress versus strain at RT (a) and the calculated fracture energy (b) for the swaged WZC and rolled WZC alloys. - Highlights: • No cracks or surface melting were detected on the rolled WZC alloy samples after thermal shock at 0.66 GW/m{sup 2} for 5 ms. • Hot rolled WZC alloy plates exhibit a flexural strength of 2.4 GPa and a strain of 1.8% at RT. • The fracture energy of the rolled WZC alloy is 3.23 × 10{sup 7} J/m{sup 3} at RT, about 10 times higher than that of the swaged WZC. • A detailed analysis of the relationships between the mechanical properties and the thermal shock resistance is given.

EXAFS study of short range order in Fe-Zr amorphous alloys

International Nuclear Information System (INIS)

Fernandez-Gubieda, M.L.; Gorria, P.; Barandiaran, J.M.; Barquin, L.F.

1995-01-01

Room temperature X-ray absorption spectra on Fe K-edge have been performed in Fe 100-x-y Zr x B y and Fe 86 Zr 7 Cu 1 B 6 alloys (x=7, 7.7, 9; y=0, 2, 4, 6). Fe-Fe coordination number and interatomic distances do not change in any sample. However, small changes in the Fe-Zr short range order, which could explain the evolution of the magnetic properties, have been observed. (orig.)

Evidence of zirconium nano-agglomeration in as-cast dilute U–Zr alloys

International Nuclear Information System (INIS)

Mukherjee, S.; Kaity, S.; Saify, M.T.; Jha, S.K.; Pujari, P.K.

2014-01-01

Microstructure evaluation of as-cast and annealed U–Zr (Zr = 2, 6 and 10 wt.%) alloys has been carried out for the first time using positrons as a probe. The chemical signature in the matter–antimatter annihilation gamma and the positron lifetime data suggests that majority of positrons are annihilating from Zr sites in the as-cast alloys. The results have been interpreted as due to the presence of Zr nano-agglomerates in the as-cast alloys which have a higher positron affinity as compared to the rest of the U matrix. A minimum agglomerate size of ∼2 nm diameter has been calculated from the difference in positron affinity between the agglomerates and the matrix. Upon annealing, the Zr signature in the annihilation gamma photons vanishes suggesting that the Zr agglomerates diffuse out of U matrix and form micron-sized precipitates. This has been confirmed by scanning electron microscopy which shows a 3 times increase in the surface density of the precipitates in the annealed alloys as compared to the as-cast ones. Shorter positron diffusion length (measured using slow positron beam) as compared to precipitate separation has been invoked to explain the observed data

Effect of Mn and AlTiB Addition and Heattreatment on the Microstructures and Mechanical Properties of Al-Si-Fe-Cu-Zr Alloy.

Science.gov (United States)

Yoo, Hyo-Sang; Kim, Yong-Ho; Lee, Seong-Hee; Son, Hyeon-Taek

2018-09-01

The microstructure and mechanical properties of as-extruded Al-0.1 wt%Si-0.2 wt%Fe- 0.4 wt%Cu-0.04 wt%Zr-xMn-xAlTiB (x = 1.0 wt%) alloys under various annealing processes were investigated and compared. After the as-cast billets were kept at 400 °C for 1 hr, hot extrusion was carried out with a reduction ratio of 38:1. In the case of the as-extruded Al-Si-Fe-Cu-Zr alloy at annealed at 620 °C, large equiaxed grain was observed. When the Mn content is 1.0 wt%, the phase exhibits a skeleton morphology, the phase formation in which Mn participated. Also, the volume fraction of the intermetallic compounds increased with Mn and AlTiB addition. For the Al-0.1Si-0.2Fe-0.4Cu-0.04Zr alloy with Mn and AlTiB addition from 1.0 wt%, the ultimate tensile strength increased from 100.47 to 119.41 to 110.49 MPa. The tensile strength of the as-extruded alloys improved with the addition of Mn and AlTiB due to the formation of Mn and AlTiB-containing intermetallic compounds.

Solubility and partitioning of hydrogen in meta-stable ZR-based alloys used in the nuclear industry

International Nuclear Information System (INIS)

Khatamian, D.

1998-11-01

Terminal solubility and partitioning of hydrogen in Zr-Nb alloys with different Nb concentrations were examined using differential scanning calorimetry and hot vacuum extraction mass spectrometry. Specimens were charged to different concentrations of hydrogen and annealed at 1123 K to generate a two-phase structure consisting of α-Zr (Zr-0.6 wt.% Nb) and meta-stable β-Zr (Zr-20 wt.% Nb) within the alloy. Specimens were aged at 673 and 773 K for up to 1000 h to evaluate the effect of the decomposition of the meta-stable β-Zr to α-Zr + β-Nb on the solubility limit. The results show that the solubility limit for hydrogen in the annealed Zr-Nb alloys is higher than in unalloyed Zr and that the solubility limit increases with the Nb concentration of the alloy. They also show that the hydrogen solubility limits of the completely aged Zr-Nb alloys are similar and approach the values for pure α-Zr. The solubility ratio of hydrogen in β-Zr (Zr-20 wt.% Nb) to that in α-Zr (Zr-0.6 wt.% Nb) was found to range from 9 to 7 within the temperature range of 520 to 580 K. (author)

A study on the development of hypo-stoichiometric Zr-based hydrogen storage alloys with ultra-high capacity for anode material of Ni/MH secondary battery

Energy Technology Data Exchange (ETDEWEB)

Lee, S.-M.; Lee, H.; Kim, J.-H.; Lee, P.S.; Lee, J.-Y. [Korea Advanced Inst. of Science and Technology, Taejon (Korea). Dept. of Materials Science and Engineering

2000-08-10

Some hypo-stoichiometric Zr-based Laves phase alloys were prepared and studied from a viewpoint of discharge capacity for electrochemical application. After careful alloy design of ZrMn{sub 2}-based hydrogen storage alloys through changing their stoichiometry while substituting or adding some alloying elements, the Zr(Mn{sub 0.2}V{sub 0.2}Ni{sub 0.6}){sub 1.8} alloy reveals relatively good properties with regard to hydrogen storage capacity, hydrogen equilibrium pressure and electrochemical discharge capacity. In order to improve the discharge capacity and rate-capability, Zr is partially replaced by Ti. The discharge capacity of Zr{sub 1-x}Ti{sub x}(Mn{sub 0.2}V{sub 0.2}Ni{sub 0.6}){sub 1.8} (x=0.0, 0.2, 0.3, 0.4, 0.6) alloy electrodes at 30 C reaches a maximum value and decreases as the Ti fraction increases. In view of electrochemical and thermodynamic characteristics, the occurrence of a maximal phenomenon of the electrochemical discharge capacity of the alloy is attributed to a competition between decreasing hydrogen storage capacity and increasing rate-capability with Ti fraction. However, as the Ti fraction increases, the discharge capacity decreases drastically with repeated electrochemical cycling. Judging from the analysis of surface composition by Auger electron spectroscopy (AES), the rapid degradation with increasing Ti fraction in Zr-based alloy is ascribed to the fast growth of the oxygen-penetrated layer with cycling. Therefore, it is assured that the stoichiometry and Ti fraction should be optimized to obtain a good cycle life of the electrode maintaining high discharge capacity. On the basis of above results, the hydrogen storage capacity of the alloy with optimized composition (Zr{sub 0.65}Ti{sub 0.35}(Mn{sub 0.3}V{sub 0.14}Cr{sub 0.11}Ni{sub 0.65}){sub 1.76}) is about 1.68 wt% under 10 atm of equilibrium hydrogen pressure. (orig.)

A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

Energy Technology Data Exchange (ETDEWEB)

Huang, Y.J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shen, J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: junshen@hit.edu.cn; Sun, J.F. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yu, X.B. [Lab of Energy Science and Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)]. E-mail: yuxuebin@hotmail.com

2007-01-16

The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 42.5-x}Ni{sub 7.5}Si{sub 1}Sn {sub x} (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy. The activation energies for glass transition and crystallization for Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy also possesses superior mechanical properties.

Passivation kinetics of Mg-Nd-Gd-Zn-Zr (EV31A and Mg-Y-Nd-Gd-Zr (WE43C in NaOH solutions

Directory of Open Access Journals (Sweden)

Jakraphan Ninlachart

2017-09-01

Full Text Available Passivation kinetics of two Mg-RE alloys, such as Mg-Nd-Gd-Zn-Zr (EV31A, and Mg-Y-Nd-Gd-Zr (WE43C were investigated in two different heat treated conditions (solution treated and overaged in 0.01 - 1.0 M NaOH solutions under potentiostatic conditions. Negative reaction order was observed in dilute NaOH which transitioned to positive values as the passivation time increased and in the 1 M NaOH as well. The passive layers showed platelet morphology and the size of the platelets decreased with increase in the NaOH concentration. The hydrogen evolution reaction (HER kinetics was not improved on the passive layer covered surface of the Mg-RE alloys in contrast to the improvements reported on the hydroxide covered pure magnesium. The electrochemical impedance increased with increase in the NaOH concentration in the solution treated condition of both Mg-RE alloys, whereas the overaged EV31A alloy showed a reverse trend. The passive layer of EV31A showed almost 100% higher charge carrier density than the film formed on the WE43C in the overaged condition. A better passivation behavior was observed in the solution treated condition than that in the overaged condition which could be attributed to the uniform distribution of the RE elements in the solution treated specimens. The WE43C alloy revealed better corrosion resistance in the alkaline solution than the EV31A alloy.

Experimental determination of the phase relationships in Zr/2.5 8.0 at% Nb/0 6.7 at% Al alloys with 750 at ppm 0 and 250 at ppm N between 730 900° C

Science.gov (United States)

Peruzzi, A.; Bolcich, J.

1990-11-01

Zr alloys with 2.5 to 8.0 at% Nb and 0 to 6.7 at% Al were subjected to dynamic and static treatments between 730-900° C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zn-Nb-Al alloys with 750 at ppm O and 250 at ppm N are the following: (i) Equilibrium relationships are established between the α (hcp), β (bcc) and Zr 3Al (Cu 3Au) phases along isothermal sections at 730, 771 and 800°C. (ii) The β/ α + β boundaries are determined along iso-aluminum vertical sections at 6.7, 3.3 and 0 at% Al. (iii) The addition of Al to Zr-Nb alloys increases the solubility of Nb in the α phase, its maximum value at 730° C being about 0.7-0.8 at% for 4 at% Al. (iv) Solubility values for Al in the α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy in the Zr-Al system.

Experimental determination of the phase relationships in Zr/2.5-8.0 at% Nb/0-6.7 at% Al alloys with 750 at ppm O and 250 at ppm N between 730-900deg C

International Nuclear Information System (INIS)

Peruzzi, A.; Bolcich, J.

1990-01-01

Zr alloys with 2.5 to 8.0 at% Nb and 0 to 6.7 at% Al were subjected to dynamic and static treatments between 730-900deg C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zn-Nb-Al alloys with 750 atppm O and 250 atppm N are the following: (i) Equilibrium relationships are established between the α (hcp), β (bcc) and Zr 3 Al (Cu 3 Au) phases along isothermal sections at 730, 771 and 800deg C. (ii) The β/α+β boundaries are determined along iso-aluminum vertical sections at 6.7, 3.3 and 0 at% Al. (iii) The addition of Al to Zr-Nb alloys increases the solubility of Nb in the α phase, its maximum value at 730deg C being about 0.7-0.8 at% for 4 at% Al.(iv) Solubility values for Al in the α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy in the Zr-Al system. (orig.)

Phase Transformation and Shape Memory Effect of Ti-Pd-Pt-Zr High-Temperature Shape Memory Alloys

Science.gov (United States)

Yamabe-Mitarai, Yoko; Takebe, Wataru; Shimojo, Masayuki

2017-12-01

To understand the potential of high-temperature shape memory alloys, we have investigated the phase transformation and shape memory effect of Ti-(50 - x)Pt- xPd-5Zr alloys ( x = 0, 5, and 15 at.%), which present the B2 structure in the austenite phase and B19 structure in the martensite phase. Their phase transformation temperatures are very high; A f and M f of Ti-50Pt are 1066 and 1012 °C, respectively. By adding Zr and Pd, the phase transition temperatures decrease, ranging between 804 and 994 °C for A f and 590 and 865 °C for M f. Even at the high phase transformation temperature, a maximum recovery ratio of 70% was obtained for one cycle in a thermal cyclic test. A work output of 1.2 J/cm3 was also obtained. The recovery ratio obtained by the thermal cyclic test was less than 70% because the recovery strain was training effect was also investigated.

Structure and mechanical properties of as-cast (ZrTi){sub 100−x}B{sub x} alloys

Energy Technology Data Exchange (ETDEWEB)

Xia, C.Q.; Jiang, X.J.; Wang, X.Y.; Zhou, Y.K.; Feng, Z.H. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Tan, C.L. [Beijing Institute of Spacecraft System Engineering, Beijing 100094 (China); Ma, M.Z. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, R.P., E-mail: riping@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

2015-07-15

Highlights: • Trace boron additions result in significant grain refinement. • Large numbers of stacking faults are observed in ZrB{sub 2} and TiB intermetallics. • The tensile strength is enhanced by increasing the amount of B. • Intermetallics microcracking causes the failure of the alloys. - Abstract: The microstructure, mechanical properties, and fracture characteristics of (Zr{sub 50}Ti{sub 50}){sub 100−x}B{sub x} alloys (x = 0, 0.5, 1, 2 at.%) obtained by casting were investigated. Trace additions of boron (B) to the Zr{sub 50}Ti{sub 50} alloys induced significant microstructural changes. Changes included the promotion of dendritic growth and refinement in prior-β grain and α′-lath size. Large numbers of stacking faults were also observed in ZrB{sub 2} and TiB intermetallics. The location of B atoms and the lattice mismatch energy between intermetallics and matrix were responsible for the stacking faults. (ZrTi)B alloys demonstrated higher tensile strength than matrix material. Both the intermetallics with high strength and modulus and the grain refinement played important roles in improving the mechanical properties of alloys. This result could be explained in terms of a shear-lag model based on the load transfer concept and Hall–Petch mechanism. The elongation-to-failure of (ZrTi)B alloys decreased with increased B concentration. The reduction in elongation-to-failure of (ZrTi)B alloys could be attributed to the presence of ZrB{sub 2} and TiB intermetallics and refinement of α′-laths.

U-Zr alloy: XPS and TEM study of surface passivation

Science.gov (United States)

Paukov, M.; Tkach, I.; Huber, F.; Gouder, T.; Cieslar, M.; Drozdenko, D.; Minarik, P.; Havela, L.

2018-05-01

Surface reactivity of Uranium metal is an important factor limiting its practical applications. Bcc alloys of U with various transition metals are much less reactive than pure Uranium. So as to specify the mechanism of surface protection, we have been studying the U-20 at.% Zr alloy by photoelectron spectroscopy and transmission electron microscopy. The surface was studied in as-obtained state, in various stages of surface cleaning, and during an isochronal annealing cycle. The analysis based on U-4f, Zr-3p, and O-1 s spectra shows that a Zr-rich phase segregates at the surface at temperatures exceeding 550 K, which provides a self-assembled coating. The comparison of oxygen exposure of the stoichiometric and coated surfaces shows that the coating is efficiently preventing the oxidation of uranium even at elevated temperatures. The coating can be associated with the UZr2+x phase. TEM study indicated that the coating is about 20 nm thick. For the clean state, the U-4f core-level lines of the bcc alloy are practically identical to those of α-U, revealing similar delocalization of the 5f electronic states.

FeCrAl and Zr alloys joined using hot isostatic pressing for fusion energy applications

International Nuclear Information System (INIS)

Park, Dong Jun; Kim, Hyun Gil; Park, Jeong Yong; Jung, Yang Il; Park, Jung Hwan; Koo, Yang Hyun

2016-01-01

Highlights: • FeCrAl and Zr alloys were successfully joined by hot isostatic pressing (HIP). • The thickness of diffusion layer increased with an increase in HIP temperature. • Significant inter-diffusion was observed for HIP at 1150 °C. • Maximum joint strength was achieved at HIP temperature of 700 °C. - Abstract: FeCrAl and Zr alloys were joined by a hot isostatic pressing (HIP) method for fusion energy applications. The optimum conditions for the joining process were studied. The HIP temperatures were varied from 700 to 1050 °C. The mechanical properties of the HIPed samples were evaluated by four-point bending and tensile tests. The FeCrAl and Zr alloys HIPed at 700 °C showed higher joint strength than the other samples. The joint strength decreased with an increase in the HIP temperature from 700 to 950 °C and significantly dropped at 1050 °C. Transmission electron microscopy, scanning electron microscopy, and optical microscopy were used to characterize the joints and interface region of the HIPed samples. The joints appeared to be tightly bonded and no intermetallic compounds or gaps were observed at the interface for HIP temperatures up to 950 °C. A diffusion layer formed at the interface and its thickness increased with the HIP temperature. HIP at 1050 °C, on the other hand, resulted in significant inter-diffusion and formation of brittle inter-metallic compounds at the interface.