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Sample records for alloy aa5182 effect

  1. Effect of pre-treatment on recrystallization and recrystallization textures of cold rolled CC AA 5182 aluminum alloy

    International Nuclear Information System (INIS)

    The effect of pre-treatment on recrystallization and recrystallization textures of cold rolled continuous cast (CC) AA 5182 aluminum alloy as well as on the earing behavior was investigated. The progress of recrystallization was tracked by means of measurements of tensile properties. The texture of cold rolled and annealed samples was determined by X-ray diffraction. The results show that the recrystallization temperature of cold rolled CC AA 5182 aluminum alloy without pre-treatment is about 24 deg. C higher than that of the alloy with pre-treatment. The recrystallization textures of cold rolled CC AA 5182 aluminum alloy are characterized by the R, cube and Goss orientations. The recrystallization textures of cold rolled CC AA 5182 aluminum alloy without pre-treatment exhibit stronger cube and Goss components and a weaker R component than those of the alloy with pre-treatment. The deformed and recovered samples without pre-treatment possess a significantly higher 45 deg. earing than the samples with pre-treatment, while the recrystallized samples without pre-treatment possess a slightly lower 45 deg. earing than the samples with pre-treatment

  2. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    DEFF Research Database (Denmark)

    Cecchetto, L; Ambat, Rajan; Davenport, A.J.;

    2007-01-01

    AA5182 aluminium alloy cold rolled samples were coated by thin Wlms of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very eVective for corrosion protection of aluminium alloys in neutral environment. This study underlines...... the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties, the enhanced corrosion resistance observed on the EB coated samples could partly arise from two other mains...... factors: • a weak redox activity of the polymer which passivate the metal, • a proton involving self-healing process taking place at the polymer–metal interface, which contributes to delay local acidiWcation in Wrst steps of corrosion on EB coated aluminium surfaces....

  3. Effect of strain rate on shear properties and fracture characteristics of DP600 and AA5182-O sheet metal alloys

    Science.gov (United States)

    Rahmaan, Taamjeed; Butcher, Cliff; Abedini, Armin; Worswick, Michael

    2015-09-01

    Shear tests were performed at strain rates ranging from quasi-static (.01 s-1) to 600 s-1 for DP600 steel and AA5182-O sheet metal alloys at room temperature. A miniature sized shear specimen was modified and validated in this work to perform high strain rate shear testing. Digital image correlation (DIC) techniques were employed to measure the strains in the experiments, and a criterion to detect the onset of fracture based on the hardening rate of the materials is proposed. At equivalent strains greater than 20%, the DP600 and AA5182 alloys demonstrated a reduced work hardening rate at elevated strain rates. At lower strains, the DP600 shows positive rate sensitivity while the AA5182 was not sensitive to strain rate. For both alloys, the equivalent fracture strain and elongation to failure decreased with strain rate. A conversion of the shear stress to an equivalent stress using the von Mises yield criterion provided excellent agreement with the results from tensile tests at elevated strain rates. Unlike the tensile test, the shear test is not limited by the onset of necking so the equivalent stress can be determined over a larger range of strain.

  4. Effect of strain rate on shear properties and fracture characteristics of DP600 and AA5182-O sheet metal alloys

    Directory of Open Access Journals (Sweden)

    Rahmaan Taamjeed

    2015-01-01

    Full Text Available Shear tests were performed at strain rates ranging from quasi-static (.01 s−1 to 600 s−1 for DP600 steel and AA5182-O sheet metal alloys at room temperature. A miniature sized shear specimen was modified and validated in this work to perform high strain rate shear testing. Digital image correlation (DIC techniques were employed to measure the strains in the experiments, and a criterion to detect the onset of fracture based on the hardening rate of the materials is proposed. At equivalent strains greater than 20%, the DP600 and AA5182 alloys demonstrated a reduced work hardening rate at elevated strain rates. At lower strains, the DP600 shows positive rate sensitivity while the AA5182 was not sensitive to strain rate. For both alloys, the equivalent fracture strain and elongation to failure decreased with strain rate. A conversion of the shear stress to an equivalent stress using the von Mises yield criterion provided excellent agreement with the results from tensile tests at elevated strain rates. Unlike the tensile test, the shear test is not limited by the onset of necking so the equivalent stress can be determined over a larger range of strain.

  5. Comparison of recrystallization and recrystallization textures in cold-rolled DC and CC AA 5182 aluminum alloys

    International Nuclear Information System (INIS)

    The recrystallization and recrystallization textures in cold-rolled direct chill cast (DC) and continuous cast (CC) AA 5182 aluminum alloys were investigated. The recrystallization behavior of cold-rolled DC and CC AA 5182 aluminum alloys was evaluated by tensile properties. The evolution of recrystallization textures in cold-rolled DC and CC AA 5182 aluminum alloys was determined by X-ray diffraction. The results showed that the recrystallization temperature of cold-rolled DC AA 5182 aluminum alloy was somewhat lower than that of cold-rolled CC AA 5182 aluminum alloy. The resulting recrystallization textures of cold-rolled AA 5182 aluminum alloy were characterized by the strong R orientation and the cube orientation with strong scattering about the rolling direction towards the Goss orientation. CC AA 5182 aluminum alloy showed slightly weaker recrystallization textures than DC AA 5182 aluminum alloy

  6. Effect of temperature and displacement rate on behaviour of as-cast AA5182 and Al–3.3%Cu alloys under tensile loading near solidus temperature

    Indian Academy of Sciences (India)

    Suyitno

    2013-08-01

    Hot cracking develops in the still semi-solid casting during the last stages of solidification. The micromechanism of its origin is not generally accepted. There exists considerable doubt whether it is initiated by a void or develops as an instantaneous crack. The aim of this work is to study the mechanism of fracture behaviour of aluminum alloys around solidus temperature. Tensile tests were performed on notched specimens of as-cast AA5182 and Al–3.3%Cu alloys using a Gleeble 3500® thermomechanical simulator. The effect of temperature and strain rate on the propagation of fracture in the semi-solid state has been studied to establish fracture mechanism. The transition from ductile to brittle mode of fracture has been observed around the solidus temperature. The fracture is intergranular and propagates through interdendritic channels.

  7. Quantification of recrystallization texture evolution in cold rolled AA 5182 aluminum alloy

    International Nuclear Information System (INIS)

    The evolution of recrystallization textures in cold rolled AA 5182 aluminum alloy was investigated by X-ray diffraction. The transformation kinetics of recrystallization textures during isothermal annealing was quantified by using an Avrami type equation

  8. Quantification of recrystallization texture evolution in cold rolled AA 5182 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.C.; Zhai, T.; Man, C.-S.; Morris, J.G

    2003-09-15

    The evolution of recrystallization textures in cold rolled AA 5182 aluminum alloy was investigated by X-ray diffraction. The transformation kinetics of recrystallization textures during isothermal annealing was quantified by using an Avrami type equation.

  9. Comparison of the texture evolution in cold rolled DC and SC AA 5182 aluminum alloys

    International Nuclear Information System (INIS)

    The hot bands of direct chill cast (DC) and strip cast (SC) AA 5182 aluminum alloys were annealed at 454 deg. C for 3 h, and then cold rolled to different reductions. The ODFs of the cold rolled samples were determined by X-ray diffraction in order to compare the texture evolution of DC and SC AA 5182 aluminum alloys during rolling. The texture volume fractions were computed by a new method, in which the Euler space representing all possible crystallographic orientations in rolling was subdivided into the cube, r-cube, Goss, r-Goss, β fiber, and random orientation regions based on the slip pattern combined with the characteristics of microstructure and texture. Empirical formulae of the texture volume fractions and true strain were constructed to predict the texture of cold rolled DC and SC AA 5182 aluminum alloys. The results show that the processing method (DC vs. SC) strongly affects the texture after annealing at 454 deg. C and the texture evolution during the subsequent rolling

  10. Lattice rotation and stability of 22.5 deg. ND rotated cube orientation in cold rolled polycrystalline AA 5182 aluminum alloy

    International Nuclear Information System (INIS)

    AA 5182 aluminum alloy with a strong cube texture was cold rolled to different reductions at an angle of 22.5 deg. to the prior rolling direction. The texture evolution at this new rolling direction was investigated by X-ray diffraction. The rotation paths and stability of the 22.5 deg. ND rotated cube orientation were determined based on the variation in the three-dimensional orientation distribution function (ODF) with rolling reduction. The results show that most of the grains with the 22.5 deg. ND rotated cube orientation are directly rotated to the β fiber along different rotation paths, but there are a few grains moving through the cube orientation to the β fiber. The {0 0 1} oriented grains possess the lowest stability during rolling, and the stability increases as the initial orientation changes from the {0 0 1} orientation to the {0 0 1} orientation along the φ1 axis

  11. Numerical modelling of complex shaped particle break-up with application to rolling of aluminium alloys

    OpenAIRE

    Moulin, Nicolas

    2008-01-01

    The aluminium alloy AA5182, largely employed in the form of plates used for the body panels in automotive industry, contains intermetallic particles Mg2Si and AlxFe. In as cast state, these particles (of a size > 50 µm) present complex shapes. During hot rolling, the particles are broken and redistributed in the sheet metal. However, the size and the spatial distribution of the intermetallic particles mainly control the formability of sheets after cold transformation.This work identifies morp...

  12. Oxide growth on aluminium alloys in the presence of ammonium fluoborate

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, J.; Paterson, P.; Flavell, T. [Royal Melbourne Inst. of Tech., VIC (Australia); Biddle, G. [Alcoa Rolled Products (Australia)

    1996-12-31

    The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH{sub 4}BF{sub 4}. At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH{sub 4}BF{sub 4} atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg C , AA5182 alloys undergo incipient melting at the grain boundaries with magnesium diffusing through to the surface. 5 refs., 1 fig.

  13. Application of a Pore Fraction Hot Tearing Model to Directionally Solidified and Direct Chill Cast Aluminum Alloys

    Science.gov (United States)

    Dou, Ruifeng; Phillion, A. B.

    2016-08-01

    Hot tearing susceptibility is commonly assessed using a pressure drop equation in the mushy zone that includes the effects of both tensile deformation perpendicular to the thermal gradient as well as shrinkage feeding. In this study, a Pore Fraction hot tearing model, recently developed by Monroe and Beckermann (JOM 66:1439-1445, 2014), is extended to additionally include the effect of strain rate parallel to the thermal gradient. The deformation and shrinkage pore fractions are obtained on the basis of the dimensionless Niyama criterion and a scaling variable method. First, the model is applied to the binary Al-Cu system under conditions of directional solidification. It is shown that for the same Niyama criterion, a decrease in the cooling rate increases both the deformation and shrinkage pore fractions because of an increase in the time spent in the brittle temperature region. Second, the model is applied to the industrial aluminum alloy AA5182 as part of a finite element simulation of the Direct Chill (DC) casting process. It is shown that an increase in the casting speed during DC casting increases the deformation and shrinkage pore fractions, causing the maximum point of pore fraction to move towards the base of the casting. These results demonstrate that including the strain rate parallel to the thermal gradient significantly improves the predictive quality of hot tearing criteria based on the pressure drop equation.

  14. Shape memory effect alloys

    International Nuclear Information System (INIS)

    Although the pseudo- or super-elasticity phenomena and the shape memory effect were known since the 1940's, the enormous curiosity and the great interest to their practical applications emerged with the development of the NITINOL alloy (Nickel-Titanium Naval Ordance Laboratory) by the NASA during the 1960's. This fact marked the appearance of a new class of materials, popularly known as shape memory effect alloys (SMEA). The objective of this work is to present a state-of-the-art of the development and applications for the SMEA. (E.O.)

  15. Modeling the microstructural changes during hot tandem rolling of AA5 XXX aluminum alloys: Part I. Microstructural evolution

    Science.gov (United States)

    Wells, M. A.; Samarasekera, I. V.; Brimacombe, J. K.; Hawbolt, E. B.; Lloyd, D. J.

    1998-06-01

    A comprehensive mathematical model of the hot tandem rolling process for aluminum alloys has been developed. Reflecting the complex thermomechanical and microstructural changes effected in the alloys during rolling, the model incorporated heat flow, plastic deformation, kinetics of static recrystallization, final recrystallized grain size, and texture evolution. The results of this microstructural engineering study, combining computer modeling, laboratory tests, and industrial measurements, are presented in three parts. In this Part I, laboratory measurements of static recrystallization kinetics and final recrystallized grain size are described for AA5182 and AA5052 aluminum alloys and expressed quantitatively by semiempirical equations. In Part II, laboratory measurements of the texture evolution during static recrystallization are described for each of the alloys and expressed mathematically using a modified form of the Avrami equation. Finally, Part III of this article describes the development of an overall mathematical model for an industrial aluminum hot tandem rolling process which incorporates the microstructure and texture equations developed and the model validation using industrial data. The laboratory measurements for the microstructural evolution were carried out using industrially rolled material and a state-of-the-art plane strain compression tester at Alcan International. Each sample was given a single deformation and heat treated in a salt bath at 400 °C for various lengths of time to effect different levels of recrystallization in the samples. The range of hot-working conditions used for the laboratory study was chosen to represent conditions typically seen in industrial aluminum hot tandem rolling processes, i.e., deformation temperatures of 350 °C to 500 °C, strain rates of 0.5 to 100 seconds and total strains of 0.5 to 2.0. The semiempirical equations developed indicated that both the recrystallization kinetics and the final recrystallized

  16. Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties

    International Nuclear Information System (INIS)

    Inconsistency between a conventional thermodynamic description of alloys as a mechanical mixture of phases and a real alloys state as a common thermodynamic system in which there is a complicated physical-chemical phases interaction has been considered. It is supposed that in heterogeneous alloys (eutectic ones, for instance), so called interphase thermodynamic bond can become apparent due to a partial electron levels splitting under phase interaction. Thermodynamic description of phase equilibrium in alloys is proposed taking into account a thermodynamic bond for the system with phase diagram of eutectic type, and methods of the value of this bond estimation are presented. Experimental evidence (Al-Cu-Si, Al-Si-Mg-Cu, U-Mo + Al) of the effect of interphase thermodynamic bond on temperature and enthalpy of melting of alloys are produced as well as possibility of its effects on alloys electrical conduction, strength, heat and corrosion resistance is substantiated theoretically

  17. Hydrogen effects in aluminum alloys

    International Nuclear Information System (INIS)

    The permeability of six commercial aluminum alloys to deuterium and tritium was determined by several techniques. Surface films inhibited permeation under most conditions; however, contact with lithium deuteride during the tests minimized the surface effects. Under these conditions phi/sub D2/ = 1.9 x 10-2 exp (--22,400/RT) cc (NTP)atm/sup --1/2/ s-1cm-1. The six alloys were also tested before, during, and after exposure to high pressure hydrogen, and no hydrogen-induced effects on the tensile properties were observed

  18. Fermi surface effects in terbium alloys

    International Nuclear Information System (INIS)

    Work is reported which was conducted to test of the relation of the generalized susceptibility (and therefore, the ordering properties) for Tb to the Fermi energy of Tb. In order to properly analyze the data a simple theory was developed to account for the effects on band structure which accompany alloying and attendant lattice size changes. Using this simple theory, the alloys of Tb with Mg are understood as a combination of Fermi energy lowering and of lattice contraction. The tendency of Th to promote the ferromagnetic structure in Th is understood as a combination of the Fermi energy being raised and of the lattice being expanded. The theory was also useful in explaining the interesting behavior of the Tb with Yb alloys which upon preliminary analysis did not seem to follow the theoretical predictions. After consideration of the volume effect, indeed the Tb with Yb alloys showed promotion of the helical structure as predicted. The complicated behavior of the Tb with Yb alloys is a case where the volume and valence effects compete. Results show that the magnetic ordering properties of the rare earths are intimately related to the Fermi surface geometry through the generalized susceptibility

  19. Effects of segregation of primary alloying elements on the creep response in magnesium alloys

    DEFF Research Database (Denmark)

    Huang, Y.D.; Dieringa, H.; Hort, N.; Leil, T.A.; Kainer, K.U.; Liu, Yi-Lin

    2008-01-01

    The segregation of primary alloying elements deteriorates the high temperature creep resistance of magnesium alloys. Annealing at high temperatures alleviating their segregations can improve the creep resistance. Present investigation on the effect of segregation of primary alloying elements on the...... creep response may provide some useful information about how to improve the creep resistance of magnesium alloys in the future. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved....

  20. Mechanocaloric effects in shape memory alloys.

    Science.gov (United States)

    Mañosa, Lluís; Planes, Antoni

    2016-08-13

    Shape memory alloys (SMA) are a class of ferroic materials which undergo a structural (martensitic) transition where the associated ferroic property is a lattice distortion (strain). The sensitiveness of the transition to the conjugated external field (stress), together with the latent heat of the transition, gives rise to giant mechanocaloric effects. In non-magnetic SMA, the lattice distortion is mostly described by a pure shear and the martensitic transition in this family of alloys is strongly affected by uniaxial stress, whereas it is basically insensitive to hydrostatic pressure. As a result, non-magnetic alloys exhibit giant elastocaloric effects but negligible barocaloric effects. By contrast, in a number of magnetic SMA, the lattice distortion at the martensitic transition involves a volume change in addition to the shear strain. Those alloys are affected by both uniaxial stress and hydrostatic pressure and they exhibit giant elastocaloric and barocaloric effects. The paper aims at providing a critical survey of available experimental data on elastocaloric and barocaloric effects in magnetic and non-magnetic SMA.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'. PMID:27402931

  1. Localized Corrosion of Alloy 22 -Fabrication Effects-

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2005-11-05

    general and localized corrosion behavior both in the wrought and annealed condition and in the as-welded condition. The specimens for testing were mostly prepared from flat plates of material. It was important to determine if the process of fabricating a full diameter Alloy 22 container will affect the corrosion performance of this alloy. Specimens were prepared directly from a fabricated container and tested for corrosion resistance. Results show that both the anodic corrosion behavior and the localized corrosion resistance of specimens prepared from a welded fabricated container were the same as from flat welded plates. That is, rolling and welding plates using industrial practices do not hinder the corrosion resistant of Alloy 22. (3) Effect of Black Annealing Oxide Scale: The resistance of Alloy 22 to localized corrosion, mainly crevice corrosion, has been extensively investigated in the last few years. This was done mostly using freshly polished specimens. At this time it was important to address the effect an oxide film or scale that forms during the high temperature annealing process or solution heat treatment (SHT) and its subsequent water quenching. Electrochemical tests such as cyclic potentiodynamic polarization (CPP) have been carried out to determine the repassivation potential for localized corrosion and to assess the mode of attack on the specimens. Tests have been carried out in parallel using mill annealed (MA) specimens free from oxide on the surface. The comparative testing was carried out in six different electrolyte solutions at temperatures ranging from 60 to 100 C. Results show that the repassivation potential of the specimens containing the black anneal oxide film on the surface was practically the same as the repassivation potential for oxide-free specimens. (4) Heat-to-Heat Variability--Testing of Ni-Cr-Mo Plates with varying heat chemistry: The ASTM standard B 575 provides the range of the chemical composition of Nickel-Chromium-Molybdenum (Ni

  2. Size Effect on Magnesium Alloy Castings

    Science.gov (United States)

    Li, Zhenming; Wang, Qigui; Luo, Alan A.; Zhang, Peng; Peng, Liming

    2016-06-01

    The effect of grain size on tensile and fatigue properties has been investigated in cast Mg alloys of Mg-2.98Nd-0.19Zn (1530 μm) and Mg-2.99Nd-0.2Zn-0.51Zr (41 μm). The difference between RB and push-pull fatigue testing was also evaluated in both alloys. The NZ30K05-T6 alloy shows much better tensile strengths (increased by 246 pct in YS and 159 pct in UTS) and fatigue strength (improved by ~80 pct) in comparison with NZ30-T6 alloy. RB fatigue testing results in higher fatigue strength compared with push-pull fatigue testing, mainly due to the stress/strain gradient in the RB specimen cross section. The material with coarse grains could be hardened more in the cyclic loading condition than in the monotonic loading condition, corresponding to the lower σ f and the higher σ f/ σ b or σ f/ σ 0.2 ratio compared to the materials with fine grains. The fatigue crack initiation sites and failure mechanism are mainly determined by the applied stress/strain amplitude. In LCF, fatigue failure mainly originates from the PSBs within the surface or subsurface grains of the samples. In HCF, cyclic deformation and damage irreversibly caused by environment-assisted cyclic slip is the crucial factor to influence the fatigue crack. The Coffin-Manson law and Basquin equation, and the developed MSF models and fatigue strength models can be used to predict fatigue lives and fatigue strengths of cast magnesium alloys.

  3. Effect of ternary alloying elements on microstructure and superelastictity of Ti-Nb alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.C.; Mao, Y.F.; Li, Y.L.; Li, J.J.; Yuan, M. [Key Laboratory of Low Di-mensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan, Hunan 411105 (China); Faculty of Material and Optical-Electronic Physics, Xiangtan University, Xiangtan, Hunan 411105 (China); Lin, J.G., E-mail: lin_j_g@xtu.edu.cn [Key Laboratory of Low Di-mensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan, Hunan 411105 (China); Faculty of Material and Optical-Electronic Physics, Xiangtan University, Xiangtan, Hunan 411105 (China)

    2013-01-01

    The effect of ternary alloying elements (X=Ta, Fe, Zr, Mo, Sn and Si) on the microstructure, the mechanical properties and the superelasticity of Ti--22Nb-X alloys were investigated. The 1% addition of a ternary alloying element (X=Ta, Fe, Zr, Mo, Sn and Si) has a slight influence on the microstructure of the Ti-22Nb alloy. All the alloys after solution-treatment at 1073 K for 1.8 ks contain {beta} and {alpha} Double-Prime phases. The elements of Sn, Si, Fe and Ta with a high number of valence electrons or a small atomic size have a strong solid-solution strengthening effect to the {beta} phases in the alloys and the alloys with high Md{sup Macron} and low Bo{sup Macron} exhibit low elastic moduli. All the alloying elements improve the superelasticity of Ti-22Nb-X alloys. The elements, Fe, Mo, Sn and Si, which are with a high number of valence electrons and a small atomic size, strongly increase {sigma}{sub SIM} of the Ti-22Nb alloy.

  4. Effect of ternary alloying elements on microstructure and superelastictity of Ti–Nb alloys

    International Nuclear Information System (INIS)

    The effect of ternary alloying elements (X=Ta, Fe, Zr, Mo, Sn and Si) on the microstructure, the mechanical properties and the superelasticity of Ti–-22Nb–X alloys were investigated. The 1% addition of a ternary alloying element (X=Ta, Fe, Zr, Mo, Sn and Si) has a slight influence on the microstructure of the Ti–22Nb alloy. All the alloys after solution-treatment at 1073 K for 1.8 ks contain β and α″ phases. The elements of Sn, Si, Fe and Ta with a high number of valence electrons or a small atomic size have a strong solid–solution strengthening effect to the β phases in the alloys and the alloys with high Md¯ and low Bo¯ exhibit low elastic moduli. All the alloying elements improve the superelasticity of Ti–22Nb–X alloys. The elements, Fe, Mo, Sn and Si, which are with a high number of valence electrons and a small atomic size, strongly increase σSIM of the Ti–22Nb alloy.

  5. Effect of alloy elements on the anti-corrosion properties of low alloy steel

    Indian Academy of Sciences (India)

    Baorong Hou; Yantao Li; Yanxu Li; Jinglei Zhang

    2000-06-01

    Effect of alloy elements on corrosion of low alloy steel was studied under simulated offshore conditions. The results showed that the elements Cu, P, Mo, W, V had evident effect on corrosion resistance in the atmosphere zone; Cu, P, V, Mo in the splash zone and Cr, Al, Mo in the submerged zone.

  6. Effects of alloying side B on Ti-based AB2 hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    王家淳; 于荣海; 刘庆

    2004-01-01

    Ti-based AB2-type hydrogen storage alloys are a group of promising materials, which will probably replace the prevalent rare earth-based AB5-type alloys and be adopted as the main cathode materials of nickelmetal hydride (Ni-MH) batteries in the near future. Alloying in side B is a major way to improve the performance of Ti-based AB2-type alloys. Based on recent studies, the effects of alloying elements in side B upon the performance of Ti-based AB2 -type hydrogen storage alloys are systematically reviewed here. These performances are divided into two categories, namely PCI characteristics, including hydrogen storage capacity (HSC), plateau pressure (PP), pressure hysteresis (PH) and pressure plateau sloping (PPS) , and electrochemical properties, including discharge capacity (DC), activation property (AP), cycling stability (CS) and high-rate dischargeability (HRD). Furthermore, the existing problems in these investigations and some suggestions for future research are proposed.

  7. Neutron irradiation effect on thermomechanical properties of shape memory alloys

    International Nuclear Information System (INIS)

    Alloys of Ti-Ni, Ti-Ni-Pd, Fe-Mn-Si, Mn-Cu-Cr, Mn-Cu, Cu-Al-Mn, Cu-Al-Ni systems are investigated after irradiation in IVV-2M reactor at various temperatures with neutron fluence of 1019 - 1020 cm-2. The degradation of shape memory effect in titanium nickelide base alloys is revealed after irradiation. Mn-Cu and Mn-Cu-Cr alloys show the best results. Trends in shape memory alloy behaviour depending on irradiation temperature are found. A consideration is given to the possibility of using these alloys for components of power reactor control and protection systems

  8. Transformation Volume Effects on Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Anna Kosogor

    2013-07-01

    Full Text Available It is generally accepted that the martensitic transformations (MTs in the shape memory alloys (SMAs are mainly characterized by the shear deformation of the crystal lattice that arises in the course of MT, while a comparatively small volume change during MT is considered as the secondary effect, which can be disregarded when the basic characteristics of MTs and functional properties of SMAs are analyzed. This point of view is a subject to change nowadays due to the new experimental and theoretical findings. The present article elucidates (i the newly observed physical phenomena in different SMAs in their relation to the volume effect of MT; (ii the theoretical analysis of the aforementioned volume-related phenomena.

  9. Effect of alloying elements Al and Ca on corrosion resistance of plasma anodized Mg alloys

    Science.gov (United States)

    Anawati, Asoh, Hidetaka; Ono, Sachiko

    2016-04-01

    Plasma anodizing is a surface treatment used to form a ceramic-type oxide film on Mg alloys by the application of a high anodic voltage to create intense plasma near the metal surface. With proper selection of the process parameters, the technique can produce high quality oxide with superior adhesion, corrosion resistance, micro-hardness, wear resistance and strength. The effect of alloying element Al on plasma anodizing process of Mg alloys was studied by comparing the anodizing curves of pure Mg, AZ31, and AZ61 alloys while the effect of Ca were studied on AZ61 alloys containing 0, 1, and 2 wt% Ca. Anodizing was performed in 0.5 M Na3PO4 solution at a constant current density of 200 Am-2 at 25°C. Anodic oxide films with lava-like structure having mix composition of amorphous and crystal were formed on all of the alloys. The main crystal form of the oxide was Mg3(PO4)2 as analyzed by XRD. Alloying elements Al and Ca played role in modifying the plasma lifetime during anodization. Al tended to extend the strong plasma lifetime and therefore accelerated the film thickening. The effect of Ca on anodizing process was still unclear. The anodic film thickness and chemical composition were altered by the presence of Ca in the alloys. Electrochemical corrosion test in 0.9% NaCl solution showed that the corrosion behavior of the anodized specimens depend on the behavior of the substrate. Increasing Al and Ca content in the alloys tended to increase the corrosion resistance of the specimens. The corrosion resistance of the anodized specimens improved significantly about two orders of magnitude relative to the bare substrate.

  10. Effect of alloying elements on the shape memory properties of ductile Cu-Al-Mn alloys

    International Nuclear Information System (INIS)

    The effect of alloying elements on the Ms temperature, ductility and the shape memory properties of Cu-Al-Mn ductile shape memory (SM) alloys was investigated by differential scanning calorimetry, cold-rolling and tensile test techniques. It was found that the addition of Au, Si and Zn to the Cu73-Al17-Mn10 alloy stabilized the martensite (6M) phase increasing the Ms temperature, while the addition of Ag, Co, Cr, Fe, Ni, Sn and Ti decreased the stability of the martensite phase, decreasing the Ms temperature. The SM properties were improved by the addition of Co, Ni, Cr and Ti. (orig.)

  11. Radiation effects on metals, alloys and cement

    International Nuclear Information System (INIS)

    High - energy particle irradiation of materials brings as a consequence changes in their atomic structures that alter the electrical, magnetic and mechanical properties which are the most important characteristics for practical applications of metals and alloys. A review is made on experimental results of in-pile (IEA-RI reactor) and CV-28 cyclotron irradiated materials. Resistivity measurements on CuPd and FeNi alloys showed different behaviour during fast neutron irradiation. While CuPd had almost coincidental relaxation curves, FeNi presented a distinguishable short and long-range ordering with the critical order-disorder temperature at 5150C. Vacancy supersaturation curves of FeNiSi (49-49-2 at %), FeNiCr (49-95-49, 95-0,1 at. %), FeNiMo (50-50 at.% + 50 ppm) and pure FeNi (50-50 at.%), determined by means of the Magnetic After Effect are presented as an effective pre-selection method of nuclear materials before the destructive stage of void formation and swelling. A displacement of damage peak from 480 to 500 and 5700C was detected on pure AISI 321 stainless steel and with 0,05 wt.% and 0,10 wt.% of Nb additions by means of resistivity and micro-hardness. Ultrasound techniques applied to fast neutron irradiated portland cement paste (fluence 7,2 x 1018 n/cm2) showed a 24% decrease in its dynamic elasticity modulus. Helium diffusion on Au, Ag and Al foils irradiated in cyclotron was studied, suggesting a vacancy mechanism for single He atom diffusion. Embrittlement by Alpha particle implantation in cyclotron to simulate in-pile (n,α) reaction-was measured by high temperature creep on AISI 316 stainles steel. (author)

  12. Effect of alloying elements on the hydrogen embrittlement of medium-alloy deposited metal

    International Nuclear Information System (INIS)

    The effect was investigated of the main alloying elements in the metal of electrodes for welding steels upon the tendency to hydrogen embrittlement of medium-alloy built-up metal which was evaluated by the work of inception of cracks and by the work of crack propagation. Specimens from blanks were tested for static bending and rupture. It was established that when developing welding electrodes in was expedient to choose the alloying range of the built-up metal with due regard for the effect of alloying elements upon the hydrogen embrittlement. For a low content of diffusion hydrogen in the built-up metal, the work of inception of a crack diminishes with the increase in carbon, silicon, nickel and molybdenum contents. The work of crack propagation increases with the content of nickel ans varies according to a curve with a maxium as the contents of carbon, silicon, manganese and chromium rise

  13. Effective interactions approach to phase stability in alloys under irradiation

    International Nuclear Information System (INIS)

    Phase stability in alloys under irradiation is studied considering effective thermodynamic potentials. A simple kinetic model of a binary alloy with phase separation is investigated. Time evolution in the alloy results from two competing dynamics: thermal diffusion, and irradiation induced ballistic exchanges The dynamical (steady state) phase diagram is evaluated exactly performing Kinetic Monte Carlo simulations. The solution is then compared to two theoretical frameworks: the effective quasi-interactions model as proposed by Vaks and Kamishenko, and the effective free energy model as proposed by Martin. New developments of these models are proposed to allow for quantitative comparisons. Both theoretical frameworks yield fairly good approximations to the dynamical phase diagram

  14. Site Preference and Alloying Effect of Excess Ni in Ni–Mn–Ga Shape Memory Alloys

    International Nuclear Information System (INIS)

    The formation energies and electronic structures of Ni-rich Ni–Mn–Ga alloys have been investigated by first-principles calculations using the pseudopotential plane wave method based on density functional theory. The results show that the alloying Ni prefers to occupy the Mn site directly in Ni9Mn3Ga4 and to occupy the Mn site and drive the displaced Mn atom to the Ga site in Ni9Mn4Ga3, which is in accordance with the experimental result. According to the lattice constants and the density of states analyses, these site preference behaviours are closely related to the smaller lattice distortion and the lower-energy electronic structure when the excess Ni occupies the Mn site. The effect of Ni alloying on martensitic transformation is discussed and the enhancement of martensitic transformation temperature by Ni alloying is estimated by the calculated formation energy difference between austenite and martensite phases

  15. Site Preference and Alloying Effect of Excess Ni in Ni-Mn-Ga Shape Memory Alloys

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie; LI Yan; SHANG Jia-Xiang; XU Hui-Bin

    2009-01-01

    @@ The formation energies and electronic structures of Ni-rich Ni-Mn-Ga alloys have been investigated by first-principles calculations using the pseudopotential plane wave method baaed on density functional theory. The results show that the alloying Ni prefers to occupy the Mn site directly in Ni9Mn3Ga4 and to occupy the Mn site and drive the displaced Mn atom to the Ga site in Ni9Mn4Ga3, which is in accordance with the experimental result. According to the lattice constants and the density of states analyses, these site preference behaviours are closely related to the smaller lattice distortion and the lower-energy electronic structure when the excess Ni occupies the Mn site. The effect of Ni alloying on martensitic transformation is discussed and the enhancement of martensitic transformation temperature by Ni alloying is estimated by the calculated formation energy difference between anstenite and martensite phases.

  16. Shear strength developments during shock loading in tantalum alloys: Effects of cold work and alloying

    International Nuclear Information System (INIS)

    The development of shear strength behind the shock front in tantalum alloys of 2.5 and 10 wt% tungsten has been monitored by the use of laterally mounted stress gauges. Results show that in common with pure tantalum, shear strength decreases behind the shock front. At 2.5 wt%, we believe that tungsten modifies the mechanical response by mitigating the effects of interstitial solute atoms, thus easing dislocation motion, as evidenced by the smaller reduction in shear strength compared to pure tantalum. At higher tungsten levels, it would appear that this is overcome by an overall increase in Peierls stress, which renders dislocation motion more difficult, thus giving the alloy a response more in common with that of the pure metal. Cold rolling of the 2.5% W alloy also appears to increase shear strength reduction behind the shock front (compared to the annealed alloy), although at present the reasons for this are unclear.

  17. La doping effect on TZM alloy oxidation behavior

    International Nuclear Information System (INIS)

    Highlights: • The oxidation can be resisted by doping La into TZM alloy. • La doped TZM alloy has more compact organization. • It can rise the starting temperature of severe oxidation reaction by more than 50 °C. • Effectively slow down the oxidation rate. • Provide guidance for experiments of improving high-temperature oxidation resistance. - Abstract: Powder metallurgy methods were utilized to prepare lanthanum-doped (La-TZM) and traditional TZM alloy plates. High temperature oxidation experiments along with the differential thermal analysis were employed to study the oxidation behavior of the two kinds of TZM alloys. An extremely volatile oxide layer was generated on the surface of traditional TZM alloy plates when the oxidation started. Molybdenum oxide volatilization exposed the alloy matrix, which was gradually corroded by oxygen, losing its quality with serious surface degradation. The La-TZM alloy has a more compact structure due to the lanthanum doping. The minute lanthanum oxide particles are pinned at the grain boundaries and refine the grains. Oxide layer generated on the matrix surface can form a compact coating, which effectively blocks the surface from being corroded by oxidation. The oxidation resistance of La-TZM alloys has been enhanced, expanding its application range

  18. Influence of alloying and secondary annealing on anneal hardening effect at sintered copper alloys

    Indian Academy of Sciences (India)

    Svetlana Nestorovic

    2005-08-01

    This paper reports results of investigation carried out on sintered copper alloys (Cu, 8 at%; Zn, Ni, Al and Cu–Au with 4 at%Au). The alloys were subjected to cold rolling (30, 50 and 70%) and annealed isochronally up to recrystallization temperature. Changes in hardness and electrical conductivity were followed in order to investigate the anneal hardening effect. This effect was observed after secondary annealing also. Au and Al have been found to be more effective in inducing anneal hardening effect.

  19. Aluminum Alloying Effects on Lattice Types, Microstructures, and Mechanical Behavior of High-Entropy Alloys Systems

    Science.gov (United States)

    Tang, Zhi; Gao, Michael C.; Diao, Haoyan; Yang, Tengfei; Liu, Junpeng; Zuo, Tingting; Zhang, Yong; Lu, Zhaoping; Cheng, Yongqiang; Zhang, Yanwen; Dahmen, Karin A.; Liaw, Peter K.; Egami, Takeshi

    2013-12-01

    The crystal lattice type is one of the dominant factors for controlling the mechanical behavior of high-entropy alloys (HEAs). For example, the yield strength at room temperature varies from 300 MPa for the face-centered-cubic (fcc) structured alloys, such as the CoCrCuFeNiTi x system, to about 3,000 MPa for the body-centered-cubic (bcc) structured alloys, such as the AlCoCrFeNiTi x system. The values of Vickers hardness range from 100 to 900, depending on lattice types and microstructures. As in conventional alloys with one or two principal elements, the addition of minor alloying elements to HEAs can further alter their mechanical properties, such as strength, plasticity, hardness, etc. Excessive alloying may even result in the change of lattice types of HEAs. In this report, we first review alloying effects on lattice types and properties of HEAs in five Al-containing HEA systems: Al x CoCrCuFeNi, Al x CoCrFeNi, Al x CrFe1.5MnNi0.5, Al x CoCrFeNiTi, and Al x CrCuFeNi2. It is found that Al acts as a strong bcc stabilizer, and its addition enhances the strength of the alloy at the cost of reduced ductility. The origins of such effects are then qualitatively discussed from the viewpoints of lattice-strain energies and electronic bonds. Quantification of the interaction between Al and 3 d transition metals in fcc, bcc, and intermetallic compounds is illustrated in the thermodynamic modeling using the CALculation of PHAse Diagram method.

  20. Effect of mechanical alloying and Ti addition on solution and ageing treatment of an AA7050 aluminium alloy

    OpenAIRE

    Kátia Regina Cardoso; Dilermando Nagle Travessa; Asunción García Escorial; Marcela Lieblich

    2007-01-01

    In this work, solution heat treatments at different temperatures were performed in a commercial based AA7050 aluminium alloy, with and without titanium addition, produced by mechanical alloying and hot extrusion with the aim to investigate the effect of titanium addition and mechanical alloying in the precipitates stability. The same heat treatment conditions were used in a reference sample obtained from a commercial AA7050 alloy. Solution heat treated samples were characterised by differenti...

  1. Effect of alloy elements and hydride morphology on hydrogen embrittlement of zirconium alloy

    International Nuclear Information System (INIS)

    The effects of Nb and Sn on hydride embrittlement of Zr alloys were investigated. For this, experimental Zr alloys were prepared in a sheet shape and charged with hydrogen. The microstructure and hydride morphology were analyzed and the tensile properties were measured to understand the role of Nb and Sn on the hydride embrittlement of Zr alloy. With addition of Nb and Sn, recrystallization was retarded during the final annealing heat treatment. The retardation was mainly caused from β-Nb precipitates and Sn solute atoms, which was confirmed from texture analyses. Of the two, Sn was found to more effective in retarding recrystallization. When hydrogen was charged, hydride clusters with stacked hydride platelets were observed in unalloyed Zr. However, with addition of Nb and Sn, such hydride clusters were replaced with hydrides platelets which were more or less aligned with the rolling direction and linked up on the rolling plane, and hydride length and the spacing between hydrides were increased. This change in hydride morphology was caused by the retardation of recrystallization. Again, Sn was found to be more effective in in modifying the hydride morphology and aligning hydrides on the rolling plane. Both Nb and Sn contributed to the strengthening of Zr alloys, but Sn is more effective in strengthening than Nb. However, tensile strengths of the experimental alloys were nearly independent of the absorbed hydrogen contents. While ductility was reduced with increasing hydrogen contents, the degree of ductility loss was dependent on Nb and Sn contents which increased hydrogen solubility and retarded recrystallization. For alloys with 1%-Nb and/or 1%-Sn, increase in hydrogen solubility was the main contributor to increase in resistance to hydride embrittlement. On the other hand, for an alloy with 2%-Nb resulted in large amount of β-Nb precipitates, which in turn significantly retarded recrystallization. Therefore, the added contribution of retardation of

  2. Anodic behavior of alloy 22 in bicarbonate containing media: Effect of alloying

    International Nuclear Information System (INIS)

    Alloy 22 is one of the candidates for the manufacture of high level nuclear waste containers. These containers provide services in natural environments characterized by multi-ionic solutions.It is estimated they could suffer three types of deterioration: general corrosion, localized corrosion (specifically crevice corrosion) and stress corrosion cracking (SCC). It has been confirmed that the presence of bicarbonate and chloride ions is necessary to produce cracking, . It has also been determined that the susceptibility to SCC could be related to the occurrence of an anodic peak in the polarization curves in these media at potentials below transpassivity. The aim of this work is to study the effect of alloying elements on the anodic behavior of Alloy 22 in media containing bicarbonate and chloride ions at different concentrations and temperatures. Polarization curves were made on alloy 22 (Ni-22% Cr-13% Mo), Ni-Mo (Ni-28, 5% Mo) and Ni-Cr (Ni-20% Cr) in the following solutions: 1 mol/L NaCl at 90oC, and 1.148 mol/L NaHCO3; 1.148 mol/L NaHCO3 + 1 mol/L NaCl; 1.148 mol/L NaHCO3 + 0.1 mol/L NaCl, at 90oC, 75oC, 60oC and 25oC. It was found that alloy 22 has a anodic current density peak at potentials below transpassivity, only in the presence of bicarbonate ions. Curves performed in 1 mol/L NaCl did not show any anodic peak, in any of the tested alloys. The curves made on alloys Ni-Mo and Ni-Cr in the presence of bicarbonate ions, allowed to determine that Cr, is responsible for the appearance of the anodic peak in alloy 22. The curves of alloy Ni-Mo showed no anodic peak in the studied conditions. The potential at which the anodic peak appears in alloy 22 and Ni-Cr alloy, increases with decreasing temperature. The anodic peak was also affected by solution composition. When chloride ion is added to bicarbonate solutions, the anodic peak is shifted to higher potential and current densities, depending on the concentration of added chloride ions (author)

  3. Tunable magnetocaloric effect in transition metal alloys

    Science.gov (United States)

    Belyea, Dustin D.; Lucas, M. S.; Michel, E.; Horwath, J.; Miller, Casey W.

    2015-10-01

    The unpredictability of geopolitical tensions and resulting supply chain and pricing instabilities make it imperative to explore rare earth free magnetic materials. As such, we have investigated fully transition metal based “high entropy alloys” in the context of the magnetocaloric effect. We find the NiFeCoCrPdx family exhibits a second order magnetic phase transition whose critical temperature is tunable from 100 K to well above room temperature. The system notably displays changes in the functionality of the magnetic entropy change depending on x, which leads to nearly 40% enhancement of the refrigerant capacity. A detailed statistical analysis of the universal scaling behavior provides direct evidence that heat treatment and Pd additions reduce the distribution of exchange energies in the system, leading to a more magnetically homogeneous alloy. The general implications of this work are that the parent NiFeCoCr compound can be tuned dramatically with FCC metal additives. Together with their relatively lower cost, their superior mechanical properties that aid manufacturability and their relative chemical inertness that aids product longevity, NiFeCoCr-based materials could ultimately lead to commercially viable magnetic refrigerants.

  4. Effect of hydrogen on aluminium and aluminium alloys: A review

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1996-01-01

    Susceptibility of aluminium and its alloys towards hydrogen embrittlement has been well established. Still a lot of confusion exists on the question of transport of hydrogen and its possible role in stress corrosion cracking. This paper reviews some of the fundamental properties of hydrogen in...... aluminium and its alloys and its effect on mechanical properties. The importance of hydrogen embrittlement over anodic dissolution to explain the stress corrosion cracking mechanism of these alloys is also examined in considerable detail. The various experimental findings concerning the link between...

  5. Correlation effects driven by reduced dimensionality in magnetic surface alloys

    Indian Academy of Sciences (India)

    U Manju

    2015-06-01

    The evolution of electronic properties and correlation effects in manganese-based two-dimensional magnetic surface alloys are discussed. Enhanced correlations resulting from the reduced dimensionality of the surface alloys lead to the modification of the core level and valence band electronic structures resulting in the appearance of distinct satellite features. Apart from this, surface alloying-induced strong modifications in the substrate surface states arising from charge reorganization and electron transfer to the surface states as well as band-gap openings are also discussed.

  6. Effect of Al-3Nb-1B Master Alloy on the Grain Refinement of AZ91D Magnesium Alloy

    Science.gov (United States)

    Zhang, Lei; Zhou, Wei; Hu, Penghe; Zhou, Quan

    2016-06-01

    An Al-3Nb-1B master alloy has been prepared using a melt reaction method. The microstructure of the master alloy and its refinement performance on AZ91D magnesium alloy were investigated. Experimental results showed that the Al-3Nb-1B master alloy was mainly composed of α-Al and NbB2 phases. With the increase of the addition amount of Al-3Nb-1B master alloy, the primary α-Mg grains of AZ91D magnesium alloy were further refined. Upon adding 0.5 wt pct Al-3Nb-1B master alloy, the average grain size of the primary α-Mg decreased from 240 to 52 μm. The present results indicated that NbB2 can act as effective heterogeneous nucleus of the primary α-Mg, which accounted for the good grain refining performance on AZ91D magnesium alloy. Compared with the unrefined alloy, the yield strength, ultimate tensile strength, and elongation of AZ91D magnesium alloy refined by 0.5 wt pct Al-3Nb-1B master alloy were increased by 18.4, 15.7, and 27.3 pct, respectively due to the grain refinement effect.

  7. The irradiation effects on zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Negut, Gh. [Institute for Nuclear Research Pitesti, Campului Str., 1, Mioveni P.O. Box 78, 0300 Pitesti (Romania)]. E-mail: joenegut@yahoo.com; Ancuta, M. [Institute for Nuclear Research Pitesti, Campului Str., 1, Mioveni P.O. Box 78, 0300 Pitesti (Romania); Radu, V. [Institute for Nuclear Research Pitesti, Campului Str., 1, Mioveni P.O. Box 78, 0300 Pitesti (Romania); Ionescu, S. [Institute for Nuclear Research Pitesti, Campului Str., 1, Mioveni P.O. Box 78, 0300 Pitesti (Romania); Stefan, V. [Institute for Nuclear Research Pitesti, Campului Str., 1, Mioveni P.O. Box 78, 0300 Pitesti (Romania); Uta, O. [Institute for Nuclear Research Pitesti, Campului Str., 1, Mioveni P.O. Box 78, 0300 Pitesti (Romania); Prisecaru, I. [University Politehnica Bucharest, Bucharest (Romania); Danila, N. [University Politehnica Bucharest, Bucharest (Romania)

    2007-05-31

    Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment.

  8. The irradiation effects on zirconium alloys

    International Nuclear Information System (INIS)

    Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment

  9. Simulation study for atomic size and alloying effects during forming processes of amorphous alloys

    Institute of Scientific and Technical Information of China (English)

    ZHENG Caixing; LIU Rangsu; PENG Ping; ZHOU Qunyi

    2004-01-01

    A molecular dynamics (MD) simulation study has been performed for the solidification processes of two binary liquid alloys Ag6Cu4 and CuNi by adopting the quantum Sutton-Chen many-body potentials. By analyzing bond-types, it is demonstrated that at the cooling rate of 2×1012K/s, the CuNi forms fcc crystal structures, while the Ag6Cu4 forms amorphous structures. The original reason is that the atomic radius ratio (1.13) of the CuAg is bigger than that (1.025) of the CuNi. This shows that the atomic size difference is indeed the main factor for forming amorphous alloys. Moreover, for Ag60Cu40,corresponding to the deep eutectic point in the phase diagram, it forms amorphous structure easily. This confirms that as to the forming tendency and stability of amorphous alloys, the alloying effect plays a key role. In addition, having analyzed the transformation of microstructures by using the bond-type index and cluster-type index methods, not only the key role of the icosahedral configuration to the formation and stability of amorphous alloys can be explained, but also the solidification processes of liquid metals and the characteristics of amorphous structures can be further understood.

  10. Effect of hydrogen on mechanical properties of -titanium alloys

    Indian Academy of Sciences (India)

    H-J Christ; A Senemmar; M Decker; K Prüßner

    2003-06-01

    Conflicting opinions exist in the literature on the manner in which hydrogen influences the mechanical properties of -titanium alloys. This can be attributed to the -stabilizing effect of hydrogen in these materials leading to major changes in the microstructure as a result of hydrogen charging. The resulting (extrinsic) effect of hydrogen on the mechanical properties can possibly cover up the direct (intrinsic) influences. On the basis of experimentally determined thermodynamic and kinetic data regarding the interaction of hydrogen with -titanium alloys, hydrogen concentrations of up to 8 at.% were established in three commercial alloys by means of hydrogen charging from the gas phase. In order to separate intrinsic and extrinsic effects the charging was carried out during one step of the two-step heat treatment typical of metastable -titanium alloys, while the other step was performed in vacuum. The results on the single-phase condition represent the intrinsic hydrogen effect. Monotonic and cyclic strength increase at the expense of ductility with increasing hydrogen concentration. The brittle to ductile transition temperature shifts to higher values and the fatigue crack propagation threshold value decreases. The microstructure of the metastable, usually two-phase -titanium alloys is strongly affected by hydrogen, although the extent of this effect depends not only on the hydrogen concentration but also on the temperature of charging. This microstructural influence (extrinsic effect) changes the mechanical properties in the opposite direction as compared to the intrinsic hydrogen effect.

  11. In vivo effects of dental casting alloys

    Czech Academy of Sciences Publication Activity Database

    Venclíková, Z.; Benada, Oldřich; Bártová, J.; Joska, L.; Mrklas, L.; Procházková, J.; Stejskal, V.D.M.; Podzimek, Š.

    2006-01-01

    Roč. 27, č. 1 (2006), s. 25-32. ISSN 0172-780X R&D Projects: GA MZd NK7437 Institutional research plan: CEZ:AV0Z50200510 Keywords : dental alloys * metals * gingiva Subject RIV: EE - Microbiology, Virology Impact factor: 0.924, year: 2006

  12. Effect of Annealing on Rare Earth Based Hydrogen Storage Alloys

    Institute of Scientific and Technical Information of China (English)

    Li Jinhua

    2004-01-01

    Rare earth-based hydrogen storage alloy used as negative electrode materials for nickel-metal hydride (Ni-MH) batteries are used commercially.The effect of annealing treatment with different annealing temperature and time on the MLNi3.68 Co0.78 Mn0.35 Al0.27 and MMNi3.55 Co0.75 Mn0.40 Al0.30 alloys were investigated.The crystal microstructure,pressure-composition-isotherms (p-C-T) and electrochemical properties of alloys were examined by X-ray diffraction (XRD), automatic PCI monitoring system and electrical performance testing instruments.The optimum annealing treatment conditions of two kinds of alloys were determined.

  13. Environmental and alloying effects on corrosion of metals and alloys

    Science.gov (United States)

    Liang, Dong

    2009-12-01

    species could be missed in standard laboratory exposures such as ASTM B117. Initial efforts focused on the effects UV radiation, O3, relative humidity on the atmospheric corrosion of bare silver. Later work addressed the corrosion of silver samples deposited with NaCl particles. An exposure chamber that can simulate various environmental effects was built. The effects of UV radiation, O3, and relative humidity were varied separately while keeping the other factors the same level. The corrosion products were analyzed by the galvanostatic reduction method and characterization techniques such as SEM and EDS. It was found that both UV and O3 are necessary for fast corrosion on bare silver and this fast corrosion reaction results from atomic oxygen generated photodegradation of O3. In the presence of UV and O3, relative humidity has little effect on the atmospheric corrosion of bare silver in contrast to conventional atmospheric corrosion. The degree of corrosion is found to increase with O3 concentration. Moreover, a kinetic study of atmospheric corrosion of bare silver found that an incubation time for the atmospheric corrosion attack is needed. This incubation time is related to the chemisorption process of atomic oxygen. Though UV radiation can form reactive atomic oxygen which is more reactive than O3 alone as shown in the last chapter, the enhancement of corrosion by UV is limited for Ag with NaCl particles at low ozone concentration and high RH. The corrosion rate of silver with NaCl particles is found to increase with relative humidity, which is different than the case of bare silver. This indicates that different mechanisms control the atmospheric corrosion of silver. The incubation time for corrosion of silver with NaCl particles is shorter than for bare silver. This result from chemisorption of Cl 2 is favored over that of atomic oxygen. Interestingly, the total corrosion product of silver with NaCl particles is less than that of bare silver. This could be due to

  14. Numerical simulation of the alloying elements effect on steels’ properties

    Directory of Open Access Journals (Sweden)

    W. Sitek

    2011-03-01

    Full Text Available Purpose: The goal of the research carried out was evaluation of alloying elements effect on high-speed steels hardness and fracture toughness and austenite transformations during continuous cooling of structural steels.Design/methodology/approach: Multi-layer feedforward neural networks with learning rule based on the error backpropagation algorithm were employed for modelling the steels properties. Then the neural networks worked out were employed for the computer simulation of the effect of particular alloying elements on the steels’ properties.Findings: Obtained results show that neural network are useful in evaluation of synergic effect of alloying elements on selected materials properties when classical investigations’ results do not provide evaluation of the effect of two or more alloying elements.Practical implications: Numerical simulation presented in the work, based on using the adequate material models may feature an alternative for classical investigations on effect of alloying elements on steels’ properties.Originality/value: The use of the neural networks as an tool for evaluation of the chemical composition effect on steels’ properties.

  15. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)

    K T Kashyap; T Chandrashekar

    2001-08-01

    Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the scientific literature. The nucleant effects i.e. which particle and its characteristics nucleate -Al, has been the subject of intensive research. Lately the solute effect i.e. the effect of dissolved titanium on grain refinement, has come into forefront of grain refinement research. The present paper attempts to review the literature on the nucleant effects and solute effects on grain refinement and addresses the importance of dissolved titanium in promoting nucleation of -Al on nucleant particles.

  16. First-principles study on the effect of alloying elements on the elastic deformation response in β-titanium alloys

    International Nuclear Information System (INIS)

    Theoretical deformation response of hypothetical β-titanium alloys was investigated using first-principles calculation technique under periodic boundary conditions. Simulation was carried out on hypothetical 54-atom supercell of Ti–X (X = Cr, Mn, Fe, Zr, Nb, Mo, Al, and Sn) binary alloys. The results showed that the strength of Ti increases by alloying, except for Cr. The most effective alloying elements are Nb, Zr, and Mo in the current simulation. The mechanism of bond breaking was revealed by studying the local structure around the alloying element atom with respect to volume change. Moreover, the effect of alloying elements on bulk modulus and admissible strain was investigated. It was found that Zr, Nb, and Mo have a significant effect to enhance the admissible strain of Ti without change in bulk modulus

  17. First-principles study on the effect of alloying elements on the elastic deformation response in β-titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gouda, Mohammed K., E-mail: mohamed.kamal@ejust.edu.eg; Gepreel, Mohamed A. H. [Materials Science and Engineering Department, Egypt-Japan University of Science and Technology, Borg El Arab, Alexandria 21934 (Egypt); Nakamura, Koichi [Materials Science and Engineering Department, Egypt-Japan University of Science and Technology, Borg El Arab, Alexandria 21934 (Egypt); Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 615-8540 (Japan)

    2015-06-07

    Theoretical deformation response of hypothetical β-titanium alloys was investigated using first-principles calculation technique under periodic boundary conditions. Simulation was carried out on hypothetical 54-atom supercell of Ti–X (X = Cr, Mn, Fe, Zr, Nb, Mo, Al, and Sn) binary alloys. The results showed that the strength of Ti increases by alloying, except for Cr. The most effective alloying elements are Nb, Zr, and Mo in the current simulation. The mechanism of bond breaking was revealed by studying the local structure around the alloying element atom with respect to volume change. Moreover, the effect of alloying elements on bulk modulus and admissible strain was investigated. It was found that Zr, Nb, and Mo have a significant effect to enhance the admissible strain of Ti without change in bulk modulus.

  18. Effect of homogenization and alloying elements on hot deformation behaviour of 1XXX series aluminum alloys

    Science.gov (United States)

    Shakiba, Mohammad

    In the present study, the effect of different alloying elements as well as the homogenization treatment on the hot workability and microstructure of dilute Al-Fe-Si alloys was investigated using hot compression tests, optical microscopy, SEM, electron EBSD, TEM, electrical conductivity measurements. The effect of the homogenization treatment on the microstructure and hot workability of two dilute Al-Fe-Si alloys was first investigated. Homogenization promoted the phase transformation from the metastable AlmFe or alpha-AlFeSi phase to the Al3Fe equilibrium phase and induced a significant change in solute levels in the solid solution. Homogenization at 550°C significantly reduced the solid solution levels due to the elimination of the supersaturation originating from the cast ingot and produced the lowest flow stress under all of the deformation conditions studied. The hot deformation behavior of dilute Al-Fe-Si alloys containing different amounts of Fe (0.1 to 0.7 wt%) and Si (0.1 to 0.25 wt%) was studied by uniaxial compression tests conducted at various temperatures (350-550 °C) and strain rates (0.01-10 s-1). The flow stress of the 1xxx alloys increased with increasing Fe and Si content. Increasing the Fe content from 0.1 to 0.7% raised the flow stress by 11-32% in Al-Fe-0.1Si alloys, whereas the flow stress increased 5-14% when the Si content increased from 0.1 to 0.25% in Al-0.1Fe-Si alloys. The experimental stress-strain data were employed to drive constitutive equations correlating flow stress, deformation temperature and strain rate considering the influence of the chemical composition. The microstructural analysis results revealed that dynamic recovery is the sole softening mechanism during hot deformation of dilute Al-Fe-Si alloys. Increasing the Fe and Si content retarded dynamic recovery and resulted in a decrease in the subgrain size and mean misorientation angle of the boundaries. Furthermore, the hot deformation behavior of dilute Al-Fe-Si alloys

  19. The effect of cast Al-Si-Cu alloy solidification rate on alloy thermal characteristics

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-04-01

    Full Text Available Purpose: In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters. Thus, a thermal analysis cooling curve of the alloy is used for process control in the aluminum casting industry. In this work effect of cooling rate on the size of the grains, SDAS, size of the β precipitation and thermal characteristic results of AC AlSi9Cu cast alloy have been described. The solidification process was studied using the cooling curve and crystallization curve at solidification rate ranging from 0,16 ºCs-1 up to 1,04 ºCs-1Design/methodology/approach: The experimental alloy used in this investigation was prepared by mixing the ACAlSi5Cu commercial alloys and two master alloys AlSi49 and AlCu55. Thermal analysis tests were conducted using the UMSA Technology Platform. Cooling curve thermal analysis was performed on all samples using high sensitivity thermocouples of K type. Data were acquired by a high speed data acquisition system linked to a PC computer. Each chilled sample was sectioned horizontally where the tip of the thermocouple was located and it was prepared by standard grinding and polishing procedures. Optical microscopy was used to characterize the microstructure and intermetallic phases. Secondary Dendrite Arm Spacing measurements were carried out using an Leica Q-WinTM image analyzer.Findings: Increasing the cooling rate increases significantly the liquidus temperature, nucleation undercooling temperature, solidification range and decreases the recalescence undercooling temperature. Increasing cooling rate refines all microstructural features.Research limitations/implications: This paper presents results for one alloy - AC AlSi9Cu only, for the assessment of the Silicon Modification Level didn’t include the arrangement of a Si crystal in a matrix.Originality/value: Original value of the work is applied the artificial intelligence for the assessment of the Silicon

  20. Configurational thermodynamics of alloys from first principles: effective cluster interactions

    International Nuclear Information System (INIS)

    Phase equilibria in alloys to a great extent are governed by the ordering behavior of alloy species. One of the important goals of alloy theory is therefore to be able to simulate these kinds of phenomena on the basis of first principles. Unfortunately, it is impossible, even with present day total energy software, to calculate entirely from first principles the changes in the internal energy caused by changes of the atomic configurations in systems with several thousand atoms at the rate required by statistical thermodynamics simulations. The time-honored solution to this problem that we shall review in this paper is to obtain the configurational energy needed in the simulations from an Ising-type Hamiltonian with so-called effective cluster interactions associated with specific changes in the local atomic configuration. Finding accurate and reliable effective cluster interactions, which take into consideration all relevant thermal excitations, on the basis of first-principles methods is a formidable task. However, it pays off by opening new exciting perspectives and possibilities for materials science as well as for physics itself. In this paper we outline the basic principles and methods for calculating effective cluster interactions in metallic alloys. Special attention is paid to the source of errors in different computational schemes. We briefly review first-principles methods concentrating on approximations used in density functional theory calculations, Green's function method and methods for random alloys based on the coherent potential approximation. We formulate criteria for the validity of the supercell approach in the calculations of properties of random alloys. The generalized perturbation method, which is an effective and accurate tool for obtaining cluster interactions, is described in more detail. Concentrating mostly on the methodological side we give only a few examples of applications to the real systems. In particular, we show that the ground

  1. Hydride effect on the tensile properties of HANA-4 alloy

    International Nuclear Information System (INIS)

    KAERI has developed some Zr-based new alloys, called HANA alloys, for high burn-up fuel cladding material. The sample specimens of HANA cladding tube material showed good performance in corrosion and creep properties at the irradiation test in Halden test reactor up to 10GW/MtU as well as the un-irradiation tests. Zirconium alloys has been used as nuclear fuel cladding material because they have satisfactory mechanical strength and corrosion resistance. It was reported that zirconium alloys responded abnormally in mechanical behavior over a certain temperature and strain rates. For example, the embrittlement of Zircaloy-4 (Zr-1.5Sn-0.2Fe-0.1Cr) alloy can be increased over 227 ∼ 427 .deg. C due to dynamic strain aging(DSA). The change of mechanical properties of HANA-4(Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr) alloy from DSA was already studied from room temperature to 500 .deg. C when its specimens had been tested with the strain rate of 1.67x10-2/s and 8.33x10-5/s. When a zirconium alloy is used in a nuclear reactor, hydrides form in it from not only external hydrogen sources such as waterside corrosion, dissolved hydrogen in coolant, water radiolysis but also internal sources such as hydrogen content in fuel pellets and moisture absorbed by the uranium dioxide fuel pellet. Hydrogen embrittlement of zirconium alloys has been extensively studied because hydrides may act as a sudden failure at very low strain. For low and medium hydrogen content, the hydrides crack during tensile loading and accelerate the ductile fracture process. To study the effect of hydride on the mechanical properties of HANA-4 cladding tube which had been finally heat-treated at 470 .deg. C, this research was done with tensile tests as an extension of the prior study

  2. Effects of Si alloying and T6 treatment on mechanical properties and wear resistance of ZA27 alloys

    OpenAIRE

    Rui Zhang; Guang-lei Liu; Nai-chao Si

    2016-01-01

    To improve the mechanical properties and wear resistance of ZA27 alloy, Si was introduced to the alloy, and the effect of Si alloying and T6 heat treatment on the microstructure, mechanical properties and wear resistance was investigated. The results show that with 0.55% Si, the microstructure of the alloy can be refined effectively, which leads to the increase of hardness. But the tensile strength and elongation decrease because Si undermines the integrity of the matrix. On the other hand, t...

  3. Barkhausen effect during hydrogen interaction with amorphous alloy 2NSR

    International Nuclear Information System (INIS)

    The Barkhausen effect electromotive force measurements by the two-side saturation of the 2NSR (Fe78B12Si19Ni1) alloy amorphous band through hydrogen is carried out. The multiple increase in the Barkhausen effect electromotive force by hydrogen saturation is determined. It is assumed that in the metallic alloy over-saturated by hydrogen there originates a special structural state providing for decrease in the potential barrier by transition of the 180 deg boundary of the magnetic domain from the equilibrium state to another one. The value of the Barkhausen effect link with the hydrogen content in the material is indicated

  4. Ligand and ensemble effects in adsorption on alloy surfaces

    DEFF Research Database (Denmark)

    Liu, Ping; Nørskov, Jens Kehlet

    2001-01-01

    Density functional theory is used to study the adsorption of carbon monoxide, oxygen and nitrogen on various Au/Pd(111) bimetallic alloy surfaces. By varying the Au content in the surface we are able to make a clear separation into geometrical (or ensemble) effects and electronic (or ligand......) effects determining the adsorption properties....

  5. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    International Nuclear Information System (INIS)

    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 ± 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a β-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle–antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  6. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moreira dos Santos, Margarida, E-mail: margarida.santos@fct.unl.pt; Queiroz, Margarida Joao; Baptista, Pedro V. [Universidade Nova de Lisboa, CIGMH, Departamento Ciencias da Vida, Faculdade de Ciencias e Tecnologia (Portugal)

    2012-05-15

    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 {+-} 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a {beta}-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle-antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  7. Point defects and diffusion in alloys: correlation effects

    International Nuclear Information System (INIS)

    Kinetic models in alloys aim at predicting the transport properties of a system starting from the microscopic jump frequencies of defects. Such properties are of prior importance in systems which stay out of equilibrium for a long time, as for example irradiated alloys in nuclear reactors. We hereby propose several developments of the recent self-consistent mean field (SCMF) kinetic theory, which deals particularly with the correlation effects due to the coupling of atomic and defect fluxes. They are taken into account through a non-equilibrium distribution function of the system, which is derived from the time evolution of small clusters (of two or more atoms or defects). We therefore introduce a set of 'dynamic' interactions called effective Hamiltonian. The SCMF theory is extended to treat high jump frequency ratios for the vacancy mechanism, as well as the transport through interstitial defects. We use in both cases an atomic model which accounts for the thermodynamic properties of the alloy, as e.g. the short-range order. Those models are eventually applied to predict the diffusion properties in two model alloys of nuclear interest: the concentrated Fe-Ni-Cr solid solution and the dilute Fe(P) alloy. We present adapted atomic models and compare our predictions to experimental data. (author)

  8. Inconvenient magnetocaloric effect in ferromagnetic shape memory alloys

    International Nuclear Information System (INIS)

    Highlights: ► Critical analysis of the available experimental results on isothermal magnetic entropy change in ferromagnetic shape memory alloys Ni–Mn–X (X = Ga, In, Sn, Sb) is given. ► Based on available in literature experimental data on total entropy change at martensitic transformation it is shown that the isothermal magnetic entropy change in Ni–Mn–X (X = Ga, In, Sn, Sb) should not greatly exceed 30 J/kg K. -- Abstract: Critical analysis available in the literature experimental results on magnetocaloric effect in ferromagnetic shape memory alloys Ni–Mn–X (X = Ga, In, Sn, Sb) is given. Based on a model developed by Pecharsky et al. [22], it is shown that the isothermal magnetic field-induced entropy change in the Ni–Mn–X alloys should not greatly exceed 30 J/kg K. Considering thermodynamics of temperature- and magnetic field-induced martensitic transformations, it is demonstrated that a contribution of the structural subsystem to the magnetocaloric effect in the Ni–Mn–X alloys studied so far is irreversible in magnetic fields below 5 T. This makes ferromagnetic shape memory alloys an inconvenient system for the practical application in modern magnetic refrigeration technology

  9. Effect of titanium content and aging temperature on the properties of uranium-titanium alloys

    International Nuclear Information System (INIS)

    The mechanical properties and microstructures of four uranium-titanium alloys were examined as functions of titanium content and aging temperature. Titanium alloy content was varied from 0.41 to 0.79 weight percent. Aging temperatures from 350 to 4500C (all for six hours) were evaluated for each alloy in addition to tests in the unaged conditions. Titanium and aging temperature were both shown to be strong effects in determining alloy properties. It was determined that the uranium-0.41 weight percent titanium alloy underwent extensive age-hardening even though the alloy did not exhibit a martensitic microstructure characteristic of the alloys richer in titanium

  10. Effects of rare earths on friction and wear characteristics of magnesium alloy AZ91D

    Institute of Scientific and Technical Information of China (English)

    祁庆琚; 刘勇兵; 杨晓红

    2003-01-01

    The influence of various rare-earth contents on the friction and wear characteristics of magnesium alloyAZ91D was studied. The results show that the wear resistance properties of rare-earth magnesium alloys are betterthan those of the matrix alloy under the testing conditions. Magnesium alloys undergo transition from mild wear tosevere wear. The addition of rare earths refines the structure of alloys, improves the comprehensive behaviors of themagnesium alloys, increases the stability of oxidation films on worn surfaces, enhances the loading ability of rare-earth magnesium alloys, and delays the transition from mild wear to severe wear effectively.

  11. Effect of recasting of nickel-chromium alloy on its porosity

    OpenAIRE

    Jayant Palaskar; Nadgir, D.V.; Ila Shah

    2010-01-01

    Statement of Problem: As per the review of literature very few studies have been carried on recasting of dental casting alloy and in particlular its effect on occurrence of porosities. Purpose of Study: This study was designed to find out occurrence of porosities in new alloy and recasted alloy using a scanning electron microscope. Materials and Methods: Different percentage combinations of new and once casted alloy were used to produce twenty five samples. Castings obtained from new alloy we...

  12. The Effect of Cold Work on Properties of Alloy 617

    Energy Technology Data Exchange (ETDEWEB)

    Richard Wright

    2014-08-01

    Alloy 617 is approved for non-nuclear construction in the ASME Boiler and Pressure Vessel Code Section I and Section VIII, but is not currently qualified for nuclear use in ASME Code Section III. A draft Code Case was submitted in 1992 to qualify the alloy for nuclear service but efforts were stopped before the approval process was completed.1 Renewed interest in high temperature nuclear reactors has resulted in a new effort to qualify Alloy 617 for use in nuclear pressure vessels. The mechanical and physical properties of Alloy 617 were extensively characterized for the VHTR programs in the 1980’s and incorporated into the 1992 draft Code Case. Recently, the properties of modern heats of the alloy that incorporate an additional processing step, electro-slag re-melting, have been characterized both to confirm that the properties of contemporary material are consistent with those in the historical record and to increase the available database. A number of potential issues that were identified as requiring further consideration prior to the withdrawal of the 1992 Code Case are also being re-examined in the current R&D program. Code Cases are again being developed to allow use of Alloy 617 for nuclear design within the rules of the ASME Boiler and Pressure Vessel Code. In general the Code defines two temperature ranges for nuclear design with austenitic and nickel based alloys. Below 427°C (800°F) time dependent behavior is not considered, while above this temperature creep and creep-fatigue are considered to be the dominant life-limiting deformation modes. There is a corresponding differentiation in the treatment of the potential for effects associated with cold work. Below 427°C the principal issue is the relationship between the level of cold work and the propensity for stress corrosion cracking and above that temperature the primary concern is the impact of cold work on creep-rupture behavior.

  13. Effects of alloying elements (Sn, Nb, Cr, and Mo) on the microstructure and mechanical properties of zirconium alloys

    International Nuclear Information System (INIS)

    The alloying effects of Sn, Nb, Cr, and Mo on zirconium alloys were elucidated and compared. Electron backscatter diffraction, transmission electron microscopy, tensile test, and fractographic observation were jointly utilized to carry out detailed microstructural characterization and mechanical property evaluation. Results show that Mo is the most effective among these elements from the viewpoints of strengthening and reducing grain size. The strengthening mechanism for each element is also discussed. The order of solid-solution strengthening of these alloying elements is Cr > Nb > Sn, and the sequence is Cr ≈ Mo > Nb when precipitation strengthening is considered. Further, as far as the ability to impede dislocation motion is concerned, the sequence is Mo > Cr > Nb > Sn. The experimental results demonstrate that minor amount of Mo addition in zirconium alloys is greatly effective in strengthening the alloy and reducing the grain size. (author)

  14. Effects of self-irradiation in plutonium alloys

    Science.gov (United States)

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2016-04-01

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35 °C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  15. Effect of Low Strain Rate on Formability of Aluminium Alloy

    OpenAIRE

    Bidulská, J.; T. Kvačkaj; Bidulský, R.; Cabbibo, M.; Evangelista, E.

    2007-01-01

    Effect of low strain rate on formability of aluminium alloy 2014 by means of torsion test was performed. The presented experimental results exhibit decrease of the ductility with increase and decrease of ε and T, respectively, and optimal values of , ε T are thus obtained.

  16. 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.

  17. The Barkhausen effect in Fe-V alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fruchart, D.; Skryabina, N.; Spivak, L

    2004-11-30

    It is known that the Barkhausen effect can be used as a very effective method to investigate physical and mechanical properties of ferromagnetic systems. To our knowledge the Barkhausen effect has never been used for the analysis of the magnetic microstructure of the Fe{sub 100-x}V{sub x} system. In the present work we report on the investigation of the structure of Barkhausen jumps as a function of the vanadium concentration in Fe-V alloys.

  18. Effect of heat treatment on Fe-B-Si-Nb alloy powder prepared by mechanical alloying

    Directory of Open Access Journals (Sweden)

    Rodrigo Estevam Coelho

    2005-06-01

    Full Text Available The effect of heat treatment on crystallization behavior of Fe73.5B15Si10Nb1.5 alloy powder prepared by mechanical alloying was studied. The powder samples were prepared by mechanical alloying (MA and for different milling times (1, 5, 25, 70 and 100 hours. Crystalline powders of iron, boron, silicon and niobium were sealed with tungsten carbide balls in a cylindrical vial under nitrogen atmosphere. The ball-to-powder weight ratio was 20 to 1. A Fritsch Pulverizette 5 planetary ball mill was used for MA the powders at room temperature and at 250 rpm. To study the microstructural evolution, a small amount of powder was collected after different milling times and examined by X-ray diffraction, using CuKalpha radiation (lambda = 0.15418 nm. The crystallization behavior was studied by differential thermal analysis, from 25 up to 1000 °C at a heating rate of 25 °C min-1.

  19. Numerical simulation of the alloying elements effect on steels’ properties

    OpenAIRE

    W. Sitek; J. Trzaska

    2011-01-01

    Purpose: The goal of the research carried out was evaluation of alloying elements effect on high-speed steels hardness and fracture toughness and austenite transformations during continuous cooling of structural steels.Design/methodology/approach: Multi-layer feedforward neural networks with learning rule based on the error backpropagation algorithm were employed for modelling the steels properties. Then the neural networks worked out were employed for the computer simulation of the effect of...

  20. Effect of titanium addition on fracture toughness behavior of ZL108 alloy

    Institute of Scientific and Technical Information of China (English)

    WENG Yong-gang; LI Zi-jing; LIU Zhi-yong; LIU Wen-cai; WANG Ming-xing; SONG Tian-fu

    2006-01-01

    Two different titanium alloying methods were applied to ZL108 alloy for preparing specimens containing titanium. The specimens were tested on the MTS 810 material test system for studying their behavior of the plane strain fracture toughness KIC. The experimental data were analyzed by the statistical significance tests. The results show that the fracture toughness of the ZL108 alloy containing titanium is superior to that of common ZL108 alloy containing no titanium, but there is no significant difference for different titanium alloying methods. Therefore titanium addition is an effective method for improving the fracture toughness of the alloy ZL108.

  1. Refining Effect of Boron on Hypoeutectic Al-Si Alloys

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the α-Al and eutectic Si with the different additions of Al-B master alloys made at 850℃ was investigated; and the Al-B master alloys formed under different temperature conditions have been studied to explore the morphologies of AlB2 particles;slowly cooled sample with addition of Al-B was made to explore the refinement mechanism. AlB master alloy can refine not only α-Al, but eutectic Si. Theoretical analysis indicates that,although AlB2 does not take part directly in the nucleation process in pure Al in the presence of Si, it provides a substrate for precipitation of a small content of Si from which α-Al will grow without any undercooling. When the temperature decreases to eutectic line, AlB2 subsequently nucleates eutectic Si; AlB2 particles appear in two different morphologies, namely, hexagonal platelet and tetradehedron morphology which depend on the processing temperature conditions.

  2. Effect of hydrogen content on the embrittlement of ZR alloys

    International Nuclear Information System (INIS)

    An experimental series has been carried out in the KFKI Atomic Energy Research Institute in order to clear up the role of oxidation and H uptake in the Zr cladding embrittlement process. Russian E110 type Zr1%Nb and Zircaloy-4 cladding were used and the differences between the two alloys were also examined. The sample preparation covered the following cases: Oxidation in steam, Oxidation in Ar+O2 atmosphere, Hydrogenisation of as received and oxidised in Ar+O2 atmosphere samples. The oxidation in Ar+O2 and later hydrogenisation possible to produce samples with well characterised H and O content. The hydrogen content of samples oxidised in steam was determined after mechanical testing using high temperature desorption. The results of the experiments provided detailed information on the effect of H and O content of the embrittlement of Zr alloys. The most important conclusions were the following: Hydrogen seems to play a more important role in embrittlement of Zr alloys than oxygen. The Zry-4 samples becomes brittle at lower H content than the Zr1%Nb. Under steam oxidation conditions the Zr1%Nb alloy takes up much more H than the Zry-4 and it resulted in earlier embrittlement. This explains the observed difference in ring compression tests with E110 (Zr1%Nb) and Zry-4 claddings. (author)

  3. Effect of silicon on oxidation of Ni-15Al alloy

    Institute of Scientific and Technical Information of China (English)

    WU Ying; NIU Yan; WU Wei-tao

    2005-01-01

    The oxidation of binary Ni-Al alloy containing 15% (mole fraction, the same below if not mentioned)Al (Ni-15Al), and of a ternary alloy with the same Al content but also containing 4% Si (Ni-4Si-15Al) has been studied at 1 000 ℃ under 1.0× 105Pa O2 to examine the effect of the addition of Si on the oxidation of Ni-15Al. Oxidation of Ni-15Al produces a duplex scale composed of an outer NiO layer and an inner layer riched in Al2O3. On the contrary, Ni-4Si-15Al forms an external alumina layer directly in contact with the alloy presenting only trace of NiO and the Ni-Al spinel. As a result, the kinetics of Ni-15Al shows a fast initial stage followed by two subsequent parabolic stages with decreasing rate constants, while Ni-4Si-15Al presents essentially a single nearly-parabolic behavior with a rate constant similar to that of the final stage of Ni-15Al. Therefore, the addition of 4% Si significantly reduces the oxidation rate during the initial stage by preventing the formation of Ni-riched scales and promoting an earlier development of an exclusive external alumina layer on the alloy surface.

  4. Effect of alloying Mo on mechanical strength and corrosion resistance of Zr-1% Sn-1% Nb-1% Fe alloy

    International Nuclear Information System (INIS)

    It had been done research on Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy. The ingot was prepared by means of electrical electrode technique. The chemical analysis was identified by XRF, the metallography examination was perform by an optical microscope, the hardness test was done by Vickers microhardness, and the corrosion test was done in autoclave. The objective of this research were making Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy with Mo concentration; comparing effect of Mo concentration to metal characteristics of Zr-1%Sn-1%Nb-1%Fe which covered microstructure; composition homogeneity, mechanical strength; and corrosion resistance in steam, and determining the optimal Mo concentration in Zr-1%Sn-1%Nb-1%Fe-(x)% Mo alloy for nuclear fuel cladding which had corrosion resistance and high hardness. The results were as follow: The alloying Mo refined grains at concentration in between 0,1%-0,3% and the concentration more than that could coarsened grains. The hardness of the Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was controlled either by the flaw or the dislocation, the intersection of the harder alloying element, the solid solution of the alloying element and the second phase formation of ZrMo2. The corrosion rate of the Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was controlled by the second phase of ZrMo2. The 0.3% Mo concentration in Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was the best for second phase formation. The Mo concentration in between 0,3-0,5% in Zr-1%Sn-1%Nb-1%Fe-(x)%Mo alloy was good for the second phase formation and the solid solution. (author)

  5. Effect of micro alloying elements on the interfacial reactions between molten aluminum alloy and tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, K.A. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Shabestari, S.G. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of)], E-mail: shabestari@iust.ac.ir

    2009-06-10

    The morphology and growth kinetics of intermetallic compounds that are formed in the interface of H13 tool steel and A380 molten aluminum has been investigated through immersion experiments. The effect of addition of micro alloying elements to the melt on the formation and thickness of intermetallic layer was also studied. Microstructural investigation showed that three intermetallic layers formed through the liquid-solid reaction during immersion of steel samples in the liquid aluminum at a temperature of 680 deg. C for the duration time of 2 min to 2.5 h. These intermetallic compounds are Al{sub 8}Fe{sub 2}Si, Al{sub 5}FeSi and Al{sub 12}Fe{sub 5}Si. The effect of nitride coating of the surface of H13 steel on the growth of intermetallic phases has also been studied. Micro alloying elements such as strontium and titanium have been used in the melt and their effects on the morphology of intermetallic compound and their growth rate have been investigated by the immersion experiments at the temperature of 680 deg. C for the time of 0.5-2.5 h. The results showed that two layers of Al{sub 8}Fe{sub 2}Si and Al{sub 5}FeSi formed at the interface and Al{sub 12}Fe{sub 5}Si layer was not observed. Nitride coating decreased the overall thickness of the intermetallic layer about 50% after immersion time of 0.5 h. Addition of micro alloying elements such as Sr (0.05 wt%) and Ti (0.2 wt%) to the melt decreased the total thickness of the intermetallic layer about 31% after immersion of steel for 0.5 h in the melt. Both nitride coating and addition of strontium (0.05 wt%) and titanium (0.2 wt%) micro alloying elements to the melt had the most influence on decreasing the overall thickness of the intermetallic layer. The thickness of the intermetallic layer decreased about 60% after immersion of steel for 2.5 h in the aluminum melt. The experimental results clearly indicate the beneficial effect of strontium on the kinetics of the formation and growth of the intermetallic layers.

  6. Effects of Alloying Elements on Martensitic Transformation Behavior and Damping Capacity in Fe-17Mn Alloy

    OpenAIRE

    Baik, S.; Kim, J; Jee, K.; Jang, W.; Shin, M.

    1997-01-01

    Effect of carbon and Ti on γ ←→ εmartensitic transformation behavior and damping capacity has been investigated in an Fe-17Mn alloy. The suppressive force of carbon against γ ←→ ε transformation increases linearly with an increase in carbon content, lowering Ms temperature and volume fraction of ε martensite. Carbon deteriorates damping capacity by reducing the area of γ/ε interfaces and by decreasing the mobility of the interfaces operated as damping source. The reduction in the mobility of ...

  7. Effect of micro alloying elements on the interfacial reactions between molten aluminum alloy and tool steel

    International Nuclear Information System (INIS)

    The morphology and growth kinetics of intermetallic compounds that are formed in the interface of H13 tool steel and A380 molten aluminum has been investigated through immersion experiments. The effect of addition of micro alloying elements to the melt on the formation and thickness of intermetallic layer was also studied. Microstructural investigation showed that three intermetallic layers formed through the liquid-solid reaction during immersion of steel samples in the liquid aluminum at a temperature of 680 deg. C for the duration time of 2 min to 2.5 h. These intermetallic compounds are Al8Fe2Si, Al5FeSi and Al12Fe5Si. The effect of nitride coating of the surface of H13 steel on the growth of intermetallic phases has also been studied. Micro alloying elements such as strontium and titanium have been used in the melt and their effects on the morphology of intermetallic compound and their growth rate have been investigated by the immersion experiments at the temperature of 680 deg. C for the time of 0.5-2.5 h. The results showed that two layers of Al8Fe2Si and Al5FeSi formed at the interface and Al12Fe5Si layer was not observed. Nitride coating decreased the overall thickness of the intermetallic layer about 50% after immersion time of 0.5 h. Addition of micro alloying elements such as Sr (0.05 wt%) and Ti (0.2 wt%) to the melt decreased the total thickness of the intermetallic layer about 31% after immersion of steel for 0.5 h in the melt. Both nitride coating and addition of strontium (0.05 wt%) and titanium (0.2 wt%) micro alloying elements to the melt had the most influence on decreasing the overall thickness of the intermetallic layer. The thickness of the intermetallic layer decreased about 60% after immersion of steel for 2.5 h in the aluminum melt. The experimental results clearly indicate the beneficial effect of strontium on the kinetics of the formation and growth of the intermetallic layers.

  8. Alloying effect on the titanium alloys tendency to the salt corrosion

    International Nuclear Information System (INIS)

    Salt corrosion tendency of commercial titanium alloys, such as OT4, 0T4-1 (the Ti-Al-Mn system); VT14, VT16 (the Ti-Al-Mo-V system) and VT30 (the Ti-Mo-Sn-Zr system) is compared with the intensity of salt corrosion of VT1-0 titanium and experimental alloys of the Ti-Al and Ti-Mo systems. It is established that the salt corrosion tendency of alloys of the Ti-Al system increases when they are alloyed with manganese and decreases when they are alloyed with vanadium and molybdenum in combination. Alloys of the Ti-Mo system have no tendency to salt corrosion. Alloying with zirconium and tin brings about the propagation of salt corrosion in the alloys

  9. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    Directory of Open Access Journals (Sweden)

    Xu Chunxiang

    2013-09-01

    Full Text Available To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.% master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu master alloy is 4wt.%. In this case, primary Si and eutectic Si as well as メ-Al phase were clearly refined, and this refining effect shows an excellent long residual action as it can be heat-retained for at least 5 h. After being T6 heat treated, the morphology of primary and eutectic Si in the Al-25Si alloys with the addition of 4wt.% Al-20.6Mn-12Ti-0.9P-6.1Cu alloy changes into particles and short rods. The average grain size of the primary and eutectic Si decreases from 250 レm (unmodified to 13.83 レm and 35 レm (unmodified to 7 レm; the メ-Al becomes obviously finer and the distribution of Si phases tends to be uniform and dispersed. Meanwhile, the tensile properties are improved obviously; the tensile strengths at room temperature and 300 ìC reach 241 MPa and 127 MPa, increased by 153.7% and 67.1%, respectively. In addition, the tensile fracture mechanism changes from brittle fracture for the alloy without modification to ductile fracture after modification. Modifying the morphology of Si phase and strengthening the matrix can effectively block the initiation and propagation of cracks, thus improving the strength of the hypereutectic Al-25Si alloy.

  10. Influence of system and degree of alloying on the parameters of shape-memory effect in titanium alloys

    International Nuclear Information System (INIS)

    The influence of chemical composition, compression degree, heating rate on characteristics of shape memory effect of Ti-Nb, Ti-V, Ti-Al-V, Ti-Al-V-Cr is studied. A comparative analysis is made between experimentally defined values of restitution deformation degree and calculated values of crystographically reversible deformation of martensitic transformation. Main reasons for non complete restitution of form in the titanium base alloy are as the formation of embrittling ω-phase in titanium alloys of critical composition with a β-stabilizer; the proximity of martensitic transformation-induced stresses and sliding ones on deformation; low thermal stability of β- and α''-phase of titanium alloys in the range of temperatures of reverse martensitic transformation. Aluminium and chromium alloying of titanium alloys permits increasing the value of restitution deformation due to the suppression of ω-phase formation during quenching of critical composition alloys and the increase of sliding stresses. The optimal composition of the titanium alloy is proposed

  11. Effects of scandium and zirconium combination alloying on as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy

    OpenAIRE

    Xiang Qingchun; Zhao Jing; Pan Haicheng

    2011-01-01

    The influences of minor scandium and zirconium combination alloying on the as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy have been experimentally investigated. The experimental results show that when the minor elements of scandium and zirconium are simultaneously added into the Al-4Cu-1.5Mg alloy, the as-cast microstructure of the alloy is effectively modified and the grains of the alloy are greatly refined. The coarse dendrites in the microstructure of the alloy with...

  12. Effect of Deep Cryogenic Treatment on Microstructure and Properties of AE42 Mg Alloy

    Science.gov (United States)

    Bhale, Pranav; Shastri, H.; Mondal, A. K.; Masanta, M.; Kumar, S.

    2016-07-01

    The effect of deep cryogenic treatment (DCT) on microstructure and mechanical properties including corrosion behavior of the squeeze-cast AE42 alloy has been investigated. For comparison, the same has also been studied on the untreated alloy. Both the untreated and deep cryogenic-treated (DCTed) alloys comprised α-Mg and Al4RE phases. Volume fraction of the Al4RE phase in the AE42 alloy reduced gradually following DCT carried out from 4 to 16 h. Ductility and UTS increase significantly with a marginal increase in YS of all the DCTed alloys. The improvement was attributed to the dissolution of the brittle Al4RE phase following DCT. Among the alloys employed, the best tensile properties were obtained for the 16-h DCT alloy due to its lowest content of the brittle Al4RE phase. Creep resistance of the DCTed alloys was lower than that of the untreated alloy owing to the presence of less amount of thermally stable intermetallic Al4RE phase. Wear resistance of the alloy reduces following DCT due to reduced hardness of the DCTed alloys. The untreated alloy exhibits the best corrosion resistance, whereas poor corrosion resistance of the DCTed alloys is attributed to the reduced amount of Al4RE phase that fails to built a corrosion resistance barrier.

  13. Effect of Zr on behavior of compressive creep in as cast ZA27 alloy

    Institute of Scientific and Technical Information of China (English)

    魏晓伟; 沈保罗

    2003-01-01

    The effect of Zr on the behavior of compressive creep in as cast ZA27 alloy was investigated in the temperature range of 20-160 ℃ and under different compressive stresses in the range of 50-137.5 MPa with special apparatus. The results show that the primary compressive creep strains and steady creep rates of ZA27-Zr alloy and ZA27 alloy increase with increasing temperature and stress. However, the primary compressive creep strain and steady creep rate of the ZA27-Zr alloy are lower than that of the ZA27 alloy below 100 ℃, but higher at 160 ℃. The compressive creep behaviors in both ZA27-Zr alloy and ZA27 alloy obey an empirical equation lnt=C-nlnσ+Q/RT, and the exponent stress n is 3.63 for ZA27-Zr alloy and 3.46 for ZA27 alloy, respectively, the activation energy Q is 87.32 kJ/mol for ZA27-Zr alloy and 81.09 kJ/mol for ZA27 alloy. Different material structural constants are associated with different compressive creep behaviors in the alloy. The compressive creep rate in the alloy is controlled by the lattice diffusion of zinc and dislocation limb.

  14. Effect of the 718 alloy metallurgical status on hydrogen embrittlement

    International Nuclear Information System (INIS)

    The Inconel 718 is a nickel superalloy which is widely used in the nuclear industry, but is sensitive to hydrogen embrittlement induced by corrosion and stress corrosion cracking phenomena, and by the presence of dissolved hydrogen in pressurized water reactor environments. As this alloy is hardened by precipitation of different intermetallic phases, it appeared that the presence of these precipitates has a strong influence on the hydrogen embrittlement. The authors report the study of the nature and effect of the different traps (intermetallic phases, carbides or their interfaces) on the hydrogen embrittlement susceptibility of the 718 alloy, and more particularly on the observed failure modes. Experiments are performed on tensile samples in which hydrogen content can be measured. The type and grain size of the observed microstructures are given with respect with the thermal treatment, as well as the mechanical properties with or without hydrogen loading

  15. Bonding effects in dilute transition-metal alloys

    International Nuclear Information System (INIS)

    The Moessbauer isomer-shift data of transition-metal nuclei as impurities in metals were considered in previous papers where it was shown that, once volume effects were suitably accounted for, the data fell on a ''universal'' curve. In this paper, the deviations from universality are examined in more detail in an attempt to better understand the alloying behavior. It is found that atom A as an impurity in metal B does not sustain a shift of the same magnitude as atom B does when it is an impurity in metal A. The results are discussed in terms of d-band hybridization and of the asymmetry in the solubility behavior in transition-metal-alloy phase diagrams

  16. Bonding effects in dilute transition-metal alloys

    Energy Technology Data Exchange (ETDEWEB)

    Watson, R.E.; Swartzendruber, L.J.; Bennett, L.H.

    1981-12-01

    The Moessbauer isomer-shift data of transition-metal nuclei as impurities in metals were considered in previous papers where it was shown that, once volume effects were suitably accounted for, the data fell on a ''universal'' curve. In this paper, the deviations from universality are examined in more detail in an attempt to better understand the alloying behavior. It is found that atom A as an impurity in metal B does not sustain a shift of the same magnitude as atom B does when it is an impurity in metal A. The results are discussed in terms of d-band hybridization and of the asymmetry in the solubility behavior in transition-metal-alloy phase diagrams.

  17. Effect of helium on tensile properties of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States)

    1997-08-01

    Tensile properties of V-4Cr-4Ti (Heat BL-47), 3Ti-1Si (BL-45), and V-5Ti (BL-46) alloys after irradiation in a conventional irradiation experiment and in the Dynamic Helium Charging Experiment (DHCE) were reported previously. This paper presents revised tensile properties of these alloys, with a focus on the effects of dynamically generated helium of ductility and work-hardening capability at <500{degrees}C. After conventional irradiation (negligible helium generation) at {approx}427{degrees}C, a 30-kg heat of V-4Cr-4Ti (BL-47) exhibited very low uniform elongation, manifesting a strong susceptibility to loss of work-hardening capability. In contrast, a 15-kg heat of V-3Ti-1Si (BL -45) exhibited relatively high uniform elongation ({approx}4%) during conventional irradiation at {approx}427{degrees}C, showing that the heat is resistant to loss of work-hardening capability.

  18. Effect of dissolved oxygen on IGSCC of Alloy 600

    International Nuclear Information System (INIS)

    The effect of dissolved oxygen on the SCC of Alloy 600 was studied by the slow strain rate test(SSRT) method. The SSRT tests were carried out in aerated and in deaerated pure water at 360 C at the strain rate of 2.5 x 10-7/s. Hump specimens were used to shorten test time. The SCC susceptibility was higher in the deaerated water environment than in aerated water environments. The shape of load-deformation curves of the tests in those two environments indicates that oxygen content in water significantly influences the SCC susceptibility of Alloy 600. It was considered that the increase of SCC resistance in aerated water is due to the high corrosion potential of the metal surface, and the according decrease of corrosion current due to the formation of a protective oxide layer. (authors)

  19. Effect of heat treatment on high strength aluminium silicon alloy

    International Nuclear Information System (INIS)

    To improve the mechanical properties of domestically manufactured motor cycle pistons, the modification of structure by heat treatment has been studied. Pistons were subjected to different heat treatment cycles and optimum parameters were determined. Optical microscopic techniques and mechanical testing have been employed to study the effect of heat treatment o the microstructure and mechanical properties. A comparison of the properties of the domestically manufactured and imported pistons has also been made. Aluminum Silicon based alloys have been widely used for the production of automobile pistons due to their promising features like low coefficient of thermal expansion, high strength and favorable tribological characteristics. These properties can be further modified by alloying and heat treatment. (author)

  20. Effect of whitening toothpaste on titanium and titanium alloy surfaces

    Directory of Open Access Journals (Sweden)

    Adriana Cláudia Lapria Faria

    2012-12-01

    Full Text Available Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt alloy was melted in an arc melting furnace and compared with cp Ti. Disks and toothbrush heads were embedded in PVC rings to be mounted onto a toothbrushing test apparatus. A total of 260,000 cycles were carried out at 250 cycles/minute under a load of 5 N on samples immersed in toothpaste slurries. Surface roughness and Vickers microhardness were evaluated before and after toothbrushing. One sample of each material/toothpaste was analyzed by Scanning Electron Microscopy (SEM and compared with a sample that had not been submitted to toothbrushing. Surface roughness increased significantly after toothbrushing, but no differences were noted after toothbrushing with different toothpastes. Toothbrushing did not significantly affect sample microhardness. The results suggest that toothpastes that contain and those that do not contain peroxides in their composition have different effects on cp Ti and Ti-5Ta surfaces. Although no significant difference was noted in the microhardness and roughness of the surfaces brushed with different toothpastes, both toothpastes increased roughness after toothbrushing.

  1. Chloride ion effect and alloying effect on dealloying-induced formation of nanoporous AuPt alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan, E-mail: mse_wangy@ujn.edu.cn; Xu, Junling; Wu, Bo

    2013-07-01

    The dealloying of the rapidly solidified Al{sub 66}Au{sub 23.8}Pt{sub 10.2} precursor in the 5 wt.% HCl or 20 wt.% NaOH solution has been investigated using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and transmission electron microscopy, in order to clarify the chloride ion effect and alloying effect on the formation of nanoporous Au–Pt alloy. The Al{sub 66}Au{sub 23.8}Pt{sub 10.2} precursor is composed of a single Al{sub 2}Au-type intermetallic compound and only Au(Pt) solid solution can be identified in the as-dealloyed sample. The Pt addition can significantly refine the nanoporous structure during the dealloying of the Al{sub 66}Au{sub 23.8}Pt{sub 10.2} precursor either in the HCl or NaOH solution. Moreover, the alloying effect of Pt markedly exceeds the coarsening effect of chloride ion adsorption for the formation of nanoporous Au–Pt. The average ligament size is 5.2 ± 0.7 and 3.3 ± 0.4 nm for the nanoporous Au–Pt alloy obtained in the HCl and NaOH solution, respectively. In addition, electrochemical measurements including potentiodynamic polarization and cyclic voltammetry have also been performed on the Al{sub 66}Au{sub 23.8}Pt{sub 10.2} precursor.

  2. Alloying effect on K-shell fluorescence parameters of porous NiTi shape memory alloys

    International Nuclear Information System (INIS)

    Highlights: • The Kα,β shell production cross-sections and Kβ/Kα intensity ratios of porous NiTi SMAs were determined by ED-XRF. • To analyze the changes in the structures due to the preheating and solution heat treatment processes, XRD and XPS measurements were also performed. • The deviations between the experimental and theoretical were interpreted to charge transfer phenomena. - Abstract: The Kα,β shell production cross-sections and Kβ/Kα intensity ratios of porous Ni −49 at% Ti shape memory alloys were determined using energy dispersive X-ray fluorescence (EDXRF) technique. Also, the alloying effect on the K shell fluorescence parameters was investigated. The samples were excited by 59.5 keV γ-rays from an 241Am annular radioactive source. The K X-rays emitted by the samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The structure analyses of the samples were also made using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The deviations between the present results and theoretical values, calculated for pure Ti and Ni, were attributed to charge transfer phenomena and/or rearrangement of valance shell electrons and porosity

  3. Anisotropic Effects on Constitutive Model Parameters of Aluminum Alloys

    Science.gov (United States)

    Brar, Nachhatter; Joshi, Vasant

    2011-06-01

    Simulation of low velocity impact on structures or high velocity penetration in armor materials heavily rely on constitutive material models. The model constants are required input to computer codes (LS-DYNA, DYNA3D or SPH) to accurately simulate fragment impact on structural components made of high strength 7075-T651 aluminum alloys. Johnson-Cook model constants determined for Al7075-T651 alloy bar material failed to simulate correctly the penetration into 1' thick Al-7075-T651plates. When simulations go well beyond minor parameter tweaking and experimental results are drastically different it is important to determine constitutive parameters from the actual material used in impact/penetration experiments. To investigate anisotropic effects on the yield/flow stress of this alloy we performed quasi-static and high strain rate tensile tests on specimens fabricated in the longitudinal, transverse, and thickness directions of 1' thick Al7075-T651 plate. Flow stresses at a strain rate of ~1100/s in the longitudinal and transverse direction are similar around 670MPa and decreases to 620 MPa in the thickness direction. These data are lower than the flow stress of 760 MPa measured in Al7075-T651 bar stock.

  4. Effect of Heat Treatment on the Microstructure and Corrosion Resistance of Cu-Zn Alloy

    Institute of Scientific and Technical Information of China (English)

    Xu Tao; Zhang Hailong; Xiao Nianxin; Zhao Xiangling

    2007-01-01

    The microstructure of Cu-Zn alloy with different heat treatment conditions in 3.5% NaCl + NH3 solution were observed, and the average corrosion rates and electrochemical data of Cu-Zn alloy were measured, as well as the effect of heat treatment on microstructure and corrosion resistance of Cu-Zn alloy was analyzed. The results show that the microstructure of Cu-Zn alloy has been changed due to the heat treatment. As a results, the better corrosion resistance can be obtained for the Cu-Zn alloy quenched from 900℃ for 0.5h followed by tempered at 100℃ for 2h.

  5. Effect of oxidation on tensile behavior of V-5Cr-5Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Soppet, W.K. [Argonne National Lab., Chicago, IL (United States)

    1995-04-01

    The objectives of this task are to (a) evaluate the oxygen uptake behavior of V-5Cr-5Ti alloy as a function of temperature and oxygen partial pressure in the exposure environment, (b) examine the microstructural characteristics of oxide scales and oxygen entrapped at the grain boundaries in the substrate alloy, (c) evaluate the influence of oxygen uptake on the tensile properties of the alloy at room and elevated temperatures, (d) evaluate oxidation kinetics of the alloy with the aluminum-enriched surface layers, and (e) determine the effect of oxygen uptake on tensile behavior of the alloy.

  6. Effect of different oxidation treatments on the bonding strength of new dental alloys

    International Nuclear Information System (INIS)

    The influences of heat treatment and addition of a small amount of base metal (In, Sn, and Ir) for oxidation in Au-Pt-based alloy were investigated by electron spectroscopy and scanning electron microscopy. Au-Pt-based alloys were prepared by argon-arc melting furnace and then they are heat treated. Oxidation on alloy was significantly affected by addition of base metal (In and Sn) and heat treatment. The bond strength of the alloys was not dependent on the changing heat treatment. These results indicated that the Sn and In could be effective as oxidation elements for porcelain bonding to gold alloys.

  7. Effect of different oxidation treatments on the bonding strength of new dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Bae; Lee, Ju-hye [Department of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University 120-752, Seoul (Korea, Republic of); Kim, Woong-Chul; Oh, Sae-Yoon [Dept. of Dental Laboratory Science, College of Health Science, Korea University (Korea, Republic of); Kim, Kyoung-Nam, E-mail: kimkn@yuhs.a [Department of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University 120-752, Seoul (Korea, Republic of); Kim, Ji-Hwan, E-mail: kjh2804@korea.ac.k [Dept. of Dental Laboratory Science, College of Health Science, Korea University (Korea, Republic of)

    2009-07-01

    The influences of heat treatment and addition of a small amount of base metal (In, Sn, and Ir) for oxidation in Au-Pt-based alloy were investigated by electron spectroscopy and scanning electron microscopy. Au-Pt-based alloys were prepared by argon-arc melting furnace and then they are heat treated. Oxidation on alloy was significantly affected by addition of base metal (In and Sn) and heat treatment. The bond strength of the alloys was not dependent on the changing heat treatment. These results indicated that the Sn and In could be effective as oxidation elements for porcelain bonding to gold alloys.

  8. FRICTION STIR LAP WELDING OF ALUMINUM - POLYMER USING SCRIBE TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Piyush; Hovanski, Yuri; Fifield, Leonard S.; Simmons, Kevin L.

    2015-02-16

    Friction Stir Scribe (FSS) technology is a relatively new variant of Friction Stir Welding (FSW) which enables lap joining of dissimilar material with very different melting points and different high temperature flow behaviors. The cutter scribe attached at the tip of FSW tool pin effectively cuts the high melting point material such that a mechanically interlocking feature is created between the dissimilar materials. The geometric shape of this interlocking feature determines the shear strength attained by the lap joint. This work presents first use of scribe technology in joining polymers to aluminum alloy. Details of the several runs of scribe welding performed in lap joining of ~3.175mm thick polymers including HDPE, filled and unfilled Nylon 66 to 2mm thick AA5182 are presented. The effect of scribe geometry and length on weld interlocking features is presented along with lap shear strength evaluations.

  9. Effects of Ce on damping capacity of AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    黄正华; 郭学锋; 张忠明

    2004-01-01

    The microstructures and damping capacity of AZ91D cast alloys containing various Ce contents were investigated. Damping capacity (Q-1) of the alloys was measured by cantilever beam technique, and the relationship between damping capacity and strain amplitude was investigated. The results show that Al4 Ce phase is formed in AZ91D alloy after adding a certain quantity of Ce contents, then as-cast microstructures of the alloys are refined.Meanwhile the damping capacity of the alloys is also improved. When the mass fraction of Ce is 0.7 %, the most obvious refinement effect and the maximum damping capacity can be obtained. When the damping capacity (Q-1) is 2. 728 × 10-3 , 61% increment can be obtained compared with unmodified AZ91D alloy. The damping capacity of the alloys is relative to strain amplitude, and the damping behavior can be explained by the theory of Granato and Lucke.

  10. Effect of Silicon on the casting properties of Al-5.0%Cu alloy

    Institute of Scientific and Technical Information of China (English)

    LI Weijing; CUI Shihai; HAN Jianmin; XU Chao

    2006-01-01

    Poor casting properties restrict the application of high strength casting Al-5.0%Cu alloy.The addition of element can improve the casting properties of this alloy.Effect of Si on the casting properties of Al-5.0%Cu alloy was studied.It has been found that the addition of Si can improve the casting properties of Al-5.0%Cu alloy obviously.With the increase of Si content, the hot cracking tendency of the alloy decreases significantly, and the fluidity of the alloy increases firstly and then decreases slowly.When the content of Si element is higher than 2wt.%, the fluidity of the alloy increases greatly with the increasing of Si content.

  11. Effect of aging on the corrosion of aluminum alloy 6061

    International Nuclear Information System (INIS)

    Not only alloying additions may affect the corrosion resistance of aluminum alloys, but also practices that result in a nonuniform microstructure may introduce susceptibility to some forms of corrosion, especially if the microstructural effect is localized. This work was intended to study the effect of aging time at 225, 185 and 140 degree C and the effect of constant aging time ( 24 hrs ) in the temperature range 100 - 450 degree C as well as the influence of the solution ph on the corrosion characteristics of 6061 aluminum alloy, (Al-Mg-Si alloy) containing 0.22 wt% Cu. The investigation was performed by standard immersion corrosion test according to the British Standard BS 11846 method B and by applying potentiodynamic polarization technique in neutral deaerated 0.5 % M NaCl solution as well as in alkaline NaOH solution (ph = 10). The susceptibility to corrosion and the dominant corrosion type was evaluated by examination of transverse cross sections of corroded samples after the immersion test and examination of the corroded surfaces after potentiodynamic polarization using optical microscope. Analysis of the polarization curves was used to determine the effect of different aging parameters on corrosion characteristics such as the corrosion current density I (corr), the corrosion potential E (corr), the cathodic current densities and the passivation behavior.Results of the immersion test showed susceptibility to intergranular corrosion in the under aged tempers while pitting was the dominant corrosion mode for the over aged tempers after aging at 225 and 185 degree C.Analysis of the potentiodynamic polarization curves showed similar dependence of I (corr) and cathodic current densities on the aging treatment in the neutral 0.5 %M NaCl solution and in the alkaline NaOH solution. It was observed that E(corr) values in the NaCl solution were shifted in the more noble direction for the specimens aged before peak aging while it decreased again with aging time for

  12. High temperature shape memory effect in some alloys and compounds

    International Nuclear Information System (INIS)

    High-temperature shape memory effect (HTSME) takes place in different alloys and compounds, such as: TiNi with Pt, Pd, Zr and Hf additions, Zr-based quasibinary intermetallics, NiAl-based, Cu-Al-Mn, Cu-Al-Zn and Fe-Ni-Co-Ti. It can be presumably adopted that all materials exhibit SME higher than 200 C should be considered as high-temperature SMA. The origin of the HTSME can be associated with: reverse martensitic transformation; precipitation-dissolution processes during dynamic aging. (orig.)

  13. The reactive element effect (REE) in oxidation of alloys

    OpenAIRE

    Saito, Yasutoshi; Önay, Bülent; MARUYAMA, TOSHIO

    1993-01-01

    The reactive element effect (REE) in high temperature oxidation is discussed, for chromia-forming alloys, in terms of a mechanistic model based on postulations that (a) reactive element/oxide additions promote nucleation of Cr2O3 and (b) reactive element-oxides react with Cr2O3 to form perovskite-type compounds, such as YCrO3, along scale boundaries which promote inward oxygen diffusion. The standard Gibbs energy of formation and concentrations of ionic defects for YCrO3 are calculated. For s...

  14. The Effect of Impurities on the Processing of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zi-Kui Liu; Shengjun Zhang; Qingyou Han; Vinod Sikka

    2007-04-23

    For this Aluminum Industry of the Future (IOF) project, the effect of impurities on the processing of aluminum alloys was systematically investigated. The work was carried out as a collaborative effort between the Pennsylvania State University and Oak Ridge National Laboratory. Industrial support was provided by ALCOA and ThermoCalc, Inc. The achievements described below were made. A method that combines first-principles calculation and calculation of phase diagrams (CALPHAD) was used to develop the multicomponent database Al-Ca-K-Li-Mg-Na. This method was extensively used in this project for the development of a thermodynamic database. The first-principles approach provided some thermodynamic property data that are not available in the open literature. These calculated results were used in the thermodynamic modeling as experimental data. Some of the thermodynamic property data are difficult, if not impossible, to measure. The method developed and used in this project allows the estimation of these data for thermodynamic database development. The multicomponent database Al-Ca-K-Li-Mg-Na was developed. Elements such as Ca, Li, Na, and K are impurities that strongly affect the formability and corrosion behavior of aluminum alloys. However, these impurity elements are not included in the commercial aluminum alloy database. The process of thermodynamic modeling began from Al-Na, Ca-Li, Li-Na, K-Na, and Li-K sub-binary systems. Then ternary and higher systems were extrapolated because of the lack of experimental information. Databases for five binary alloy systems and two ternary systems were developed. Along with other existing binary and ternary databases, the full database of the multicomponent Al-Ca-K-Li-Mg-Na system was completed in this project. The methodology in integrating with commercial or other aluminum alloy databases can be developed. The mechanism of sodium-induced high-temperature embrittlement (HTE) of Al-Mg is now understood. Using the thermodynamic

  15. Nonlinear Model of Pseudoelastic Shape Memory Alloy Damper Considering Residual Martensite Strain Effect

    OpenAIRE

    Y.M. Parulekar; G.R. Reddy

    2012-01-01

    Recently, there has been increasing interest in using superelastic shape memory alloys for applications in seismic resistant-design. Shape memory alloys (SMAs) have a unique property by which they can recover their original shape after experiencing large strains up to 8% either by heating (shape memory effect) or removing stress (pseudoelastic effect). Many simplified shape memory alloy models are suggested in the past literature for capturing the pseudoelastic response of SMAs in passive vib...

  16. Effects of Deformation on Microstructure of Cu-Zn-Ni Alloy

    OpenAIRE

    ALDIRMAZ, Emine; CELIK, Harun; AKSOY, Ilhan

    2012-01-01

    The thermal and mechanical effects on microstructure of Cu-12.44%Zn-4.75%Ni (wt%) alloy were investigated. The effects mechanical on both rapidly cooled sample and slowly cooled sample obtained from Cu-Zn-Ni alloy were investigated by using scanning electron microscopy (SEM), X-ray diffraction techniques (XRD). The thermal energy changes of in the alloy were examined by means of differential scanning calorimetry (DSC). As a result of SEM observations, annealing twins structures are observed i...

  17. EFFECTS OF EXTREME AND UNUSUAL CONDITIONS ON LANA ALLOYS: INTERIM REPORT, FY14 (U)

    Energy Technology Data Exchange (ETDEWEB)

    Shanahan, Kirk L.

    2014-04-25

    The TTP proposed research aimed at determining: a) the rate at which these changes occurred and the effect of initial conditions, especially in the early phases of Hydrogen Heat Treatment (HHT), b) whether or not different LANA alloys would show similar effects, and c) whether common contaminants/poisons impacted LANA alloy hydride chemistry similarly to what had been found for Pd and Pd-alloy hydride chemistry.

  18. Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys

    International Nuclear Information System (INIS)

    Liquid phase sintering, heat treatment and swaging studies on three tungsten heavy alloys, 93W–4.9Ni–2.1Fe (wt%), 93W–4.2Ni–1.2Fe–1.6Co (wt%) and 93W–4.9Ni–1.9Fe–0.2Re (wt%) were carried out in detail with respect to microstructure, tensile and impact properties. All the alloys were sintered and swaged to 40% deformation. The results indicate that Re addition reduces the grain size of the alloy compared to W–Ni–Fe and W-Ni-Fe-Co alloys. W–Ni–Fe–Re alloy shows superior tensile properties in heat treated condition as compared to W–Ni–Fe and W–Ni–Fe–Co alloys. SEM study of fractured specimens clearly indicates that the failure in case of W–Ni–Fe–Re was due to transgranular cleavage of tungsten grains and W–W de-cohesion. W–Ni–Fe and W–Ni–Fe–Co alloys also failed by mixed mode failure. However, in these cases, ductile dimples corresponding the failure of the matrix phase was rarely seen. Thermo-mechanical processing resulted in significant changes in mechanical properties. While W–Ni–Fe–Re alloy showed the highest tensile strength (1380 MPa), W–Ni–Fe–Co exhibited the highest elongation (12%) to failure. A detailed analysis involving microstructure, mechanical properties and failure behavior was undertaken in order to understand the property trends

  19. Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kiran, U., E-mail: uravikiran@gmail.com [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Panchal, A.; Sankaranarayana, M. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Nageswara Rao, G.V.S. [National Institute of Technology, Warangal 506004 (India); Nandy, T.K. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India)

    2015-07-29

    Liquid phase sintering, heat treatment and swaging studies on three tungsten heavy alloys, 93W–4.9Ni–2.1Fe (wt%), 93W–4.2Ni–1.2Fe–1.6Co (wt%) and 93W–4.9Ni–1.9Fe–0.2Re (wt%) were carried out in detail with respect to microstructure, tensile and impact properties. All the alloys were sintered and swaged to 40% deformation. The results indicate that Re addition reduces the grain size of the alloy compared to W–Ni–Fe and W-Ni-Fe-Co alloys. W–Ni–Fe–Re alloy shows superior tensile properties in heat treated condition as compared to W–Ni–Fe and W–Ni–Fe–Co alloys. SEM study of fractured specimens clearly indicates that the failure in case of W–Ni–Fe–Re was due to transgranular cleavage of tungsten grains and W–W de-cohesion. W–Ni–Fe and W–Ni–Fe–Co alloys also failed by mixed mode failure. However, in these cases, ductile dimples corresponding the failure of the matrix phase was rarely seen. Thermo-mechanical processing resulted in significant changes in mechanical properties. While W–Ni–Fe–Re alloy showed the highest tensile strength (1380 MPa), W–Ni–Fe–Co exhibited the highest elongation (12%) to failure. A detailed analysis involving microstructure, mechanical properties and failure behavior was undertaken in order to understand the property trends.

  20. Effect of Microstructure on the Performance of Corrosion Resistant Alloys

    OpenAIRE

    Kishan Roodbari, Marzieh

    2015-01-01

    Corrosion by pitting in aluminum alloys is a very complex process that can be affected by various factors such as chemical composition and microstructure of the alloys. The electrochemistry and distribution of second phases populating the alloy are the main factors that significantly influence the corrosion of aluminum alloys. The purpose of the present work is to contribute to a deeper understanding of how the chemical composition and microstructure affect the ability of an al...

  1. Band anticrossing effects in highly mismatched semiconductor alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Junqiao

    2002-09-09

    The first five chapters of this thesis focus on studies of band anticrossing (BAC) effects in highly electronegativity- mismatched semiconductor alloys. The concept of bandgap bowing has been used to describe the deviation of the alloy bandgap from a linear interpolation. Bowing parameters as large as 2.5 eV (for ZnSTe) and close to zero (for AlGaAs and ZnSSe) have been observed experimentally. Recent advances in thin film deposition techniques have allowed the growth of semiconductor alloys composed of significantly different constituents with ever- improving crystalline quality (e.g., GaAs{sub 1-x}N{sub x} and GaP{sub 1-x}N{sub x} with x {approx}< 0.05). These alloys exhibit many novel and interesting properties including, in particular, a giant bandgap bowing (bowing parameters > 14 eV). A band anticrossing model has been developed to explain these properties. The model shows that the predominant bowing mechanism in these systems is driven by the anticrossing interaction between the localized level associated with the minority component and the band states of the host. In this thesis I discuss my studies of the BAC effects in these highly mismatched semiconductors. It will be shown that the results of the physically intuitive BAC model can be derived from the Hamiltonian of the many-impurity Anderson model. The band restructuring caused by the BAC interaction is responsible for a series of experimental observations such as a large bandgap reduction, an enhancement of the electron effective mass, and a decrease in the pressure coefficient of the fundamental gap energy. Results of further experimental investigations of the optical properties of quantum wells based on these materials will be also presented. It will be shown that the BAC interaction occurs not only between localized states and conduction band states at the Brillouin zone center, but also exists over all of k-space. Finally, taking ZnSTe and ZnSeTe as examples, I show that BAC also occurs between

  2. Effect of Alloy 625 Buffer Layer on Hardfacing of Modified 9Cr-1Mo Steel Using Nickel Base Hardfacing Alloy

    Science.gov (United States)

    Chakraborty, Gopa; Das, C. R.; Albert, S. K.; Bhaduri, A. K.; Murugesan, S.; Dasgupta, Arup

    2016-04-01

    Dashpot piston, made up of modified 9Cr-1Mo steel, is a part of diverse safety rod used for safe shutdown of a nuclear reactor. This component was hardfaced using nickel base AWS ER NiCr-B alloy and extensive cracking was experienced during direct deposition of this alloy on dashpot piston. Cracking reduced considerably and the component was successfully hardfaced by application of Inconel 625 as buffer layer prior to hardface deposition. Hence, a separate study was undertaken to investigate the role of buffer layer in reducing the cracking and on the microstructure of the hardfaced deposit. Results indicate that in the direct deposition of hardfacing alloy on modified 9Cr-1Mo steel, both heat-affected zone (HAZ) formed and the deposit layer are hard making the thickness of the hard layer formed equal to combined thickness of both HAZ and deposit. This hard layer is unable to absorb thermal stresses resulting in the cracking of the deposit. By providing a buffer layer of Alloy 625 followed by a post-weld heat treatment, HAZ formed in the modified 9Cr-1Mo steel is effectively tempered, and HAZ formed during the subsequent deposition of the hardfacing alloy over the Alloy 625 buffer layer is almost completely confined to Alloy 625, which does not harden. This reduces the cracking susceptibility of the deposit. Further, unlike in the case of direct deposition on modified 9Cr-1Mo steel, dilution of the deposit by Ni-base buffer layer does not alter the hardness of the deposit and desired hardness on the deposit surface could be achieved even with lower thickness of the deposit. This gives an option for reducing the recommended thickness of the deposit, which can also reduce the risk of cracking.

  3. Effects of Friction Stir Welding Speed on AA2195 alloy

    Directory of Open Access Journals (Sweden)

    Lee Ho-Sung

    2016-01-01

    Full Text Available The application of friction stir welding (FSW to aerospace has grown rapidly due to the high efficiency and environmental friendly nature of the process. FSW is achieved by plastic flow of frictionally heated material in solid state and offers many advantages of avoiding hot cracking and limiting component distortion. Recently low density, high modulus and high strength AA2195 are used as substitute for conventional aluminum alloys since the weight saving is critical in aerospace applications. One of the problems for this alloy is weld metal porosity formation leading to hot cracking. Combination of FSW and AA2195 provides synergy effect to improve mechanical properties and weight saving of aerospace structure such as cryogenic fuel tanks for launch systems. The objective of this paper is to investigate the effect of friction stir welding speed on mechanical and microstructural properties of AA2195. The friction stir welded materials were joined with four different tool rotation speeds (350~800 rpm and five welding speeds (120~360 mm/min, which are the two prime welding parameters in this process.

  4. Effect of alloy composition on the volume fraction of beta phase in duplex titanium alloys

    International Nuclear Information System (INIS)

    Titanium alloys are strong, light, corrosion resistant and superplastic. While many of them show superplastic behavior, working and forging temperatures are still high, 850-925 degree C, and their range is narrow. Moreover, the material's resistance to deformation is not negligible and, therefore, the cost of making dies and presses for forging or hot deformation is high and it poses a serious problem. To increase the efficiency and to reduce the temperature of hot deformation, increasing the volume fraction of the beta phase present in duplex titanium alloys is suggested. With the introduction of the beta-modified Ti-6Al-4V alloy the decrease in the temperature and the increase in the strain rate of the superplastic regime promise to make superplastic forming of this alloy even more economical, and many researches have been made. In this study, efforts are put on designing new duplex alloys based on the Ti-6Al-4V and Ti-Al-Fe systems, which will have a beta volume fraction of 40-50 percent at around 800 degree C. To accomplish this, experimental volume fractions of the beta phase in several titanium alloys are being compared with predicted and calculated ones using phase equilibria analyses and some suggestions will be made on modifying the alloy compositions. For comparison, the quaternary Ti-V-Fe-Al system and their subsystems are chosen due to availability of both experimental and thermodynamic data

  5. Effect of Nitriding on Phase Transformations in the Fe-Mn Alloys

    OpenAIRE

    BINNATOV, K. G.; ALİ-ZADE, I. I.

    2001-01-01

    We present results concerning the nitriding effects on phase transformations in Fe -- 40 at. % Mn and Fe -- 50 at. % Mn alloys. These alloys were studied by means of X-ray diffraction and Mössbauer-effect spectroscopy methods at room temperature. Results indicate that, after nitriding, in the absorption spectra of these alloys appears lines with hyperfine field H\\sim 330 kOe which corresponds to the field on the 57 Fe nuclei in the a -Fe. Annealing of the alloys at 650 oC temperat...

  6. SHAPE MEMORY EFFECT AND MECHANICAL BEHAVIOUR OF AN Fe-30Mn-1Si ALLOY SINGLE CRYSTAL

    OpenAIRE

    Sato, A; Soma, K.; Chishima, E.; Mori, T.

    1982-01-01

    The present paper deals with two main problems associated with the γ⇄ε transformation in an Fe-30Mn-1Si alloy. The first is the shape memory effect ; it has been found that an Fe-30Mn-1Si alloy single crystal exhibits a nearly complete shape memory effect caused by entirely different origin from that adopted for the usual shape memory alloys such as TiNi and Cu based alloys. The second concerns the large hardening produced by the pre-injected ε-martensites. This is in contrast to the relative...

  7. Effect of metal primers and tarnish treatment on bonding between dental alloys and veneer resin

    OpenAIRE

    Choo, Seung-Sik; Huh, Yoon-Hyuk; Cho, Lee-Ra; Park, Chan-Jin

    2015-01-01

    PURPOSE The aim of this study was to evaluate the effect of metal primers on the bonding of dental alloys and veneer resin. Polyvinylpyrrolidone solution's tarnish effect on bonding strength was also investigated. MATERIALS AND METHODS Disk-shape metal specimens (diameter 8 mm, thickness 1.5 mm) were made from 3 kinds of alloy (Co-Cr, Ti and Au-Ag-Pd alloy) and divided into 4 groups per each alloy. Half specimens (n=12 per group) in tarnished group were immersed into polyvinylpyrrolidone solu...

  8. Improvement of shape memory effect in Fe-Mn-Si alloy by slight tantalum addition

    International Nuclear Information System (INIS)

    The effects of slight tantalum (Ta) addition on the microstructures, precipitates, martensitic transformation and shape memory performance of Fe-30Mn-6Si-based alloys were investigated. Experimental results show that the slight Ta addition will increase the c/a ratio of ε martensite, reduce the Ms temperature and improve the alloy's shape recovery ability. After TMT at 650 deg. C, the alloy's Ms temperature is reduced and lots of (Fe, Mn)3Si and TaC precipitates form. The effective nuclei and well-aligned precipitates within the grain interior after TMT will improve significantly the alloy's shape memory performance.

  9. Effect of neodymium on the as-extruded ZK20 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    赵亚忠; 潘复生; 彭建; 王维青; 罗素琴

    2010-01-01

    The effect of Nd addition on the microstructure and mechanical properties of ZK20 magnesium alloy was investigated by room tensile test, optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to develop a magnesium alloy with higher ductility. Results showed that the crystal grains of as-extruded ZK20+0.5%Nd magnesium alloy were effectively refined, and the alloy exhibited higher strength and ductility, with the UTS of 237 MPa and the elongation of 32.8%, increasing by 5...

  10. Effect of rolling temperature of the magnesium alloy AZ31B formability

    International Nuclear Information System (INIS)

    The magnesium alloy AZ31B presents an interesting set of properties, which makes it potential candidate for applications in automotive and aeronautics. The main limitation of magnesium alloys is the low capacity of plastic forming at room temperature. The main motivation of this project is to understand and control the microstructure and crystallographic texture of magnesium alloys, to improve their formability. The effect of rolling temperature on the formability of the alloy was studied in this stage of the project. The alloy in the form of annealed and recrystallized sheets (2 mm thick) was deformed by rolling at four different temperatures: 25, 100, 200 and 250 deg C. The microstructural characterization was achieved using several complementary techniques of microstructural analysis, such as optical microscopy, scanning electron microscopy, X-ray analysis by energy dispersive, X-ray diffraction and microhardness. Results about the effect of rolling temperature on the alloy formability were presented and discussed. (author)

  11. Effects of high magnetic field on modification of Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    LIAN Feng; QI Feng; LI Ting-ju; HU Guo-bing

    2005-01-01

    Effects of high magnetic field on modification of Al-6 %Si hypoeutectic alloy, Ak-12.6%Si eutectic alloy and Al-18 % Si hypereutectic alloy were studied. For the Al-6 % Si alloy, it is found that the sample modified by Na salt does not lose efficacy after remelting under high magnetic field. For the Al-12.6%Si alloy, if the sample modi fied by Na-salt is kept at the temperature of modification reaction, high magnetic field can postpone the effective time of the modification. For Al-18%Si alloy modified by P-salt, the primary Si in solidified structure concentrates at the edge of the sample and eutectic Si appears in the center of the sample under the condition without high magnetic field, while the primary Si distributes evenly in the sample when the high magnetic field is imposed. It is thought that the high magnetic field restrains the convection of the melt.

  12. Local lattice relaxations in random metallic alloys: Effective tetrahedron model and supercell approach

    DEFF Research Database (Denmark)

    Ruban, Andrei; Simak, S.I.; Shallcross, S.;

    2003-01-01

    We present a simple effective tetrahedron model for local lattice relaxation effects in random metallic alloys on simple primitive lattices. A comparison with direct ab initio calculations for supercells representing random Ni0.50Pt0.50 and Cu0.25Au0.75 alloys as well as the dilute limit of Au-ri...

  13. La2O3 effects on TZM alloy recovery, recrystallization and mechanical properties

    International Nuclear Information System (INIS)

    Titanium, zirconium and molybdenum (TZM) alloy with different amounts of rare earth lanthanum oxide was prepared by powder metallurgy into 0.5 mm thick sheets. The effects of the La2O3 content on recrystallization temperature and mechanical properties of the TZM alloy were studied. La2O3 increased the recrystallization and recovery temperature of the TZM alloy and increased its tensile strength and elongation

  14. Effect of equal channel angular pressing on aging treatment of Al-7075 alloy

    OpenAIRE

    M.H. Shaeri; M. Shaeri; M.T. Salehi; S. H Seyyedein; M.R. Abutalebi

    2015-01-01

    The effect of aging treatment on microstructure and mechanical properties of equal channel angular pressed Al-7075 alloy was examined. Commercial Al-7075 alloy in the solid solution heat-treated condition was processed by equal channel angular pressing through route BC at both the room temperature and 120 °C. Only three passes of equal channel angular pressing was possible due to the low ductility of the alloy at both temperatures. Followed by equal channel angular pressing, the specimens hav...

  15. Effect of trapping and temperature on the hydrogen embrittlement susceptibility of alloy 718

    OpenAIRE

    Galliano, Florian; Andrieu, Eric; Blanc, Christine; Cloué, Jean-Marc; Connétable, Damien; Odemer, Grégory

    2014-01-01

    Ni-based alloy 718 is widely used to manufacture structural components in the aeronautic and nuclear industries. Numerous studies have shown that alloy 718 may be sensitive to hydrogen embrittlement. In the present study, the susceptibilities of three distinct metallurgical states of alloy 718 to hydrogen embrittlement were investigated to identify both the effect of hydrogen trapping on hydrogen embrittlement and the role of temperature in the hydrogen-trapping mechanism. Cathodic charging i...

  16. The effect of alloying on the ordering processes in near-alpha titanium alloys

    International Nuclear Information System (INIS)

    The substructure of near-alpha Ti–Al–Sn–Zr–Mo–Si alloys containing up to 12.5 at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500 °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700 °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and properties of alloys, depending on modes of heat treatment has been analyzed. Also the influence of aluminides and silicides precipitation on the mechanical alloy properties after aging was examined. It was shown that the aluminide formation led to a slight hardening and a significant viscosity decrease. The silicide particles formation reduced the heat resistance properties, due to the depletion of the solid solution by silicon

  17. The effect of alloying on the ordering processes in near-alpha titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Popov, Artemiy, E-mail: p.artemii@mail.ru [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation); Rossina, Natalya [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation); Popova, Maria, E-mail: pmaria777@mail.ru [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation)

    2013-03-01

    The substructure of near-alpha Ti–Al–Sn–Zr–Mo–Si alloys containing up to 12.5 at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500 °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700 °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and properties of alloys, depending on modes of heat treatment has been analyzed. Also the influence of aluminides and silicides precipitation on the mechanical alloy properties after aging was examined. It was shown that the aluminide formation led to a slight hardening and a significant viscosity decrease. The silicide particles formation reduced the heat resistance properties, due to the depletion of the solid solution by silicon.

  18. Effects of neutron irradiation on deformation behavior of nickel-base fastener alloys

    International Nuclear Information System (INIS)

    This paper presents the effects of neutron irradiation on the fracture behavior and deformation microstructure of high-strength nickel-base alloy fastener materials, Alloy X-750 and Alloy 625. Alloy X-750 in the HTH condition, and Alloy 625 in the direct aged condition were irradiated to a fluence of 2.4x1020 n/cm2 at 264 C in the Advanced Test Reactor. Deformation structures at low strains were examined. It was previously shown that Alloy X-750 undergoes hardening, a significant degradation in ductility and an increase in intergranular fracture. In contrast, Alloy 625 had shown softening with a concomitant increase in ductility and transgranular failure after irradiation. The deformation microstructures of the two alloys were also different. Alloy X-750 deformed by a planar slip mechanism with fine microcracks forming at the intersections of slip bands with grain boundaries. Alloy 625 showed much more homogeneous deformation with fine, closely spaced slip bands and an absence of microcracks. The mechanism(s) of irradiation assisted stress corrosion cracking (IASCC) are discussed

  19. Effects of neutron irradiation on deformation behavior of nickel-base fastener alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, R.; Mills, W.J.; Kammenzind, B.F.; Burke, M.G.

    1999-07-01

    This paper presents the effects of neutron irradiation on the fracture behavior and deformation microstructure of high-strength nickel-base alloy fastener materials, Alloy X-750 and Alloy 625. Alloy X-750 in the HTH condition, and Alloy 625 in the direct aged condition were irradiated to a fluence of 2.4x10{sup 20} n/cm{sup 2} at 264 C in the Advanced Test Reactor. Deformation structures at low strains were examined. It was previously shown that Alloy X-750 undergoes hardening, a significant degradation in ductility and an increase in intergranular fracture. In contrast, Alloy 625 had shown softening with a concomitant increase in ductility and transgranular failure after irradiation. The deformation microstructures of the two alloys were also different. Alloy X-750 deformed by a planar slip mechanism with fine microcracks forming at the intersections of slip bands with grain boundaries. Alloy 625 showed much more homogeneous deformation with fine, closely spaced slip bands and an absence of microcracks. The mechanism(s) of irradiation assisted stress corrosion cracking (IASCC) are discussed.

  20. Effects of annealing on the corrosion and creep resistance of Zr-Nb- Mo or P alloys

    International Nuclear Information System (INIS)

    They have reported that the fabrication processes including especially the different annealing treatments have a significant effect on corrosion and creep resistance of Zr-Nb alloys. So many researchers have studied to establish the ideal alloying elements and their amounts. In this study, two kinds of alloys were designed to improve corrosion and creep resistances. One is Zr-Nb .P alloy; P system (P-1∼4), the other is Zr-Nb-Mo alloys; Mo system (Mo-1∼3). The purpose of this investigation is to get the more effective alloying system and annealing temperature which has good corrosion and creep resistance. The effects of the alloying elements and annealing conditions for the Zr-Nb alloys with P or Mo were investigated. The corrosion resistance of P system alloys were worse than that of Mo system alloys. Because Mo system alloys contain more precipitates that causes more improving corrosion resistance than P system alloys. In the same alloying system, as the heat treatment temperature increased, the corrosion resistance were improved. The creep resistances of P system alloys was better than that of Mo system alloys

  1. Effect of mechanical alloying on FeCrC reinforced Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, S. Osman [Univ. of Namik Kemal, Tekirdag (Turkey); Teker, Tanju [Adiyaman Univ. (Turkey). Dept. of Metallurgical and Materials Engineering; Demir, Fatih [Batman Univ. (Turkey)

    2016-05-01

    Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. In the present study, the intermetallic matrix composites (IMCs) of Ni-Al reinforced by M{sub 7}C{sub 3} were produced by powder metallurgical routes via solid state reaction of Ni, Al and M{sub 7}C{sub 3} particulates by mechanical alloying processes. Ni, Al and M{sub 7}C{sub 3} powders having 100 μm were mixed, mechanical alloyed and the compacts were combusted in a furnace. The mechanically alloyed (MAed) powders were investigated by X-ray diffraction (XRD), microhardness measurement, optic microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The presence of the carbides depressed the formation of unwanted NiAl intermetallic phases. The mechanical alloyed M{sub 7}C{sub 3} particles were unstable and decomposed partially within the matrix during alloying and sintering, and the morphology of the composites changed with the dissolution ratio of M{sub 7}C{sub 3} and sintering temperature.

  2. Effect of mechanical alloying on FeCrC reinforced Ni alloys

    International Nuclear Information System (INIS)

    Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. In the present study, the intermetallic matrix composites (IMCs) of Ni-Al reinforced by M7C3 were produced by powder metallurgical routes via solid state reaction of Ni, Al and M7C3 particulates by mechanical alloying processes. Ni, Al and M7C3 powders having 100 μm were mixed, mechanical alloyed and the compacts were combusted in a furnace. The mechanically alloyed (MAed) powders were investigated by X-ray diffraction (XRD), microhardness measurement, optic microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The presence of the carbides depressed the formation of unwanted NiAl intermetallic phases. The mechanical alloyed M7C3 particles were unstable and decomposed partially within the matrix during alloying and sintering, and the morphology of the composites changed with the dissolution ratio of M7C3 and sintering temperature.

  3. Effect of La addition on glass-forming ability and stability of mechanically alloyed Zr-Ni amorphous alloys

    International Nuclear Information System (INIS)

    Research highlights: → The minor large atom La addition can improve the glass forming ability of Zr-Ni-La and enhance the stability of the amorphous phase against the mechanically induced crystallization. → The stability of the Zr-Ni-La amorphous phase decreases with increasing La content. → The effect of La addition in contrast with the small atomic size C addition plays a significant role in promoting the stability of the amorphous phase. → We try to systematically discuss the reasons of La addition effect on GFA and stability of the amorphous phase from three factor of negative heat of mixing, distance between neighboring atoms and atomic size mismatch, respectively. - Abstract: In this study, the role of La in the microstructural evolution of Zr66.7-xNi33.3Lax (x = 1, 3, 5 at.%) alloys during mechanical alloying has been investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results show that the single amorphous phase of Zr-Ni-La can be obtained through mechanical alloying. The minor La addition can improve the glass forming ability of Zr-Ni-La, enhance the mechanical stability of the amorphous phase against the mechanically induced crystallization and lead to an altered crystallization mode of Zr-Ni alloy. Moreover, the stability of the Zr-Ni-La amorphous phase decreases with further increasing La content. The best effect is obtained for the Zr65.7Ni33.3La1 alloy. Additionally, the effect of La addition in contrast with the small atomic size C addition plays a more significant role in promoting the stability of the amorphous phase. In addition, the reasons of La addition effect on GFA and stability have also been discussed from three factors of negative heat of mixing, distance between neighboring atoms and atomic size mismatch, respectively.

  4. Effect of yttrium on the microstructure of a semi-solid A356 Al alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng; HU Yongmei

    2008-01-01

    The semi-solid slurry of an A356 Al alloy,which was grain-freed by yttrium,was manufactured by low temperature pouring.The effects of grain-refining on the morphology and the grain size of the primary α phase in the semi-solid A356 Al alloy were researched.The results indicate that the semi-solid A356 Al alloy with particle-like and rosette-like primary α-Al can be prepared by low temperature pouring from a liquid grain-refined A356 alloy.The grain size and particle morphology of primary α-Al in the A356 Al alloy are markedly improved by the addition of 0.5 wt.% Y.The fining mechanism of Y on the morphology and grain size of the primary α-Al in the semi-solid A356 Al alloy was delved.

  5. Effects of zincate treatment on adhesion of electroless Ni-P coating onto various aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Makoto HINO; Koji MURAKAMI; Yutaka MITOOKA; Ken MURAOKA; Teruto KANADANI

    2009-01-01

    The effects of alloying elements on zincate treatment and adhesion of electroless Ni-P coating onto various aluminum alloy substrates were examined. Surface morphology of zinc deposits in the 1st zincate treatment and its adhesion were changed depending on the alloying element. The zinc deposits in the 2nd zincate treatment became thinly uniform, and the adhesion between aluminum alloy substrate and Ni-P coating was improved irrespective of the alloying element. XPS analysis revealed the existence of zinc on the surface of each aluminum alloy substrate after the pickling in 5% nitric acid. This zinc on the surface should be an important factor influencing the morphology of zinc deposit at the 2nd zincate treatment and its adhesion.

  6. Effect of Indium Content on the Microstructure, Mechanical Properties and Corrosion Behavior of Titanium Alloys

    OpenAIRE

    Mi-Kyung Han; Jae-Bong Im; Moon-Jin Hwang; Bong-Jun Kim; Hae-Young Kim; Yeong-Joon Park

    2015-01-01

    Ti-xIn (x = 0, 5, 10, 15 and 20 wt%) alloys were prepared to investigate the effect of indium on the microstructure, mechanical properties, and corrosion behavior of titanium with the aim of understanding the relationship between phase/microstructure and various properties of Ti-xIn alloys. The Ti-xIn alloys exhibited a lamellar α-Ti structure at an indium content of up to 20 wt%. High-resolution TEM images of the Ti-xIn alloys revealed that all the systems contained a fine, acicular martensi...

  7. Effect of vapor phase corrosion inhibitor on microbial corrosion of aluminum alloys.

    Science.gov (United States)

    Yang, S S; Ku, C H; Bor, H J; Lin, Y T

    1996-02-01

    Vapor phase corrosion inhibitors were used to investigate the antimicrobial activities and anticorrosion of aluminum alloy. Aspergillus flavus, A. niger, A. versicolor, Chaetomium globosum and Penicillium funiculosum had moderate to abundant growth on the aluminum alloy AA 1100 at Aw 0.901, while there was less growth at Aw 0.842. High humidity stimulated microbial growth and induced microbial corrosion. Dicyclohexylammonium carbonate had a high inhibitory effect on the growth of test fungi and the microbial corrosion of aluminum alloy, dicyclohexylammonium caprate and dicyclohexylammonium stearate were the next. Aluminum alloy coating with vapor phase corrosion inhibitor could prevent microbial growth and retard microbial corrosion. PMID:10592784

  8. Synergetic effect of Er and Zr on the precipitation hardening of Al-Er-Zr alloy

    International Nuclear Information System (INIS)

    The precipitation hardening of dilute Al-Er, Al-Zr and Al-Er-Zr alloys was investigated by microhardness measurements and transmission electron microscopy. The Al-0.04Er (at.%) alloy obtains its maximum aging hardness of 400 MPa due to the precipitation of Al3Er. The Al-0.04Er-0.08Zr obtains a maximum hardness of 560 MPa, which is significant greater than that of the Al-Er and Al-Zr alloys. The synergetic effect of Er and Zr on the precipitation hardening of Al-Er-Zr alloys is discussed.

  9. Unified theoretical approach for binary and ternary alloys via an effective field theory

    Science.gov (United States)

    Freitas, Augusto S.; de Albuquerque, Douglas F.

    2016-01-01

    We describe the phase diagram of binary and ternary disordered alloys using the mixed-bond Ising model, via effective field theory (EFT). For example, we describe the Fe-Al alloy as a mixed-bond system instead of as diluted alloy. In our approach, we obtain the percolation threshold for some lattices and describe the lines of ferro-paramagnetic transition of Fe-Al, Fe-Mn, Fe-Mn-Al and Fe-Ni-Mn alloys and we obtain good agreement with the experimental data.

  10. Comparative study of the Portevin-Le Chatelier effect in interstitial and substitutional alloy

    International Nuclear Information System (INIS)

    Tensile tests were carried out by deforming polycrystalline samples of an interstitial alloy, low carbon steel at room temperature in a wide range of strain rates where the Portevin-Le Chatelier (PLC) effect was observed. The observed stress time series data were analyzed using the non-linear dynamical methods. From the analyses, we could establish the presence of marginal deterministic chaos in the PLC effect of the low carbon steel. Moreover, we made a comparative study of the PLC effect of this interstitial alloy with the substitutional Al-Mg alloy, which shows that the dynamics of the PLC effect in the interstitial alloy is more complex compared to that of the substitutional alloy

  11. Effects of sodium tartrate anodizing on fatigue life of TA15 titanium alloy

    Directory of Open Access Journals (Sweden)

    Fu Chunjuan

    2015-08-01

    Full Text Available Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy. The sodium tartrate anodizing is a new kind of environmental anodizing method. In this work, the effects of sodium tartrate anodizing on mechanical property were studied. The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former. The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared. The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life. While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.

  12. Effect of oxide films on hydrogen permeability of candidate Stirling heater head tube alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schuon, S R; Misencik, J A

    1981-01-01

    High pressure hydrogen has been selected as the working fluid for the developmental automotive Stirling engine. Containment of the working fluid during operation of the engine at high temperatures and at high hydrogen gas pressures is essential for the acceptance of the Stirling engine as an alternative to the internal combustion engine. Most commercial alloys are extremely permeable to pure hydrogen at high temperatures. A program was undertaken at NASA Lewis Research Center (LeRC) to reduce hydrogen permeability in the Stirling engine heater head tubes by doping the hydrogen working fluid with CO or CO/sub 2/. Small additions of these gases were shown to form an oxide on the inside tube wall and thus reduce hydrogen permeability. A study of the effects of dopant concentration, alloy composition, and effects of surface oxides on hydrogen permeability in candidate heater head tube alloys is summarized. Results showed that hydrogen permeability was similar for iron-base alloys (N-155, A286, IN800, 19-9DL, and Nitronic 40), cobalt-base alloys (HS-188) and nickel-base alloys (IN718). In general, the permeability of the alloys decreased with increasing concentration of CO or CO/sub 2/ dopant, with increasing oxide thickness, and decreasing oxide porosity. At high levels of dopants, highly permeable liquid oxides formed on those alloys with greater than 50% Fe content. Furthermore, highly reactive minor alloying elements (Ti, Al, Nb, and La) had a strong influence on reducing hydrogen permeability.

  13. Effect of zirconium content on the microstructure, physical properties and corrosion behavior of Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    Han, Mi-Kyung; Hwang, Moon-Jin [Department of Dental Materials and MRC for Biomineralization Disorders, School of Dentistry, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Yang, Min-Soo; Yang, Hong-So [Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Song, Ho-Jun [Department of Dental Materials and MRC for Biomineralization Disorders, School of Dentistry, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Park, Yeong-Joon, E-mail: yjpark@jnu.ac.kr [Department of Dental Materials and MRC for Biomineralization Disorders, School of Dentistry, Chonnam National University, Gwangju 500-757 (Korea, Republic of)

    2014-10-20

    A series of Ti–xZr alloys with Zr contents ranging from 5 to 20 wt% was prepared and the effects of Zr addition on the microstructure, physical properties, and corrosion behavior of Ti alloys were investigated. The phase and microstructures were characterized using X-ray diffractometry (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The Ti–xZr alloys exhibited α-Ti structure at Zr content of 20 wt% or below. Commercially pure titanium (cp-Ti) was used as a control. We also investigated the effects of alloying element Zr on the mechanical property, oxidation protection ability, and corrosion behavior of Ti–xZr binary alloys. The physical properties and corrosion behavior of Ti–xZr alloys were sensitive to the Zr content. The addition of Zr did contribute to the hardening of cp-Ti due to solid-solution strengthening of α-Ti. Ti–xZr alloys containing up to 10 wt% Zr resulted in good oxidation resistance, while Ti–xZr alloys with above 10 wt% Zr demonstrated higher oxidation weight gain than cp-Ti. Electrochemical experiments showed that the Ti–xZr alloys exhibited better corrosion resistance compared to that of cp-Ti.

  14. Effect of zirconium content on the microstructure, physical properties and corrosion behavior of Ti alloys

    International Nuclear Information System (INIS)

    A series of Ti–xZr alloys with Zr contents ranging from 5 to 20 wt% was prepared and the effects of Zr addition on the microstructure, physical properties, and corrosion behavior of Ti alloys were investigated. The phase and microstructures were characterized using X-ray diffractometry (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The Ti–xZr alloys exhibited α-Ti structure at Zr content of 20 wt% or below. Commercially pure titanium (cp-Ti) was used as a control. We also investigated the effects of alloying element Zr on the mechanical property, oxidation protection ability, and corrosion behavior of Ti–xZr binary alloys. The physical properties and corrosion behavior of Ti–xZr alloys were sensitive to the Zr content. The addition of Zr did contribute to the hardening of cp-Ti due to solid-solution strengthening of α-Ti. Ti–xZr alloys containing up to 10 wt% Zr resulted in good oxidation resistance, while Ti–xZr alloys with above 10 wt% Zr demonstrated higher oxidation weight gain than cp-Ti. Electrochemical experiments showed that the Ti–xZr alloys exhibited better corrosion resistance compared to that of cp-Ti

  15. Effects of alloying elements on nitrogen diffusion behavior around TiN/Ti interface α region in as-cast titanium alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α-stabilizing or β-stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as-cast samples. The content profiles of nitrogen and alloying elements around N-containing solid in αTi region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen-induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.

  16. Cooperative effect of silicon and other alloying elements on creep resistance of titanium alloys: insight from first-principles calculations

    Science.gov (United States)

    Li, Yang; Chen, Yue; Liu, Jian-Rong; Hu, Qing-Miao; Yang, Rui

    2016-01-01

    Creep resistance is one of the key properties of titanium (Ti) alloys for high temperature applications such as in aero engines and gas turbines. It has been widely recognized that moderate addition of Si, especially when added together with some other elements (X), e.g., Mo, significantly improves the creep resistance of Ti alloys. To provide some fundamental understandings on such a cooperative effect, the interactions between Si and X in both hexagonal close-packed α and body-centered cubic β phases are systematically investigated by using a first-principles method. We show that the transition metal (TM) atoms with the number of d electrons (Nd) from 3 to 7 are attractive to Si in α phase whereas those with Nd > 8 and simple metal (SM) alloying atoms are repulsive to Si. All the alloying atoms repel Si in the β phase except for the ones with fewer d electrons than Ti. The electronic structure origin underlying the Si-X interaction is discussed based on the calculated electronic density of states and Bader charge. Our calculations suggest that the beneficial X-Si cooperative effect on the creep resistance is attributable to the strong X-Si attraction. PMID:27466045

  17. Effect of heat treatment on transformation behavior of Ti-Ni-V shape memory alloy

    International Nuclear Information System (INIS)

    Highlights: → New shape memory alloy (SMA) - Ti-50.8Ni-0.5V SMA. → The evolution laws of transformation types of annealed Ti-50.8Ni-0.5V SMA. → The evolution laws of transformation types of aged Ti-50.8Ni-0.5V SMA. → The effect laws of annealing on transformation temperature and hysteresis of the alloy. → The effect laws of aging on transformation temperature and hysterises of the alloy. - Abstract: Effects of annealing and aging processes on the transformation behaviors of Ti-50.8Ni-0.5V (atomic fraction, %) shape memory alloy were investigated by means of differential scanning calorimetry (DSC). The A → R/R → A (A - parent phase, R - R phase) type one-stage reversible transformation occurs in 350-400 deg. C annealed alloy, the A → R → M/M → R → A (M - martensite) type two-stage transformation occurs in 450-500 deg. C annealed alloy, the A → R → M/M → A type transformation occurs in 550 deg. C annealed alloy, and A → M/M → A type transformation occurs in the alloy annealed at above 600 deg. C upon cooling/heating. The transformation type of 300 deg. C aged alloy is A → R/R → A, and that of 500 deg. C aged alloy is A → R → M/M → A, while that of 400 deg. C aged alloy changes from A → R/R → A to A → R → M/M → R → A with increasing aging time. The effects of annealing and aging processes on R and M transformation temperatures and temperature hysteresis are given. The influence of annealing and aging temperature on transformation behaviors is stronger than that of annealing and aging time.

  18. Effect of hydrogen on the behavior of metals II - Hydrogen embrittlement of titanium alloy TV13CA - effect of oxygen - comparison with non-alloyed titanium

    International Nuclear Information System (INIS)

    The effect of oxygen on the hydrogen embrittlement of non-alloyed titanium and the metastable β titanium alloy, TV13 CA, was studied during dynamic mechanical tests, the concentrations considered varying from 1000 to 5000 ppm (oxygen) and from 0 to 5000 ppm (hydrogen) respectively. TV13 CA alloy has a very high solubility for hydrogen. The establishment of a temperature range and a rate of deformation region in which the embrittlement of the alloy is maximum leads to the conclusion that an embrittlement mechanism occurs involving the dragging and accumulation of hydrogen by dislocations. This is the case for all annealings effected in the medium temperature range, which, by favoring the re-establishment of the stable two-phase α + β state of the alloy, produce hardening. The same is true for oxygen which, in addition to hardening the alloy by the solid solution effect, tends to increase its instability and, in consequence, favors the decomposition of the β phase. Nevertheless oxygen concentrations of up to 1500 ppm contribute to increasing the mechanical resistance without catastrophically reducing the deformation capacity. In the case of non-alloyed titanium, the hardening effect also leads to an increase in E0.2pc and R, and to a reduction in the deformation capacity. Nevertheless, hydrogen is only very slightly soluble at room temperature and a distribution of the hydride phase linked to the thermal history of the sample predominates. Thus a fine acicular structure obtained from the β phase by quenching, enables an alloy having a good mechanical resistance to be conserved even when large quantities of hydrogen are present; the deformation capacity remains small. On the other hand, when the hydride phase separates the metallic phase into large grains, a very small elongation leads to a breakdown in mechanical resistance. (author)

  19. Analysis of the effect of alloy elements on martensitic transformation in titanium alloy with the use of valence electron structure parameters

    International Nuclear Information System (INIS)

    Research highlights: → Bond length difference analysis for martensite phases in Ti alloys is conducted. → Martensitic transformation is studied with the use of electron structure parameters. → The effect of alloy elements on martensitic tranformatio is analyzed. - Abstract: Because martensitic transformation in titanium alloy significantly affects properties and applications of the alloys, the analysis of the effect of alloy elements on martensitic transformation becomes primarily important. Through using the valence electron structure parameters calculated by the empirical electron theory (EET) of solids and molecules, our analysis results reveal that the addition of alloy elements (such as Zr, Nb, W, Mo, V) has the beneficial effect on the formation of orthorhombic martensite α'' as well as the addition of alloy elements (e.g., Al, Fe, Cr, Sn) has advantage to the formation of hcp-structured martensite α'. Our analysis results not only present the understanding about the effect of alloy elements on martensitic transformation at the electron structure level, but also provide a theoretical basis for the chemical composition design of titanium alloys.

  20. Effect of alloying and heat treatment on the formation of recrystallization cube texture in nickel alloys

    International Nuclear Information System (INIS)

    Specific features of manufacturing thin ribbons with acute cubic texture of nickel and nickel base alloys (Ni-Cr, Ni-W, Ni-Nb, Ni-V) are under consideration. The ribbons are used as substrates to create perfect crystal structure during epitaxial deposition of buffer and functional layers. It is shown that on using alloying elements when obtaining FCC nickel alloys the application of 99.93% pure nickel is possible. To obtain the perfect structure with a {100} cubic component content of 90-95% the initial grain size prior to deformation is desirable to be no greater than 30-40 μm. Nickel base alloys with Va, VIa and VIIa group transition elements remain the cubic texture of recrystallization up to 1000-1150 Deg C. Magnetic and nonmagnetic (with Tc<70 K) ribbons-substrates with a perfect cubic texture can be manufactured from textureless alloy billets with fine grains (below 40 μm) by 98-99% deformation and an one-hour annealing at 900-1100 Deg C in vacuum or protective environment

  1. Effect of chemical component on shape memory effect of Fe-Mn-Si-Ni-C-RE shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    Naichao Si; Zhihong Jia; Longbiao Qi

    2004-01-01

    Effect of chemical component on shape memory effect (SME) of Fe-Mn-Si-Ni-C-RE shape memory alloys was studied by bent measurement, thermal cycle training, SEM etc. Results of study indicate that the alloys with high Mn content (25%) appeare better SME, especially in lower strain. SME improves evidently when Si is higher content, especially it′s range from 3% up to 4%.But brittleness of Fe-Mn-Si-Ni-C-RE alloy increases by increasing the Si content. SME of the alloy is weakening gradually as carbon content increases under small strain (3%). But in the condition of large strain (above 6%), SME of the alloy whose carbon content ranges from 0.1% to 0.12% shows small decreasing range, especially of alloy with the addition of compound RE.

  2. Preirradiation effect on quenching structure of Cu-4 at.% Ti alloy

    International Nuclear Information System (INIS)

    Methods of X-ray diffraction analysis and microhardness were used to study the effect of preliminary neutron irradiation by various fluences on formation of the structure of two-phase copper-titanium alloy (4 at.%) after quenching from 1223 K. It was established that quenched alloy was characterized by different structure and microhardness, depending on neutron fluence under preirradiation

  3. Effect of Mo content on thermal and mechanical properties of Mo–Ru–Rh–Pd alloys

    International Nuclear Information System (INIS)

    Metallic inclusions are precipitated in irradiated oxide fuels. The composition of the phases varies with the burnup and the conditions such as temperature gradients and oxygen potential of the fuel. In the present work, Mox/(0.7+x) (Ru0.5Rh0.1Pd0.1)(0.7)/(0.7+x) (x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) alloys were prepared by arc melting, followed by annealing in a high vacuum. The thermal and mechanical properties of the alloys such as elastic moduli, Debye temperature, micro-Vickers hardness, electrical resistivity, and thermal conductivity have been evaluated to elucidate the effect of Mo content on these physical properties of the alloys. The alloys with lower Mo contents show higher thermal conductivity. The thermal conductivity of the alloy with x = 0 is almost twice of that of the alloy with x = 0.25. The thermal conductivities of the alloys are dominated by electronic contribution, which has been evaluated using the Wiedemann–Franz–Lorenz relation from the electrical resistivity data. It is confirmed that the variation of the Mo contents of the alloys considerably affects the mechanical and thermal properties of the alloys

  4. Effect of thermomechanical processing on evolution of various phases in Ti–Nb alloys

    Indian Academy of Sciences (India)

    S Banumathy; K S Prasad; R K Mandal; A K Singh

    2011-12-01

    This paper deals with the effect of thermomechanical processing on microstructural evolution of three alloys, viz. Ti–8Nb, Ti–12Nb and Ti–16Nb. The alloys were hot rolled at 800°C and then subjected to various heat treatments. Samples from hot-rolled alloys were given solution-treatment in and + phase fields, respectively followed by water quenching and furnace cooling. The solution-treated alloys were subsequently aged at different temperatures for 24 h. Phases evolved after various heat treatments were studied using X-ray diffractometer, optical, scanning and transmission electron microscopes. The alloy Ti–8Nb exhibits and phases while the alloys Ti–12Nb and Ti–16Nb show the presence of '', and phases in the as-cast and hot-rolled conditions. The solution treated and water quenched specimen of the alloy Ti–8Nb displays '' phase while the alloys Ti–12Nb and Ti–16Nb exhibit '', and phases. The alloy Ti–8Nb shows the presence of , and phases while those of Ti–12Nb and Ti–16Nb display the presence of , '', and in + solution treated and water quenched condition. The observation of phase in solution treated condition depends on the cooling rate and the Nb content while in the aged specimens, it is governed by aging temperature as well as the Nb content.

  5. Effects of Te on intergranular embrittlement of a Ni–16Mo–7Cr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hongwei [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Han, Fenfen, E-mail: hanfenfen@sinap.ac.cn [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences (China); Jia, Yanyan [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences (China); Li, Zhijun, E-mail: lizhijun@sinap.ac.cn [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences (China); Zhou, Xingtai, E-mail: zhouxingtai@sinap.ac.cn [Thorium Molten Salts Reactor Center, Shanghai Institute of Applied Physics, Chinese Academy of Sciences (China)

    2015-06-15

    Highlights: • The alloy surface formation products are primarily Ni{sub 3}Te{sub 2}, CrTe and MoTe{sub 2}. • The room temperature yield strength did not significantly change with Te content. • The ultimate tensile strength and elongation decreased with increasing of Te. • Te content determines cracks width but affects little its diffusion depth. • Te embrittle the grain boundaries, and further weaken the mechanical properties. - Abstract: Te was deposited on the surface of a Ni–16Mo–7Cr alloy by thermal evaporation at 700 °C, and the effect of Te on the intergranular cracking behavior and the tensile properties of the alloy was investigated. The results show that the reaction products formed on the surface of the alloy, the diffusion depth of Te in the alloy, and the yield strength of the alloy attacked by Te at room temperature are not changed remarkably with Te content increasing, whereas the ultimate tensile strength and elongation of the alloy is decreased distinctly. The primary surface reaction product are mainly composed of Ni{sub 3}Te{sub 2}, CrTe, and MoTe{sub 2}, and the diffusion depth of Te in the alloys is about 50 μm. The intergranular embrittlement mechanism of the alloy induced by Te of is also discussed in this paper.

  6. The Effect of Oscillating Traverse Welding on Performance of Cr-Fe-C Hardfacing Alloys

    Science.gov (United States)

    Lai, Hsuan-Han; Hsieh, Chih-Chun; Wang, Jia-Siang; Lin, Chi-Ming; Wu, Weite

    2015-11-01

    In this study, a series of experiments involving Cr-Fe-C hardfacing alloys is conducted to evaluate the effect of oscillating traverse welding on microstructure and performance of clad alloys. The alloys are designed to exhibit hypoeutectic, eutectic, and hypereutectic morphology. The morphology of the heat-affected zone (HAZ) of the unmelted metal, the solidified remelted metal, and the fusion boundary exhibited distinct characteristics. In the hypoeutectic and the eutectic alloys, the same lamellar eutectic structure can be observed as the solidified structure, and they also showed the same evolution in the HAZ. In the hypereutectic alloy, the incomplete weld pool blending results in a eutectic morphology instead of a fully hypereutectic morphology. The hardness result reveals that, for the hypereutectic alloy, the eutectic region, instead of the HAZ, is the weak point. The wear test shows that the hypoeutectic alloy exhibits the same wear behaviors in both the remelted metal and the HAZ, and so is the hypereutectic alloy; the eutectic alloy remelted metal and the HAZ have different wear morphologies.

  7. Mechanical behavior and coupling between mechanical and oxidation in alloy 718: effect of solide solution elements

    International Nuclear Information System (INIS)

    Alloy 718 is the superalloy the most widely used in industry due to its excellent mechanical properties, as well as oxidation and corrosion resistance in wide range of temperatures and solicitation modes. Nevertheless, it is a well-known fact that this alloy is sensitive to stress corrosion cracking and oxidation assisted cracking under loading in the range of temperatures met in service. Mechanisms explaining this phenomenon are not well understood: nevertheless, it is well established that a relation exists between a change in fracture mode and the apparition of plastic instabilities phenomenon. During this study, the instability phenomenon, Portevin-Le Chatelier effect, in alloy 718 was studied by tensile tests in wide ranges of temperatures and strain rates. Different domains of plastic instabilities have been evidenced. Their characteristics suggest the existence of interactions between dislocations and different types of solute elements: interstitials for lower temperatures and substitutionals for higher testing temperatures. Mechanical spectroscopy tests have been performed on alloy 718 and various alloys which composition is comparable to that of alloy 718. These tests prove the mobility of molybdenum atoms in the alloy in the studied temperature range. Specific tests have been performed to study interaction phenomenon between plasticity and oxidation. These results highlight the strong effect of plastic strain rate on both mechanical behavior and intergranular cracking in alloy 718. The subsequent discussion leads to propose hypothesis on coupling effects between deformation mechanisms and oxidation assisted embrittlement in the observed cracking processes. (author)

  8. The effect of alloying on the ordering processes in near-alpha titanium alloys

    OpenAIRE

    Popov, A.; Rossina, N.; Popova, M.

    2013-01-01

    The substructure of near-alpha Ti-Al-Sn-Zr-Mo-Si alloys containing up to 12.5. at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500. °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700. °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and proper...

  9. Size effects in band gap bowing in nitride semiconducting alloys

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede;

    2011-01-01

    Chemical and size contributions to the band gap bowing of nitride semiconducting alloys (InxGa1-xN, InxAl1-xN, and AlxGa1-xN) are analyzed. It is shown that the band gap deformation potentials of the binary constituents determine the gap bowing in the ternary alloys. The particularly large gap...

  10. Effect of Plastic Deformation on Magnetic Properties of Fe-40%Ni-2%Mn Austenitic Alloy

    Institute of Scientific and Technical Information of China (English)

    Selva Büyükakkas; H Aktas; S Akturk

    2007-01-01

    The effects of plastic deformation on the magnetic properties of austenite structure in an Fe-40%Ni-2%Mn alloy is investigated by using Mssbauer spectroscopy and Differential Scanning Calorimetry (DSC) techniques The morphology of the alloy has been obtained by using Scanning Electron Microscopy (SEM). The magnetic behaviour of austenite state is ferromagnetic. After plastic deformation, a mixed magnetic structure including both paramagnetic and ferromagnetic states has been obtained at the room temperature. The volume fraction changes, the effective hyperfine fields of the ferromagnetic austenite phase and isomery shift values have also been determined by Mssbauer spectroscopy. The Curie point (TC) and the Neel temperature (TN) have been investigated by means of DSC system for non-deformed and deformed Fe-Ni-Mn alloy. The plastic deformation of the alloy reduces the TN and enhances the paramagnetic character of austenitic Fe-Ni-Mn alloy.

  11. Local environmental effects in magnetic alloys and multilayers

    International Nuclear Information System (INIS)

    The authors have developed an ab-initio method for calculating the static response functions in substitutional alloys. For magnetic alloys, in addition to the nuclear diffuse scattering, a contribution to the alloy diffuse scattering intensities results from the response of the local moments to changes in the local chemical environment (i.e. jμi/jcj) The authors present results of first-principles calculations of these local response functions in magnetic alloys. These response functions, which may be directly compared to neutron-scattering and Moeβbauer experiments, are derived via a mean-field statistical mechanical description of compositional fluctuations in alloys. The statistical averages are performed via the Korringa-Kohn- Rostoker coherent potential approximation, which incorporates the electronic structure of the high-temperature, chemically disordered state

  12. Effects of Cr and Nb contents on the susceptibility of Alloy 600 type Ni-base alloys to stress-corrosion cracking in a simulated BWR environment

    International Nuclear Information System (INIS)

    In order to discuss the effects of chromium and niobium contents on the susceptibility of Alloy 600 type nickel-base alloys to stress-corrosion cracking in the BWR primary coolant environment, a series of creviced bent-beam (CBB) tests were conducted in a high-temperature, high-purity water environment. Chromium, niobium, and titanium as alloying elements improved the resistivity to stress-corrosion cracking, whereas carbon enhanced the susceptibility to it. Alloy-chemistry-based correlations have been defined to predict the relative resistances of alloys to stress-corrosion cracking. A strong correlation was found, for several heats of alloys, between grain-boundary chromium depletion and the susceptibility to stress-corrosion cracking

  13. Effect of Electric Field on Conductivity and Vickers Hardness of an A1-Li Alloy

    Institute of Scientific and Technical Information of China (English)

    刘兵; 陈大融; 陈铮; 王永欣; 李晓玲

    2003-01-01

    Static electric fields were applied on an aluminium-lithium alloy during solution treatment.The conductivity and Vickers hardness of the quenched Al-Li alloy is changed with the effect of electric field.The Vickers hardness increases with the applied electric field for a certain solutionizing time but decreases with the time under an electric field.In the absence of the electric field,the Vickers hardness and the conductivity increase synchronously,while reversed after electric field treatment.Positive and negative electric fields had the similar effect.The change of the local electron density in alloy caused by electric field is presented to explain the effect.

  14. Effect of precipitates on mechanical and damping properties of Mg–Zn–Y–Nd alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Hao, E-mail: haofeng804@gmail.com [Department of Physics, College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Liu, Haipeng [Department of Mechanical Engineering, Zhangjiakou Vocational and Technical College, Zhangjiakou 075000, Hebei (China); Cao, Hong [Zhangjiakou Vocational and Technical College, Zhangjiakou 075000, Hebei (China); Yang, Yang [Department of Physics, College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Xu, Yongchun; Guan, Jinyu [Department of Mathematics, College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China)

    2015-07-15

    The effects of aging precipitates on microstructure, mechanical properties and damping capacities of Mg–Zn–Y–Nd alloy were investigated in this study. The structure results indicate that the as-cast alloys consist of α-Mg and W-phase when Zn/RE (rare earth element) weight ratio is about 1.7. After solution-aging treatment, the dissolved W-phase precipitates in the form of large amount of nano-scaled MgZn{sub 2} and Mg{sub 12}Nd phases. The tensile strengths of aged Mg–Zn–Y–Nd alloys are continuously enhanced with the precipitation of MgZn{sub 2} and Mg{sub 12}Nd phase particles, the highest ultimate tensile strength, yield strength and elongation reach up to 257 MPa, 152 MPa and 13.9%. The aging precipitates inhibit deformation twin from growing up and decrease its size, this favors homogeneous deformation and reduces the source of crack initiation, which results in the high elongation of aged Mg–Zn–Y–Nd alloys. The damping capacities of aged Mg–Zn–Y–Nd alloys decrease dramatically at high strain–amplitude stage compared with that of as-cast alloy. The appearance of aging twins and movement or slippage of thin twin boundaries can explain the better damping and unusual damping growth in aged Mg–3.0%–0.9%Y–0.9%Nd (wt%) alloy and Mg–4.0%Zn–1.2%Y–1.2%Nd (wt%) alloys (alloys 2 and 3). The formation of aging twin relates closely to the amount of aging precipitates, no aging twin occurs in the aged Mg–2.0%Zn–0.6%Y–0.6%Nd (wt%) alloy (alloy 1) due to lower precipitates content. The aged Mg–4.0%Zn–1.2%Y–1.2%Nd (wt%) alloy (alloy 3) with more precipitates shows lower damping values than Mg–3.0%Zn–0.9%Y–0.9%Nd (wt%) alloy (alloy 2) because of the stronger pinning effect of precipitates on dislocation.

  15. Interactive effect of cerium and aluminum on the ignition point and the oxidation resistance of magnesium alloy

    International Nuclear Information System (INIS)

    This paper focused on the interactive effect of cerium (Ce) addition and aluminum (Al) content in magnesium alloy on ignition point and oxidation resistance. Ce content played an important role in improving the oxidation resistance of Mg alloy. Ignition point ascended with increasing Ce content. 0.25 wt% Ce content in Mg alloys could greatly improve tightness of the oxide film of Mg alloys. However, when Ce content in the alloy exceeded its solid solubility, ignition point descended. Furthermore, Al content in the alloy also influenced the ignition point. The higher the Al content was, the lower the ignition point

  16. Influence of precipitation on the Portevin-Le Chatelier effect in Al-Mg alloys

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the alloy with solute content higher than the limiting solubility,the solute atoms that have failed to dissolve will precipitate from the solid solution and form precipitations.In this study, the Portevin-Le Chatelier(PLC) effects in annealed 5456 and 5052 aluminum alloys with different precipitation contents have been investigated under different applied strain rates.The results suggest that precipitations have significant effect on the PLC effect and the more the precipitations are, the greater the ...

  17. Effects of Sr and Sn on microstructure and corrosion resistance of Mg–Zr–Ca magnesium alloy for biomedical applications

    International Nuclear Information System (INIS)

    Highlights: ► Element alloying is one of the effective ways to modify the performance of alloys. ► Sr and Sn were simultaneously used to improve the corrosion resistance of Mg–Zr–Ca. ► Mg2Sn was mainly found within the grain interior. ► Corrosion resistance was improved obviously. -- Abstract: Magnesium based alloy is a biodegradable metal that has significant potential advantages as an implant material. Element alloying is one of the effective methods to modify the performance of the magnesium alloy. In the paper, Sr and Sn as alloy elements were simultaneously added into the Mg–Zr–Ca alloy to improve the corrosion resistance. The differences of Mg–Zr–Ca alloy and Mg–Zr–Ca–Sr–Sn alloy were compared. The X-ray diffractometer (XRD) and the scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) were used to analysis the phases and the microstructure of the alloys. The results indicated that the addition of Sn could form Mg2Sn mainly within the grain interior; Sr phase was mainly detected along the grain boundary. Immersion tests and electrochemical measurements showed that the corrosion resistance was improved obviously with simultaneous addition of Sr and Sn in Mg–Zr–Ca alloy. It suggested that bio-magnesium based alloy can use Sr and Sn as effective alloy elements to modify its performance.

  18. Effects of Ce additions on the age hardening response of Mg–Zn alloys

    International Nuclear Information System (INIS)

    The effects of Ce additions on the precipitation hardening behaviour of Mg–Zn are examined for a series of alloys, with Ce additions at both alloying and microalloying levels. The alloys are artificially aged, and studied using hardness measurement and X-ray diffraction, as well as optical and transmission electron microscopy. It is found that the age-hardening effect is driven by the formation of fine precipitates, the number density of which is related to the Zn content of the alloy. Conversely, the Ce content is found to slightly reduce hardening. When the alloy content of Ce is high, large secondary phase particles containing both Ce and Zn are present, and remain stable during solutionizing. These particles effectively reduce the amount of Zn available as solute for precipitation, and thereby reduce hardening. Combining hardness results with thermodynamic analysis of alloy solute levels also suggests that Ce can have a negative effect on hardening when present as solutes at the onset of ageing. This effect is confirmed by designing a pre-ageing heat treatment to preferentially remove Ce solutes, which is found to restore the hardening capability of an Mg–Zn–Ce alloy to the level of the Ce-free alloy. - Highlights: • The effects of Ce additions on precipitation in Mg–Zn alloys are examined. • Additions of Ce to Mg–Zn slightly reduce the age-hardening response. • Ce-rich secondary phase particles deplete the matrix of Zn solute. • Hardening is also decreased when Ce is present in solution. • Pre-ageing to preferentially precipitate out Ce restores hardening capabilities

  19. Effect of filtration on reoxidation proceses in aluminium alloys

    Directory of Open Access Journals (Sweden)

    D. Bolibruchova

    2010-01-01

    Full Text Available This article is focused on reoxidation processes during filtration of aluminium alloys. Many of our experimental works pointed out, that using filtration media placed in gating system causes reoxidation of poured aluminium alloy. Main aim of our latest work was to validate our arguments, that filter in gating system can be considered as obstacle for continuous pouring, with help of computer simulations. This article is only a small part of our researches focused on reoxidation processes during filtration of aluminium alloys.

  20. Ni-Ti-Hf shape memory alloy: effect of aging and thermal cycling

    International Nuclear Information System (INIS)

    A great effort was performed in order to develop alloys which exhibit transformation temperatures higher than about 150 C. This request has a 2-fold aim: (a) to provide an alloy that can be used in devices in which exercise temperatures as high as 100 C are easily reached (e.g. automotive applications, production plants, etc.); (b) to decrease the reset time by increasing the temperature gap between normal exercise and actuation temperatures. It has been demonstrated that ternary Ni-Ti-Hf alloys can be a viable option to increase the operating temperature range of SMA. In this work, a Ni-Ti-Hf alloy has been produced by a plasma arc melting furnace. Plasma technology ensures a good control of alloy composition and contamination, because of its high working pressure (850 mbar) and possibility to melt in a pure gas atmosphere. The produced material has been processed to obtain specimens suitable for calorimetric measurements. The effect of aging and thermal cycling on the thermoelastic martensitic transformation that takes place in the alloy has been evaluated. Specifically, samples taken from plasma melted buttons have been aged at different temperatures. Aging effects and evolution under thermal cycling on martensitic transformation behavior have been investigated by calorimetric measurements. Results obtained allow us to fix the reference framework for the effect of thermal treatments on the transformation properties of the chosen alloy and to compare with similar ones performed on semi-finished products, to evaluate the effect of plastic deformation and residual cold work. (orig.)

  1. Effect of Ca addition on the corrosion behavior of Mg-Al-Mn alloy

    Science.gov (United States)

    Yang, Jiang; Peng, Jian; Nyberg, Eric A.; Pan, Fu-sheng

    2016-04-01

    The microstructures and corrosion resistance of magnesium-5 wt% aluminum-0.3 wt% manganese alloys (Mg-Al-Mn) with different Ca additions (0.2-4 wt%) were investigated. Results showed that with increasing Ca addition, the grain of the alloys became more refined, whereas the corrosion resistant ability of the alloys initially increased and then decreased. The alloy with 2 wt% Ca addition exhibited the best corrosion resistance, attributed to the effect of the oxide film and (Mg,Al)2Ca phases which were discontinuously distributed on the grain boundaries. These phases acted as micro-victims, they preferentially corroded to protect the α-Mg matrix. The oxide film formed on the alloy surface can hinder the solution further to protect the α-Mg matrix.

  2. Effects of copper-based alloy on the synthesis of single-crystal diamond

    CERN Document Server

    Chen Li Xue; Ma Hong An; Jia Xiao Peng; Wakatsuki, M; Zou Guang Tian

    2002-01-01

    The catalytic effects of copper-based alloys in diamond growth have been investigated. A single crystal of diamond has been obtained by the temperature gradient method (TGM), using Cu-Mn-Co and Cu-Co alloys as catalysts. It was found that the melted Cu-Mn-Co and Cu-Co alloys show low viscosity. The eutectic temperatures of these two alloys with graphite were between 1130 and 1150 deg. C, and the temperature of the transition to diamond was over 1300 deg. C at 5.5 GPa. High-quality diamond could not be obtained in Cu-Co alloy by the TGM. Our results suggest that adding Cu to a catalyst cannot decrease the reaction temperature for diamond growth.

  3. Effect of Sn on the Color and Tarnishing of Cu-Mn-Zn Alloys

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The effect of Sn on the color and tarnishing of Cu-Mn-Zn alloys is investigated quantitatively. Using the CIE LAB color system,color parameters such as L*, a* and b* are selected to describe the surface color of alloys while the color difference (△E*)is used to evaluate the color stability. The results show that with the increase of Sn, the color change of Cu-Mn-Zn alloys is greatly reduced and the corrosion resistance in the synthetic sweat is improved dramatically. However, up to 4.4 wt pct Sn does not change the color of Cu-Mn-Zn alloys much. XPS and AES are employed to analyze the tarnished surface. It is proved that a Sn enriched film is formed and Sn takes the form of Sn oxide. This thin and protective oxide film can prevent alloy from further tarnishing.

  4. Effects of Ni addition on liquid phase separation and giant magnetoresistance of Cu-Co alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effects of Ni addition on the liquid phase separation and giant magnetoresistance (GMR) of Cu-Co alloys were discussed. The results reveal that Ni addition can partially restrain the liquid phase separation of Cu-Co alloys, resulting in a decrease of volume fraction for the Co-rich particles separated from the liquid phase and in refined microstructures. The composition analyses indicate that Ni is dissolved in both the Co-rich and the Cu-rich phases, but Ni content in the Co-rich phase is much higher than that in the Cu matrix. At the same time, Ni addition enhance the solubility between Cu and Co, especially Cu in Co solid solution. Ni alloying into Cu-Co alloys can fully prevent the liquid phase separation during melt spinning, which is very beneficial to improve GMR of Cu-Co alloys.

  5. Effects of titanium on microstructure and mechanical properties of ZnAl4Y alloy

    OpenAIRE

    Wang Jianhua; Wang Xiande; Tu Hao

    2011-01-01

    The effect of Ti on the microstructure and mechanical properties of zinc-aluminum ZnAl4Y alloy has been investigated in this work. Small amount of Ti was added into ZnAl4Y alloy in the form of Al-10wt.%Ti alloy. The results show that Ti addition into ZnAl4Y alloy refines the primary η-Zn phase and increases the amount of η-Zn + α-Al eutectic structure. There exists a ternary T phase in Zn-Al-Ti alloy. Fine TiAl3 particles and Ti-Zn compounds can serve as the nucleation sites of the α-Al and η...

  6. Appearance of anodised aluminium: Effect of alloy composition and prior surface finish

    DEFF Research Database (Denmark)

    Aggerbeck, Martin; Canulescu, Stela; Dirscherl, Kai; Johansen, Villads Egede; Engberg, Sara Lena Josefin; Schou, Jørgen; Ambat, Rajan

    2014-01-01

    Effect of alloy composition and prior surface finish on the optical appearance of the anodised layer on aluminium alloys was investigated. Four commercial alloys namely AA1050, Peraluman 706, AA5754, and AA6082 were used for the investigation. Microstructure and surface morphology of the substrate...... prior to anodising were analysed using scanning electron microscopy and atomic force microscopy. The optical appearance of the anodised surface with and without sealing was investigated using a photography setup, photospectrometry and bidirectional reflectance distribution function. It was found that...... the roughness of the as-etched surface increases with the degree of alloying due to second phase particles making the reflection more diffused, and that the as-etched surface morphology is similar to the oxide–substrate interface after anodising. Proper polishing is achieved on hard alloys and the...

  7. Recrystallization microstructure modelling from superimposed deformed microstructure on microstructure model

    Indian Academy of Sciences (India)

    Prantik Mukhopadhyay

    2009-08-01

    The recovered cold rolled microstructure obtained from orientation image microstructure of Al–4%Mg–0.5%Mn alloy (AA5182 alloy) was superimposed on the grid of cellular automata based microstructure model. The Taylor factors of deformed/cold rolled orientations were considered as the driving force for recrystallization. The local development of recrystallized microstructure and texture were simulated with orientation dependent grain boundary mobility and compared with the experimental results.

  8. Effect of Al–5Ti–C Master Alloy on the Microstructure and Mechanical Properties of Hypereutectic Al–20%Si Alloy

    Directory of Open Access Journals (Sweden)

    Wanwu Ding

    2014-02-01

    Full Text Available Al–5Ti–C master alloy was prepared and used to modify hypereutectic Al–20%Si alloy. The microstructure evolution and mechanical properties of hypereutectic Al–20%Si alloy with Al–5Ti–C master alloy additions (0, 0.4, 0.6, 1.0, 1.6 and 2.0 wt% were investigated. The results show that, Al–5Ti–C master alloy (0.6 wt%, 10 min can significantly refine both eutectic and primary Si of hypereutectic Al–20%Si alloy. The morphology of the primary Si crystals was significantly refined from a coarse polygonal and star-like shape to a fine polyhedral shape and the grain size of the primary Si was refined from roughly 90–120 μm to 20–50 μm. The eutectic Si phases were modified from a coarse platelet-like/needle-like structure to a fine fibrous structure with discrete particles. The Al–5Ti–C master alloy (0.6 wt%, 30 min still has a good refinement effect. The ultimate tensile strength (UTS, elongation (El and Brinell hardness (HB of Al–20%Si alloy modified by the Al–5Ti–C master alloy (0.6 wt%, 10 min increased by roughly 65%, 70% and 51%, respectively, due to decreasing the size and changing the morphology on the primary and eutectic Si crystals. The change in mechanical properties corresponds to evolution of the microstructure.

  9. Effects of Si Addition and Heating Ar on the Electromigration Performance of Al-Alloy Interconnects

    Science.gov (United States)

    Lee, Dok Won; Lee, Byung-Zu; Jeong, Jong Yeul; Park, Hyun; Shim, Kyu Cheol; Kim, Jong Seok; Park, Young Bae; Woo, Sun-Woong; Lee, Jeong-gun

    2002-02-01

    The electromigration (EM) performance of Ti/Al-alloy multilayered metallization with one-step sputtered Al-alloy has been studied. The Al-alloys investigated included Al-1.0%Si-0.5%Cu and Al-0.5%Cu, and the Al-alloy films were prepared with and without heating Ar. The package-level EM test results indicate that the EM resistance of the Al-Si-Cu stack is nearly identical to that of the Al-Cu stack. Si addition was found to degrade the microstructure of the Al-alloy film, while it had the retarding effect on the Ti/Al reaction, which suggests that there exists a trade-off between the film microstructure and the formation of TiAl3 intermetallic compound. The EM performance of the one-step sputtered Al-alloy stack was enhanced by the use of heating Ar during the deposition of Al-alloy film, which has been attributed to the improved microstructure of the Al-alloy film by the use of heating Ar.

  10. Modification Effects of Lanthanum-Rich Mischmetal on A357 Alloy

    Institute of Scientific and Technical Information of China (English)

    李华基; 刘昌明; 李革胜; 薛寒松

    2001-01-01

    A357 alloy was modified with lanthanum -rich mischmetal, and modification effects of the mischmetal on its as-cast and heat-treated structures, mechanical properties and hydrogen content were investigated and compared with that of strontium metal. It is shown that the modification effect of La-rich mischmetal is better than that of strontium in the aspects of refining eutectic silicon, ejecting hydrogen from the melt and improving comprehensive mechanical properties of the alloy. Therefore Al-Si-Mg alloy with high strength and improved toughness can be obtained by modification with La-rich mischmetal.

  11. Domain structure and Barkhausen effect in Fe78B12Si9Ni1 amorphous alloy

    International Nuclear Information System (INIS)

    Domain structure is investigated by using new approaches, which are based on registration of micro-volume material magnetization. One demonstrated absence of correlation of dimensions of domain structure elements of Fe78B12Si9Ni1 magnetically soft alloy in initial state upon hydrogen saturation or annealing with the Barkhausen effect characteristics in the mentioned alloy. It is pointed out that conventional view of the Barkhausen effect the nature of which is linked with domain dimensions and mobility of their boundaries, are not true in disordered structures represented by magnetically soft amorphous metal alloys

  12. 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.

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

    International Nuclear Information System (INIS)

    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 + twindense) → (α-Mg + twinloose) → (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 + twindense) → (α-Mg + twinloose) → (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.

  14. Diagonal and local environmental effect in magnetic properties of disordered alloys

    International Nuclear Information System (INIS)

    The most simple cases of studies in the magnetic properties like the diagonal and local environmental effects are studied for a simple and general model of cluster configuration having elements of binary alloys

  15. Effect of Microalloying on Wettability, Oxidation and Solidification Morphology of Sn-9Zn Alloy

    Institute of Scientific and Technical Information of China (English)

    Wei Xiuqin; Huang Huizhen; Zhou Lang; Zhang Meng

    2005-01-01

    Eutectic alloy Sn-9Zn is an attractive candidate for lead-free solders. However, its wettability to copper is poor thus,its development was limited. Effects of less than 1% (mass fraction) additions of mischmetal consisting mainly of La and Ce, heavy rare earth Y, pure P, Al, Mg and Ti elements on the wetting/adhesion behavior of Sn-9Zn alloy to copper, as well as the associated oxidation and solidification morphology of this alloy were examined. The results show that harmful effect on the wettability can be found when adding Al and Ti elements, while the wettability can be improved slightly by adding Mg and Y elements. The adhesion of the alloy to copper can be decreased by Mg element. The RE and P are found to significantly improve the wettability. In addition, oxidation of the alloy can be increased by adding RE, while little effect on the oxidation behavior can be found by adding P element. As-solidified Sn-9Zn alloy has a rough surface with protrusions and cavities shaped by coarse needle-like crystallites, while the Sn-37Pb sample has a rather smooth surface, which indicates the different solidification behavior of Sn-9Zn alloy and the Sn-37Pb one. The additions of the different elements investigated in this study do not alter Sn-9Zn's as-solidified morphology.

  16. EFFECTS OF ALLOYING ELEMENTS ON TWINNING IN ALPHA-TITANIUM ALLOYS

    OpenAIRE

    Fitzner, Arnas Gerald

    2015-01-01

    It has been found that commercially pure (CP) Titanium (Ti) undergoes substantial amount of deformation twinning during plastic forming in a wide range of temperatures and strain rates giving CP-Ti good ductility and allowing up to 90% thickness reduction by cold rolling. Aluminium (Al) rich ! Ti-alloys lack this superior ductility but exhibit therefore up to five times higher yield strength, which was connected experimentally to reduced activity of deformation twinning with addition of Al to...

  17. The shape memory effect in systems Cu-based alloys

    OpenAIRE

    2013-01-01

    330a The aim of this work was to analyse the mechanisms of hindered internal passivation of silver based alloys which was obtained by the modification of basic chemical composition. A generalisation of the phenomenon, experimental verification and the estimated range of micro-element concentration is also introduced. The ability for inoculation of a particular alloy is determined by the differences between the formation energies of oxides, as well as their crystallographic similarity. Therefo...

  18. Purifying effect of new flux on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    高洪涛; 吴国华; 丁文江; 朱燕萍

    2004-01-01

    A new flux which can remove both Fe and non-metallic inclusions in magnesium alloy was introduced.The Fe content of the magnesium alloy can be decreased greatly from 0. 062% to lower than 0. 005% (degree of AZ91D) after being purified by this new flux. The optimum addition of B2O3 in the flux is 0. 58 % by Gaussian Curve Fitting. Corrosion rate was measured after the specimen being immersed in 5 % NaCl solution for 3 d. The resuits show that the corrosion rate of the magnesium alloy after purification by the new flux is only 0.3 mg · cm-2 ·d-1. On the other hand, non-metallic inclusions in the magnesium alloy decrease with increasing addition of JDMJ in the new flux. Average volume fraction of the non-metallic inclusions in the magnesium alloy decreases from 1.52 % to 1.08%, which leads to improvement in the mechanical properties of the magnesium alloy by 30%. The mechanisms of Fe reduction and non-metallic inclusion-removing in magnesium melt by purification with the new flux were also revealed.

  19. Effect of inter-critical quenching on mechanical properties of casting low-alloy steel

    OpenAIRE

    Liu Zhongli; Shang Yong

    2013-01-01

    For some casting low-alloy steels, traditional quenching and tempering heat treatments can improve the strength; however, sometimes the ductility is not satisfied. Therefore, some kind of effective heat treatment method seems necessary; one which could improve the ductility, but not seriously affect the strength. In this paper, the effect of inter-critical quenching (IQ) on the mechanical properties of casting low-alloy steel was studied. IQ was added between quenching and tempering heat trea...

  20. Surface effect theory in binary alloys: surfaces with cut-off

    International Nuclear Information System (INIS)

    A surface effect theory in binary alloys which ore ordered with surfaces with cut-off is presented. This theory is based in a model of pair interaction between first neighbours and includes long and short range effects. The (120) surface with sup(-) (110) monoatomic cut-off and terrace in the (110) planes of an alloy with body centered cubic structure is presented as example. Results for the concentrations in all the different surface sites are given. (L.C.)

  1. Effect of Viscosity on the Microformability of Bulk Amorphous Alloy in Supercooled Liquid Region

    International Nuclear Information System (INIS)

    Previously published results have shown that viscosity greatly influences on the deformation behavior of the bulk amorphous alloy in supercooled liquid region during microforming process. And viscosity is proved to be a component of the evaluation index which indicating microformability. Based on the fluid flow theory and assumptions, bulk amorphous alloy can be regarded as the viscous materials with a certain viscosity. It is helpful to understand how the viscosity plays an important role in viscous materials with various viscosities by numerical simulation on the process. Analysis is carried out by linear state equation in FEM with other three materials, water, lubricant oil and polymer melt, whose viscosities are different obviously. The depths of the materials flow into the U-shaped groove during the microimprinting process are compared in this paper. The result shows that the deformation is quite different when surface tension effect is not considered in the case. With the lowest viscosity, water can reach the bottom of micro groove in a very short time. Lubricant oil and polymer melt slower than it. Moreover bulk amorphous alloys in supercooled liquid state just flow into the groove slightly. Among the alloys of different systems including Pd-, Mg- and Zr-based alloy, Pd-based alloy ranks largest in the depth. Mg-based alloy is the second. And Zr-based alloy is the third. Further more the rank order of the viscosities of the alloys is Pd-, Mg- and Zr-based. It agrees well with the results of calculation. Therefore viscosity plays an important role in the microforming of the bulk amorphous alloy in the supercooled liquid state.

  2. Influence of degree of deformation in rolling on anneal hardening effect of a cast copper alloy

    Indian Academy of Sciences (India)

    Svetlana Nestorovic; Desimir Markovic; Ljubica Ivanic

    2003-10-01

    This paper reports results of investigations carried out on a cast copper alloy containing 8 at.% Al. The alloy, and pure copper for the sake of comparison, were subjected to cold rolling with a final reduction of 30, 50 or 70%. The cold rolled copper and copper alloy samples were isochronally and isothermally annealed up to the recrystallization temperature. The hardness, strength and electrical conductivity were measured and X-ray and DSC analyses performed. Anneal hardening effect was observed in the alloy in the temperature range 180–300°C, followed by an increase in the electrical conductivity. The amount of strengthening increases with increasing degree of prior cold work. The X-ray analysis shows a change in the lattice parameter during annealing when anneal hardening effect was observed. The DSC analysis shows the exothermic character of this effect.

  3. Effects of Nb content and annealing parameter on corrosion in Zr-Sn-Nb alloys

    International Nuclear Information System (INIS)

    To investigate the effects of Nb content and annealing parameter on corrosion resistance in Zr-Sn-Nb alloys, corrosion tests have been carried under 400 deg C steam and 360 deg C LiOH water conditions. As the annealing parameter increased, the weight gain was rapidly decreased in Zr-0.8Sn-0.1Nb and Zr-0.8Sn-0.2Nb alloys but increased in Zr-0.8Sn-0.4Nb and Zr-0.8Sn- 0.8Nb alloys in both corrosion conditions. As the Nb content increased, the weight gain decreased up to 0.4 % Nb content and then slightly increased in content by more than 0.4 %. The lower Nb-contained alloys (Zr-0.8Sn-0.1Nb and Zr-0.8Sn-0.2Nb alloys) was even more sensitive to corrosion resistance by the annealing parameter than the higher Nb-contained alloys (Zr-0.8Sn-0.4Nb and Zr-0.8Sn-0.8Nb). When the Zr-0.8Sn-0.4Nb and Zr-0.8Sn-0.8Nb alloys were inversely annealed with the same annealing parameter, the effect of the annealing parameter on corrosion showed the same trend as normal annealed specimens

  4. Effect of Rare Earth Metals on Structure and Properties of Electroless Co-B Alloy Coating

    Institute of Scientific and Technical Information of China (English)

    宣天鹏; 张雷; 黄秋华

    2002-01-01

    The effect of rare earth metals cerium, lanthanum and yttrium on chemical composition, structure and properties of electroless Co-B alloy coating was studied. By plasma transmitting spectrograph, electron energy spectrometer, X-ray diffractometter, micro-hardometer and vibratory sample magnetometer the chemical constitution, structure and properties of the alloy coatings were analyzed and inspected. The results show that with a tiny quantity of rare earth metal added into Co-B alloy coating, the content of boron is decreased in the alloy coatings, and the kinds of rare earth metal have enormous effect on the structure and properties of electroless Co-B alloy coating. At the same time electroless Co-B alloy with amorphous structure is transformed to electroless Co-B-RE alloy with microcrystalline or crystalline structure. In this way microhardness of the coatings is increased remarkably. Cerium and lanthanum would also increase the saturated magnetic intensity and decrease coercitive force of the coating. So soft magnetization of the coatings would be improved.

  5. The effect of the existing state of Y on high temperature oxidation properties of magnesium alloys

    Science.gov (United States)

    Yu, Xiaowen; Shen, Shijun; Jiang, Bin; Jiang, Zhongtao; Yang, Hong; Pan, Fusheng

    2016-05-01

    This paper studies the effect of the existing state of Y element on the high temperature oxidation resistance of magnesium alloys. Different levels of Al element were added into Mg-2.5Y alloy to obtain different existing state of Y. The oxidation rate of Mg-2.5Y-2.5Al alloy is the highest among Mg-2.5Y, Mg-2.5Y-2.5Al and Mg-2.5Y-4.2Al alloys at 500 °C. An effective and protective Y2O3/MgO composite oxide film was formed on the surface of Mg-2.5Y alloy after oxidized at 500 °C for 360 min. The results show that the dissolved Y element in the matrix was beneficial to improve the oxidation resistance of magnesium alloys. Once Y element transformed to the high temperature stable Al2Y compound, its ability in preventing oxidation would disappear. The formation of Al2Y compound severely deteriorated the oxidation resistance of Mg-2.5Y alloy. In addition, the dissolved Al can also cause the rise of oxidation resistance at a certain extent.

  6. The effect of fusion-relevant helium levels on the mechanical properties of isotopically tailored ferritic alloys

    International Nuclear Information System (INIS)

    The yield and maximum strengths of an irradiated series of isotopically tailored ferritic alloys were evaluated using the shear punch test. The composition of three of the alloys was Fe-12Cr-1.5Ni. Different balances of nickel isotopes were used in each alloy in order to produce different helium levels. A fourth alloy, which contained no nickel, was also irradiated. The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys, and as expected, the strength of the alloys decreased with increasing irradiation temperature. Helium itself, up to 75 appm over 7 dpa appears to have little effect on the mechanical properties of the alloys

  7. EFFECT OF Si ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF THE Al-4.5%Cu ALLOYS

    Institute of Scientific and Technical Information of China (English)

    N. Han; X.F. Bian; Z.K. Li; T. Mao; C.D. Wang

    2006-01-01

    The effect of Si on the microstructure and mechanical properties of binary Al-4.5% Cu alloy has been investigated. The results show that the addition of Si does not have any effect on alloy strength; however, it decreases the ductility of the as-cast Al-4.5% Cu alloy. It is obvious that after T4 heat treatment, the microstructure and mechanical properties of Al-4.5% Cu-Si alloys are improved, especially for the alloy with an Si addition of 2%.

  8. EFFECTS OF INCLUSIONS ON AN Al-Cu 4-Mg1.5 ALLOY

    Directory of Open Access Journals (Sweden)

    Sacit DÜNDAR

    2002-03-01

    Full Text Available Filtering through refractory material is accepted as an efficient method for the removal of inclusions from the structure of aluminum-base alloys. The effects of inclusions are examined in relation to the anisotropy of the wrought aluminum alloy, Al – Cu 4 – Mg 1.5. The experimental variables selected were the filtration technique, casting methods, variations in heat treatments as well as variations in rolling reductions. Reduction in the solid particle inclusion content could be achieved by using sintered filter material. Quite high short transverse ductility could be achieved in rolled plates of commercial high strength aluminum alloy.

  9. Shape memory effect and superelasticity of titanium nickelide alloys implanted with high ion doses

    International Nuclear Information System (INIS)

    The state of the art in ion implantation of superelastic NiTi shape memory alloys is analyzed. Various technological applications of the shape memory effect are outlined. The principles and techiques of ion implantation are described. Specific features of its application for modification of surface layers in surface engineering are considered. Key properties of shape memory alloys and problems in utilization of ion implantation to improve the surface properties of shape memory alloys, such as corrosion resistance, friction coefficient, wear resistance, etc. are discussed. The bibliography includes 162 references

  10. Effect of high-temperature pre-precipitation on microstructure and properties of 7055 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    陈康华; 黄兰萍

    2003-01-01

    The near-solvus pre-precipitation following higher temperature solution treatment was performed on 7055 aluminum alloy. The effect of the pre-precipitation on the microstructure, age hardening and stress corrosion cracking of 7055 alloy was investigated. The optical and transmission electron microscopy results show that the near-solvus pre-precipitation can be limited to grain boundary and enhance the discontinuity of grain boundary precipitates in the sequent age. The stress corrosion cracking resistance of aged 7055 alloys could be improved with non-deteriorated strength and plasticity via the pre-precipitation.

  11. Effect of Cerium on Mechanical Properties and Morphology of ZZn4-1 Alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Effect of the addition of cerium in appropriate amount on the mechanical properties and morphology of ZZn4-1 alloy was investigated. In the case of samples collected from metal mould, the results show that the addition of cerium in appropriate amount can increase tensile strength and HB hardness, and can refine the microstructure of ZZn4-1 alloy considerably. In the case of samples collected from pressure die-casting, the addition of cerium in appropriate amount can refine the primary η-phase and the eutectic structure of pressure die-casting and improve mechanical and processing properties of the alloy.

  12. Catalytic Effect of SCN- on Electrodeposition of Zinc-Nickle Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The electrodeposition of zinc-nickle alloy was obtained on a copper cathode of 1 × lcm2. The deposited alloys are quantitatively analyzed by atomic absorption spectrometry. The morphology of the deposits was observed by means of scanning electron microscopy(SEM). We observed that the electrodeposition of zinc-nickle alloy is an anomalous codeposition. The catalytic effects of SCN- on the electrochemical behavior of Ni deposition and hydrogen discharge are obvious. SEM analysis shows that the surface morphology of the coating appears to be more compact and homogeneous with the increase of SCN- concentration.

  13. The effects of. gamma. -irradiation on Ti-Ni shape-memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Guilin; Xu Feng; Liu Wenhong; Hu Wenxiang; Yu Fanghua; Zhang Yiping (Academia Sinica, Shanghai, SH (China). Shanghai Inst. of Nuclear Research); Wang Jingcheng; Shao Zichang (Shanghai Iron and Steel Research Inst, SH (China))

    1992-04-01

    Because gamma irradiation provides a means of introducing lattice defects into crystalline solids in a controlled fashion, it can be used to study the influence of lattice defects on the physical properties of solids such as shape-memory alloys (SMAs). The study described here shows that gamma irradiation can be used to ameliorate the performance of SMAs and to understand the mechanism of the shape memory further in these alloys. In particular it shows the effect of gamma irradiation on the martensitic transformation temperatures of Ti-Ni alloys. (UK).

  14. The effects of γ-irradiation on Ti-Ni shape-memory alloy

    International Nuclear Information System (INIS)

    Because gamma irradiation provides a means of introducing lattice defects into crystalline solids in a controlled fashion, it can be used to study the influence of lattice defects on the physical properties of solids such as shape-memory alloys (SMAs). The study described here shows that gamma irradiation can be used to ameliorate the performance of SMAs and to understand the mechanism of the shape memory further in these alloys. In particular it shows the effect of gamma irradiation on the martensitic transformation temperatures of Ti-Ni alloys. (UK)

  15. Shape memory effect and superelasticity of titanium nickelide alloys implanted with high ion doses

    Science.gov (United States)

    Pogrebnjak, A. D.; Bratushka, S. N.; Beresnev, V. M.; Levintant-Zayonts, N.

    2013-12-01

    The state of the art in ion implantation of superelastic NiTi shape memory alloys is analyzed. Various technological applications of the shape memory effect are outlined. The principles and techiques of ion implantation are described. Specific features of its application for modification of surface layers in surface engineering are considered. Key properties of shape memory alloys and problems in utilization of ion implantation to improve the surface properties of shape memory alloys, such as corrosion resistance, friction coefficient, wear resistance, etc. are discussed. The bibliography includes 162 references.

  16. Large elastic strain and elastocaloric effect caused by lattice softening in an iron-palladium alloy.

    Science.gov (United States)

    Kakeshita, Tomoyuki; Xiao, Fei; Fukuda, Takashi

    2016-08-13

    A Fe-31.2Pd (at.%) alloy exhibits a weak first-order martensitic transformation from a cubic structure to a tetragonal structure near 230 K. This transformation is associated with significant softening of elastic constant C'. Because of the softening, the alloy shows a large elastic strain of more than 6% in the [001] direction. In addition, the alloy has a critical point and shows a high elastocaloric effect in a wide temperature range for both the parent and the martensite phases.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'. PMID:27402932

  17. Effect of Yttrium Addition on Glass Forming Ability of ZrCuAlSi Alloy

    International Nuclear Information System (INIS)

    The effect of yttrium addition on glass formation of a ZrCuAlSi alloy is investigated. The maximum diameter 8mm of the glassy rods for (Zr46.3Cu43.3Al8.9Si1.5)100−xYx alloy with x = 2.5 is obtained by copper mould casting. Apparent enhancement of the glass formation ability is found with addition of yttrium, mainly due to the purification of the alloy melt and the suppression of formation of the primary phases by yttrium. (condensed matter: structure, mechanical and thermal properties)

  18. Composition effects on the early-stage oxidation kinetics of (001) Cu-Au alloys

    Science.gov (United States)

    Zhou, G.-W.; Eastman, J. A.; Birtcher, R. C.; Baldo, P. M.; Pearson, J. E.; Thompson, L. J.; Wang, L.; Yang, J. C.

    2007-02-01

    An in situ environmental transmission electron microscopy study of the nucleation and growth of oxide islands during the early-stage oxidation of (001) Cu1-xAux alloys (x⩽38at.%) was undertaken in order to investigate the effects of alloying on oxide island nucleation behavior and growth kinetics. The kinetic data reveal that Au enhances the nucleation density of oxide islands and suppresses their growth rate. Our results provide insight into reasons for the decreased passivation properties of Cu when alloyed with Au.

  19. Pressure effects on Al89La6Ni5 amorphous alloy crystallization

    DEFF Research Database (Denmark)

    Zhuang, Yanxin; Jiang, Jianzhong; Zhou, T. J.;

    2000-01-01

    The pressure effect on the crystallization of the Al89La6Ni5 amorphous alloy has been investigated by in situ high-pressure and high-temperature x-ray powder diffraction using synchrotron radiation. The amorphous alloy crystallizes in two steps in the pressure range studied (0-4 GPa). The first......(s). The applied pressure strongly affects the crystallization processes of the amorphous alloy. Both temperatures first decrease with pressure in the pressure range of 0-1 GPa and then increase with pressure up to 4 GPa. The results are discussed with reference to competing processes between the thermodynamic...

  20. Effect of heat treatment on corrosion resistance of WE54 alloy

    Directory of Open Access Journals (Sweden)

    T. Rzychoń

    2007-01-01

    Full Text Available Purpose: Poor corrosion resistance is one of the main causes to prevent magnesium alloys for wide applications.The addition of rare earth elements (RE is an effective way to improve corrosion resistance of magnesiumalloys. Heat treatment condition can also influence the corrosion behavior of magnesium alloys. The purpose ofthe investigation was to study the corrosion resistance of WE54 alloy after heat treatment.Design/methodology/approach: The study was conducted on WE54 alloy in the as-cast condition and after heattreatment at 250-300˚C for periods of time 4 – 96 h. Immersion test was performed using not deaerated 3.5%NaCl solution at room temperature. Specimens were placed in 3.5% NaCl solution for periods of time betweenone and 7 days. The dissolution rates (mg cm-2 day-1 were determined by weight loss measurements. Afterimmersion test, the microstructure and the appearances of the corroded structure were examined by scanningelectron microscopy.Findings: The corrosion rate of WE54 alloy strongly depends on heat treatment condition. WE54 alloy in theas-cast and after solution treated have similar corrosion behavior, different from that of aged specimens. Thecurves of corrosion rate for aged specimens were higher than that for as-cast and solution treated conditions. Itwas also noticed that the longer time of ageing the higher corrosion rates were observed.Research limitations/implications: The knowledge about corrosion behavior of Mg-RE-Zr alloys is currentlyunder evaluation on many speciality applications where lightweight connected with optimum corrosionresistance are required.Practical implications: The knowledge about corrosion behavior of Mg-RE-Zr alloys is currently underevaluation on many speciality applications where lightweight connected with optimum corrosion resistance arerequired.Originality/value: This paper includes the effect of heat treatment condition on corrosion resistance of WE54magnesium alloy.

  1. Effects of Tin Content and Heat Treatment on the Anodic Characteristics of Al-Sn Alloy

    International Nuclear Information System (INIS)

    Anodic characteristics of specifically prepared laboratory Al-Sn binary alloys in 3% NaCl aqueous solution have been studied to clarify the effect of Sn addition to Al sacrificial anode. Five nine grade pure Al and reagent grade Sn were melted in a high purity graphite crucible in a glove box under Ar atmosphere. The amount of Sn addition to Al was varied in the range of 0.05 to 0.8% by weight. Alloys thus prepared were fashioned into electrode specimens as cast or after different heat-treatments. Distribution of Sn in alloy specimens was examined by EPMA method, which revealed that only the alloy specimens containing less than 0.2% w/o Sn maintain the Al-Sn solid solution after homogenizing heat-treatment at 620 .deg. C for 18 hrs. Segregation of Sn at grain boundaries and even within grains occurs in other specimens. Only the Sn dissolved within aluminum grains appeared to have a major effect on the anodic characteristics of alloy. Most Al-Sn alloy containing more than 0.05 w/o Sn exhibited very low corrosion potential of -1450 ± 20mV vs. SCE except those heat-treated at 500 .deg. C. In potentiostatic anodic polarization measurements for alloy specimens, the largest polarized currents at each set potentials were observed in the alloy specimen which contains 0.2 w/o Sn and homogenized at 620 .deg. C as well. Galvanic couples of the latter alloy specimen coupled to mild steel cathode with the apparent area ratio of anode to cathode 1:63 gave steady state galvanic current of 17 mA and exhibited electrode potential of -1190 mV vs. SCE in 3% NaCl solution, completely protecting the steel cathode even after 72 hours passed

  2. Superficial effects during the activation of zirconium AB2 alloys

    International Nuclear Information System (INIS)

    The activation of zirconium nickel alloys with and without the addition of chromium and titanium is investigated through electrochemical and optical techniques.These alloys show high hydrogen absorption capacity and are extensively used in metal hydride batteries.Recent investigations in aqueous 1 M KOH indicate oxide layer growth and occlusion of hydrogen species in the alloys during the application of different cathodic potential programmes currently used in the activation process.In this research several techniques such as voltammetry, ellipsometry, energy dispersive analysis of X-rays EDAX, and scanning electron microscopy SEM are applied on the polished massive alloy Zr1-xTix, x=0.36 y 0.43, and Zr1-xTixCrNi, x=0.1,0.2 y 0.4.Data analysis shows that the stability, compactness and structure of the passive layers are strongly dependent on the applied potential programme.The alloy activation depends on the formation of deepen crevices that remain after a new polishing. Microscopic observation shows increase in the crevices thickness after the cathodic sweep potential cycling, which produces fragmentation of the grains and oxide growth during the activation process.This indicates metal breaking and intergranular dissolution that take place together with oxide and hydride formation.In some cases the resultant crevice thickness is one or two orders higher than that of the superficial oxide growth indicating intergranular localised corrosion

  3. Effect of alloying elements on tendency to reversible temper brittleness of low alloy welds

    International Nuclear Information System (INIS)

    Results of assessing the role of impurity and alloying elements contained in multicomponent (Cr-Ni-Mo system) weld in development of embrittlement during decelerated cooling after tempering to treat for stress-relieve are given as well as of establishing basic concentration and time-temperature regularities of this process. Cr-Mn-Ni-Mo system wires were used in experiments. Quantitative relation between temperature level of transition to brittle state of welds and elements contents affecting embrittlement has been determined. Parametric dependence revealed permits to assess with high confidence cold resistance of Cr-Ni-Mo welds at this stage of choosing the weld material composition, welding and thermal treatment conditions

  4. Effects of scandium and zirconium combination alloying on as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy

    Directory of Open Access Journals (Sweden)

    Xiang Qingchun

    2011-02-01

    Full Text Available The influences of minor scandium and zirconium combination alloying on the as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy have been experimentally investigated. The experimental results show that when the minor elements of scandium and zirconium are simultaneously added into the Al-4Cu-1.5Mg alloy, the as-cast microstructure of the alloy is effectively modified and the grains of the alloy are greatly refined. The coarse dendrites in the microstructure of the alloy without Sc and Zr additions are refined to the uniform and fine equiaxed grains. As the additions of Sc and Zr are 0.4% and 0.2%, respectively, the tensile strength, yield strength and elongation of the alloy are relatively better, which are 275.0 MPa, 176.0 MPa and 8.0% respectively. The tensile strength is increased by 55.3%, and the elongation is nearly raised three times, compared with those of the alloy without Sc and Zr additions.

  5. Effects of reversible shape memory and aging in the Ni-50.5 at. % Ni alloy

    International Nuclear Information System (INIS)

    By the method of dilatometry and transmission electron microscopy the effects of reversible shape memory (ERSM) and structural changes in alloy Ti-50.5 at. % Ni after rolling in austenitic state and various thermal treatments were studied. it is ascertained that the alloy in non-deformed state is an aging one the process of Ti3Ni4 particles isolation takes place during long-term holding at temperatures approximately 150 deg C lower than in alloy Ti-51 at. % Ni. Deformation accelerates the process of particle isolation by two orders. It is shown that the deformation value during ERSM correlates with Ti3Ni4 particles dissolution-isolation, if alloy has not been recrystallized. Memory of reversible shape memory effect (double memory) was revealed, stemming from regular isolation of particles in deformed B2-phase and texture retaining in their arrangement

  6. Mechanical Effects of Hafnium and Boron Addition to Aluminum Alloy Films for Submicrometer LSI Interconnects

    Science.gov (United States)

    Onoda, Hiroshi; Takahashi, Eishi; Kawai, Yasuaki; Madokoro, Shoji; Fukuyo, Hideaki; Sawada, Susumu

    1993-11-01

    This is the first report on the mechanical properties of hafnium- and boron-added Al-Si-Cu alloy film for LSI interconnects. Two to three hundred ppm of hafnium and boron addition into Al-Si-Cu alloy film does not influence the Al alloy properties for metal lines as LSI interconnects, such as its low resistivity, low ohmic contact resistance with Si, and fine-line patterning feasibility. The mechanical properties of the Al alloy film, however, change greatly. Vertical hillock and lateral hillock formation is considerably suppressed during heat treatments used in LSI fabrication processes. Stress-induced void formation is also reduced during aging test at 125°C. These effects due to hafnium and boron addition are considered to be an impurity precipitation effect ihat was confirmed by X-ray diffraction analysis and electron probe microanalysis.

  7. Effects of Palladium Content, Quaternary Alloying, and Thermomechanical Processing on the Behavior of Ni-Ti-Pd Shape Memory Alloys for Actuator Applications

    Science.gov (United States)

    Bigelow, Glen

    2008-01-01

    The need for compact, solid-state actuation systems for use in the aerospace, automotive, and other transportation industries is currently driving research in high-temperature shape memory alloys (HTSMA) having transformation temperatures above 100 C. One of the basic high temperature systems under investigation to fill this need is NiTiPd. Prior work on this alloy system has focused on phase transformations and respective temperatures, no-load shape memory behavior (strain recovery), and tensile behavior for selected alloys. In addition, a few tests have been done to determine the effect of boron additions and thermomechanical treatment on the aforementioned properties. The main properties that affect the performance of a solid state actuator, namely work output, transformation strain, and permanent deformation during thermal cycling under load have mainly been neglected. There is also no consistent data representing the mechanical behavior of this alloy system over a broad range of compositions. For this thesis, ternary NiTiPd alloys containing 15 to 46 at.% palladium were processed and the transformation temperatures, basic tensile properties, and work characteristics determined. However, testing reveals that at higher levels of alloying addition, the benefit of increased transformation temperature begins to be offset by lowered work output and permanent deformation or "walking" of the alloy during thermal cycling under load. In response to this dilemma, NiTiPd alloys have been further alloyed with gold, platinum, and hafnium additions to solid solution strengthen the martensite and parent austenite phases in order to improve the thermomechanical behavior of these materials. The tensile properties, work behavior, and dimensional stability during repeated thermal cycling under load for the ternary and quaternary alloys were compared and discussed. In addition, the benefits of more advanced thermomechanical processing or training on the dimensional stability of

  8. Effect of Microstructure and Sulfide on Corrosion of Cu-Ni Alloys in Seawater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The microstructure and the corrosion product films have been investigated on Cu-Ni alloys by TEM, SEM, AES and electrochemical technique as well as natural seawater exposure tests. Experimental results showed that the alloys had two kinds of microstructure, I.e. Recrystallization and incomplete recrystallization. In synthetic seawater containing 2×10-6 S2-, the stability of the alloy increased with the increase of deformation and annealing temperature, I.e., the degree of recrystallization. After exposure to natural seawater for different periods of time, the corrosion product films of the recrystallized alloy were rich in Ni and compact, and there were cracks in the outer layer which contained a small amount of S; the films of the alloy of incomplete recrystallization became thick, loose and porous, and obviously of layered structure. And the intergranular corrosion took place in the underlying substrate. Besides, a great amount of seawater substance existed in the outer layer and some sulfur was found within the grain boundaries that prefer to corrode. The accelerating effect of sulfides in corrosion of Cu-Ni alloys in seawater is attributed to the coexistence and absorption of sulfides and carbides promoting the preference of corrosion where they absorb, and the formation of dissolvable Cu2S results in keeping the surface of the alloys in the active state.

  9. The effect of hydrogen embrittlement on the localized plastic deformation of aluminum alloy

    Science.gov (United States)

    Bochkareva, Anna; Lunev, Aleksey; Barannikova, Svetlana; Gorbatenko, Vadim; Shlyakhova, Galina; Zuev, Lev

    2015-10-01

    The effect of hydrogen embrittlement on the localized plastic deformation of aluminum alloy D1 was investigated. The studies were performed for the test samples of aluminum alloy subjected to electrolytic hydrogenation. It is found that the mechanical properties and localized plastic deformation parameters of aluminum alloy are affected adversely by hydrogen embrittlement. The hydrogenated counterpart of alloy has a lower degree of ductility relative to the original alloy; however, the plastic flow behavior of material remains virtually unaffected. Using scanning electron and atomic force microscopy methods, the changes in the fracture surface were investigated. The deformation diagrams were examined for the deformed samples of aluminum alloy. These are found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Ludwik-Holomon equation. Using digital speckle image technique, the local strain patterns were being registered for the original alloy D1 and the counterpart subjected to electrolytic hydrogenation for 100 h.

  10. The effect of hydrogen embrittlement on the localized plastic deformation of aluminum alloy

    International Nuclear Information System (INIS)

    The effect of hydrogen embrittlement on the localized plastic deformation of aluminum alloy D1 was investigated. The studies were performed for the test samples of aluminum alloy subjected to electrolytic hydrogenation. It is found that the mechanical properties and localized plastic deformation parameters of aluminum alloy are affected adversely by hydrogen embrittlement. The hydrogenated counterpart of alloy has a lower degree of ductility relative to the original alloy; however, the plastic flow behavior of material remains virtually unaffected. Using scanning electron and atomic force microscopy methods, the changes in the fracture surface were investigated. The deformation diagrams were examined for the deformed samples of aluminum alloy. These are found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Ludwik-Holomon equation. Using digital speckle image technique, the local strain patterns were being registered for the original alloy D1 and the counterpart subjected to electrolytic hydrogenation for 100 h

  11. Effect of mischmetal and yttrium on microstructures and mechanical properties of Mg-Al alloy

    Institute of Scientific and Technical Information of China (English)

    张诗昌; 魏伯康; 蔡启舟; 王立世

    2003-01-01

    The effect of yttrium and mischmetal(MMs) on the as-cast and solid solution treated structures of Mg-Al alloys with different Al-contents was investigated. The results show that the MMs in Mg-Al alloy existed in rodAl4 (Ce, La)compound while Y in Mg-Al alloy in polygonal Al2 Y compound. The amount of Mg17 Al12 in Mg-Al al-loy is decreased with increasing Y or MMs addition, and Mg17 Al12 intermetallic compound is changed from continu-ous network to discontinuous one. The Al4 (Ce, La) and Al2 Y compounds are not dissolved into Mg-Al alloy matrixduring solid solution treatment so that their high heat stability can be exhibited. The experiment of mechanical prop-erties indicate that elongation and impact toughness of the Mg-Al-Y alloy with polygonal Al2 Y compound are higherthan those of Mg-Al-MMs alloy with rod Al4 (Ce, La) compound.

  12. Effect of Ce addition on the mechanical and electrochemical properties of a lithium battery shell alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junchao [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Ding, Dongyan, E-mail: dyding@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, Xinglong [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua [Huafon NLM Al Co., Ltd, Shanghai 201506 (China); Huang, Yuanwei; Tang, Jinsong [Shanghai Huafon Materials Technology Institute, Shanghai 201203 (China)

    2014-12-25

    Highlights: • Fabrication of Ce-free and Ce-containing Al–Cu–Mn–Fe–Mg alloy. • TEM, tensile and electrochemical characterization of the alloys. • Ce element greatly affects the precipitation of the alloy. • Ce element had great impact on the tensile strength and corrosion potential of the alloys. - Abstract: Due to severe application environment lithium battery shell of new-energy automotives requires increasing demands for using high performance aluminum alloys. In the present work, effect of Ce addition on the microstructure, tensile and electrochemical properties of an Al–Cu–Mn–Mg–Fe alloy were investigated through using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), tensile tests and electrochemical tests. The experimental results indicated that the addition of Ce element could promote the precipitation of second phases. With addition of 0.36% Ce, high melting point Al{sub 8}Cu{sub 4}Ce phase and many Al{sub 20}Cu{sub 2}Mn{sub 3} particles could be found. In addition, the precipitation of conventionally dominant phase of Al{sub 2}Cu could be suppressed in alloy. The Ce addition was found to result in enhanced tensile strength and improved corrosion resistance.

  13. Effect of Ce addition on the mechanical and electrochemical properties of a lithium battery shell alloy

    International Nuclear Information System (INIS)

    Highlights: • Fabrication of Ce-free and Ce-containing Al–Cu–Mn–Fe–Mg alloy. • TEM, tensile and electrochemical characterization of the alloys. • Ce element greatly affects the precipitation of the alloy. • Ce element had great impact on the tensile strength and corrosion potential of the alloys. - Abstract: Due to severe application environment lithium battery shell of new-energy automotives requires increasing demands for using high performance aluminum alloys. In the present work, effect of Ce addition on the microstructure, tensile and electrochemical properties of an Al–Cu–Mn–Mg–Fe alloy were investigated through using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), tensile tests and electrochemical tests. The experimental results indicated that the addition of Ce element could promote the precipitation of second phases. With addition of 0.36% Ce, high melting point Al8Cu4Ce phase and many Al20Cu2Mn3 particles could be found. In addition, the precipitation of conventionally dominant phase of Al2Cu could be suppressed in alloy. The Ce addition was found to result in enhanced tensile strength and improved corrosion resistance

  14. Effect of Mo on recrystallization characteristics of Zr-Nb-(Sn)-Mo experimental alloys

    International Nuclear Information System (INIS)

    Feasibility of using Mo as a crucial alloying element in Zr-based alloys is addressed in terms of grain growth characteristics, texture and mechanical properties. In binary Zr-1Nb alloy, addition of Mo retarded recovery and recrystallization of cold worked microstructure and suppressed grain coarsening. Mo also prevented abnormal grain growth that occurred in the binary alloy. The grain refinement effect of Mo was explained in terms of β-phase forming at the interface of α-phase plates. Yield strength and ultimate tensile strength of heat-treated Zr-1Nb and Zr-1Nb-ySn-0.1Fe alloys were also enhanced by Mo addition due to solid-solution hardening and persistent cold-worked dislocation substructure. As cold-rolled Zr-1Nb alloys showed a rather high basal texture along the normal direction of plate surface and this was relaxed by Mo addition, which was attributed to grain refinement and promotion of β-phase. The present work indicates that Mo can be a valuable addition in Zr-based alloys particularly under extended high temperature exposure. (orig.)

  15. Abnormal grain growth of Zr-1wt.%Nb alloy and the effect of Mo addition

    International Nuclear Information System (INIS)

    Increasingly harsh operation conditions of water reactors, such as high burn-up fuel cycles, demand improved Zr-based alloys for the reactor core applications. Enhanced corrosion resistance, better than that of Zircaloy-4, was realized in the newly developed Zr-based alloys containing Nb and Sn. Zr-Nb alloy was developed for pressure tubes of heavy water reactors while Zr-Nb-Si alloys such as ZIRLO and E635 alloys are currently under evaluation as candidate materials for advanced fuel claddings. In the Zr-based alloys containing Nb, generally a fine grain structure is maintained due to the presence of a small amount of retained β. There is a good possibility, therefore, of abnormal grain growth provided that the role of β phase is consistent. Addition of Mo in Zr-Nb alloy, in this respect, is expected to bring about a crucial effect on stabilizing the microstructure. The present work addresses the problem of abnormal grain growth in Zr-Nb system and presents a possible way of curing it by addition of Mo

  16. Fractal study of Ni-Cr-Mo alloy for dental applications: effect of beryllium

    International Nuclear Information System (INIS)

    Different Ni-based alloys with various compositions were prepared by varying the amounts of beryllium. Effect of the amount of beryllium added to the alloy on its corrosion in an electrolyte solution of artificial saliva was investigated. Fractal dimension was used as a quantitative factor for surface analysis of the alloys before and after storage in the artificial salvia. The fractal dimensions of the electrode surfaces were determined by means of the most reliable method in this context viz. time dependency of the diffusion-limited current for a system involving 'diffusion towards electrode surface'. The results showed that increase of the beryllium amount in the alloy composition significantly increases the alloy corrosion. It is accompanied by increase of the fractal dimension and roughness of the electrode surface, whereas a smooth and shiny surface is required for dentures. From the methodology point of view, the approach utilized for fractal analysis of the alloy surfaces (Au-masking of metallic surfaces) is a novel and efficient method for study of denture surfaces. Generally, this approach is of interest for corrosion studies of different metals and alloys, particularly where changes in surface structure have a significant importance

  17. Fractal study of Ni-Cr-Mo alloy for dental applications: effect of beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhari, Ali

    2003-12-30

    Different Ni-based alloys with various compositions were prepared by varying the amounts of beryllium. Effect of the amount of beryllium added to the alloy on its corrosion in an electrolyte solution of artificial saliva was investigated. Fractal dimension was used as a quantitative factor for surface analysis of the alloys before and after storage in the artificial salvia. The fractal dimensions of the electrode surfaces were determined by means of the most reliable method in this context viz. time dependency of the diffusion-limited current for a system involving 'diffusion towards electrode surface'. The results showed that increase of the beryllium amount in the alloy composition significantly increases the alloy corrosion. It is accompanied by increase of the fractal dimension and roughness of the electrode surface, whereas a smooth and shiny surface is required for dentures. From the methodology point of view, the approach utilized for fractal analysis of the alloy surfaces (Au-masking of metallic surfaces) is a novel and efficient method for study of denture surfaces. Generally, this approach is of interest for corrosion studies of different metals and alloys, particularly where changes in surface structure have a significant importance.

  18. Effect of Microstructure on Thermal Expansion Coefficient of 7A09 Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    Hongzhi Ji; Lin Yuan; Debin Shan

    2011-01-01

    The relationship between microstructure evolution and coefficient of thermal expansion (CTE) of 7A09 aluminum alloy was investigated in this paper. Differential scanning calorimetry (DSC) was combined with transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) to investigate microstructure evolution taking place in 7A09 aluminum alloy during heating and cooling process. The corresponding CTE curves of the 7A0g alloy were recorded by thermal dilatometer. Results indicated that GPII zones and Ur phase were main precipitates in the highest strength tempered (T6) 7A09 alloy. The r/phase was the main participate in 7A09 alloy during the cooling process. The nonlinear dependency existed between CTE and temperature in both changing temperature processes. During the heating process, obvious additional contraction of alloy volume was directly caused by phase transition, such as dissolution of η' phase, transition from η' to η phase and dissolution of η phase. The additional contraction could slow down the increase of CTE greatly and be expressed in the nonlinearity of CTE curve. Volume and energy changes of alloy system influenced the variation trend of CTE directly, which was caused by the precipitation of U phase during the cooling process. These effects were revealed by the corresponding nonlinear change of CTE.

  19. Effects of electromagnetic stirring on microstructures of solidified aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    时海芳; 张伟强

    2003-01-01

    Al-20%Cu, Al-33%Cu and Al-7%Si alloys were solidified with electromagnetic stirring(EMS). The fluid flow induced by electromagnetic stirring leads to the increases of the lamellar spacing of Al-CuAl2 and Al-Si eutectics and the secondary dendritic arm spacing. Rod-like eutectic structure plus pro-eutectic α(Al) are observed in Al-Cu eutectic alloy when the agitating voltage is increased over 130 V, and in the hypoeutectic alloys, globular grains of proeutectic α(Al) grains may form when the magnetic field is strong enough. The Si flakes in the Al-Si eutectic are also coarsened by applying forced flow during solidification, which is always related to the depression of their branching in the growth by the forced convection.

  20. Effect of B addition to hypereutectic Ti-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Louzguina-Luzgina, Larissa V. [Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan); Louzguine-Luzgin, Dmitri V. [WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)], E-mail: dml@imr.tohoku.ac.jp; Inoue, Akihisa [WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

    2009-04-17

    The structure and mechanical properties of Ti-Fe-B and Ti-Fe-Co-B alloys produced in the shape of the arc-melted ingots of about 25 mm diameter and 10 mm height are studied. The hypereutectic alloys showed excellent compressive mechanical properties. The structures of the high-strength and ductile hypereutectic alloys studied by X-ray diffractometry and scanning electron microscopy were found to consist of the primary cubic cP2 intermetallic compound (TiFe-phase or a solid solution on its base) and a dispersed eutectic consisting of this cP2 intermetallic compound + BCC cI2 {beta}-Ti supersaturated solid solution phase. The addition of B increased mechanical strength. Si causes embrittlement owing to the formation of alternative intermetallic compounds. The structure and deformation behaviour were studied.

  1. EFFECTS OF INCLUSIONS ON AN Al-Cu 4-Mg1.5 ALLOY

    OpenAIRE

    Sacit DÜNDAR

    2002-01-01

    Filtering through refractory material is accepted as an efficient method for the removal of inclusions from the structure of aluminum-base alloys. The effects of inclusions are examined in relation to the anisotropy of the wrought aluminum alloy, Al – Cu 4 – Mg 1.5. The experimental variables selected were the filtration technique, casting methods, variations in heat treatments as well as variations in rolling reductions. Reduction in the solid particle inclusion content could be achieved by...

  2. Effect of scandium and zirconium additions on the corrosion properties of Al-Mg alloys

    International Nuclear Information System (INIS)

    Effect of scandium and zirconium additions and also models of annealing and induced heating on corrosion cracking resistance, stratifying intercrystalline and general corrosion by loss of mass is studied and electrochemical characteristics of semifinished products from Al-Mg-alloys are determined. New regime of stabilizing providing for manufacture of semifinished products with improved level of corrosion is developed. It is shown that electrochemical factor plays an important role in the mechanism of corrosion cracking of the alloys under consideration

  3. THE EFFECT OF THE ALUMINIUM ALLOY SURFACE ROUGHNESS ON THE RESTITUTION COEFFICIENT

    OpenAIRE

    Stanisław Bławucki; Kazimierz Zaleski

    2015-01-01

    The paper presents the results of research on the effect of the surface roughness of aluminum alloy on its coefficient of restitution. It describes the current method of finishing the workpiece surface layer after cutting and innovative measuring device which was used in the research. The material used in the research was aluminium alloy EN AW 7075. The paper also presents a relationship between the coefficient of restitution and surface roughness of the milled samples as well as impressions ...

  4. AbstractEffect of Hydrogen on the Corrosion Performance of Zirconium Alloys

    OpenAIRE

    Wei, Jianfei

    2012-01-01

    This study is part of the multidisciplinary research program funded by the EPSRC aimed at further understanding the mechanisms behind the oxidation, transition and breakaway of zirconium alloys. The current study concentrates on the effect of artificially introduced hydride rich rim region upon the corrosion performance of zirconium alloys.The methodology of cathodic hydrogen charging of zirconium specimen has been described. The intention is to create a hydride rich rim similar to observatio...

  5. Effect of short range order on electronic and magnetic properties of disordered Co based alloys

    OpenAIRE

    Ghosh, Subhradip; Chaudhuri, Chhanda Basu; Sanyal, Biplab; Mookerjee, Abhijit

    2000-01-01

    We here study electronic structure and magnetic properties of disordered CoPd and CoPt alloys using Augmented Space Recursion technique coupled with the tight-binding linearized muffin tin orbital (TB-LMTO) method. Effect of short range ordering present in disordered phase of alloys on electronic and magnetic properties has been discussed. We present results for magnetic moments, Curie temperatures and electronic band energies with varying degrees of short range order for different concentrat...

  6. Effect of processing parameters on the corrosion behaviour of friction stir processed AA 2219 aluminum alloy

    Science.gov (United States)

    Surekha, K.; Murty, B. S.; Prasad Rao, K.

    2009-04-01

    The effect of processing parameters (rotation speed and traverse speed) on the corrosion behaviour of friction stir processed high strength precipitation hardenable AA 2219-T87 alloy was investigated. The results indicate that the rotation speed has a major influence in determining the rate of corrosion, which is attributed to the breaking down and dissolution of the intermetallic particles. Corrosion resistance of friction stir processed alloy was studied by potentiodynamic polarization, electrochemical impedance spectroscopy, salt spray and immersion tests.

  7. Effect of annealing on magnetic properties of Fe-47.5% Ni alloy

    International Nuclear Information System (INIS)

    The effect of annealing temperature on grain size, maximum permeability and coercive force of 47.5% nickel-iron alloys with different sulfur contents was investigated. Alloys with lower sulfur content require lower annealing temperature to attain specific values of magnetic properties. The experimental results show that the coefficient 3 γ/M ., where γ is the domain wall energy and M, is the saturation magnetization, can be used to correlate both coercive force and maximum permeability to grain size. (author)

  8. Thermal mechanic processing effects on the microstructural evolution of Al-Li alloys

    International Nuclear Information System (INIS)

    The investigation of the effects of different thermomechanical treatments on the microstructure of alloys 8090 and 8091 (Al-Li-Cu-MgZr) is the aim of the present work. In this context, the intervention of static recrystallization during solution treatment after hot working is the determining factor on the final microstructure of products in form of plates. The results could reveal that the rolling temperature is a very important variable if microstructural control is to be achieved in these alloys. (author)

  9. Effect of cobalt powder morphology on the properties of WC-Co hard alloys

    OpenAIRE

    Kurlov, A. S.; Rempel, A. A.

    2013-01-01

    The effect of cobalt powder morphology on the microstructure of WC-Co hard alloys produced by sintering cobalt + tungsten carbide powder mixtures has been studied using X-ray diffraction, laser diffraction, scanning electron microscopy, density measurements, and Vickers microhardness tests. The results indicate that, under identical sintering conditions, the densest and most homogeneous microstructure is formed in hard alloys sintered using cobalt powders consisting of rounded particles. The ...

  10. Effect of Squeeze Cast Process Parameters on Fluidity of Hypereutectic Al-Si Alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of processing variables on the fluidity of hypereutectic Al-Si alloy melt during squeeze casting were investigated. The maximum fluidity of Al-16.0%Si alloy during squeeze casting was obtained under the applied pressure of 30 MPa. The fluidity increased with superheat. The fluidity increased with silicon content in the range from 12.0% to 20.0%. That was decreased respectively by eutectic modification and primary silicon refinement.

  11. Some effects of alloy composition on stress corrosion cracking in Al–Zn–Mg–Cu alloys

    International Nuclear Information System (INIS)

    Highlights: • A copper content of ∼0.6 wt% may be overaged when the quench-rate is not too rapid. • Crack arrest markings spacings could be related to the hydrogen diffusivity. • XPS showed that the oxide of AA7075 was slightly more hydrated than on AA7079. - Abstract: Stress corrosion cracking (SCC) of two lower-copper Al–Zn–Mg–Cu alloys, AA7079 and AA7022 (0.6–0.9 wt% Cu), and a higher-copper AA7075 (1.5 wt% Cu) alloy are reported. In aqueous chloride, copper content of grain boundary precipitates is believed to be controlling, whereas in moist air it appears that the hydrogen diffusivity could be evident from the rate of crack growth between crack arrest markings. In moist air, the rate of hydrogen entry may control crack growth rates. X-ray photoelectron spectroscopy showed that the oxide formed in ambient conditions (e.g. ∼50% RH) was more hydrated on the AA7075-T651 than AA7079-T651

  12. Effect of Surface Pretreatment on Adhesive Properties of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Jinsheng ZHANG; Xuhui ZHAO; Yu ZUO; Jinping XIONG; Xiaofeng ZHANG

    2008-01-01

    The lap-shear strength and durability of adhesive bonded AI alloy joints with different pretreatments were studied by the lap-shear test and wedge test. The results indicate that the maximum lap-shear strength and durability of the bonding joints pretreated by different processes are influenced by the grade of abrasive papers and can be obviously improved by phosphoric acid anodizing. Alkali etching can obviously improve the durability of bonding joints although it slightly influences the maximum lap-shear strength. The process which is composed of grit-finishing, acetone degreasing, alkali etching and phosphoric acid anodizing, provides a better adhesive bonding property of AI alloy.

  13. Alloying effect on the electronic structures of hydrogen storage compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, H.; Moringa, M.; Takahashi, Y. [Nagoya Univ. (Japan). Dept. of Mater. Sci. and Eng.

    1997-05-20

    The electronic structures of hydrogenated LaNi{sub 5} containing various 3d transition elements were investigated by the DV-X{alpha} molecular orbital method. The hydrogen atom was found to form a strong chemical bond with the Ni rather than the La atoms. The alloying modified the chemical bond strengths between atoms in a small metal octahedron containing a hydrogen atom at the center, resulting in the change in the hydrogen absorption and desorption characteristics of LaNi{sub 5} with alloying. (orig.) 7 refs.

  14. Effect of zirconium addition on the recrystallization behaviour of a commercial Al–Cu–Mg alloy

    Indian Academy of Sciences (India)

    K T Kashyap

    2001-12-01

    It is well known that the second phase particles have an effect on recrystallization and grain growth behaviour of an alloy. Particularly the bimodal distribution of second phase particles has an effect which is opposite in sense where coarse second phase particles (> 1 m) stimulate nucleation while fine particles exhibit Zener drag. In the literature, the effect of zirconium addition to aluminium alloys has been well documented in order to produce superplasticity by giving ultra fine grain size to the alloy. Addition of zirconium produces Al3Zr particles which pin the grain boundaries during recrystallization and grain growth. In the present work, zirconium was added to a commercial Al–Cu–Mg alloy and by heat treatment Al3Zr particles were precipitated and after forging, the grain size was an order of magnitude lower than the alloy without zirconium. Transmission electron microscopy was employed to characterize the second phase particles, i.e. Al3Zr particles and found to be rod shaped and identified to be cubic ordered 12 phase with a lattice parameter of 0.408 nm. Further, it was observed that fine (100 nm) Al3Zr particles promote only continuous recrystallization which is polygonization of subgrains and subgrain growth. It was found that the fine dispersion of Al3Zr particles inhibits both recrystallization and grain growth in the commercial Al–Cu–Mg alloy.

  15. Effects of internal and external hydrogen on mechanical properties of beta III titanium alloy sheet

    International Nuclear Information System (INIS)

    Results of investigation of Ti-base--Mo--Zr--Sn (Beta III alloy), Ti-base--Mo--Cr--Al (VT-15 alloy), and Ti-base-V-Cr-Al (Beta I alloy) show that in the β condition, Beta III is less susceptible to hydrogen elongation (HE) than the other β alloys Beta I and VT 15, similarly H-charged during solution treatment (ST). Not only He, but also H softening can occur in the alloy H charged during various heat treatments. The α-stabilizing effects of cold working (CW) and of previously absorbed O compete with the high temperature β-stabilization by H, decrease H softening and favor HE. The influence of stress state on H effects and the need for sensitive enough tests are again evidenced. A new criterion is proposed to select materials to be stressed in an H environment. H dragging by dislocations plays an important role in HE. This points out the influence of strain rate testing. Furthermore it becomes critically important when environmental degradation depends on film rupture and repassivation. The disk pressure tests are more sensitive than tensile tests and present the adequate sensitivity and versatility to meet the requirements of the complex H effects situation in Ti alloys. With a single set up, using only one specimen geometry, tests can be run at rates ranging from low to high, then the inhomogeneous biaxial stresses involved make them to approach the kind of data usually supplied by impact tests

  16. Grain refinement of AZ31 magnesium alloy by electromagnetic stirring under effect of grain-refiner

    Indian Academy of Sciences (India)

    S Y Gao; Q C Le; Z Q Zhang; J Z Cui

    2012-08-01

    The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semicontinuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al4C3 grain refiner. Electromagnetic stirring can `activate’ the Al4C3 particles, resulting in more heterogeneous nucleation sites for the primary -Mg grains. But, longer holding time can `deactivate’ the Al4C3 particles and poison the grain refining effect.

  17. Effects of minor alloying additions on the strength and swelling behavior of an austenitic stainless steel

    International Nuclear Information System (INIS)

    A set of 32 alloys consisting of various additions of the elements Mo, W, Al, Ti, Nb, C and Si to an Fe-7.5 Cr-20 Ni alloy were made in order to investigate the effects of these solute additions on alloy swelling and strength. Both single and multiple additions were examined. The influence of various solute elements on the swelling behavior in the range 500 to 7300C was investigated using 4 MeV Ni ion bombardment to a dose 170 dpa. It was found that on an atomic percent basis, the elements may be arranged in order of decreasing effectiveness in reducing peak temperature swelling as follows: Ti, C, Nb, Si, and Mo. Small amounts of aluminum enhance swelling. Additions of Si, Ti, or Nb truncate the high temperature swelling regime of the ternary alloy. Mo, W, and C do not have a strong effect on the temperature dependence of swelling. The results may be interpreted in terms of the effect of point defect trapping on void growth rates, and it is suggested that the changes in peak temperature are the result of small changes in the free vacancy formation energy. A method for treating certain multiple additions is proposed. The effect of these alloying additions on short time high temperature strength properties was estimated using hot hardness measurements over the temperature range 22 to 8500C. On an atom percent basis Nb and Ti were most effective in conferring solid solution strengthening and Si the least effective. In the regime 22 to approximately 6500C, the hardness data was found to fit an equation of the form: H = H0 + b/T; where H is the hardness, T is the temperature, and H0 and b are constants for a given alloy. An empirical method was devised to estimate the hot hardness of alloys containing more than one solute addition

  18. Shape memory effect in Fe-Mn-Ni-Si-C alloys with low Mn contents

    International Nuclear Information System (INIS)

    Highlights: → A class of new Fe-Mn-Ni-Si-C shape memory alloys with low Mn contents has been designed. → A Mn content for the onset of the α' martensite is less than 13 mass%, and the ε martensite still exists in the alloy with a 9 mass% Mn. → The shape recovery strain decreases considerably when the Mn content is reduced from 13 to 11 mass%. → The sudden decrease in the shape recovery strain is mainly caused by the formation of α' martensite. - Abstract: An attempt was made to develop a new Fe-Mn-Si-based shape memory alloy from a Fe-17Mn-6Si-0.3C (mass%) shape memory alloy, which was previously reported to show a superior shape memory effect without any costly training treatment, by lowering its Mn content. The shape memory effect and the phase transformation behavior were investigated for the as-solution treated Fe-(17-2x)Mn-6Si-0.3C-xNi (x = 0, 1, 2, 3, 4) polycrystalline alloys. The shape recovery strain exceeded 2% in the alloys with x = 0-2, which is sufficient for an industrially applicable shape memory effect; however, it suddenly decreased in the alloys between x = 2 and 3 although the significant shape recovery strain still exceeded 1%. In the alloys with x = 3 and 4, X-ray diffraction analysis and transmission electron microscope observation revealed the existence of α' martensite, which forms at the intersection of the ε martensite plates and suppresses the crystallographic reversibility of the γ austenite to ε martensitic transformation.

  19. Effect of Temperature on the Cyclic Stress Components of Gamma – TiAl Based Alloy with Niobium Alloying

    Czech Academy of Sciences Publication Activity Database

    Petrenec, Martin; Buček, Petr; Kruml, Tomáš; Polák, Jaroslav

    Zurich : Trans Tech Publications, 2011 - (Šandera, P.), s. 447-450 ISBN 978-3-03785-006-0. ISSN 1013-9826. - (Key Engineering Materials. 465). [MSMF /6./ Materials Structure and Micromechanics of Fracture. Brno (CZ), 28.06.2010-30.06.2010] R&D Projects: GA ČR GA106/08/1631 Institutional research plan: CEZ:AV0Z20410507 Keywords : Low cycle fatigue * lamellar TiAl alloys * Hysteresis loop * Effective and internal stress es Subject RIV: JL - Materials Fatigue, Friction Mechanics

  20. Effects of high frequency current in welding aluminum alloy 6061

    Science.gov (United States)

    Fish, R. E.

    1968-01-01

    Uncontrolled high frequency current causes cracking in the heat-affected zone of aluminum alloy 6061 weldments during tungsten inert gas ac welding. Cracking developed when an improperly adjusted superimposed high frequency current was agitating the semimolten metal in the areas of grain boundary.

  1. Effect of the addition of Ge to the FINEMET alloy

    International Nuclear Information System (INIS)

    The results obtained by partially substituting Ge for B and Si in the FINEMET alloy for the purpose of improving its magnetic properties at high temperatures are presented in this work. Nanocrystalline ribbons were obtained from controlled crystallization of amorphous material made employing the melt spinning technique. The studied compositions were: Fe73.5Si13.5Ge2Nb3B7Cu1 and Fe73.5Si13.5Ge4Nb3B5Cu1. The structural evolution of these alloys was studied using X-ray diffraction (XRD) and differential scanning calorimetry (DSC) and these results were correlated with their magnetic properties at different annealing temperatures. The coercivity obtained for both alloys was below 1 A/m at anneling temperatures between 773 and 823 K. The amorphous saturation magnetization was satisfactory, almost 137 emu/g, comparable with that obtained for FINEMET alloys. The nanocrystallization and the Curie temperatures are dependent on Ge concentration

  2. Alloying effects on hydrogen permeability of V without catalytic Pd overlayer

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Y.; Yukawa, H.; Suzuki, A. [Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Nambu, T. [Department of Materials Science and Engineering, Suzuka National College of Technology, Shiroko-cho, Suzuka, Mie 510-0294 (Japan); Matsumoto, Y. [Department of Mechanical Engineering, Oita National College of Technology, Maki, Oita 870-0152 (Japan); Murata, Y. [Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan)

    2015-10-05

    Highlights: • Air–treated V–based alloy membranes without catalytic Pd overlayer are found to possess excellent hydrogen permeability. • They also exhibit good durability at high temperature. • Alloying effects are discussed in view of the new description of hydrogen permeation based on hydrogen chemical potential. - Abstract: Hydrogen permeability of air–treated V–based alloy membranes without Pd coating have been investigated. The diffusion–limiting hydrogen permeation reaction takes place even without catalytic Pd overlayer on the surface. It is shown that pure V and its alloy membranes without Pd overlayer possess excellent hydrogen permeability and good durability at high temperature. The new description of hydrogen permeation based on hydrogen chemical potential has been applied and the hydrogen flux is analyzed in terms of the mobility of hydrogen atom and the PCT factor, f{sub PCT}.

  3. Effect of Sr on forming properties of Al-Mg-Si based alloy sheets

    Institute of Scientific and Technical Information of China (English)

    LU Guang-xi; CHEN Hai-jun; GUAN Shao-kang

    2006-01-01

    The effects of Sr element on the forming properties of the Al-Mg-Si based alloy sheets were studied by tensile test,metallograph, DSC, XRD, SEM and TEM. The results show that the tensile strength of aluminum alloy sheet added 0.033%(mass fraction)Sr increases comparing with that of free Sr. Simultaneously, the forming properties of sheets evidently increase, the elongation hardenability (n) and plastic strain ratio (r) and Erichsen number increase 27.8%, 11.1%, 10.8% and 12%, respectively,and the forming limit diagram increases evidently, too. The analysis shows that Sr is surface active element, which can refine grains of alloys, promote precipitation, reduce activation energy ofβ" phase, and lead the formation of α-(Al8Fe2Si) phase instead of β-(Al5FeSi) phase. As a result, the forming properties of the alloy sheet increase.

  4. Effect of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Temperature is one of the key parameters for BT20 titanium alloy cylindrical workpiece manufactured by vacuum hot bulge forming. A two-dimensional nonlinear thermo-mechanical coupled FE model was established. Numerical simulation of vacuum hot bulge forming process of titanium alloy cylindrical workpiece was carried out using FE analysis software MSC Marc. The effects of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece were analyzed by numerical simulation.The simulated results show that the Y-direction displacement and the equivalent plastic strain of the workpiece increase with increasing bulge temperature. The residual stress decreases with increasing bulge temperature. The optimal temperature range of BT20 titanium alloy during vacuum hot bulge forming is 750-850 ℃. The corresponding experiments were carried out. The simulated results agreed well with the experimental results.

  5. Effect of cold working on the stress corrosion cracking resistance of nickel-chromium-iron alloys

    International Nuclear Information System (INIS)

    In order to grasp the stress corrosion cracking resistance of cold worked nickel base alloys in PWR primary water, the effect of cold working on the stress corrosion cracking resistance of alloys 600, X-750 and 690, in high temperature water, have been studied. Stress corrosion cracking tests were conducted at 3600C (633K) in a simulated PWR primary water for about 12,000 hours (43.2Ms). From the test results, it is concluded that the stress corrosion cracking resistance in the cold worked Alloy 600 at the same applied stress level increases with an increase in cold working ratio, and the cold worked alloys of thermally treated 690 and X-750 have excellent stress corrosion cracking resistance. (Author)

  6. Effect of Temperature and Electrolyte Composition on the Susceptibility of Alloy 22 to Localized Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    S.D. Day; K.J. Evans; G.O. Ilevbare

    2002-10-07

    The study of the electrochemical behavior of Alloy 22 has been carried out in various concentrated environments using different sample configurations. Comparisons were made between the electrochemical behaviors of Alloy 22 in concentrated chloride solutions, and in concentrated chloride solutions with nitrate ions (NO{sub 3}{sup -}). In other experiments, the effect of fluoride ions (F{sup -}) was investigated. These comparative studies were performed at various temperatures. The rate of corrosion was found to increase with increase in temperature. The presence of nitrate ions reduced corrosion attack on Alloy 22. F{sup -} was found to be more benign to Alloy 22 compared with chloride ions (Cl{sup -}). However a combination of F{sup -} and Cl{sup -} was found to initiate deeper crevices compared with the only Cl{sup -} in the electrolyte.

  7. Effect of Sn on as-cast ageing behavior of Al-Si-Mg alloy

    Institute of Scientific and Technical Information of China (English)

    王桂青; 边秀房; 段佑峰; 张均艳

    2003-01-01

    The effect of minor additions of Sn on the as-cast ageing behavior of Al-11Si-0.35Mg alloy was investigated. It is shown that precipitation has been retarded in Sn containing alloy and more time is needed to reach its peak hardness,which is bigger than that of the base alloy. Analysis of the kinetic data shows that Sn addition does not change the growth dependent parameter n, but increases the nucleation density dependent parameter k. TEM results show that there are little precipitates in Sn containing alloy at the initial stage of as-cast ageing. However, the Sn addition increases the net density of precipitates during as-cast ageing, because there are many dislocation loops formed as ageing progresses and Sn segregated at the edges of dislocation loops, which acts as the nuclei of precipitates.

  8. Effects of Ca addition on microstructure and properties of AZ63 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    钱宝光; 耿浩然; 陶珍东; 赵鹏; 田宪法

    2004-01-01

    Effects of Ca addition on the microstructure and viscosity as well as electrochemical properties of casting AZ63 magnesium alloy were studied. Testing results show that the viscosity value increases with the increase of calcium content, especially at the higher temperature, and there exists such a relation between the ignition temperature and viscosity of magnesium alloy: when the melt viscosity increases, the ignition temperature increases too. The microstructure of AZ63 magnesium alloy is first refined and then coarsened with the increase of Ca addition. By the addition of 0.15% Ca, AZ63 alloy has more negative open-circuit potential(1. 624 5V), bigger anode efficiency (55.65%) and lower corrosion rate(0.214g/(m2·h).AZ63 allo6y containing some Ca content is a high driving-potential and high-efficiency sacrificial anodes material.

  9. Effect of disorder on electronic and magnetic properties of Co2VGa Heusler alloy

    International Nuclear Information System (INIS)

    This paper presents the effect of disorder on electronic, magnetic and half-metallic properties of Co2VGa Heusler alloy using density functional theory. Binary mixing is the most common form of atomic disorder in these compounds. We have considered three types of disorders: DO3, A2 and B2 disorder which corresponds to X-Y, X-Z and Y-Z mixing respectively. After structural optimization, we found that A2 disorder has high formation energy and is most unlikely to occur. The half-metallic nature of the alloy is destroyed in presence of DO3 and A2 disorder. The destruction of half-metallicity is due to reconstruction of energy states. Also the loss of half-metallicity is accompanied by reversal of spin-polarization at the Fermi level. B2 disorder retains the half-metallic nature of the alloy but spin-polarization value is reduced as compared to the ordered alloy

  10. Interface conjunction factors of the second phase particles in alloys and their effects

    Institute of Scientific and Technical Information of China (English)

    LI; Zhilin(李志林); LIU; Zhilin(刘志林); LIU; Weidong(刘伟东); ZHANG; Lingwen(张凌雯)

    2002-01-01

    The second phase in multi-phase alloys has connection with many important phenomena such as aging strengthening,dispersion strengthening,secondary hardening,crystal refinement.In this paper,the interface conjunction factors of the interface between MC(M=V,Nb,Ti) and austenite and martensite are calculate out.The relationship between these factors and the characteristics are analyzed.The reason for the second phases being fine and dispersing and their strengthening and toughening effect on the alloy is explained using the relationship.Based on the relationship,the valence electron structure of the interface between the second phase particles and the matrix can be optimized by changing the alloying elements,which make it possible to design the composition of alloys from the valence electron structure of the second phase particles.``

  11. Effect of age condition on fatigue properties of 2E12 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    YAN Liang; DU Feng-shan; DAI Sheng-long; YANG Shou-jie

    2010-01-01

    The fatigue behaviors of 2E12 aluminum alloy in T3 and T6 conditions at room temperature in air were investigated.The microstructures and fatigue fracture surfaces of the alloy were examined by transmission electron microscopy(TEM)and scanning electron microscopy(SEM).The results show that the alloy exhibits higher fatigue crack propagation(FCP)resistance in T3condition than in T6 condition,the fatigue life is increased by 54% and the fatigue crack growth rate(FCGR)decreases significantly.The fatigue fractures of the alloy in T3 and T6 conditions are transgranular.But in T3 condition,secondary cracks occur and fatigue striations are not clear.In T6 condition,ductile fatigue striations are observed.The effect of aging conditions on fatigue behaviors is explained in terms of the slip planarity of dislocations and the cyclic slip reversibility.

  12. Effects of Solid-Liquid Mixing on Microstructure of Semi-Solid A356 Aluminum Alloy

    Science.gov (United States)

    Guo, H. M.; Wang, L. J.; Wang, Q.; Yang, X. J.

    2014-08-01

    The desired starting material for semi-solid processing is the semi-solid slurry in which the solid phase is present as fine and globular particles. A modified solid-liquid mixing (SLM) is reported wherein semi-solid slurry can be produced by mixing a solid alloy block into a liquid alloy, and mechanical vibration is utilized to enhance the mixing. Effects such as liquid alloy temperature, mass ratio, and mixing intensity on the microstructure and the cooling curves during SLM were evaluated. 2D and 3D microstructure analysis of treated A356 aluminum alloy shows that microstructure can be refined significantly with a considerable morphology change in primary Al phase. It is critical that the temperature of mixture after mixing is lower than its liquidus temperature to obtain a valid SLM process. Specially, mixing intensity is identified as a primary factor for a favorable microstructure of semi-solid slurry.

  13. Effect of homogenization process on the hardness of Zn–Al–Cu alloys

    Institute of Scientific and Technical Information of China (English)

    Jose D. Villegas-Cardenas; Maribel L. Saucedo-Mu?oz; Victor M. Lopez-Hirata; Antonio De Ita-De la Torre; Erika O. Avila-Davila; Jorge Luis Gonzalez-Velazquez

    2015-01-01

    The effect of a homogenizing treatment on the hardness of as-cast Zn–Al–Cu alloys was investigated. Eight alloy compositions were prepared and homogenized at 350 ℃ for 180 h, and their Rockwell "B" hardness was subsequently measured. All the specimens were analyzed by X-ray diffraction and metallographically prepared for observation by optical microscopy and scanning electron microscopy. The results of the present work indicated that the hardness of both alloys (as-cast and homogenized) increased with increasing Al and Cu contents; this increased hardness is likely related to the presence of theθandτ′ phases. A regression equation was obtained to determine the hardness of the homogenized alloys as a function of their chemical composition and processing parameters, such as homogenization time and tem-perature, used in their preparation.

  14. Effect of Ca and Y additions on oxidation behavior of magnesium alloys at high temperatures

    Institute of Scientific and Technical Information of China (English)

    FAN Jianfeng; YANG Changlin; XU Bingshe

    2012-01-01

    Oxidation and ignition of magnesium alloys at elevated temperature were successfully retarded by additions of Y and Ca.which could be melted at 1173 K in air without any protection.Thermogravimetric measurements in dry air revealed that the oxidation dynamics curves of Mg-2.5Ca alloy and Mg-3.5Y-0.79Ca alloy at high temperatures followed the parabolic-line law or the ubic-line law.X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis indicated that the oxide film on the surface of Mg-3.5Y-0.79Ca and Mg-2.5Ca alloys exhibited a duplex structure.which agreed with the results of thermodynamic analysis.By comparison,the ignition-proof effect of the combination addition of Y and Ca was better than that of the single addition of Ca.

  15. The effective reinforcement of magnesium alloy ZK60A using Al2O3 nanoparticles

    International Nuclear Information System (INIS)

    ZK60A nanocomposite containing Al2O3 nanoparticle reinforcement (50 nm average size) was fabricated using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size to the monolithic alloy, reasonable Al2O3 nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 15% higher hardness than the monolithic alloy. Compared to the monolithic alloy (in tension), the nanocomposite exhibited lower yield strength (0.2%TYS) (−4%) and higher ultimate strength (UTS), failure strain, and work of fracture (WOF) (+13%, +170%, and +200%, respectively). Compared to the monolithic alloy (in compression), the nanocomposite exhibited lower yield strength (0.2%CYS) (−5%) and higher ultimate strength (UCS), failure strain, and WOF (+6%, +41%, and +43%, respectively). The effects of Al2O3 nanoparticle addition on the enhancement of tensile and compressive properties of ZK60A are investigated in this article.

  16. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    International Nuclear Information System (INIS)

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H2SO4, even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni2(Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like μ, σ and P, may

  17. Effect of rare earth elements on high cycle fatigue behavior of AZ91 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtarishirazabad, M., E-mail: mehdi-mokhtari@hotmail.com [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Boutorabi, S.M.A. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Azadi, M.; Nikravan, M. [Irankhodro Powertrain Company (IPCO), Tehran (Iran, Islamic Republic of)

    2013-12-10

    This article investigates effects of adding rare earth elements (RE) into a magnesium–aluminum–zinc alloy (the AZ91 alloy) on its high cycle fatigue (HCF) behavior. For this purpose, AZ91 and AZ91+1% RE (AZE911) alloys were gravity casted in a metallic die. RE elements were added to the AZ91 alloy in the form of mischmetals. Microscopic evaluations with the scanning electron microscopy (SEM) and mechanical tests include tensile, hardness and HCF behaviors, were performed on prepared samples. Rotary bending fatigue tests were carried out at a stress ratio (R) of −1 and a frequency of 125 Hz, at the room temperature, in the air. The microscopic investigation demonstrates that the addition of 1% RE elements leads to the formation of Al{sub 11}RE{sub 3} intermetallic particles which is associated to the reduction of β-(Mg{sub 17}Al{sub 12}) phases. Results of mechanical experiments suggest a negligible effect of adding 1% RE elements on mechanical properties of the AZ91 alloy. Curves of stress-life (S–N) shows an increase in the fatigue strength at 10{sup 5} cycles, from 100±10 MPa to 135±10 MPa, when RE elements were added to the AZ91 alloy.

  18. The Sintering Temperature Effect on the Shrinkage Behavior of Cobalt Chromium Alloy

    Directory of Open Access Journals (Sweden)

    M. G. Kamardan

    2010-01-01

    Full Text Available Problem Statement: Co-Cr based alloys which is well known for its high Youngs modulus, fatigue strength, wear resistance and corrosion resistance is an important metallic bio-material. However, till date there are only two type of Co-Cr alloy which are the castable and wrought cobalt alloy. Powder Metallurgy route for cobalt is expected to give better result of Co-Cr alloy. The purpose of this research was mainly to study the sintering temperature effect to the shrinkage behavior of Cobalt Chromium (Co-Cr alloy of the powder metallurgy route. Approach: Co-Cr was produced following P/M route under sintering temperature of 1000, 1100, 1200, 1300 and 1400°C. The sintering time was fixed at 60 min. Several tests has been conducted to determine this effect such as the rate of shrinkage measurement, the bulk density and porosity percentage measurement, compression and hardness tests and micro structural study. Result: From the study, it was found that the sintering temperature has caused the shrinkage of Co-Cr. The increasing of the sintering temperature has caused to the increasing of shrinkage of Co-Cr. This has resulted to the reduction of the pore volume and hence increased it density. In conjunction to that, the strength and the hardness of Co-Cr was increased. Conclusion: Therefore, it is hope that it will bring new view of powder metallurgy Co-Cr alloy as bio-material.

  19. Effect of aluminum on microstructure and property of Cu–Ni–Si alloys

    International Nuclear Information System (INIS)

    The effect of aluminum on the microstructure and properties of Cu–Ni–Si alloys has been investigated using hardness test, electrical conductivity measurement, optical microscopy, X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. Compared with Cu–Ni–Si alloy, Cu–Ni–Si–Al alloy had finer grains. After homogenization treatment at 940 °C for 4 h, hot rolling by 80% at 850 °C, solution treatment at 970 °C for 4 h, cold rolling by 50% and ageing treatment at 450 °C for 60 min, properties better than Cu–Ni–Si alloy have been obtained in Cu–Ni–Si–Al alloy: hardness was 343 HV, electrical conductivity was 28.1% IACS, tensile strength was 1080 MPa, yield strength was 985 MPa, elongation percentage was 3.1% and stress relaxation rate was 9.83% (as tested at 150 °C and loading for 100 h). β-Ni3Si and δ-Ni2Si formed during the ageing process and the crystal orientation relationship between matrix and precipitates was : (02-bar 2-bar )Cu (01-bar 1-bar )β (010)δ, [100]Cu [100]β [001]δ; (111-bar )Cu (111-bar )β (02-bar 1)δ, [112]Cu [112]β [012]δ. Addition of Al promoted the precipitation, and effectively enhanced the anti-stress relaxation property. Quasi-cleavage fracture with shallow dimples appeared in designed Cu–Ni–Si–(Al) alloy

  20. Twice reverse shape memory effect in CuZnAl shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    李周; 汪明朴; 徐根应; 郭明星

    2004-01-01

    The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction, %) alloy upon successive heating (the rate of heating is 5 ℃/min) have been studied by means of p-T curve , shape memory effect measurement, optical metallographical observation and X-ray diffraction. The first abnormal reverse shape memory effect occurs when the tested alloy is heated to the temperature below 320 ℃; when it is heated to the temperature between 320 ℃ and 450 ℃, the forward shape memory effect occurs; in the two stages, the shape of the sample remains the same as that in the furnace when it is taken out from the furnace and air-cooled; when the tested alloy is heated to the temperature above 450 ℃, the shape of the sample remains unchanged during heating, but the second reverse shape memory effect occurs after it is air-quenched.

  1. Theoretical description of magnetocaloric effect in the shape memory alloy exhibiting metamagnetic behavior

    Energy Technology Data Exchange (ETDEWEB)

    L' vov, Victor A. [Institute of Magnetism, Kyiv 03142 (Ukraine); Taras Shevchenko National University, Kyiv 01601 (Ukraine); Kosogor, Anna, E-mail: annakosogor@gmail.com [Institute of Magnetism, Kyiv 03142 (Ukraine); National University of Science and Technology ‘MISiS’, Moscow 119049 (Russian Federation); Barandiaran, Jose M. [BCMaterials and University of Basque Country, UPV/EHU, Bilbao 48080 (Spain); Chernenko, Volodymyr A. [BCMaterials and University of Basque Country, UPV/EHU, Bilbao 48080 (Spain); Ikerbasque, Basque Foundation for Science, Bilbao 48013 (Spain)

    2016-01-07

    A simple thermodynamic theory is proposed for the quantitative description of giant magnetocaloric effect observed in metamagnetic shape memory alloys. Both the conventional magnetocaloric effect at the Curie temperature and the inverse magnetocaloric effect at the transition from the ferromagnetic austenite to a weakly magnetic martensite are considered. These effects are evaluated from the Landau-type free energy expression involving exchange interactions in a system of a two magnetic sublattices. The findings of the thermodynamic theory agree with first-principles calculations and experimental results from Ni-Mn-In-Co and Ni-Mn-Sn alloys, respectively.

  2. Theoretical description of magnetocaloric effect in the shape memory alloy exhibiting metamagnetic behavior

    International Nuclear Information System (INIS)

    A simple thermodynamic theory is proposed for the quantitative description of giant magnetocaloric effect observed in metamagnetic shape memory alloys. Both the conventional magnetocaloric effect at the Curie temperature and the inverse magnetocaloric effect at the transition from the ferromagnetic austenite to a weakly magnetic martensite are considered. These effects are evaluated from the Landau-type free energy expression involving exchange interactions in a system of a two magnetic sublattices. The findings of the thermodynamic theory agree with first-principles calculations and experimental results from Ni-Mn-In-Co and Ni-Mn-Sn alloys, respectively

  3. Magnetic properties and magnetocaloric effect in Ni–Mn–Sn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dan, N.H., E-mail: dannh@ims.vast.ac.vn [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam); Duc, N.H.; Yen, N.H.; Thanh, P.T. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam); Bau, L.V.; An, N.M. [Hong Duc University, 565 Quang Trung, Dong Ve, Thanh Hoa (Viet Nam); Anh, D.T.K.; Bang, N.A.; Mai, N.T. [Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Hanoi (Viet Nam); Anh, P.K. [Vietnam Academy of Military Science, 322 Le Trong Tan, Thanh Xuan, Hanoi (Viet Nam); Thanh, T.D. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam); Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Phan, T.L. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Yu, S.C., E-mail: scyu@chungbuk.ac.kr [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2015-01-15

    Magnetic and magnetocaloric properties in Ni{sub 50}Mn{sub 50−x}Sn{sub x} alloys with wide range of the Sn-concentration (x=0–40) were investigated. The alloys were prepared by arc-melting and subsequently annealing at 850 °C for 4 h. The X-ray diffraction analyses manifest the formation of the crystalline phases (Ni{sub 2}MnSn, NiMn, Ni{sub 3}Sn{sub 2}, Mn{sub 3}Sn, and MnSn{sub 2}) in the alloys with various compositions and fabrication conditions. With increasing x, the saturation magnetization first increases from near zero (at x=10) to above 40 emu/g (at x=20) and then decreases to below 10 emu/g (at x=40) for both the as-melted and annealed cases. The martensitic–austenitic transition was observed in the alloys with a narrow range of x (13–15). The magnetic transitions in the alloy can be controlled by changing Sn-concentration. The alloy reveals both the positive and negative entropy changes with quite large magnitude (∆S{sub m}>1 J/kg K with ∆H=12 kOe) with appropriate compositions and annealing conditions. - Highlights: • Crystalline phases and magnetic properties in Ni{sub 50}Mn{sub 50−x}Sn{sub x} alloys (x=0–40). • Simultaneous transitions of structural and magnetic phases. • Coexistence of positive and negative giant magnetocaloric effect in Heusler alloys. • Tuning giant magnetocaloric effect in room temperature region.

  4. Effects of can parameters on canned-forging process of TiAl base alloy(Ⅰ)--Microstructural analyses

    Institute of Scientific and Technical Information of China (English)

    刘咏; 韦伟峰; 黄伯云; 何双珍; 周科朝; 贺跃辉

    2002-01-01

    By using thermal simulation technique, the conventional canned-forging process of TiAl based alloy was studied. The effect of can parameters on the microstruct ures of TiAl alloy was analyzed in this process. The results show that, the defo rmation microstructure of TiAl based alloy without canning is inhomogeneous. In lateral area, crack and shearing lines can be found; while in central area, fine -grained shearing zone can be found. The effect of can is to reduce the seconda ry tensile stress. However, only when the deformation of the steel can is coinci dental with that of TiAl alloy ingot, can this effect be effective. Moreover, a thick can would enhance the microstructural homogeneity in TiAl based alloy. With the H/D ratio of the ingot increasing, the deformation of TiAl alloy would be more unsteady, therefore, a thicker can should be needed.

  5. Effect of Equal Channel Angular Extrusion on the Microstructures and Properties of Two Extruded Al-Mg-Si Alloys

    Institute of Scientific and Technical Information of China (English)

    M. Cai; G. W. Lorimer

    2005-01-01

    The effect of equal channel angular extrusion (ECAE) on the microstructure of two Al-Mg-Si extrusion alloys was investigated by high resolution electron backscattered diffraction (EBSD) using a field emission gun scanning electron microscope (FEG-SEM) and a transmission electron microscope (TEM). Two contrasting alloys: a dilute alloy, based on alloy 6061 and a concentrated alloy, based on alloy 6069 were employed for this research. It has been found that prior ECAE to extrusion promotes high angle grain boundaries (HAGBs) in the extrusions, and the increase in HAGBs ratio is due to the large shear deformation involved in the processof ECAE. Tensile testing results show that a further ageing treatment strengthens the alloys after extrusion and the ECAE processedextrusions are more ductile than conventional extrusions.

  6. Effect of Scandium Doping on The Corrosion Resistance and Mechanical Behavior of Al-3Mg Alloy in Neutral Chloride Solutions

    OpenAIRE

    Mohammad Abbas; Abdul Aleem B. Aleem; Zaki Ahmad

    2011-01-01

    Scandium addition significantly alters the corrosion resistance and mechanical strength of Al-3 Mg alloys. The addition of 0.3% - 0.4% scandium with 0.14% zirconium has a beneficial effect on the corrosion resistance of the alloy under smoothly stirred condition. Addition of 0.3% Sc significantly suppresses corrosion under dynamic flow conditions. It also creates an optimal strengthening effect on the alloys. The corrosion resistance is attributed to the strong passive layer of Sc2...

  7. Effect of alloying elements Zr,Cr,V on corrosion behavior of Ti-Ni-Nb shape memory alloy

    International Nuclear Information System (INIS)

    In this paper, by testing anodic polarization curves of Ti-Ni-Nb based shape memory alloys, the stability of passive film was investigated after alloying with elements Zr,Cr,V. In artificial sea water (3.5%NaCl) and physiological solution (5%NaCl+0.1%H2O2), the results show that the alloying elements influence the corrosion behavior of Ti-Ni-Nb alloy. Generally, Zr improves the corrosion resistance of Ti-Ni-Nb alloy, Cr reduces its corrosion resistance and V does not change the property. (orig.)

  8. Investigation of Effects of Neutron Irradiation on Tantalum Alloys for Radioisotope Power System Applications

    International Nuclear Information System (INIS)

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for space nuclear power systems such as Radioisotopic Thermoelectric Generators (RTG) since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. A number of tantalum alloys have been developed over the years to increase high-temperature strength (Ta-10%W) and to reduce creep strain (T-111). These tantalum alloys have demonstrated sufficient high-temperature toughness to survive the increasing high pressures of the RTG's operating environment resulting from the alpha decay of the 238-plutonium dioxide fuel. However, 238-plutonium is also a powerful neutron source. Therefore, the RTG operating environment produces large amounts of 3-helium and neutron displacement damage over the 30 year life of the RTG. The literature to date shows that there has been very little work focused on the mechanical properties of irradiated tantalum and tantalum alloys and none at the fluence levels associated with a RTG operating environment. The minimum, reactor related, work that has been reported shows that these alloys tend to follow trends seen in the behavior of other BCC alloys under irradiation. An understanding of these mechanisms is important for the confident extrapolation of mechanical-property trends to the higher doses and gas levels corresponding to actual service lifetimes. When comparing the radiation effects between samples of Ta-10%W and T-111 (Ta-8%W-2%Hf) subjected to identical neutron fluences and environmental conditions at temperatures <0.3Tm (∼700 deg. C), evidence suggests the possibility that T-111 will exhibit higher levels of internal damage accumulation and degradation of mechanical properties compared to Ta-10%W

  9. Investigation of Effects of Neutron Irradiation on Tantalum Alloys for Radioisotope Power System Applications

    Science.gov (United States)

    Barklay, Chadwick D.; Kramer, Daniel P.; Talnagi, Joseph

    2007-01-01

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for space nuclear power systems such as Radioisotopic Thermoelectric Generators (RTG) since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. A number of tantalum alloys have been developed over the years to increase high-temperature strength (Ta-10%W) and to reduce creep strain (T-111). These tantalum alloys have demonstrated sufficient high-temperature toughness to survive the increasing high pressures of the RTG's operating environment resulting from the alpha decay of the 238-plutonium dioxide fuel. However, 238-plutonium is also a powerful neutron source. Therefore, the RTG operating environment produces large amounts of 3-helium and neutron displacement damage over the 30 year life of the RTG. The literature to date shows that there has been very little work focused on the mechanical properties of irradiated tantalum and tantalum alloys and none at the fluence levels associated with a RTG operating environment. The minimum, reactor related, work that has been reported shows that these alloys tend to follow trends seen in the behavior of other BCC alloys under irradiation. An understanding of these mechanisms is important for the confident extrapolation of mechanical-property trends to the higher doses and gas levels corresponding to actual service lifetimes. When comparing the radiation effects between samples of Ta-10%W and T-111 (Ta-8%W-2%Hf) subjected to identical neutron fluences and environmental conditions at temperatures <0.3Tm (˜700 °C), evidence suggests the possibility that T-111 will exhibit higher levels of internal damage accumulation and degradation of mechanical properties compared to Ta-10%W.

  10. Effect of laser surface melting on microstructure and corrosion characteristics of AM60B magnesium alloy

    International Nuclear Information System (INIS)

    Highlights: • Laser surface melting was used on AM60B Mg alloy. • The microstructure, composition and corrosion behavior of the as-received and LSM treated specimens were compared. • The laser treated alloy exhibited better corrosion resistance than the as-received one in the long term. • A model of two different corrosion mechanisms was established. - Abstract: Surface modification of laser surface melting (LSM) was applied to the AM60B magnesium alloy using a 10 kW continuous-wave CO2 laser. The microstructure, composition and corrosion resistance of AM60B magnesium alloy after LSM treatment were investigated by using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and corrosion tests, respectively. Results showed that the LSM treatment produced a continuous and homogeneous modified layer with refined grains, enriched Al element and redistributed intermetallic compounds on AM60B alloy. The corrosion resistance of the AM60B alloy was enhanced by the LSM treatment. The enhancement of the corrosion resistance was mainly attributed to the reduced corrosion susceptibility of Al enriched α-Mg matrix and the barrier effect of uniformly distributed β-phase of the LSM modified layer

  11. The effect warming time of mechanical properties and structural phase aluminum alloy nickel

    International Nuclear Information System (INIS)

    Ferrous aluminum alloys as fuel cladding will experience the process of heat treatment above the recrystallization temperature. Temperature and time of heat treatment will affect the nature of the metal. Heating time allows will affect change in mechanical properties, thermal and structure of the metal phase. This study aims to determine the effect of time of heat treatment on mechanical properties and phase metal alloys. Testing the mechanical properties of materials, especially violence done by the method of Vickers. Observation of microstructural changes made by metallographic-optical and phase structure were analyzed Based on the x-ray diffraction patterns Elemental analysis phase alloy compounds made by EDS-SEM. Test results show the nature of violence AlFeNiMg alloy by heating at 500°C with a warm-up time 1 hour, 2 hours and 3 hours respectively decreased range 94.4 HV, 87.6 HV and 85.1 HV. The nature of violence AlFeNi alloy showed a decrease in line with the longer heating time. Metallographic-optical observations show the microstructural changes with increasing heating time. Microstructure shows the longer the heating time trend equi axial shaped grain structure of growing and the results showed a trend analyst diffraction pattern formation and phase θ α phase (FeAl3) in the alloy. (author)

  12. Effects of aging treatment on the intergranular corrosion behavior of Al–Cu–Mg–Ag alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiao Yan, E-mail: x918y@126.com; Li, Meng Jie; Gao, Fei; Liang, Shun Xing; Zhang, Xi Liang; Cui, Hao Xuan

    2015-08-05

    Highlights: • Corrosion resistance of Al–Cu–Mg–Ag alloy follows: under-aged > peak-aged > over-aged. • The simulated matrix, θ (Al{sub 2}Cu), and the precipitations free zones (PFZ) were prepared. • The self-corrosion potentials satisfy E{sub Matrix} > E{sub θ} > E{sub PFZ}. • The wider PFZ is adverse to the corrosion resistance of Al–Cu–Mg–Ag alloy. - Abstract: The effects of aging treatment on the corrosion behavior of Al–Cu–Mg–Ag alloy were studied by means of intergranular corrosion (IGC) testing, potentiodynamic polarization combined with optical microscopy (OM) and transmission electron microscopy (TEM). Corrosion testing results suggest that, the intergranular corrosion resistance properties of Al–Cu–Mg–Ag alloy decreased with increasing aging time, which is also corroborated by the potentiodynamic polarization test results for under-aged, peak-aged and the over-aged Al–Cu–Mg–Ag alloys. TEM results reveal that precipitations on the grain boundary became coarsened and distributed discontinuously with increasing aging time; widening of precipitation free zones (PFZ) is also observed. The PFZ with the lowest self-corrosion potential is preferentially attacked, and corrosion progresses along the PFZ. The corrosion resistance of over-aged Al–Cu–Mg–Ag alloy decreased because of its wider PFZ in comparison with those in other samples.

  13. Effects of aging treatment on the intergranular corrosion behavior of Al–Cu–Mg–Ag alloy

    International Nuclear Information System (INIS)

    Highlights: • Corrosion resistance of Al–Cu–Mg–Ag alloy follows: under-aged > peak-aged > over-aged. • The simulated matrix, θ (Al2Cu), and the precipitations free zones (PFZ) were prepared. • The self-corrosion potentials satisfy EMatrix > Eθ > EPFZ. • The wider PFZ is adverse to the corrosion resistance of Al–Cu–Mg–Ag alloy. - Abstract: The effects of aging treatment on the corrosion behavior of Al–Cu–Mg–Ag alloy were studied by means of intergranular corrosion (IGC) testing, potentiodynamic polarization combined with optical microscopy (OM) and transmission electron microscopy (TEM). Corrosion testing results suggest that, the intergranular corrosion resistance properties of Al–Cu–Mg–Ag alloy decreased with increasing aging time, which is also corroborated by the potentiodynamic polarization test results for under-aged, peak-aged and the over-aged Al–Cu–Mg–Ag alloys. TEM results reveal that precipitations on the grain boundary became coarsened and distributed discontinuously with increasing aging time; widening of precipitation free zones (PFZ) is also observed. The PFZ with the lowest self-corrosion potential is preferentially attacked, and corrosion progresses along the PFZ. The corrosion resistance of over-aged Al–Cu–Mg–Ag alloy decreased because of its wider PFZ in comparison with those in other samples

  14. Effect of Cerium on Gas Evolution Behavior of Pb-Ca-Sn Alloy

    Institute of Scientific and Technical Information of China (English)

    Lin Guanfa; Zhou Genshu; Li Dangguo; Zheng Maosheng

    2006-01-01

    The effect of Ce on the behavior of gas evolution on Pb-Ca-Sn alloy in 4.5 mol·L-1 H2SO4 was investigated using cyclic voltammetry (CV), cathodic polarization curves and AC impedance (EIS).Cyclic voltammetry experiments show that the current of oxygen evolution on Pb-Ca-Sn-Ce electrode is lower than that of Pb-Ca-Sn electrode in the same anodic voltage.Moreover, the oxygen evolution potential on the former electrode is greater than that on the latter, and this means that Ce can increase the potential of oxygen evolution on Pb-Ca-Sn alloy.The AC impedance experiments show that Ce can also enhance the resistance of hydrogen evolution on Pb-Ca-Sn electrode, i.e., Ce can inhibit the hydrogen evolution on Pb-Ca-Sn electrode.The reason why Ce decreases the volume of hydrogen evolution on Pb-Ca-Sn alloy is that Ce increases the resistance of absorbing step of hydrogen evolution reaction.All the experimental results indicate that Pb-Ca-Sn-Ce alloy can rapidly decrease the oxygen and hydrogen evolution on Pb-Ca-Sn-Ce alloy.It is concluded that Pb-Ca-Sn-Ce alloy can promote the maintenance-free property of lead acid battery, and can serve as the candidate of the grid material for maintenance-free lead acid battery.

  15. Microstructure, electromagnetic shielding effectiveness and mechanical properties of Mg–Zn–Cu–Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xianhua, E-mail: xhchen@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400045 (China); Liu, Lizi [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); Pan, Fusheng [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400045 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Mao, Jianjun; Xu, Xiaoyang; Yan, Tao [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China)

    2015-07-15

    Highlights: • The second phases were characterized systematically in Mg–Zn–Cu–Zr alloys. • Excellent EMI SE was successfully obtained by adding Cu. • Mechanism of EMI SE was analyzed. • Good mechanical properties could be achieved by adding low Cu content. - Abstract: The microstructure, electromagnetic interference (EMI) shielding effectiveness (SE) and mechanical properties of Mg–Zn–xCu–Zr alloys (x = 0–2.32 wt.%) were investigated in this study. The results indicated that the addition of Cu led to the formation of MgZnCu phase with a face-center cubic structure, and resulted in grain refinement. EMI SE increased significantly with increasing Cu content in extruded state. The alloy with 2.32 wt.% Cu exhibited optimal EMI shielding capacity with SE value of 84–117 dB. Meanwhile, it was found that good mechanical properties could be achieved by adding low Cu content. The extruded alloy with 0.37 wt.% Cu presented higher yield strength (276 MPa), ultimate tensile strength (346 MPa) and elongation (δ = 11.4%) compared with other extruded alloys. However, a higher Cu content would substantially deteriorate tensile properties of the alloys. Based on microstructure observation, the variation of EMI shielding capacity and mechanical properties have been discussed.

  16. The effect of phosphorus on the microstructure and mechanical properties of ATI 718Plus alloy

    International Nuclear Information System (INIS)

    Since the discovery in the 1990s of the abnormal improvement produced by phosphorus in the stress rupture and creep life of Inconel 718 (hereafter referred to as 718), a great deal of additional research followed. However, the mechanism of the action of phosphorous in 718 is still in question. This paper details an experimental study that was intended to determine how phosphorus acts upon the microstructure and mechanical properties of Ni–Fe based alloy 718Plus. The results show that phosphorus has little effect on the strength and ductility of alloy 718Plus, but can significantly improve the stress rupture life. Phase constituents such as the δ and γ′ phases were quantitatively analyzed using electrolytic phase isolation and micro-chemical and XRD analysis as the phosphorous content of the alloy was increased. A full atom mapping of the distribution of phosphorus in the 718Plus alloy was quantitatively determined using APT (Atom Probe Tomography) technique. The results showed that there is no significant segregation of phosphorus at the γ′/γ and γ′/γ′ interface, but it significantly segregates at the grain boundaries and δ/γ interface. It was found that phosphorus is extremely depleted in the δ phase, which is believed to inhibit δ-phase precipitation by preventing δ phase nucleation and growth in the 718Plus alloy. Finally, the influence of phosphorus on the microstructure and mechanical properties of the 718Plus alloy was discussed

  17. Effect of phosphor addition on eutectic solidification and microstructure of an Al-13%Si alloy

    Directory of Open Access Journals (Sweden)

    Liao Hengcheng

    2011-11-01

    Full Text Available As the refiner or modifier, the master alloys containing high concentration phosphor are widely used in preparing eutectic or hypereutectic Al-Si alloys. To study the effect of phosphor addition on the eutectic solidification and microstructure of the Al-13%Si alloy, an investigation has been undertaken by means of thermal analysis and micro/macro-structure observation. Results indicate that addition of phosphor in near eutectic Al-Si alloy promotes the nucleation of eutectic but has little refinement impact on primary Si particles as expected. Conversely, both primary Si particles and eutectic Si flakes become slightly coarser in P-rich alloys. The coarsening of eutectic Si flakes ties closely to the increased eutectic growth temperature with phosphor addition. The eutectic solidification of the alloy proceeds from the near mold zone towards the center, and it is also found that a few independent nucleation regions emerge in liquid at the solidification front due to the addition of phosphor.

  18. Effect of pre-oxidation on high temperature sulfidation behavior of FeCr and FeCrAl alloys

    Directory of Open Access Journals (Sweden)

    Pillis Marina Fuser

    2004-01-01

    Full Text Available High temperature corrosion of structural alloys in sulfur bearing environments is many orders of magnitude higher than in oxidizing environments. Efforts to increase sulfidation resistance of these alloys include addition of alloying elements. Aluminum additions to iron-chromium alloys bring about increase in sulfidation resistance. This paper reports the effect of pre-oxidation on the sulfidation behavior of Fe-20Cr and Fe-20Cr-5Al alloys in H2-2% H2S environment at 800 °C. The surfaces of sulfidized specimens were also examined. Pre-oxidation of the two alloys results in an incubation period during subsequent sulfidation. After this incubation period, the Fe-20Cr alloy showed sulfidation behavior similar to that when the alloy was not pre-oxidized. The incubation period during sulfidation of the Fe-20Cr-5Al alloy was significantly longer, over 45 h, compared to 2 h for the Al free alloy. Based on the microscopic and gravimetric data a mechanism for sulfidation of these alloys with pre-oxidation has been proposed.

  19. Effects of Ni and Mo on the microstructure and some other properties of Co-Cr dental alloys

    International Nuclear Information System (INIS)

    Influences of adding Ni and Mo on the microstructure and properties of as-cast Co-Cr base alloys have been investigated in order to determine the region of their optimal characteristics for biomedical application. The alloys were produced by arc-melting technique under argon atmosphere. Using optical metallography and scanning electron micro analyser it has been established that among 10 samples of Co-Cr-Ni alloys only samples 5 and 9 with the composition Co55Cr40Ni5 and Co60Cr30Ni10 have appropriate dendritic solidification microstructure. This microstructure, typical for commercial dental alloys, appears and beside greater number of as-cast Co-Cr-Mo alloys. The results of hardness and corrosion resistance measurements revealed the strong influence of different alloy chemistry and of as-cast microstructure. Hardness of alloys decreases with nickel content, but increases with chromium content. Therefore all Co-Cr-Ni alloys have significantly lower hardness than Co-Cr-Mo alloys. Corrosion resistance of alloys in artificial saliva was evaluated on the base of pitting potential. Superior corrosion characteristics have the samples with typical dendritic microstructure and higher chromium content, until nickel content have not significant effect. According to this, in ternary Co-Cr-Ni phase diagram was located the small concentration region (about samples 5 and 9) in them alloy properties can satisfied the high requirements for biomedical applications. This region is considerably larger in Co-Cr-Mo phase diagram

  20. Effect of rare earth elements on the microstructure of Mg-Al alloys

    Directory of Open Access Journals (Sweden)

    T. Rzychoń

    2006-04-01

    Full Text Available Purpose: The automotive use of magnesium is currently restricted to low-temperature structural components. Rare earth additions such as Ce, Nd, La and Pr are known to improve the creep performance. The aim of the research was to determine the effect of rare earths elements on the as-cast microstructure of magnesium alloys containing 4 wt% aluminum.Design/methodology/approach: The study was conducted on Mg-4Al-2RE (AE42 and a new Mg-4Al-4RE (AE44 alloys in the as-cast condition. The microstructure was characterized by optical microscopy (Olympus GX-70 and a scanning electron microscopy (Hitachi S3400 equipped with an X-radiation detector EDS (VOYAGER of NORAN INSTRUMENTS. The phase identification of these alloys was identified by X-ray diffraction (JDX-75.Findings: The microstructure of AE42 alloy consists of α-Mg solid solution with divorced eutectic Mg17Al12 + α-Mg, RE-rich phases and Mn-rich phase. The increase of RE contents from 2 wt% to 4 wt% leads to a change of microstructure of these alloys. In AE44 alloy was observed globular, lamellar and acicular precipitations of Al11RE3 and Al3RE phases. Moreover, there was found globular Mn-rich phase existence, but the Mg17Al12 phase was not observed.Research limitations/implications: The increase of RE content to 4 wt% caused the formation of new phases in the microstructure and prevented the formation Mg17Al12 phase. These factors can improve the creep resistance of the Mg-Al-RE alloys. The future research will contain creep tests and microstructural investigations of cast and die-cast alloys using TEM microscopy.Practical implications: The improvement of creep resistance of Mg-Al alloys can cause their application in automotive industry on the elevated-temperature structural components (above 150 °C. Results of investigation may be useful for preparing die casting technology of the Mg-Al-RE alloys.Originality/value: paper includes the results of microstructural investigations of new AE44

  1. Effects of minor Si on microstructures and room temperature fracture toughness of niobium solid solution alloys

    International Nuclear Information System (INIS)

    Controlling the elements content in the niobium solid solution (NbSS) is significant for the better comprehensive performance of Nb-silicide-based alloys. In this paper, the effects of minor Si on the microstructures and room temperature fracture toughness of Nb–(0/0.5/1/2)Si–27.63Ti–12.92Cr–2.07Al–1.12Hf (at%, unless stated otherwise) solid solution alloys were investigated. The alloys were processed by vacuum arc-casting (AC), and then heat treated (HT) at 1425 °C for 10 h. In HT alloys, NbSS grains are refined gradually with the increase of Si content. Meanwhile, the volume fraction of Cr2Nb and silicides phases precipitates increases. The fracture toughness of HT alloys decreases at first but then increases in the range of 0 to 2% Si, because it is a combinatorial process of positive and negative effects caused by the addition of Si. The refinement of NbSS grains displays positive effect on fracture toughness, while the increase of solid solubility of Si in NbSS and brittle Cr2Nb and Nb-silicides precipitate phases display negative effect

  2. Effect of radiation on bulk swelling of plutonium alloys

    International Nuclear Information System (INIS)

    Several studies show that plutonium alloys present bulk swelling. More precisely, length (as measured by dilatometry) and lattice parameter (as measured by X-ray diffraction) increase with time and seems to reach saturation after a few months for the microscopic scale. This bulk swelling can be correlated to self-induced radiation due to the decay of the different plutonium isotopes (238Pu, 239Pu, 241Pu and 242Pu) which also induce helium that tends to forms clusters, then bubbles. Many experimental and theoretical results have already been published on this topic. The goal of this paper is to review some of the results and to propose a strategy for both experiments and modelling to try to answer some of the remaining questions regarding swelling and more generally self-irradiation defects in plutonium alloys

  3. Alloying effect on K X-ray intensity ratio and production cross section values of Zn and Cr in Zn--Cr alloys

    International Nuclear Information System (INIS)

    In this study, σKα, σKβ production cross-sections and Kβ/Kα intensity ratios of Cr and Zn have been measured in pure metals and in different alloy compositions which have different composition values. And also, empirical and semi-empirical K-shell fluorescence yields (ωK) and Kβ/Kα intensity ratios from the available experimental data for elements with 23≤Z≤30 were calculated. The experimental data are fitted using the quantity (ωK/(1−ωK))1/4 vs. Z to deduce the empirical K-shell fluorescence yields and Kβ/Kα intensity ratios. The effects of alloying on the fluorescence parameters and bath temperatures on alloy compositions were investigated. Our analysis indicates that these effects arise from reorganization of atom and charge transfer mechanism in alloys. - Highlights: ► The alloying effect on the X-ray fluorescence parameters is investigated. ► The concentration of alloy compositions is depending on the bath temperature. ► The changes on the K X-ray fluorescence parameters are observed

  4. Hydrogen embrittlement effects on tensile properties of tungsten heavy alloys

    International Nuclear Information System (INIS)

    In this paper the strain rate sensitivities of 93% W and 70% W heavy metal alloys are characterized in the hydrogen-charged and vacuum outgassed conditions. In outgassed material, strength increases as ductility decreases with increased strain rate; however, for hydrogen-charged material, ductility as well as characteristically ductile to brittle as strain rate increases. An integrated model is presented that illustrates the change in fracture behavior with strain rate for ductile, hydrogen-embrittled, and impurity-segregation embrittled material

  5. Outstanding inhibitive effect of colchicine on aluminium alloy 6061 corrosion

    OpenAIRE

    Mudigere Krishnegowda Pavithra; Thimmappa Venkatarangaiah Venkateha; Mudigere Krishnegowda Punith Kumar; Nanjanagudu Subba Rao Anantha

    2015-01-01

    The corrosion protection ability of colchicine (CC) on Aluminium alloy 6061 (AA6061) in 3.5% NaCl medium was examined by potentiodynamic polarization, electrochemical impedance, and chronoamperometric techniques. About 99 % of protection efficiency was achieved by 2 mM concentration of CC in 3.5% NaCl solution.The adsorption of CC on AA6061 surface obeys Langmuir isotherm by following both physisorption and chemisorption mechanism. Variation in the surface morphology of inhibited and uninhibi...

  6. Effect of activity differences on hydrogen migration in dissimilar titanium alloy welds

    International Nuclear Information System (INIS)

    The effect of alloy composition on hydrogen activity was measured for seven titanium alloys as a means to determine the tendency for hydrogen migration within dissimilar metal welds. The alloys were: Ti-CP (unalloyed Ti), Ti-3Al-2.5V, Ti-3Al-2.5V-3Zr, Ti-3Al-2Nb-1Ta, Ti-6Al, Ti-6Al-4V, and Ti-6Al-2Nb-1Ta-0.8Mo. Hydrogen pressure-hydrogen concentration relationships were determined for temperatures from 600 C to 800 C and hydrogen concentrations up to approximately 3.5 at. pct (750 wppm). Fusion welds were made between Ti-CP and Ti-CP and between Ti-CP and Ti-6Al-4V to observe directly the hydrogen redistribution in similar and dissimilar metal couples. Hydrogen activity was found to be significantly affected by alloying elements, particularly Al in solid solution. At a constant Al content and temperature, an increase in the volume fraction of β reduced the activity of hydrogen in α-β alloys. Activity was also found to be strongly affected by temperature. The effect of temperature differences on hydrogen activity was much greater than the effects resulting from alloy composition differences at a given temperature. Thus, hydrogen redistribution should be expected within similar metal couples subjected to extreme temperature gradients, such as those peculiar to fusion welding. Significant hydrogen redistribution in dissimilar alloy weldments also can be expected for many of the compositions in this study. Hydride formation stemming from these driving forces was observed in the dissimilar couple fusion welds. In addition, a basis for estimating hydrogen migration in titanium welds, based on hydrogen activity data, is described

  7. Stress corrosion mechanisms of alloy-600 polycrystals and monocrystals in primary water: effect of hydrogen

    International Nuclear Information System (INIS)

    The aim of this study is to identify the mechanisms involved in Alloy 600 primary water stress corrosion cracking. Therefore, this work is mainly focussed on the two following points. The first one is to understand the influence of hydrogen on SCC of industrial Alloy 600 and the second one is to study the crack initiation and propagation on polycrystals and single crystals. A cathodic potential applied during slow strain rate tests does not affect crack initiation but increases the slow crack growth rate by a factor 2 to 5. Cathodic polarisation, cold work and 25 cm3 STP/kg hydrogen content increase the slow CGR so that the KISCC (and therefore fast CGR) is reached. The influence of hydrogenated primary water has been studied for the first time on Alloy 600 single crystals. Cracks cannot initiate on tensile specimens but they can propagate on pre-cracked specimens. Transgranular cracks present a precise crystallographic aspect which is similar to that of 316 alloy in MgCl2 solutions. Moreover, the following results improve the description of the cracking conditions. Firstly, the higher the hydrogen partial pressure, the lower the Alloy 600 passivation current transients. Since this result is not correlated with the effect of hydrogen on SCC, cracking is not caused by a direct effect of dissolved hydrogen on dissolution. Secondly, hydrogen embrittlement of Alloy 600 disappears at temperatures above 200 deg.C. Thirdly, grain boundary sliding (GBS) does not directly act on SCC but shows the mechanical weakness of grain boundaries. Regarding the proposed models for Alloy 600 SCC, it is possible to draw the following conclusions. Internal oxidation or absorbed hydrogen effects are the most probable mechanisms for initiation. Dissolution, internal oxidation and global hydrogen embrittlement models cannot explain crack propagation. On the other hand, the Corrosion Enhanced Plasticity Model gives a good description of the SCC propagation. (author)

  8. Corrosion effects of runway de-icing chemicals on aircraft alloys and coatings

    International Nuclear Information System (INIS)

    Research highlights: → Corrosion effects of urea and four new runway de-icing chemicals on Al alloy 2024, Mg alloy RZ5 and cadmium-plated and subsequently chromate-treated steel 4340 were examined by three types of corrosion tests. → Corrosion effects of urea on Al alloy 2024 were more pronounced than those of the new de-icing chemicals, with pitting corrosion being evident in urea in all tests. → The rate of corrosion in Mg alloy RZ5 was often higher in new de-icing chemicals than in urea, although the form of corrosion was the same in most cases, i.e., general corrosion. → Corrosion effects of the five runway de-icing chemicals on cadmium-plated and subsequently chromate-treated steel 4340 were slightly different in all three tests, but some loss of the coating layers was detected in all cases. - Abstract: Corrosion effects of five runway de-icing chemicals on aluminium alloy 2024, magnesium alloy RZ5 and cadmium-plated and subsequently chromate-treated steel 4340 were investigated by cyclic polarisation measurements, open circuit potential monitoring and cyclic chemical exposure tests. The runway de-icing chemicals included in the study contained urea, which has a long history as a runway de-icing chemical, and four new commercial de-icing chemicals, which were based on betaine and potassium formate. Corrosion effects of urea on aluminium alloy 2024 were more pronounced than those of the new de-icing chemicals. In urea, the breakdown potential, indicating the onset of pitting, was clearly distinguishable in the cyclic polarisation curve and pitting corrosion was detected on the specimen surface after all three types of tests. Weight losses during the chemical exposure tests were also higher for urea than for the other four chemicals, where pitting corrosion was only occasionally detected. The opposite was true in the case of magnesium alloy RZ5: although the alloy experienced general corrosion in each de-icing chemical included in the study, the rate of

  9. The thermal transient effect on some nickel-based alloys

    International Nuclear Information System (INIS)

    This paper studies two nickel-based alloys after thermal transient tests. Two alloys were tested, namely Inconel 617 (UNS N06617) and Haynes 230 (UNS N06230). These materials are study for to be used in the construction of the steam generators of the future NPP reactors which must operate in severe conditions (high temperature, thermo-mechanical stress, aggressive media). The experiment consisted in thermal transient tests using a few scenarios: fast heating rates (50OC/minute) up to 1,000OC, maintaining this temperature level (0-60 minutes) and slowly/fast cooling. The metallographic analysis consisted in microstructure, micro-hardness determinations and traction tests. The average grain size was determined by linear interception method. The micro hardness was calculated by the relationship from the device technical book. On the traction diagrams the following mechanic characteristics were obtained: breaking resistance (Rm), elongation at rupture (A) and elastic modulus (E). The tested alloys were compared with the received materials. (authors)

  10. Effect of Zr addition on fracture toughness of 2048 high strength aluminum alloy

    International Nuclear Information System (INIS)

    The effect of replacing grain refining element Mn by Zr on fracture toughness of 2048 aluminum alloys was investigated. Fracture toughness changed by Zr replacement was analyed as follows. 1. Quantity of large inclusions gave a primary effect on fracture toughness when grain size and material strength level were kept constant. 2. Dispersoids of Mn compounds were rod shape and 1.0μm in length, while those of Zr compound, Al3Zr were spherical and 0.1μm in diameter. Dispersoids of Zr compounds, Al3Zr were better than those of Mn compounds for improving fracture toughness. 3. Experimentally proved the effects of dispersoids change on fracture toughness of aluminum alloy 2048 when other metallurgical factors -grain size, inclusion, strength level- were kept constant. Zr bearing modified 2048 aluminum aiioy showed 5% improvement in yield strength and 50% in toughness compared with those of Mn bearing conventional 2048 aluminum alloy. (Author)

  11. The size-effect on the formation enthalpy of nanosized binary ti based alloy

    International Nuclear Information System (INIS)

    The effects of grain size and composition on the formation enthalpy of nano binary Ti-based alloy are investigated by taking the surface effect into account within the modified Miedema model. It is demonstrated that the formation enthalpy of binary Ti based alloy with nano grains is size-dependent and exhibits evident size-effects. The formation enthalpy increases with the size decrease, and its value turns from negative to positive at a critical size, which will weaken the thermal stability of the nano grains. Furthermore, the composition segregation taking place in the nano grains of the Ti based alloy is obvious when the grain size is less than 10 nm and the tendency of segregation is dependent on the surface formation enthalpy of nanoparticle. (authors)

  12. Poisoning effect of bismuth on modification behaviour of strontium in LM25 alloy

    Indian Academy of Sciences (India)

    S Farahany; A Ourdjini; M H Idris; L T Thai

    2011-10-01

    Nucleation and growth, temperature measurements andmicrostructure observations of silicon phase are presented for strontium modified Al–7%Si (LM25) cast alloy treated with bismuth. The results show that addition of bismuth in strontium modified alloys may have a poisoning effect resulting in lost modification of the silicon phase. With increasing Bi/Sr ratio, thermal analysis measurements showed that the eutectic growth temperature increased remarkably to 573°C and recalescence decreased to 0.2°C and the morphology of silicon displayed the same flakelike structure as in the unmodified alloys. Microstructural observation showed that a minimum Bi/Sr ratio of 1.2 which is equivalent to a Sr/Bi ratio of 0.43 is required for effective strontium modification and neutralization of the poisoning effect of bismuth.

  13. On the effect of brazing thermal cycle on the properties of niobium and its alloys

    International Nuclear Information System (INIS)

    The effect of the main parameters of the soldering thermal cycle on the properties of Nb and its alloys was studied by heating the samples under modelled conditions of soldering. The studies were made on commercial VN-niobium, alloys of the Nb-Mo-Zr system VN2A, VN2AEHM) and alloys of the Nb-Mo-Zr-C system (VN5AEH,VN5A). The degree of a preliminary plastic deformation of samples 0.3 to 0.8 mm thick made up 60 to 80%. The heating was made in vacuum (10-4 to 5x10-5 mm Hg) or in argon by passing the electric current across the samples. After heating a metallographic study and X-ray electron-probe analysis were made. The studies have shown that the changes in the heating rate result in a proportional change in the recrystallization initiation temperature. At a heating rate 300 deg C/s the recrystallization initiation temperature of commercial Nb is 930 to 960 deg as soon as the heating rate increases up to 900 deg/c the recrystallization initiation temperature rises up to about 1200 deg C. The heating temperature effect on the mechanical characteristics of commercial Nb and alloys VN2, VN2AEH and VN5AEH is shown. It is found that soldered joints of Nb and its alloys could be made of good quality when observing the thermal cycles ensuring the minimum softening of the base material. The main factors affecting the properties of Nb and alloy-VN2 are the heating temperature and the extent of a preliminary cold deformation. In a more deformed material the annealing results in the activation of the recrystallization processes. The production of high-strength soldered joints of commercial Nb is possible at the soldering temperature equal to 1100 deg C, but of Nb-Mo-Zr alloys-at 1200 to 1300 deg C and hold-up periods not exceeding one hour. A heterophase structure of alloys of the Nb-Mo-Zr-C system and the presence of Mo- and Zr-carbide phases in them result in a considerable hardening of the alloys and the increase in their recrystallization temperature. The usage of alloys

  14. Effect of cerium addition on microstructures of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    S Sriram; R Balasubramaniam; M N Mungole; S Bharagava; R G Baligidad

    2005-10-01

    The effect of Ce addition on the microstructure of carbon-alloyed Fe3Al-based intermetallic has been studied. Three different alloys of composition, Fe–18.5Al–3.6C, Fe–20.0Al–2.0C and Fe–19.2Al–3.3C–0.07Ce (in at%), were prepared by electroslag remelting process. Their microstructures were characterized using optical and scanning electron microscopies. Stereological methods were utilized to understand the observed microstructures. All the alloys exhibited a typical two-phase microstructure consisting of Fe3AlC carbides in an iron aluminide matrix. In the alloy without Ce addition, large bulky carbides were equally distributed throughout the matrix with many smaller precipitates interspersed in between. In the alloy with Ce addition, the carbide grain sizes were finer and uniformly distributed throughout the matrix. The effect of Ce addition on the carbide morphology has been explained based on the known effect of Ce in modifying carbide morphology in cast irons.

  15. Effect of Boron and Cerium on Corrosion Resistance of Cu -Fe -P Alloy

    Science.gov (United States)

    Zou, Jin; Lu, Lei; Lu, De-ping; Liu, Ke-Ming; Chen, Zhi-bao; Zhai, Qi-jie

    2016-03-01

    The effects of B and Ce on the corrosion resistance of Cu-0.22Fe-0.06P alloy were investigated by salt spray and electrochemical tests. The corrosion morphology was studied by scanning electron microscopy. The corrosion products were characterized by energy-dispersive x-ray spectroscopy and x-ray diffraction analysis. The impurity content was determined by inductively coupled plasma mass spectrometry. The conductivity was measured using an eddy current conductivity meter. The grains of Cu-0.22Fe-0.06P alloy were refined by the addition of B and Ce. The electrochemical corrosion process of alloy is retarded due to purification effect of B and Ce. After the addition of a trace amount of B, the corrosion resistance of the alloy decreased. The corrosion resistance of Cu-0.22Fe-0.06P-0.025B-0.05Ce was better than that of Cu-0.22Fe-0.06P-0.025B due to the fact that the purification effect of Ce is better than that of B. The main corrosion products of the Cu-Fe-P alloys in a NaCl solution are Cu2Cl(OH)3 and Cu2O. The addition of trace amounts of B and Ce did not change the components of the corrosion product.

  16. A thermostatistical theory for solid solution effects in the hot deformation of alloys: an application to low-alloy steels

    International Nuclear Information System (INIS)

    The hot deformation of low-alloy steels is described by a thermostatistical theory of plastic deformation. This is based on defining a statistical entropy term that accounts for the energy dissipation due to possible dislocation displacements. In this case, dilute substitutional and interstitial atom effects alter such paths. The dislocation population is described by a single parameter equation, with the parameter being the average dislocation density. Solute effects incorporate additional dislocation generation sources. They alter the energy barriers corresponding to the activation energies for dislocation recovery, grain nucleation and growth. The model is employed to describe work hardening and dynamic recrystallization softening in fifteen steels for a wide range of compositions, temperatures and strain rates. Maps for dynamic recrystallization occurrence are defined in terms of processing conditions and composition. (paper)

  17. Effects of alloying elements and solution-annealing temperature on the mechanical properties of austenitic Fe-Mn-C alloy

    International Nuclear Information System (INIS)

    In order to investigate the effects of various alloying elements including S as a free-machining element on the mechanical properties of high manganese non-magnetic steel, tensile and Charpy impact tests were carried out in the annealed condition. The mechanism of the observed large strengthening effect of V especially on the 0.2% proof stress was investigated by examining Petch relation and its solution hardening effect. A linear regression equation which relates the 0.2% proof stress to the chemical composition is obtained. The strengthening effect of ferrite-forming substitutional element becomes greater in the order of Cr, Mo and V. Especially, the effect of V on the 0.2% proof stress is comparable with that of interstitial element C. While, austenite-forming substitutional elements Ni and Mn have little effect on the strength. The elongation and Charpy impact toughness show decreasing tendencies by the additions of ferrite-forming substitutional elements and S. However, interstitial elements C and N hardly decrease the elongation irrespective of their large strengthening effect. 0.2% proof stress and tensile strength decrease with increasing solution annealing temperature and a Petch relation is found. The large strengthening effect of V cannot be explained by its small solution hardening effect and is rather considered to be mainly attributable to grain refining by the V addition. (author)

  18. Effect of Cd and Sn Addition on the Microstructure and Mechanical Properties of Al-Si-Cu-Mg Cast Alloy

    Institute of Scientific and Technical Information of China (English)

    LI Rong-de; LI Run-xia; YU Li; HU Zhuang-qi

    2004-01-01

    The present work has investigated the effect of trace elements Cd and Sn on the microstructure and mechanical properties of Al-Si-Cu-Mg cast alloy. With the increase of Cd addition the strength of alloy rises at first and then drops. The optimal amount of Cd and Sn addition for Al-Si-Cu-Mg alloy is about 0.27% and 0.1% respectively. Due to the formation of some coarse Cd-rich phases and pure Cd particles the mechanical properties of alloy decrease when Cd amount exceeds0.27%. When more than 0.1% Sn added, some Sn atoms form low-melting eutectic compound at grain boundary, and then cause over-burning in alloy when solution treated, which may deteriorate properties of alloy, especially ductility of alloy.On the other hand, the addition of Cd and Sn remarkably increases the peak hardness and reduces the time to reach aging peak in Al-Si-Cu-Mg alloy. The action of Cd/Sn in quaternary Al-Si-Cu-Mg alloy is effectively the same as that occur in binary Al-Cu alloy that the enhanced hardening associated with Cd / Sn addition is due to the promotion of the θ' phase.

  19. Further investigations on high temperature magnetic after-effect in iron alloys containing oxygen

    Science.gov (United States)

    Földeáki, M.; Stefán, M.; Köszegi, L.; Kisdi-Koszó, É.

    1980-04-01

    Magnetic after-effect and disaccommodation measurements were performed on iron alloys containing oxygen. A new effect was found. Time dependence, activation energy and ageing properties were determined and interpreted as the relaxation of dislocations with mobile oxygen Cottrell clouds and as the relaxation of interstitial clusters around the precipitates.

  20. Effect of Cerium on Microstructure and Electrochemical Performance of Ti-V-Cr-Ni Electrode Alloy

    Institute of Scientific and Technical Information of China (English)

    Qiao Yuqing; Zhao Minshou; Zhu Xinjian; Cao Guangyi

    2007-01-01

    Effect of cerium on the microstructure and electrochemical performance of the Ti0.25V0.35-xCexCr0.1Ni0.3 (x=0, 0.005) electrode alloy was investigated by X-ray diffraction (XRD), field emission scanning electron microscopy/energy dispersive X-ray spectrometry (FESEM-EDS), and electrochemical impedance spectroscopy (EIS) measurements. On the basis of XRD and FESEM-EDS analysis, the alloy was mainly composed of V-based solid solution with body-centered-cubic structure and TiNi-based secondary phase. Ce did not exist in two phases, instead, it existed as Ce-rich small white particles, with irregular edges, distributed near the grain boundaries of the V-based solid solution phase. Discharge capacity, cycle stability, and high-rate discharge ability of the alloy electrode were effectively improved with the addition of Ce at 293 K. It was very surprising that the charge retention was abnormal with larger discharge capacity after standing at the open circuit for 24 h. EIS indicated that addition of Ce improved the dynamic performance, which caused the charge transfer resistance (RT) to decrease and exchange current density (I0) to increase markedly. The exchange current density of the electrochemical reaction on the alloy surface with Ce addition was about 2.07 and 3.10 times larger than that of the alloy without Ce at 303 and 343 K, respectively. The diffusion coefficient of hydrogen (D) in the bulk alloy electrode decreased with addition of Ce, but it did not decrease so much, and the apparent activation energy (△rH) was far higher than that of the AB5 type alloy.

  1. Effect of Alloying Elements in Hot-Rolled Metastable β-Titanium Alloys: Part I. Evolution of Microstructure and Texture

    Science.gov (United States)

    Manda, Premkumar; Ghosal, P.; Chakkingal, Uday; Singh, A. K.

    2015-06-01

    The present work describes the evolution of microstructures and textures in alloys Ti-5Al-5Mo-5V-3Cr (A1), Ti-5Al-3.5Mo-7.2V-3Cr (A2), Ti-5Al-5Mo-8.6V-1.5Cr (A3), and Ti-5Al-3.5Mo-5V-3.94Cr (A4) during unidirectional hot rolling. The hot-rolled microstructures of the alloy A1 exhibit large fraction of recovered/recrystallized grains, while the alloy A3 shows small fraction of recovered/recrystallized grains. The alloy A2 displays subgrains and recrystallized grains, while the alloy A4 exhibits the microstructure consisting of the features of both the alloys A1 and A2. The alloys A1, A3, and A4 show the presence of shear bands within the β grains and also small volume fraction of the α phase. The dominance of deformation and/or recrystallization components in respective α and γ fibers varies with alloy compositions and hot rolling reductions. In alloys A1 and A2, deformation components dominate from 30 to 50 pct rolling reductions, while recrystallization components govern in 70 pct rolled samples. The deformation components prevail from 30 to 70 pct rolling reductions in alloy A3. The alloy A4 exhibits softening of texture due to recovery or early stage of recrystallization from 30 to 50 pct reductions, while texture present in 70 pct rolled sample consists of mainly the deformation components. The role of molybdenum appears to be quite critical in the evolution of microstructures and textures of these alloys. The alloys with low and high Mo contents display high and low amount of the α phase, respectively.

  2. Effect of carbon on the primary crystallization of low content U-Mo alloys

    International Nuclear Information System (INIS)

    This report gives the results concerning the effects of carbon on the primary crystallization of uranium-molybdenum alloys. In effect, low amounts of added carbon can lead to considerable refinement of the γ grain. After describing in the first part the work carried out on the laboratory and the industrial scales, the authors put forward the most likely hypotheses for explaining the results and observations made during this work. In the second part, the authors propose four methods for introducing carbon which can be applied to these alloys. (authors)

  3. Effect of electromagnetic field on macrosegregation of continuous casting 7075 alloy

    Institute of Scientific and Technical Information of China (English)

    张北江; 崔建忠; 路贵民; 张勤; 班春燕

    2003-01-01

    The effect of electromagnetic field on macrosegregation of continuous casting aluminum alloy was stud-ied. 7075 aluminum alloy ingot with diameter of 200 mm was produced by electromagnetic casting. Magnitude of coilcurrent was varied from 100 A to 600 A, and frequency from 10 Hz to 100 Hz. Variation of element content along theradius of ingot was examined by means of chemical analysis. The results show that electromagnetic casting processcan effectively reduce the macrosegregation, and electromagnetic frequency has a great influence on element distribu-tion along the radius of ingot. When frequency is 30 Hz, macrosegregation is eliminated completely.

  4. Effects of irradiation on properties of refractory alloys with emphasis on space power reactor applications

    International Nuclear Information System (INIS)

    The probable effects of irradiation on niobium and tungsten alloys in use as components of thermionic convertors in a space reactor were reviewed by the author in 1971. While considerably more data on refractory metals have been generated since that time, the data have not been reviewed with respect to space reactor applications. This paper attempts such a review. The approach used is to work from the most recently available review of irradiation effects for each alloy system (where such a review is available) and to discuss that review and more recent data judged to be the most useful in establishing likely behavior in high-temperature reactor service. 28 figures, 6 tables

  5. Effect of pre-deformation on hysteresis in TiNiFe shape memory alloys

    International Nuclear Information System (INIS)

    The mechanical properties, shape memory effect and martensitic transformation temperatures in the TiNiFe alloys were measured. A ductility of more than 20% and shape recovery strain of 5.8% were obtained in these alloys. The shape memory effect increased with the increase of deformation, and reached a maximum value appearing at 8% total strain. The pre-deformation raised significantly the reverse transformation temperatures and the hysteresis was enlarged by more than 40 C when the total strain exceeded 6%. (orig.)

  6. Effect of lithium on the casting microstructure of Cu-Li alloys

    Institute of Scientific and Technical Information of China (English)

    ZHU Dachuan; SONG Mingzhao; YANG Dingming; CHEN Jiazhao; TU Mingjing

    2005-01-01

    The effect of lithium on the casting microstructure of Cu-Li alloys was studied via the Wild MPS 46 Automatic camera, Deitz Diaplan, and scanning electron microscope. The result shows that trace lithium added to copper coarsens the grains of Cu-Li alloys in equiaxed crystal area because of the excellent purification effect. With the amount of lithium increasing, the average grain size increases sharply. But when the amount of lithium increases more, the average grain size decreases instead. At the same time, the typical dentritic crystal area of copper is diminished when lithium is added to pure copper.

  7. Scandium effect on corrosion resistance of aluminium and its alloys in 3% NaCl solution

    International Nuclear Information System (INIS)

    Scandium effect on corrosion and electrochemical features of aluminium and its high-impact alloys in NaCl 3%-solution is studied. Positive effect of scandium doping of alloys was determined. Mechanism of scandium behaviour when aluminium corrosion resistance is improved is suggested. The suggested mechanism takes account of scandium ability to be selectively dissolved and oxidized by water oxygen with formation of Sc2O3 oxide accumulated at the surface in the form of fine-dispersed precipitation insoluble in electrolyte and forming no mixed oxides with aluminium

  8. Effect of selected microadditives on the mechanical properties of aluminium alloys

    OpenAIRE

    Rzadkosz S.; Staszczak L.

    2007-01-01

    The effect of iron impurities on microstructure and mechanical properties of cast Al-Cu and Al-Zn-Mg alloys was discussed. The role of iron in the process of solutioning and ageing of these alloys was described. Basing on the results of investigations, a comparative analysis was made to disclose the effect of low content (microadditives) of the elements, like Mn, Ti, Zr, B, Cr, Ni, Zn, Sn, Cd, In, Mg, Sb, and Ag on the primary structure of castings, mainly on the morphology of iron-bonding in...

  9. Neutron spectrum effects of the defect production in fusion reactor candidate alloys

    International Nuclear Information System (INIS)

    In the present work, irradiation effects of fission and fusion neutrons on fusion reactor candidate alloys, V-4Cr-4Ti and F82H were studied using the FNS facility and the Kyoto University Reactor (KUR). The comparison of defect structures in two fusion reactor candidate alloys between fusion neutron irradiation and fission neutron irradiation was performed. Even though the irradiation doses were low, the defect formation was detected by positron annihilation spectroscopy. Higher irradiation doses and different irradiation temperatures are required to detect the effects of neutron spectra more precisely. (author)

  10. Radiation effects in the aluminium alloys irradiated with neutrons

    International Nuclear Information System (INIS)

    Full text: Materials of fuel elements for water cooled nuclear reactors are exposed to simultaneous action of an ionizing radiation, temperature and yields of water radiolysis. In particular, irradiation by fast neutrons (En> 0.1 MeV) in research reactors influences mainly the mechanical properties of aluminium alloys, increasing their strength and reducing the plasticity. Radiation can essentially affect the stability of the heat-generating assembly material, changing its structure state. The structure change may also be the result of post-radiation ageing. This paper presents the results of studying the influence of reactor neutrons (research reactor of INP AS RU) on microstructure, electrical characteristics and length changes of SAV-1 and AMG-2 aluminium alloys used in nuclear industry. These alloys are low-alloyed solid solutions and intermetallic phases of CuAl2, Mg2Si, CuMgAl2, CuMg4Al6, Al2Mg2 in an equilibrium state. Samples were cut with orientation in 111 crystallographic axis in the shape of disks with the diameter d= 15 mm and thickness h= 3 mm for the metallographic analysis, and rods with the length of 40 mm and width d = 5 mm for measuring specific electrical resistance and linear dimension changes prior and after irradiations. For precise measurements the sample surfaces were mechanically handled and polished in a chemical solution, and then washed out in the distilled water and ethanol. Further samples, were put into the aluminum container and irradiated in a vertical channel of the reactor to fluencies 1018, 1019, 1020 n/cm2. The relative elongation (extension) δ was calculated as the measured length ratio of the non-irradiated and irradiated sample: δ=L0/L1x100%. Determination of element composition and the metallographic analysis of studied samples were done at the X-ray microanalyzer 'Jeol' JSM 5910 IV. Specific resistance (ρ) values were measures with four probe technique by compensation method at the direct voltage. The sample lengths

  11. The effects of low doses of 14 MeV neutrons on the properties of various commercial copper alloys

    International Nuclear Information System (INIS)

    Miniature tensile specimens of high purity copper and five copper alloys were irradiated with D-T fusion neutrons in the RTNS-II to fluences up to 2.5x1022 n/m2 at 900C and 2900C. The series of alloys includes solution-strengthened, precipitate-strengthened and dispersion-strengthened alloys. To compare fission and fusion neutron effects, some of the alloys were also irradiated at the same temperatures to similar damage levels of the Omega West Reactor. Tensile tests were performed at room temperature, and the radiation-induced changes in tensile properties are examined as functions of fluence and displacements per atom (dpa). All the alloys sustain less irradiation-induced strengthening than pure copper. In contrast to pure copper, the effects of fission and fusion neutrons on the yield stress changes in the copper alloys correlate well on the basis of dpa. (orig.)

  12. The effects of low doses of 14 MeV neutrons on the properties of various commercial copper alloys

    International Nuclear Information System (INIS)

    Miniature tensile specimens of high purity copper and five copper alloys were irradiated with D-T fusion neutrons in the RINS-II to fluences up to 2.5 x 1022 n/m2 at 90 and 2900C. The series of alloys includes solution-strengthened, precipitate-strengthened and dispersion-strengthened alloys. To compare fission and fusion neutron effects, some of the alloys were also irradiated at the same temperatures to similar damage levels in the Omega West Reactor. Tensile tests were performed at room temperature, and the radiation-induced changes in tensile properties are examined as functions of fluence and displacements per atom (dpa). All the alloys sustain less irradiation-induced strengthening than pure copper. In contrast to pure copper, the effects of fission and fusion neutrons on the yield stress changes in the copper alloys correlate well on the basis of dpa

  13. Observation of inverse spin Hall effect in ferromagnetic FePt alloys using spin Seebeck effect

    International Nuclear Information System (INIS)

    We experimentally observed the inverse spin Hall effect (ISHE) of ferromagnetic FePt alloys. Spin Seebeck effect due to the temperature gradient generated the spin current (Js) in the FePt|Y3Fe5O12 (YIG) structure, and Js was injected from YIG to FePt and converted to the charge current through ISHE of FePt. The significant difference in magnetization switching fields for FePt and YIG led to the clear separation of the voltage of ISHE from that of anomalous Nernst effect in FePt. We also investigated the effect of ordering of FePt crystal structure on the magnitude of ISHE voltage in FePt

  14. Observation of inverse spin Hall effect in ferromagnetic FePt alloys using spin Seebeck effect

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Takeshi, E-mail: go-sai@imr.tohoku.ac.jp; Takanashi, Koki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Uchida, Ken-ichi [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Kikkawa, Takashi [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Qiu, Zhiyong [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Saitoh, Eiji [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan)

    2015-08-31

    We experimentally observed the inverse spin Hall effect (ISHE) of ferromagnetic FePt alloys. Spin Seebeck effect due to the temperature gradient generated the spin current (J{sub s}) in the FePt|Y{sub 3}Fe{sub 5}O{sub 12} (YIG) structure, and J{sub s} was injected from YIG to FePt and converted to the charge current through ISHE of FePt. The significant difference in magnetization switching fields for FePt and YIG led to the clear separation of the voltage of ISHE from that of anomalous Nernst effect in FePt. We also investigated the effect of ordering of FePt crystal structure on the magnitude of ISHE voltage in FePt.

  15. Effect of chromium concentration on microstructure and properties of Fe-3.5B alloy

    International Nuclear Information System (INIS)

    Research highlights: → With the increasing chromium additions, the boride changes from Fe2B to (Fe,Cr)2B-type boride. → The matrix of Fe-3.5B alloy transforms to supersaturated α-(Fe,Cr) solid solution when high chromium concentration is added. → The fracture toughness of boride increases with the increase of chromium addition. → Secondary phase precipitates during the heat treatment of Fe-3.5B alloy with various chromium concentrations. - Abstract: The cast low carbon Fe-3.5B alloys containing various chromium concentrations were prepared in a 10 kg medium frequency induction furnace and the effects of chromium concentration on microstructure and properties of Fe-3.5B alloys have been examined by means of optical microscope (OM), scanning electron microscope (SEM), back-scattered electron microscope (BSE), electron probe microanalyzer (EPMA), energy dispersive spectrum (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Vickers hardness. As a result, the as-cast structures of Fe-3.5B-XCr (X = 0, 2, 5, 8, 12, 18, mass fraction) alloys are mainly composed of dendrite ferrite, martensite, pearlite and boride. The boride in the alloy without chromium addition comprises the eutectic Fe2B, which is continuous netlike or fish-bone structure distributed over the metallic matrix. With the increase of chromium concentration in Fe-3.5B alloy, matrix structure turns into the supersaturated α-Fe solid solution while the morphology of boride becomes dispersed due to the transformation of boride from simple Fe2B to (Fe,Cr)2B when the chromium concentration in Fe-3.5B alloy exceeds 8 wt.%. Meanwhile, some primary M2B-type borides may precipitate under this condition. The bulk hardness of the as-cast alloy ranges from 41.8 to 46.8 HRC. However, the bulk hardness of the heat treated alloy rises first and falls later mainly because of the morphology variation of structure. Fracture toughness of boride is improved gradually owing to the entrance of

  16. Effect of phase composition on the corrosion properties of alloys of the magnesium-yttrium system in neutral solutions

    International Nuclear Information System (INIS)

    A study is made of the effect of phase composition on the corrosive dissolution of binary alloys of the system magnesium-8.2% yttrium. It is shown that the appearance of the intermetallide Mg24Y5 - being the effective cathode - intensifies self-dissolution of the alloy under conditions of anodic galvanostatic polarization

  17. Effects of impurities on hydrogen permeability through palladium alloy membrane at comparatively high pressure and temperature

    International Nuclear Information System (INIS)

    Palladium alloy membrane method is considered to be a useful technique for fusion reactor fuel purification process. To study the feasibility of this method, the effects of impurities on permeation characteristics of palladium alloy membrane were examined. Experiments were carried out at practical conditions: pressure; 120 - 1200 kPa, temperature; about 700 K. No poisoning effect on hydrogen permeability of commercial Pd-Ag (Au.Ru) alloy was observed for impurities such as NH3, CH4, CO, CO2, O2 and N2, which were mixed with hyper-pure H2 at low concentration level (10 - 10000 ppm). Deterioration occurred by contamination with oil vapor. However, regeneration of the membrane was easily performed by air baking followed by hydrogen reduction. Chemical reactions in the permeation cell were also examined. (author)

  18. Effect of hydrogen on the corrosion behavior of the Mg–xZn alloys

    Directory of Open Access Journals (Sweden)

    Yingwei Song

    2014-09-01

    Full Text Available Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys. The effect of hydrogen on the corrosion behavior of the Mg–2Zn and Mg–5Zn alloys is investigated by charging hydrogen treatment. The surface morphologies of the samples after charging hydrogen were observed using a scanning electron microscopy (SEM and the corrosion resistance was evaluated by polarization curves. It is found that there are oxide films formed on the surface of the charged hydrogen samples. The low hydrogen evolution rate is helpful to improve the corrosion resistance of Mg alloys, while the high hydrogen evolution rate can increases the defects in the films and further deteriorates their protection ability. Also, the charging hydrogen effect is greatly associated with the microstructure of Mg substrate.

  19. Effect of yttrium on the twinning and plastic deformation of AE magnesium alloy under ballistic impact

    Energy Technology Data Exchange (ETDEWEB)

    Asgari, H., E-mail: hamed.asgari@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon (Canada); Odeshi, A.G.; Szpunar, J.A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon (Canada); Zeng, L.J.; Olsson, E. [Department of Applied Physics, Chalmers University of Technology, Göteborg (Sweden); Li, D.Y. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton (Canada)

    2015-01-19

    In this research, effect of yttrium on the texture formation, microstructural evolution and mechanical response of AE42 and AE44 cast magnesium alloys were investigated under ballistic impact. The selected strain rates were 800 and 1100 s{sup −1} and the tests were conducted using Split Hopkinson Pressure Bar. It was inferred that after high velocity impact, a weaker basal texture developed in the samples with lower content of yttrium. Experimental results also showed that by increasing the concentration of yttrium in the cast AE alloys, strength, ductility and dislocation density of the impacted alloys increased but, the fraction of twinning decreased, which indicate the effective influence of yttrium on the nucleation and growth of twins. Moreover, it was inferred that accumulation of dislocations at intersections of the twins led to the cracking and fracture of the samples under shock loading conditions.

  20. Effect of hydrogen on the mechanical properties of titanium and its alloys

    Science.gov (United States)

    Beck, F. H.

    1975-01-01

    Occluded hydrogen resulting from cathodic charging of commercially pure titanium and titanium alloys, Ti-8Al-1Mo-1V and Ti-6Al-4V, was shown to cause embrittlement of the alloys. Embrittlement was a function of the interstitial hydrogen content rather than the amount of precipitated titanium hydride. The effects of hydrogen concentration on the critical strain for plastic instability along pure shear directions was determined for alloys Ti-8Al-1Mo-1V and Ti-5Al-2.5Sn. Hydrogen, in concentrations below that necessary for spontaneous hydride precipitation, increased the strain necessary for instability formation or instability failure. The strain rate sensitivity also increased with increasing hydrogen concentration. The effect of hydrogen on slip and twinning was determined for titanium single crystals. The critical resolved shear stress for prism slip was increased and the critical resolved shear stress for twinning was decreased with increasing hydrogen concentration.

  1. The Effect of Aluminum Content on the Microstructure and Cavitation Wear of Feal Intermetallic Alloys

    Directory of Open Access Journals (Sweden)

    Jasionowski Robert

    2014-03-01

    Full Text Available Intermetallic-based alloys (so called intermetallics of the Fe-Al binary system are modern construction materials, which in recent decades have found application in many branches of the power, chemical and automotive industries. High resistance of FeAl based alloys to cavitational erosion results first of all from their high hardness in the as-cast state, large compressive stresses in the material, as well as homogeneous structure. In the present paper, the effect of aluminum content on the microstructure, texture and strain implemented upon cavitation wear of FeAl intermetallic alloys, have been analyzed by field emission gun scanning electron microscopy (FEG SEM and electron backscatter diffraction (EBSD analysis. Obtained results of structural characterization indicates that with increasing aluminium content effects of orientation randomization (weakening of //ND casting texture, grain refinement and rising of mechanical strenght (and so cavitational resistance take place.

  2. Superplastic deformation and shape memory effects of Cu-Zn-Sn alloys

    International Nuclear Information System (INIS)

    The new commercial Cu-Zn based alloys having excellent hot workability and shape memory effects have been developed. Higher than 200% elongation was observed in the hot tensile test with the alloy sample containing Cu-38Zn-1.9Sn-1.9mass%Pb at the temperature range from 773 K to 873 K with the initial strain rate of 8.3 x 10-4s-1. The stress-strain curve showed the typical type of superplastic deformation. After heat treatment of the developed alloys at 1073 K, they showed shape memory effects (SME). The transformation temperatures of samples were measured by electric resistance, and found to be Ms=119K, Mf=96K, As=105K, Af=129K. From the width of hysteresis about 15 K, the formation of thermoelastic martensite has been confirmed. (orig.)

  3. Effects of erbium modification on the microstructure and mechanical properties of A356 aluminum alloys

    International Nuclear Information System (INIS)

    The effects of erbium (Er) modification on the microstructure and mechanical properties of A356 aluminum alloys were investigated using optical microscope, X-ray diffraction, scanning electronic microscope and mechanical testing. Experimental results show that additions of Er refined the α-Al grains and eutectic Si phases in its as-cast state; the addition of 0.3 wt% of Er has the best effects on them. The Fe-containing Al3Er phases were introduced by the modifications; by a T6 treatment, the eutectic Si phases were further sphereodized; the large Al3Er and β-Al5FeSi phases were changed into fine particles and short rods; which enhanced the hardness of the alloys. The highest strength and elongation were obtained for the 0.3 wt% of Er-modified and T6-treated A356 alloy

  4. Effect of yttrium on the twinning and plastic deformation of AE magnesium alloy under ballistic impact

    International Nuclear Information System (INIS)

    In this research, effect of yttrium on the texture formation, microstructural evolution and mechanical response of AE42 and AE44 cast magnesium alloys were investigated under ballistic impact. The selected strain rates were 800 and 1100 s−1 and the tests were conducted using Split Hopkinson Pressure Bar. It was inferred that after high velocity impact, a weaker basal texture developed in the samples with lower content of yttrium. Experimental results also showed that by increasing the concentration of yttrium in the cast AE alloys, strength, ductility and dislocation density of the impacted alloys increased but, the fraction of twinning decreased, which indicate the effective influence of yttrium on the nucleation and growth of twins. Moreover, it was inferred that accumulation of dislocations at intersections of the twins led to the cracking and fracture of the samples under shock loading conditions

  5. Effect of La and Nd on microstructures and mechanical properties of AZ61 wrought magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    周海涛; 曾小勤; 丁文江; 马春江; 朱燕萍

    2004-01-01

    Effects of La and Nd addition on the microstructure and mechanical properties of the AZ61 alloy have been investigated. The results show that when La and Nd are added into the AZ61 alloy respectively, the β(Mg17Al12 ) phase is refined and granulated, and new phases are formed in the form of small rod-like shape, which are verified as La3 Al11 and Nd3 Al11 phase by X-ray diffraction and TEM observation. Microstructure observations show that the effective efficiency of La addition is higher than that of Nd addition, thus the sizes ofβ(Mg17 Al12 ) and La3 Al11 phase are relatively smaller than those ofβ(Mg17 Al12 ) and Nd3 Al11 phases in both AZ61 alloy and Nd-containing alloy. The increase of the tensile strength and elongation of AZ61 alloy refers to the existence of small rod-like La3Al11 and Nd3 Al11 phases, and fine granulatedβ(Mg17 Al12) phase.

  6. Effect of boron addition on hydrogen embrittlement sensitivity in Fe-Ni based alloys

    International Nuclear Information System (INIS)

    In Fe-Ni based alloys, hydrogen embrittlement sensitivity is thought to correlate well with microstructure. The effect of boron addition on microstructure of Fe-Ni austenitic alloys has been investigated. It is found that 0.002 wt.% boron addition can significantly retard the formation of η phase, and only a few continuous carbides precipitate at the grain boundaries. As the boron content increases to 0.006 wt.%, carbides at grain boundaries become discontinuous, and are finer in size than that in the alloy with 0.002 wt.% boron. Significant decrease of the percent loss of reduction of area (RA) are seen in the alloys with boron contents lower than 0.006 wt.%. However, when further increasing the boron concentration to 0.01 wt.%, an increase in the percent loss of RA is found, due to the re-appearance of η phase and boride precipitation. Appropriate addition of boron can be an effective way of lowering hydrogen embrittlement sensitivity in Fe-Ni based alloys.

  7. Effect of ripple loads on sustained-load cracking in titanium alloys

    International Nuclear Information System (INIS)

    In the present paper, the authors have extended their study on the effect of the ripple loads on the sustained-load cracking (SLC) behavior of two titanium alloys, Ti-6Al-4V (an α-β alloy) and Ti-15V-3Cr-3Al-3Sn (a β-α alloy), in an ambient air environment. The methodology which has been used successfully to treat ripple effects on stress-corrosion cracking (SCC) is employed again to address the influence of ripple loads on sustained-load cracking. Ripple loads can significantly reduce the apparent sustained load cracking resistance of titanium alloys in a relatively benign environment such as ambient air. For a ripple-load amplitude equal to 5% of the sustained load, the ripple-load cracking thresholds (KIRLC) of beta-annealed Ti-6Al-4V and Ti-15V-3Cr-3al-3Sn are less than half of the respective sustained-load cracking thresholds (KISLC). The extent of ripple-load degradation for these alloys in ambient air -- relative to KISLC, were found comparable to those observed in a much more aggressive 3.5% NaCl aqueous solution

  8. Effect of cooling rate on microstructure and compressive performance of AZ91 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    YANG Lin; FENG Hui; QIU Ke-qiang; CHEN Li-jia; LIU Zheng

    2006-01-01

    Effect of cooling rate on both microstructure and room temperature compressive performance of the AZ91 magnesium alloy was investigated. The experimental results show that with increasing cooling rate, the quantity of the solid solution phase increases and the fraction of secondary phase Mg17Al12 decreases. The almost single solid solution phase can be obtained with using liquid nitrogen as a coolant. The compressive strengths of the rapid solidified AZ91 magnesium alloys are higher than those of normal cast alloy, and decrease with increasing cooling rate. After artificial aging treatment for 14 h at 168 ℃, the compressive strength of the rapidly solidified AZ91 magnesium alloy cooled in liquid nitrogen increases from 253.5 to 335.3 MPa, while the compressive yield strength increases from 138.1 to 225.91 MPa. The improvement in the compressive strength of the rapidly solidified AZ91magnesium alloys can be attributed to the hardening effect from fine secondary phase.

  9. Effect of homogenization treatment on microstructure and properties of Al-Mg-Mn-Sc-Zr alloy

    Institute of Scientific and Technical Information of China (English)

    NIE Bo; YIN Zhi-min; ZHU Da-peng; PENG Yong-yi; JIANG Feng; HUANG Ji-wu

    2007-01-01

    The effect of homogenization on the hardness, tensile properties, electrical conductivity and microstructure of as-cast Al-6Mg-0.4Mn-0.25Sc-0.12Zr alloy was studied. The results show that during homogenization as-cast studied alloy has obviously hardening effect that is similar to aging hardening behavior in traditional Al alloys. The precipitates are mainly Al3(Sc,Zr) and Al6Mn.When homogenization temperature increases the hardness peak value is declined and the time corresponding to hardness peak value is shortened. The electrical conductivity of the alloy monotonously increases with increasing homogenization temperature and time.The decomposition of the supersaturated solid solution containing Sc and Zr which is formed during direct chilling casting and the precipitation of Al3(Sc, Zr) cause hardness increasing. The depletion of the matrix solid solubility decreases the ability of electron scattering in the alloy, resulting in the electrical conductivity increased. Tensile property result at hot rolling state shows that the optimal homogenization treatment processing is holding at 300-350 ℃ for 6-8 h.

  10. Effect Of Cooling Rate On Thermal And Mechanical Properties Of Cu-%24.2Mn Alloy

    International Nuclear Information System (INIS)

    In this research, different heat and mechanical treatments have been applied to the Cu-%24.2Mn and some samples have been obtained from this alloy. On these samples, phase transformations have been formed by thermal and mechanical effect. Morphological, mechanical and crystallographic properties of the phase transformations have been examined by using different physical methods. Austenite phase has been obtained in the samples which have been applied slow and rapid cooling according to the SEM analysis. It has been observed that the grain size obtained by the rapid cooling is smaller than the grain size obtained by the slow cooling. Therefore, it has been concluded that the cooling process differences, changes the grain size of the alloy. Compression stress has been applied to the alloy in order to search the deformation effect on the austenite phase transformation. The structural features of the phase transformations have been examined. Slip lines and martensite structural were observed on the surface of the alloys after the deformation. Changes in phase structure of the alloy are also examined by means of XRD technique.

  11. Effect of aging on mechanical properties and localized corrosion behaviors of Al-Cu-Li alloy

    Institute of Scientific and Technical Information of China (English)

    JIANG Na; LI Jin-feng; ZHENG Zi-qiao; WEI Xiu-yu; LI Yan-fen

    2005-01-01

    The effects of aging on mechanical properties,intergranular corrosion and exfoliation corrosion behaviors of a 2197 type A1-Li alloy were investigated,and the mechanisms were studied through microstructure observation and electrochemical measurement of simulated bulk phase.The main strengthening precipitates of the alloy aged at175 ℃ and 160 ℃ are δ' and T1.T1 precipitation in the alloy aged at 160 ℃ is delayed,which results in its slower age strengthening and over-aging behavior than the alloy aged at 175 ℃.Meanwhile,aging temperature of 160 ℃causes more uniform distribution and finer size of T1,resulting in its better strengthening effect.As aging time and aging temperature are increased,the size of T1 at grain boundaries and the width of PFZ along grain boundaries are increased,leading to an increase in the susceptibility to intergranular corrosion and exfoliation corrosion.It is suggested that better comprehensive properties can be obtained when the alloy is aged at 160 ℃.

  12. Effect of yttrium on microstructure and mold filling capacity of a near-α high temperature titanium alloy

    OpenAIRE

    Zhao Ertuan; Chen Yuyong; Kong Fantao

    2012-01-01

    The addition of rare earth yttrium (Y) can improve the performances of high temperature titanium alloys, such as the tensile ductility, thermal stability and creep property, etc. However, few studies on the effect of Y on the castability of titanium alloys have been carried out, which is significant to fabrication of thin-walled complex titanium castings by investment casting. In this study, the microstructure and mold filling capacity of a Ti-1100 alloy with different Y additions (0, 0.1wt.%...

  13. Hydrogen embrittlement effects on tensile properties of tungsten heavy alloys

    International Nuclear Information System (INIS)

    In this paper the strain rate sensitivities of 93 and 70% W heavy metal alloys are characterized in the hydrogen-charged and vacuum-outgassed conditions. In outgassed material, strength increases as ductility decreases with increased strain rate; however, for hydrogen-charged material, both ductility and strength increase with strain rate. Fracture morphology changes from characteristically ductile to brittle as strain rate increases. An integrated model is presented that illustrates the change in fracture behavior with strain rate for ductile, hydrogen-embrittled, and impurity-segregation embrittled material

  14. Effect of Coolant Water Flow Rate on Aluminum Alloys Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Golosov, O.A. [Institute of Nuclear Materials, Zarechny, Sverdlovsk region, 624250 (Russian Federation)

    2011-07-01

    One of the most important factors limiting a life-time of fuel elements in high-flux research reactors are a corrosion rate of fuel cladding material and a formation rate of oxide film. This study presents the results of the corrosion tests with and without irradiation. The aluminum alloys systems Al-Fe-Ni, Al-Fe-Ni-Cu-Mg and Al-Mg-Si-Cu were irradiated in the water flow of a velocity from 1.3 to 14.2m/s at 200 {sup o}C for time within 570 to 2000 hours. (author)

  15. Thermoelastic Stress Analysis: The Mean Stress Effect in Metallic Alloys

    Science.gov (United States)

    Gyekenyesi, Andrew L.; Baaklini, George Y.

    1999-01-01

    The primary objective of this study involved the utilization of the thermoelastic stress analysis (TSA) method to demonstrate the mean stress dependence of the thermoelastic constant. Titanium and nickel base alloys, commonly employed in aerospace gas turbines, were the materials of interest. The repeatability of the results was studied through a statistical analysis of the data. Although the mean stress dependence was well established, the ability to confidently quantify it was diminished by the experimental variations. If calibration of the thermoelastic response to mean stress can be successfully implemented, it is feasible to use the relationship to determine a structure's residual stress state.

  16. Effects of Alloying on the Optical Properties of Organic-Inorganic Lead Halide Perovskite Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Ndione, Paul F.; Li, Zhen; Zhu, Kai

    2016-09-07

    Complex refractive index and dielectric function spectra of organic-inorganic lead halide perovskite alloy thin films are presented, together with the critical-point parameter analysis (energy and broadening) of the respective composition. Thin films of methylammonium lead halide alloys (MAPbI3, MAPbBr3, MAPbBr2I, and MAPbBrI2), formamidinium lead halide alloys (FAPbI3, FAPbBr3, and FAPbBr2I), and formamidinium cesium lead halide alloys [FA0.85Cs0.15PbI3, FA0.85Cs0.15PbBrI2, and FA0.85Cs0.15Pb(Br0.4I0.6)3] were studied. The complex refractive index and dielectric functions were determined by spectroscopic ellipsometry (SE) in the photon energy range of 0.7-6.5 eV. Critical point energies and optical transitions were obtained by lineshape fitting to the second-derivative of the complex dielectric function data of these thin films as a function of alloy composition. Absorption onset in the vicinity of the bandgap, as well as critical point energies and optical band transition shift toward higher energies as the concentration of Br in the films increases. Cation alloying (Cs+) has less effect on the optical properties of the thin films compared to halide mixed alloys. The reported optical properties can help to understand the fundamental properties of the perovskite materials and also be used for optimizing or designing new devices.

  17. Effect of gradient thermal distribution on butt joining of magnesium alloy to steel with Cu–Zn alloy interlayer by hybrid laser–tungsten inert gas welding

    International Nuclear Information System (INIS)

    Highlights: ► The gradient thermal distribution is put forward to affect butt joining. ► Butt joining of Mg alloy to steel is realized by hybrid welding with interlayer. ► The joint fracture happens in the Mg weld seam instead of the Mg/Fe interface. ► Metallurgical bonding is achieved. ► The tensile strength attains 203 MPa. -- Abstract: Experimental investigations on butt welding of magnesium alloy to steel by hybrid laser–tungsten inert gas (TIG) welding with Cu–Zn alloy interlayer are carried out. The results show that the gradient thermal distribution of hybrid laser–TIG welding, controlled by offset adjustment, has a noticeable effect on mechanical properties and microstructure of the joints. Particularly, at the offset of 0.2 mm, defect-free joints are obtained, and the tensile strength could attain a maximum value of 203 MPa. Moreover, the fracture of the joint with the 0.2 mm offset happens in the weld seam of Mg alloy instead of the Mg/Fe interface. Owning to the addition of the Cu–Zn alloy interlayer, a metallurgical bonding between Mg alloy and steel is achieved based on the formation of intermetallic compounds of CuMgZn and solid solutions of Cu and Al in Fe. Meanwhile, the same element distribution tendency of Fe and Al indicates the intimate interaction between Fe and Al in current experimental conditions.

  18. Effect of heat treatment and alloing elements(Mo, Cu) on mechanical properties of Zr-based alloys

    International Nuclear Information System (INIS)

    To investigate the effect of final annealing temperature, and alloying elements(Mo, Cu) on mechanical properties of zirconium alloys, the tensile and creep test and microstructural analysis were performed on M5 type(Zr-1Nb-0.2X;X=Mo,Cu) and ZIRLO type(Zr-1Nb-1Sn-0.3Fe-0.1X ;X=Mo, Cu) zirconium alloys. The strength of stress relieved specimen was about 50% higher than that of fully annealed specimen. The strengthening effects were discussed on the basis of the solid solution hardening, the precipitate hardening, and grain size effect. Tensile and creep strength were increased with increasing the alloying elements. Molybdenium is more effective than copper to increase the strength. The effect of alloying element on creep strength is similar to that on tensile strength

  19. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    OpenAIRE

    Xu Chunxiang; Zhao Gaozhan; Zhang Jinshan

    2013-01-01

    To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.%) master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu ma...

  20. Effects Of Thermo-Mechanical Treatment On ALMG2 Alloy

    International Nuclear Information System (INIS)

    Thermo-mechanical treatment consisting of hot rolling and annealing process has been applied to ALMG2 plate. The ALMG2 plate was a dressed by hot rolling process at 400o with step deformation, and the ALMG2 plate was then annealed at 425o for one-hour. The observation on the microstructure was performed by using optical metallography, the hardness test was performed using Vickers method, and thermal conductivity was measured using conductometer. Thermo-mechanical treatment generates changes in ALMG2 microstructures and mechanical properties. The changes have been identified using optical metallography and Vickers micro hardness test. The treatment transforms the ALMG-equiaxial grain to elongated grain and the alloy hardness is still relatively soft. The hardness reaches about 58,5 Kg/mm2 after deformation of 18 %, 41 % and 76 % and 66 Kg/mm2 after deformation of 133 %. An one-our annealing treatment at 425o caused decreasing of the hardness to about (41-42) Kg/mm2 for 18 %, 41 % and 76 % deformation and to about 39 Kg/mm2 for 133 % deformation. This treatment makes the form of the grain equiaxial and the site of the grain larger. The results of the measurements using conductometer on the original ALMG2 alloy and it was addressed by hot rolling indicate that thermal conductivity of 143 W/mo to 140 W/mo

  1. Effect of cerium on abrasive wear behaviour of hardfacing alloy

    Institute of Scientific and Technical Information of China (English)

    XING Shule; YU Shengfu; DENG Yu; DAI Minghui; YU Lu

    2012-01-01

    Hardfacing alloys with different amounts of ceria were prepared by self-shielded flux cored arc welding.The abrasion tests were carried out using the dry sand-rubber wheel machine according to JB/T 7705-1995 standard.The hardness of hardfacing deposits was measured by means of HR-150AL Rockwell hardness test and the fracture toughness was measured by the indentation method.Microstructure characterization and surface analysis were made using optical microscopy,scanning electron microscopy (SEM) and energy spectrum analysis.The results showed that the wear resistance was determined by the size and distribution of the carbides,as well as by the matrix microstructure.The main wear mechanisms observed at the surfaces included micro-cutting and micro-ploughing of the matrix.The addition of ceria improved the hardness and fracture toughness of hardfacing deposits,which would increase the resistance to plastic deformation and scratch,thus the wear resistance of hardfacing alloys was improved.

  2. low temperature irradiation effects in iron-alloys and ceramics

    International Nuclear Information System (INIS)

    Electron beam irradiation at 77K and neutron irradiation at 20K were carried out on Fe-Cr and Fe-Cr-Ni alloys and ZnO and graphite system ceramics, and by measuring positron annihilation lifetime, the micro-information about irradiation-introduced defects was obtained. The temperature of the movement of atomic vacancies in pure iron is about 200K, but it was clarified that by the addition of Cr, it was not much affected. However, in the case of high concentration Cr alloys, the number of atomic vacancies which take part in the formation of micro-voids decreased as compared with the case of pure iron. It is considered that among the irradiation defects of ZnO, O-vac. restored below 300degC. It is considered that in the samples without irradiation, the stage of restoration exists around 550degC, which copes with structural defects. By the measurement of graphite without irradiation, the positron annihilation lifetime corresponding with the interface of matrix and crystal grains, grain boundaries and internal surfaces was almost determined. The materials taken up most actively in the research and development of nuclear fusion reactor materials are austenitic and ferritic stainless steels, and their irradiation defects have been studied. (K.I.)

  3. Separating Effect of a Novel Combined Magnetic Field on Inclusions in Molten Aluminum Alloy

    Science.gov (United States)

    He, Yanjie; Li, Qiulin; Liu, Wei

    2012-10-01

    The feasibility and effectiveness of a novel combined magnetic field (CMF) on the removal of inclusions with a density smaller than the surrounding melt were investigated. The experiment of the separating effect of CMF was conducted on a laboratory-scale apparatus by the simultaneous application of a rotating magnetic field (RMF) and a downward traveling magnetic field (TMF). Primary silicon particles precipitating from the solidification process of Al-Si-Cu alloy were regarded as the inclusions in a molten aluminum alloy. It was found that a CMF consisting of both a RMF and a downward TMF was able to separate silicon particles from the molten Al-Si-Cu alloy by making these particles migrate vertically toward the upper part of the samples. Compared with downward TMF or RMF, CMF improved the separating effectiveness substantially. It was proposed that this type of CMF was approved to be highly effective at eliminating the inclusions with a density smaller than the surrounding molten alloy. A tentative mechanism for the high separating effect of CMF was discussed.

  4. Effect of Si content on the dry sliding wear properties of spray-deposited Al-Si alloy

    International Nuclear Information System (INIS)

    In the present investigation, Al-12Si, Al-20Si and Al-25Si (wt%) alloys were synthesized by spray atomization and deposition technique. The wear resistance of the alloys was studied using a pin-on-disc machine under four loads, namely 8.9, 17.8, 26.7 and 35.6 N. The microstructures, worn surfaces and the debris were analyzed in a scanning electron microscope. It has been found that the effect of Si content on dry sliding wear of spray-deposited Al-Si alloy was associated with applied loads. At lower load (8.9 N), with increasing Si content, the wear rate of the alloy was decreased. At higher load (35.6 N), spray-deposited Al-20Si alloy exhibited superior wear resistance to the Al-12Si and Al-25Si alloys

  5. Effect of implantation of biodegradable magnesium alloy on BMP-2 expression in bone of ovariectomized osteoporosis rats

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yue, E-mail: 373073766@qq.com [Liaoning Medical University, 40 Songpo Road, Jinzhou, 121000 (China); Ren, Ling, E-mail: lren@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Liu, Chang, E-mail: meixifan1971@163.com [Liaoning Medical University, 40 Songpo Road, Jinzhou, 121000 (China); Yuan, Yajiang, E-mail: yuan925@163.com [Liaoning Medical University, 40 Songpo Road, Jinzhou, 121000 (China); Lin, Xiao, E-mail: linx@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Tan, Lili, E-mail: lltan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Chen, Shurui, E-mail: 272146792@qq.com [Liaoning Medical University, 40 Songpo Road, Jinzhou, 121000 (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Mei, Xifan, E-mail: meixifan1971@163.com [Liaoning Medical University, 40 Songpo Road, Jinzhou, 121000 (China)

    2013-10-01

    The study was focused on the implantation of a biodegradable AZ31 magnesium alloy into the femoral periosteal of the osteoporosis modeled rats. The experimental results showed that after 4 weeks implantation of AZ31 alloy in the osteoporosis modeled rats, the expression of BMP-2 in bone tissues of the rats was much enhanced, even higher than the control group, which should promote the bone formation and be beneficial for reducing the harmful effect of osteoporosis. Results of HE stains showed that the implantation of AZ31 alloy did not have obvious pathological changes on both the liver and kidney of the animal. - Highlights: • Mg alloy greatly increased expression of BMP-2 in osteoporosis modeled rat bone. • Mg alloy showed good biological safety. • Mg alloy is beneficial for reducing the symptom of osteoporosis.

  6. Effects of partial crystallinity and quenched-in defects on corrosion of a rapidly solidified Ti–Cu alloy

    Indian Academy of Sciences (India)

    R S Dutta; G K Dey

    2003-08-01

    Rapid solidification by planar flow casting has been found to have introduced deficiencies, viz. partial crystallinity, air pockets and compositional difference in the ribbons of rapidly solidified Ti42.9-Cu57.1 alloy. In order to investigate the effects of these deficiencies on the corrosion of rapidly solidified Ti42.9-Cu57.1 alloy ribbons, electrochemical behaviour of alloy ribbons has been investigated in the acidic chloride environments at room temperature by taking into consideration each side of the alloy ribbon separately. The alloy displayed passivity followed by pitting corrosion. In the as-solidified condition, air pockets appear to be the most detrimental defect from the viewpoint of corrosion resistance of the alloy ribbons.

  7. Effect of implantation of biodegradable magnesium alloy on BMP-2 expression in bone of ovariectomized osteoporosis rats

    International Nuclear Information System (INIS)

    The study was focused on the implantation of a biodegradable AZ31 magnesium alloy into the femoral periosteal of the osteoporosis modeled rats. The experimental results showed that after 4 weeks implantation of AZ31 alloy in the osteoporosis modeled rats, the expression of BMP-2 in bone tissues of the rats was much enhanced, even higher than the control group, which should promote the bone formation and be beneficial for reducing the harmful effect of osteoporosis. Results of HE stains showed that the implantation of AZ31 alloy did not have obvious pathological changes on both the liver and kidney of the animal. - Highlights: • Mg alloy greatly increased expression of BMP-2 in osteoporosis modeled rat bone. • Mg alloy showed good biological safety. • Mg alloy is beneficial for reducing the symptom of osteoporosis

  8. Effects of Hot Rolling on Low-Cycle Fatigue Properties of Zn-22 wt.% Al Alloy at Room Temperature

    Science.gov (United States)

    Dong, X. H.; Cao, Q. D.; Ma, S. J.; Han, S. H.; Tang, W.; Zhang, X. P.

    2016-06-01

    The effects of the reduction ratio (RR) on the low-cycle fatigue (LCF) properties of the Zn-22 wt.% Al (Zn-22Al) alloy were investigated. Various grain sizes from 0.68 to 1.13 μm were obtained by controlled RRs. Tensile and LCF tests were carried out at room temperature. Superplasticity and cyclic softening were observed. Strength and ductility of the rolled Zn-22Al alloy increased with the RR, owing to the decrease in its grain size. The RR did not affect the cyclic softening behavior of the alloy. The fatigue life of the alloy decreased with increasing strain amplitude, while the fatigue life first decreased and then increased with increasing RR. The longest fatigue life was observed for the alloy rolled at a RR of 60%. A bilinear Coffin-Manson relationship was observed to hold true for this alloy.

  9. The effects of heat treatment on the recovery stresses of shape memory alloys

    International Nuclear Information System (INIS)

    The influence of annealing temperatures on the thermo-mechanical behavior of NiTi alloy in terms of transformation temperatures, mechanical properties at ambient temperature and the recovery stress under constrained end conditions were investigated experimentally. An attempt is made to correlate results obtained from the DSC test and tensile test at room temperature with results from recovery stresses at elevated temperatures. It is found that annealing the alloy above the recrystallization temperature (600 °C) reduces the maximum recovery stress significantly, even though the alloy still exhibits thermal transformations and a stress-induced martensite plateau at an annealing temperature above 600 °C. A pre-strained amount above approximately 2.4% strain is sufficient to achieve the maximum recovery stress at constrained end conditions. It is recommended that the alloy used in this study be annealed at temperatures below 450 °C in order to produce the desired thermo-mechanical properties in the alloy for applications that exploit the shape memory effect

  10. Effects of Sn contents and final annealing temperatures on the corrosion characteristics of Zr alloys

    International Nuclear Information System (INIS)

    The effects of Sn contents and final annealing treatments on the corrosion properies of Zr-1.5Nb-xSn (x= 0.0-0.2 wt.%) alloys were evaluated sysmatically. The final treatment of the alloys was carried out at the temperature range of 400 to 800 .deg. C for 2.5 hours. The final treatment at 470 .deg. C and 570 .deg. C did not affect the corrosion properties with the variation of Sn contents. But the corrosion resistance of the specimens annealed at 640 .deg. C was inferior to the that at 470. deg. C and 570 .deg. C and increased as the increase of Sn contents. This means that Zr-1.5Nb-xSn alloys, of which Nb content is higher than solubility limit, would form the β-Zr phase in the case of 640 .deg. C-final annealing. The crystallization and grain growth of Zr-1.5Nb-xSn alloy was retarded with the increase of Sn contents. Because of the lattic distortion caused by Sn addition, the Sn addition in Zr-1.5Nb-xSn alloys could affect the interferance in the movement of dislocation and crystal interface

  11. Effects of Pb on the Stress Corrosion Cracking of Alloy 600 in Weak Caustic Water

    International Nuclear Information System (INIS)

    The effects of lead on the stress corrosion cracking of Alloy 600 were investigated in weak caustic water at high temperature by Slow Strain Rate Test (SSRT). The extent and morphology of cracking were analyzed by Scanning Electron Microscope (SEM). The chemical compositions on the fracture surface were analyzed by Wavelength Dispersive X-ray spectroscopy (WDX). Alloy 600 was cracked severely under the condition of 100 ppm Pb, 1 x 10-7sec-1. PbO acted as a role of oxidizer on the surface of Alloy 600, and IGA and SCC occurred at a low concentration of PbO, while SCC only occurred at a high concentration of PbO. The strain rate is a critical factor in this SCC test, no SCC occurred in the solution containing 1000 ppm Pb at strain rates of 5x10-7 and 1 x 10-6sec-1. The transgranular stress corrosion cracking of Alloy 600 in lead doped water may be closely associated with the carbide morphology at a grain boundary, the lead concentration and the strain rate. And the transgranular cracking mechanism of Alloy 600 was interpreted on the base of the anodic dissolution followed by active slip step dissolution

  12. Biodegradable Mg-Cu alloys with enhanced osteogenesis, angiogenesis, and long-lasting antibacterial effects

    Science.gov (United States)

    Liu, Chen; Fu, Xuekun; Pan, Haobo; Wan, Peng; Wang, Lei; Tan, Lili; Wang, Kehong; Zhao, Ying; Yang, Ke; Chu, Paul K.

    2016-01-01

    A series of biodegradable Mg-Cu alloys is designed to induce osteogenesis, stimulate angiogenesis, and provide long-lasting antibacterial performance at the same time. The Mg-Cu alloys with precipitated Mg2Cu intermetallic phases exhibit accelerated degradation in the physiological environment due to galvanic corrosion and the alkaline environment combined with Cu release endows the Mg-Cu alloys with prolonged antibacterial effects. In addition to no cytotoxicity towards HUVECs and MC3T3-E1 cells, the Mg-Cu alloys, particularly Mg-0.03Cu, enhance the cell viability, alkaline phosphatase activity, matrix mineralization, collagen secretion, osteogenesis-related gene and protein expressions of MC3T3-E1 cells, cell proliferation, migration, endothelial tubule forming, angiogenesis-related gene, and protein expressions of HUVECs compared to pure Mg. The favorable osteogenesis and angiogenesis are believed to arise from the release of bioactive Mg and Cu ions into the biological environment and the biodegradable Mg-Cu alloys with osteogenesis, angiogenesis, and long-term antibacterial ability are very promising in orthopedic applications. PMID:27271057

  13. Biodegradable Mg-Cu alloys with enhanced osteogenesis, angiogenesis, and long-lasting antibacterial effects.

    Science.gov (United States)

    Liu, Chen; Fu, Xuekun; Pan, Haobo; Wan, Peng; Wang, Lei; Tan, Lili; Wang, Kehong; Zhao, Ying; Yang, Ke; Chu, Paul K

    2016-01-01

    A series of biodegradable Mg-Cu alloys is designed to induce osteogenesis, stimulate angiogenesis, and provide long-lasting antibacterial performance at the same time. The Mg-Cu alloys with precipitated Mg2Cu intermetallic phases exhibit accelerated degradation in the physiological environment due to galvanic corrosion and the alkaline environment combined with Cu release endows the Mg-Cu alloys with prolonged antibacterial effects. In addition to no cytotoxicity towards HUVECs and MC3T3-E1 cells, the Mg-Cu alloys, particularly Mg-0.03Cu, enhance the cell viability, alkaline phosphatase activity, matrix mineralization, collagen secretion, osteogenesis-related gene and protein expressions of MC3T3-E1 cells, cell proliferation, migration, endothelial tubule forming, angiogenesis-related gene, and protein expressions of HUVECs compared to pure Mg. The favorable osteogenesis and angiogenesis are believed to arise from the release of bioactive Mg and Cu ions into the biological environment and the biodegradable Mg-Cu alloys with osteogenesis, angiogenesis, and long-term antibacterial ability are very promising in orthopedic applications. PMID:27271057

  14. Effect of two-step aging on the mechanical properties of AA2219 DC cast alloy

    International Nuclear Information System (INIS)

    With its combination of high specific strength, good machinability and excellent weldability, AA2219 direct chill (DC) cast alloy has become a new category of materials for manufacturing large molds for the plastics and automotive industries. The effect of two-step aging on the microstructural evolution and mechanical properties of AA2219 DC cast alloy was investigated. The precipitate microstructure was characterized under different heat treatment conditions using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The poor mechanical properties of the air-quenched alloy were attributed to the presence of quench-induced coarse θ′ and θ precipitates, which had very limited contribution to the precipitation hardening during the aging treatment. The two-step aging treatment of the air-quenched AA2219 alloy involved the precipitation of GP zones in the first step followed by their transformation into fine θ″ strengthening precipitates in the second step, which considerably improved the mechanical properties. After undergoing 120 °C/36 h+190 °C/8 h two-step aging, the hardness, YS and UTS of the air-quenched alloy were increased by 27%, 46% and 15%, respectively, compared with 190 °C/8 h one-step aging

  15. Effects of composition, heat treatment and cold work on structure and properties of alloy 800

    International Nuclear Information System (INIS)

    The creep characteristics of alloy 800 at temperatures around 6000C are greatly affected by the composition and treatments in the final stages of manufacture. Short-term and creep properties of alloy 800 at 6000C are described for six melts covering the carbon range 0.054-0.078%, the titanium range 0.23-0.57% and the aluminium range 0.17-0.52%. The properties are related to the alloy chemistry and the microstructure. It is shown that homogeneously nucleated γ'-precipitates are the main cause of low ductility in alloy 800 but there is also some influence of, for instance, grain boundary M23C6 films and discontinuous precipitation of Ni3Ti or M23C6 in grain boundaries. The extent of γ'-precipitation is controlled primarily by the (Ti+Al)-content. To avoid γ' and ensure a high creep ductility the (Ti+Al)-content should be limited to 0.70-0.75% for alloy 800 with a carbon content of 0.054-0.078% and solution annealed at 11500C. A lower solution temperature will reduce the matrix Ti-content and push the allowed total (Ti+Al)-content upwards. The effect of grain size is such that a coarse-grained material becomes more brittle than a fine-grained one. Cold work of up to 10% will enhance the creep-rupture strength but reduce the ductility

  16. The Effects of Corrosive Media on Fatigue Performance of Structural Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Huihui Yang

    2016-07-01

    Full Text Available The effects of corrosive media on rotating bending fatigue lives (the cyclic numbers from 104 to 108 of different aluminum alloys were investigated, which involved the corrosion fatigue lives of five kinds of aluminum alloys in air, at 3.5 wt. % and 5.0 wt. % NaCl aqueous solutions. Experimental results indicate that corrosive media have different harmful influences on fatigue lives of different aluminum alloys, in which the differences of corrosion fatigue lives depend strongly on the plastic property (such as the elongation parameter of aluminum alloys and whether to exist with and without fracture mode II. The other various influence factors (such as the dropping corrosive liquid rate, the loading style, and the nondimensionalization of strength of corrosion fatigue lives in three media were also discussed in detail by using the typical cases. Furthermore, fracture morphologies and characteristics of samples, which showed the different fatigue cracking behaviors of aluminum alloys in three media, were investigated by scanning electron microscopy (SEM in this paper.

  17. Effect of nitriding treatment on corrosion behaviour of Co–Cr–Mo alloy in liquid Al

    International Nuclear Information System (INIS)

    Highlights: •Co–29Cr–6Mo alloy is nitrided in pure nitrogen. •Sample surface after nitriding is observed using transmission electron microscope. •Sample subsurface after nitriding is observed with electron backscatter diffraction. •Corrosion of nitrided samples in liquid Al is evaluated with immersion test. •Nitriding treatment is compared and discussed with oxidation treatment. -- Abstract: Effects of nitriding treatment on the corrosion behaviour of Co–29Cr–6Mo alloy in liquid Al were investigated. Because of the high solubility and high diffusion coefficient of nitrogen in Co, Cr2N and π phases formed from sample surface into alloy matrix during nitriding at 1273 K; however, the nitride layer was not continuously formed on sample surface even in a prolonged process. The Cr2N showed obviously higher resistance to liquid Al compared to alloy matrix, but owing to its discontinuous distribution, the formed Cr2N did not obviously improve the corrosion resistance of the alloy to liquid Al

  18. Microstructure and shape memory effect of Ti-20Zr-10Nb alloy

    International Nuclear Information System (INIS)

    The microstructure, martensitic transformation behavior and shape memory effect of Ti-20Zr-10Nb shape memory alloy have been studied by X-ray diffraction (XRD), optical microscopy (OM) and transmission electron microscopy (TEM) observation, differential scanning calorimetry (DSC) and tensile stress-strain measurements. The results show that the recrystallization occurs in the cold rolled Ti-20Zr-10Nb alloy by annealing at 600 deg. C and the grain size goes up with the increasing annealing temperature up to 800 deg. C. The Ti-20Zr-10Nb alloy is primarily composed of α'' martensite and a small amount of ω phase which appears after annealing. A reverse martensite transformation temperature higher than 500 deg. C upon heating has been detected for the Ti-20Zr-10Nb alloy annealed at 600 deg. C, but no obvious exothermic behavior can be found upon cooling. The tensile strength and the failure strain of the alloy are measured to be 542 MPa and 13.1%, respectively, associated with a maximum shape recovery strain of about 2.5%.

  19. Effects of alloying elements on elastic properties of Al by first-principles calculations

    Directory of Open Access Journals (Sweden)

    Wang J.

    2014-01-01

    Full Text Available The effects of alloying elements (Co, Cu, Fe, Ge, Hf, Mg, Mn, Ni, Si, Sr, Ti, V, Y, Zn, and Zr on elastic properties of Al have been investigated using first-principles calculations within the generalized gradient approximation. A supercell consisting of 31 Al atoms and one solute atom is used. A good agreement is obtained between calculated and available experimental data. Lattice parameters of the studied Al alloys are found to be depended on atomic radii of solute atoms. The elastic properties of polycrystalline aggregates including bulk modulus (B, shear modulus (G, Young’s modulus (E, and the B/G ratio are also determined based on the calculated elastic constants (cij’s. It is found that the bulk modulus of Al alloys decreases with increasing volume due to the addition of alloying elements and the bulk modulus is also related to the total molar volume (Vm and electron density (nAl31x with the relationship of nAl31x=1.0594+0.0207√B/Vm. These results are of relevance to tailor the properties of Al alloys.

  20. Effect of two-step aging on the mechanical properties of AA2219 DC cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Elgallad, E.M., E-mail: eelgalla@uqac.ca; Zhang, Z.; Chen, X.-G.

    2015-02-11

    With its combination of high specific strength, good machinability and excellent weldability, AA2219 direct chill (DC) cast alloy has become a new category of materials for manufacturing large molds for the plastics and automotive industries. The effect of two-step aging on the microstructural evolution and mechanical properties of AA2219 DC cast alloy was investigated. The precipitate microstructure was characterized under different heat treatment conditions using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The poor mechanical properties of the air-quenched alloy were attributed to the presence of quench-induced coarse θ′ and θ precipitates, which had very limited contribution to the precipitation hardening during the aging treatment. The two-step aging treatment of the air-quenched AA2219 alloy involved the precipitation of GP zones in the first step followed by their transformation into fine θ″ strengthening precipitates in the second step, which considerably improved the mechanical properties. After undergoing 120 °C/36 h+190 °C/8 h two-step aging, the hardness, YS and UTS of the air-quenched alloy were increased by 27%, 46% and 15%, respectively, compared with 190 °C/8 h one-step aging.

  1. Effects of AI Addition on the Thermoelectric Properties of Zn-Sb Based Alloys

    Institute of Scientific and Technical Information of China (English)

    CUI Jiaolin; LIU Xianglian; YANG Wei; CHEN Dongyong; MAO Liding; QIAN Xin

    2009-01-01

    The β-Zn4Sb3, emerged as a compelling p-type thermoelectric material, is widely used in heat-electricity conversion in the 400-650 K range. In order to probe the effects of slight doping on the crystal structure and physical properties, we prepared the samples of Al-added Zn-Sb based alloys by spark plasma sintering and evaluated their microstructures and thermoelectric properties. After a limited Al addition into the Zn-Sb based alloys we observed many phases in the alloys, which include a major phase β-Zn4Sb3,intermetallic phases ZnSb and AISb. The major β-Zn4Sb3 phase plays a fundamental role in controlling the thermoelectric performance, the precipitated phases ZnSb and AISb are of great importance to tailor the transport properties, such as the gradual enhancement of lattice thermal conductivity, in spite of an increased phonon scattering in additional grain boundaries. The highest thermoelectric figure of merit of 0.55 is obtained for the alloy with a limited AI addition at 653 K, which is 0.08 higher than that of un-doped β-Zn4Sb3 at the corresponding temperature. Physical property experiments indicate that there is a potentiality for the improvement of thermoelectric properties if a proper elemental doping is carried out into the Zn-Sb based alloys, which was confirmed by AI addition in the present work.

  2. Investigation of processing effects on the corrosion resistance of Ti20Mo alloy in saline solutions

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Alloy fabrication method affects both surface finish and corrosion resistance. • More porous surface finish and higher wettability produced by powder sintering. • Passive layer formed on sintered alloy breaks down in saline solution. • Increase in surface porosity facilitated electron transfer through the oxide film. • More corrosion resistant alloy produced by cold crucible levitation melting. - Abstract: The electrochemical properties of Ti20Mo alloys prepared using different fabrication procedures, namely cold crucible levitation melting (CCLM) and powder sintering, were investigated using linear potentiodynamic polarization and EIS measurements. The surface condition was established using AFM, with the observation of a more porous surface finish in the case of powder sintering. A major effect of surface conditioning on the corrosion resistance of Ti20Mo alloys was observed, where the compact finish exhibits a superior corrosion resistance in chloride-containing saline solutions. Less insulating surfaces towards electron exchange resulted for the more porous finish as revealed by scanning electrochemical microscopy (SECM)

  3. Effects of cold pre-deformation on aging behavior and mechanical properties of Ti-1300 alloy

    International Nuclear Information System (INIS)

    Highlights: • Cold pre-deformation influences aging behavior and mechanical properties. • The slip and twinning are the leading deformation mechanism in the Ti-1300 alloy. • Fine/uniform α precipitates are formed in the slightly deformed zones. • Coarse/needle-like α precipitates are formed in the heavily deformed zones. - Abstract: The effects of cold pre-deformation on aging behavior and mechanical properties in Ti-1300 alloy are examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy analyses. Results show that cold pre-deformation markedly influences the aging behavior and mechanical properties of Ti-1300 alloys. The cold deformation mechanism of Ti-1300 alloys is found to involve the dislocation slip and twinning. The microstructures of the pre-deformation specimens, which were aged at 550 °C, comprise α phases in β matrices regardless of cold deformation reduction. Fine/uniform and coarse/needle-like α precipitates are formed in the slightly and heavily deformed zones, respectively. The Vickers hardness of Ti-1300 alloys aged after cold pre-deformation respectively decreases and increases with increased aging temperature and cold pre-deformation reduction

  4. Effects of spherical quasi-crystal on microstructure and mechanical properties of ZA155 high zinc magnesium alloy

    OpenAIRE

    Zhang Jinshan; Liu Yali; Zhang Yan

    2010-01-01

    Effects of spherical quasi-crystal contained in Mg-Zn-Y-Mn master alloy on the microstructure and as-cast mechanical properties of ZA155 high zinc magnesium alloy have been investigated by means of optical microscopy, XRD, SEM, EDS, tensile test, impact test and hardness test. Experimental results show that the addition of spherical quasi-crystal contained in the Mg-Zn-Y-Mn master alloy into the ZA155 high zinc magnesium alloy resulted in grain refinement of the matrix, changing the morpholog...

  5. On the effects of partial substitution of Co for Fe in FINEMET and Nb-containing HITPERM alloys

    CERN Document Server

    Blazquez, J S; Conde, C F; Conde, A; Greneche, J M

    2003-01-01

    A comparative study of the effects of partial substitution of Co for Fe on thermal stability, crystallization and magnetic properties of Co-containing FINEMET and HITPERM alloys series is presented. The difference in metalloid and Nb content between the two alloy series and the presence of Si in the nanocrystals in the case of FINEMET alloys appear as key parameters. A recrystallization process involving the alpha-Fe type phase in nanocrystalline alloys of both series is evident from thermomagnetic results as a significant decrease in magnetization at the second crystallization stage.

  6. Effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy

    Indian Academy of Sciences (India)

    G Durashevich; V Cvetkovski; V Jovanovich

    2002-02-01

    The CuCrZr alloy undergoes processes of precipitation during ageing. Besides precipitation hardening the strength is affected by cold deformation which is performed before and after ageing. The cold deformation (1) before ageing accelerates the process of strength hardening, since it induces higher rate of precipitation from the saturated -solid solution. Cold deformation (2) after ageing primarily affects the alloy strength. In this paper the results of the effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy are presented. The aim of the paper was to evaluate the most suitable combination of thermomechanical treatment and alloy properties.

  7. On the effects of partial substitution of Co for Fe in FINEMET and Nb-containing HITPERM alloys

    International Nuclear Information System (INIS)

    A comparative study of the effects of partial substitution of Co for Fe on thermal stability, crystallization and magnetic properties of Co-containing FINEMET and HITPERM alloys series is presented. The difference in metalloid and Nb content between the two alloy series and the presence of Si in the nanocrystals in the case of FINEMET alloys appear as key parameters. A recrystallization process involving the α-Fe type phase in nanocrystalline alloys of both series is evident from thermomagnetic results as a significant decrease in magnetization at the second crystallization stage

  8. Effect of electron density transfer between the components of Fe-Cr-Si alloys on their physicochemical properties

    International Nuclear Information System (INIS)

    Mechanism of doping element effect on the change of alloy physicochemical properties is discussed taking Fe-Cr-Si system as an example. It is experimentally ascertained that electron density transfer from Fe-Cr α-solid solution atoms to silicon occurs in Fe-Cr-Si alloys, i.e. silicon in the alloy manifests acceptor properties. The direction of electron density transfer between the alloy components can be qualitatively estimated by the value of their orbital electric negation. 24 refs.; 4 figs.; 4 tabs

  9. Effect of alloying elements on austempered ductile iron (ADI properties and its process: Review

    Directory of Open Access Journals (Sweden)

    Amir Sadighzadeh Benam

    2015-01-01

    Full Text Available Austempered ductile iron (ADI parts have a unique combination of high strength and toughness with excellent design flexibility and low cost. These excellent properties are directly related to its microstructure called "ausferrite" that is the result of austempering heat treatment applied to ductile irons. Alloying elements increase ADI austemperability and change speeds of austempering reactions. Thus, they can affect ADI resultant microstructure and mechanical properties. In this paper, the effects of alloying elements on ADI mechanical properties, microstructural changes, two-stage austempering reactions, processing windows, austemperability, and other aspects are reviewed.

  10. Effect of cold work on initiation stage crack growth rate of nickel based alloys

    International Nuclear Information System (INIS)

    To investigate the effect of cold work on initiation stage crack growth rates of nickel based alloy, initiation stage crack growth rates were measured for simulated PWR primary water conditions using flat type specimens which were prepared from three different heats of alloy 600 and then 20 and 40% cold worked. Almost all data showed the stress had an increasing linear dependency on crack growth rate ; however there was some scattering of data and some materials showed a different tendency. Since yield strength was increased by cold work, for the same stress, the initiation stage crack growth rates were restrained or were not changed significantly by cold work. (author)

  11. Effect of Nitriding on Fatigue Characteristics of Cr-Mo Alloy Steel

    International Nuclear Information System (INIS)

    CrMo alloy steel was nitrided using two types of processing methods, ion-nitriding processing and nitrocarburizing. Both processes were conducted for a duration of 30 min. To compare the surface hardness of the alloys created by the different processes , microhardness tests were conducted, and fatigue tests of each material were performed by a cantilever rotary bending fatigue test machine (Yamamoto, YRB 200) in the very high cycle regime (N > 107cycle). Fractography of the fractured surfaces was conducted by scanning electron microscopy - to observe the fracture mechanisms of very high cycle fatigue and the effect of the nitriding process on the fatigue characteristics

  12. Effect of Nitriding on Fatigue Characteristics of Cr-Mo Alloy Steel

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Kwang Keun; Kim, Jae Hoon; Choi, Hoon Seok [Chungnam National University, Daejeon (Korea, Republic of)

    2015-06-15

    CrMo alloy steel was nitrided using two types of processing methods, ion-nitriding processing and nitrocarburizing. Both processes were conducted for a duration of 30 min. To compare the surface hardness of the alloys created by the different processes , microhardness tests were conducted, and fatigue tests of each material were performed by a cantilever rotary bending fatigue test machine (Yamamoto, YRB 200) in the very high cycle regime (N > 10{sup 7}cycle). Fractography of the fractured surfaces was conducted by scanning electron microscopy - to observe the fracture mechanisms of very high cycle fatigue and the effect of the nitriding process on the fatigue characteristics.

  13. Effect of Deformation on Order-Disorder Phase Transformation in Cu-Zn Alloy

    Institute of Scientific and Technical Information of China (English)

    Zhang Ruijun; Xu Liang; Liu Jianhua

    2007-01-01

    The phase transformation temperature of ordered β' to disordered β in the Cu-Zn alloy was tested by DSC. The transformation activation energy was calculated and the effect of deformation of the phase transformation was discussed. The results show that the phase transformation temperature and activation energy of ordered β' to disordered β in the Cu-Zn alloy can be decreased going through deformation, and the phase transformation time can be also decreased. As a result, the order-disorder phase transformation occurs more easily.

  14. THE EFFECT OF THE ALUMINIUM ALLOY SURFACE ROUGHNESS ON THE RESTITUTION COEFFICIENT

    Directory of Open Access Journals (Sweden)

    Stanisław Bławucki

    2015-08-01

    Full Text Available The paper presents the results of research on the effect of the surface roughness of aluminum alloy on its coefficient of restitution. It describes the current method of finishing the workpiece surface layer after cutting and innovative measuring device which was used in the research. The material used in the research was aluminium alloy EN AW 7075. The paper also presents a relationship between the coefficient of restitution and surface roughness of the milled samples as well as impressions left by bead in function of velocity and a sample surface roughness.

  15. Effect of displacement damage on the stability of oxide nanoparticles in model ODS alloys: TEM studies

    International Nuclear Information System (INIS)

    Model ODS alloy containing Fe-0.3% yttria was prepared by ball milling and hipping at high temperature and the effect of irradiation on stability of yttria nanoclusters in model ODS alloy is studied by dual beam ion irradiation using 5 MeV Fe+ and 1.5 MeV He+ ions. TEM studies on irradiated sample show that these particles are stable at 25 dpa and 40 appm He concentration. However, at 80 dpa and 360 appm He concentration Yttria particles were found to be unstable as evidenced from increase in average particle size and particle size distribution.

  16. Substitutional impurities and their effect on fracture peculiarities in W-Ni-Fe-alloy

    Energy Technology Data Exchange (ETDEWEB)

    Minakova, R.V.; Bazhenova, L.G.; Verkhovodov, P.A.; Kolchin, O.P.; Nedelyaeva, L.P.; Tolstunov, A.V. (AN Ukrainskoj SSR, Kiev. Inst. Problem Materialovedeniya)

    1983-11-01

    The paper deals with distribution of admixture elements, shape, size, content, chemical composition, distribution of nonmetal inclusions and their effect on peculiarities of W-Ni-Fe-alloy deformation and fractures. It is established that non-metal inclusions play the part of additional ''notches'' decreasing the size of the slow crack growth area in a refractory component. Segregation of the impurities and the film on the boundaries of nickel base solid solution promote intercrystalline fracture of the alloy.

  17. Effects of alloy and solution chemistry on the fracture of passive films on austenitic stainless steel

    International Nuclear Information System (INIS)

    The Taguchi analysis method was used to simultaneously study the effects of alloy chemistry, pH, and halide ion concentrations on the fracture of electrochemically grown passive films using a nanoindentation technique. Three austenitic stainless steels, 304L, 316L, and 904L were potentiostatically polarized in hydrochloric acid solutions. The fracture load was dominated primarily by alloy chemistry. Passive films mechanically weaken as the atomic iron concentration increases in the film. Prolonged anodic ageing time increases the fracture load of passive films

  18. Effects of alloy and solution chemistry on the fracture of passive films on austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Alamr, A. [School of Mechanical and Materials Engineering, Washington State University, P.O. Box 642920, Pullman, WA 99164-2920 (United States)]. E-mail: alamrz@wsu.edu; Bahr, D.F. [School of Mechanical and Materials Engineering, Washington State University, P.O. Box 642920, Pullman, WA 99164-2920 (United States)]. E-mail: bahr@mail.wsu.edu; Jacroux, Michael [Department of Statistics, Washington State University, Pullman, WA 99164-3144 (United States) ]. E-mail: jacroux@wsu.edu

    2006-04-15

    The Taguchi analysis method was used to simultaneously study the effects of alloy chemistry, pH, and halide ion concentrations on the fracture of electrochemically grown passive films using a nanoindentation technique. Three austenitic stainless steels, 304L, 316L, and 904L were potentiostatically polarized in hydrochloric acid solutions. The fracture load was dominated primarily by alloy chemistry. Passive films mechanically weaken as the atomic iron concentration increases in the film. Prolonged anodic ageing time increases the fracture load of passive films.

  19. Effective interactions between concentration fluctuations and charge transfer in chemically ordering liquid alloys

    International Nuclear Information System (INIS)

    The correlations between long-wavelength fluctuations of concentration in a liquid binary alloy are determined by a balance between an elastic strain free energy and an Ornstein-Zernike effective interaction. The latter is extracted from thermodynamic data in the case of the Li-Pb system, which is well known to chemically order with stoichiometric composition corresponding to Li4Pb. Strong attractive interactions between concentration fluctuations near the composition of chemical ordering originate from electronic charge transfer, which is estimated from the electron-ion partial structure factors as functions of composition in the liquid alloy. (author). 20 refs, 2 figs

  20. Effects of organic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.; Dietzel, W.; Kainer, K. U.

    2010-01-01

    mu m of the contaminated surface was required to reach corrosion rates less than 1 mm/year in salt spray condition. Among the three organic acids examined, acetic acid is the best choice. Oxalic acid can be an alternative while citric acid is not suitable for cleaning AZ31 sheet, because of......Organic acids were used to clean AZ31 magnesium alloy sheet and the effect of the cleaning processes on the surface condition and corrosion performance of the alloy was investigated. Organic acid cleanings reduced the surface impurities and enhanced the corrosion resistance. Removal of at least 4...

  1. EFFECT OF THE TEMPERATURE ON THE FRICTION AND WEAR PROPERTIES OF BULK AMORPHOUS ALLOY

    OpenAIRE

    DAWIT ZENEBE SEGU; PYUNG HWANG; SEOCK-SAM KIM

    2014-01-01

    The present paper report the results of an experimental investigation of the temperature effect on the sliding friction and wear properties of the bulk metallic glass (BMG). To improve the friction and wear properties of the BMG, the disk specimens were developed in the alloy system of Fe67.6C7.1Si3.3B5.5P8.7Cr2.3Mo2.6Al2Co1.0 using hot metal and industrial ferro-alloys. The friction and wear test was performed using flat-on-flat contact configuration of unidirectional tribometer and Si3N4 ce...

  2. Effect of scratch on crack initiation of alloy 690TT in high temperature high pressure water

    International Nuclear Information System (INIS)

    Full text of publication follows: This paper aims to investigate the effect of scratch on crack initiation of Alloy 690. The corrosion and stress corrosion of scratched Alloy 690 were studied using scanning electrochemical microscopy (SECM) and scanning electron microscopy (SEM). The results showed that scratch caused residual compressive stress underneath the scratch, dissolution was preferentially active at scratches and intergranular cracks initiated at the bottom of scratch after immersion in high temperature water. At the macro-compressive stressed area, localized tensile stress caused by oxide jacking could initiate crack. (authors)

  3. Simultaneous effect of mechanical alloying and arc-melting processes in the microstructure and hardness of an AlCoFeMoNiTi high-entropy alloy

    International Nuclear Information System (INIS)

    Highlights: • Multi-component systems of AlCoFeMoNiTi were produced by mechanical alloying. • Consolidated samples were fabricated by two different processing routes, sintering and arc melting. • Effect of routes of consolidation on microstructural evolution and microhardness is reported. • High hardness values are found in consolidated samples. • Alloying elements, grain size, and precipitates have a high effect on microhardness. - Abstract: A nanostructured AlCoFeMoNiTi high entropy alloy was synthesized through the mechanical alloying process. Bulk samples were obtained by two different routes to compare the microstructural evolution and hardness behavior: sintering and arc melting. Through electron microscopy analyses the formation of Mo-rich and Ti-rich phases were identified in the melted sample, while Ti-rich nano-precipitates were observed in the sintered sample. A higher microhardness value was achieved on the sintered sample than for the melted sample. The disadvantage of porosity in the sintered sample in comparison to the melted one was overcome by the hardening effect produced by the mechanical alloying

  4. Simultaneous effect of mechanical alloying and arc-melting processes in the microstructure and hardness of an AlCoFeMoNiTi high-entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Baldenebro-Lopez, F.J. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, 31109 Chihuahua, Chih. (Mexico); Facultad de Ingeniería Mochis, Universidad Autónoma de Sinaloa, Prol. Ángel Flores y Fuente de Poseidón, S.N., 81223 Los Mochis, Sinaloa (Mexico); Herrera-Ramírez, J.M. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, 31109 Chihuahua, Chih. (Mexico); Arredondo-Rea, S.P. [Facultad de Ingeniería Mochis, Universidad Autónoma de Sinaloa, Prol. Ángel Flores y Fuente de Poseidón, S.N., 81223 Los Mochis, Sinaloa (Mexico); Gómez-Esparza, C.D. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, 31109 Chihuahua, Chih. (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, 31109 Chihuahua, Chih. (Mexico)

    2015-09-15

    Highlights: • Multi-component systems of AlCoFeMoNiTi were produced by mechanical alloying. • Consolidated samples were fabricated by two different processing routes, sintering and arc melting. • Effect of routes of consolidation on microstructural evolution and microhardness is reported. • High hardness values are found in consolidated samples. • Alloying elements, grain size, and precipitates have a high effect on microhardness. - Abstract: A nanostructured AlCoFeMoNiTi high entropy alloy was synthesized through the mechanical alloying process. Bulk samples were obtained by two different routes to compare the microstructural evolution and hardness behavior: sintering and arc melting. Through electron microscopy analyses the formation of Mo-rich and Ti-rich phases were identified in the melted sample, while Ti-rich nano-precipitates were observed in the sintered sample. A higher microhardness value was achieved on the sintered sample than for the melted sample. The disadvantage of porosity in the sintered sample in comparison to the melted one was overcome by the hardening effect produced by the mechanical alloying.

  5. Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

    International Nuclear Information System (INIS)

    The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered

  6. Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tashlykova-Bushkevich, Iya I. [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

    2015-12-31

    The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered.

  7. Effect of fluoride ions on Ti6Al4V alloy passivation in lactated Ringer's serum

    Directory of Open Access Journals (Sweden)

    Schmidt Anelise M.

    2003-01-01

    Full Text Available The corrosive behavior of Ti and its alloys in fluoride media is well known. Based on electrochemical studies, this paper describes the effect of fluoride ions on the passive behavior of Ti6Al4V alloy in lactated Ringer's serum. The open circuit potential of the alloy in the serum, which lies in the passive region of TiO2, shifts to more negative values as fluoride ions are added. The voltammogram obtained in the serum presents an active-passive behavior close to -0.2 V (SCE that changes with the presence of fluoride ions, evidencing higher anodic currents. Electrochemical impedance spectroscopy plots obtained at OCP after varying immersion times in the serum display an almost capacitive behavior and the polarization resistance becomes enhanced after 7 days. With the addition of fluoride ions, the film's resistance decreases, but a stable protective layer develops after 7 days of immersion time, indicating the film's repair.

  8. Effect of Yb additions on microstructures and properties of 7A60 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    FANG Hua-chan; CHEN Kang-hua; ZHANG Zhuo; ZHU Chang-jun

    2008-01-01

    Al-Zn-Mg-Cu-Zr alloys containing Yb were prepared by cast metallurgy. Effect of 0.30% Yb additions on the microstructure and properties of 7A60 aluminum alloys with T6 and T77 aging treatments was investigated by TEM, optical microscopy, hardness and electric conductivity measurement, tensile test and stress corrosion cracking test. The results show that the Yb additions to high strength Al-Zn-Mg-Cu-Zr aluminum alloys can produce fine coherent dispersoids. Those dispersoids can strongly pin dislocation and subgrain boundaries, which can significantly retard the recrystallization by inhibiting the nucleation of recrystallization and the growth of subgrains and keeping low-angle subgrain boundaries. Yb additions can obviously enhance the resistance to stress corrosion cracking and the fracture toughness property, and mildly increase the strength and ductility with T6 and T77 treatments.

  9. Radiation-induced segregation of impurities and effects on the electrochemistry of nickel and stainless alloys

    International Nuclear Information System (INIS)

    Radiation-induced grain boundary segregation (RIS) of silicon and phosphorus in austenitic stainless steels is established and its influence on. electrochemical behavior investigated. Silicon enrichment increases with irradiation dose for both neutrons and heavy ions. Interfacial concentrations reach about 8 at% after irradiation exposures to 10 dpa. Phosphorus segregates strongly during initial thermal treatment, but no conclusive evidence of further boundary enrichment could be determined after irradiation. These impurities have different effects on the electrochemical behavior of Ni and Fe-Ni-Cr alloys. Silicon additions from 2 to 23 at% improves passivation behavior in the stainless alloys, but as little as 5 at% impairs passivity in nickel where the breakdown potential increased with Si content. Low levels of phosphorus increase passive currents in the stainless alloy, while completely eliminating passivity in nickel. This information is important for LWR core components

  10. Effect of liquid-liquid structure transition on solidification of Sn-Bi alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of the liquid-liquid structure transition(L-LST) on the solidification behaviors and morphologies of Sn-Bi alloys was studied further. The results show that the undercooling of the primary and eutectic phase increases and the microstructure becomes finer after solidifying from the melt experiencing the L-LST. In the meantime, in hypoeutectic alloy, when solidifying from the melt experiencing the L-LST, the morphology of primary phase changes from the fir-tree crystal into the equiaxed crystal, and less primary phase and more eutectic structure are observed. Moreover, in eutectic alloy, the spacing of eutectic phase decreases markedly. These investigations would be beneficial to further exploration of the correlation between the melt structure and the micro mechanism of solidification.

  11. Effect of ethyl vanillin on ZnNi alloy electrodeposition and its properties

    Indian Academy of Sciences (India)

    K O Nayana; T V Venkatesha

    2014-08-01

    The bright ZnNi alloy coating on steel surface was prepared by elctrodepostion technique using brightener ethyl vanillin (EV). To know the influence of brightener on deposition and dissolution behaviour of ZnNi alloy, cyclic voltammetric studies were carried out. FT–IR spectroscopic evidence was given to confirm selective adsorption of brightener on steel surface. The brightener enhances current efficiency and throwing power of plating bath during coating. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses in presence of brightener confirmed the change in surface morphology, phase composition and preferred orientation of ZnNi coating. In presence of brightener, nickel content of the coating was reduced at higher current density and thickness. In addition, deposit properties like appearances, hardness, adherence, ductility and corrosion resistance of ZnNi alloy deposits were also improved in bright deposit. Simultaneously, effect of deposition current density and thickness on corrosion behaviour of coating was examined.

  12. Effect and kinetic mechanism of ultrasonic vibration on solidification of 7050 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Ripeng Jiang

    2014-07-01

    Full Text Available The work described in this paper dealt with the effect of ultrasonic vibration on the solidification of 7050 aluminum alloy. Two experiments were carried out through introducing ultrasound into the semi-continuous direct-chill (DC casting of aluminum alloy and into alloy solidifying in a crucible, respectively. Results show that ultrasonic vibration can refine grains in the whole cross-section of a billet in the first experiment and is able to increase the cooling rate within the temperature range from 625 °C to 590 °C in the other one. The mechanism of particle resonance caused by ultrasonic vibration was illustrated on the basis of theoretical analysis of the kinetics and energy conversion during the solidification. It is demonstrated that the kinetic energy of resonant particles are mainly from the latent heat energy of solidification, which can shorten the cooling time, inhibit the crystal growth and then lead to the grain refinement.

  13. Studies on effective atomic numbers, electron densities and mass attenuation coefficients in Au alloys.

    Science.gov (United States)

    Han, I; Demir, L

    2010-01-01

    The total mass attenuation coefficients (mu/rho) for pure Au and Au99Be1, Au88Ge12, Au95Zn5 alloys were measured at 59.5 and 88.0 keV photon energies. The samples were irradiated with 241Am and 109Cd radioactive point source using transmission arrangement. The gamma- rays were counted by a Si(Li) detector with resolution of 160 eV at 5.9 keV. Total atomic and electronic cross-sections (sigmat and sigmae), effective atomic and electron densities (Zeff and Nel) were determined using the obtained mass attenuation coefficients for investigated Au alloys. The theoretical mass attenuation coefficients of each alloy were estimated using mixture rule. PMID:20421703

  14. Effect of caustic environment on intergranular attack and stress corrosion cracking of alloy 600

    International Nuclear Information System (INIS)

    Intergranular corrosion of alloy 600 tubes in PWR steam generators has been a continuing mode of degradation at many sites. The Steam Generator Owners Group has funded a program addressing the intergranular corrosion of commercial tubing materials for the past 6 years. In April 1987, the Mechanistic and Environmental Effects Program was reviewed at a contractors' workshop. Intergranular corrosion (IGC) of alloy 600 can occur in caustic, acid and neutral waters. This paper summarizes the work of EPRI contractors on caustic IGC and integrates different viewpoints and experimental techniques. The paper explores the postulated mechanisms of corrosion including: segregation of alloy impurities, formation of nickel sulfide, dealloying at grain boundaries, and the role of chromium oxide. The paper also focuses on the role of environment, microstructure, electrochemical potential and stress on the incidence and rate of intergranular corrosion

  15. Effect of Phosphorous Inoculation on Creep Behavior of a Hypereutectic Al-Si Alloy

    Science.gov (United States)

    Faraji, Masoumeh; Khalilpour, Hamid

    2014-10-01

    Creep behavior of Al-Si hypereutectic alloys inoculated with phosphorus was investigated using the impression creep testing. The results showed that at stress regimes of up to 400-450 MPa and temperatures up to 300 °C, no significant creep deformation occurred in both uninoculated and inoculated specimens; however, at temperatures above 300 °C, the inoculated alloys presented better creep properties. Creep data were used to calculate the stress exponent of steady-state creep rate, n, and creep activation energy, Q, for different additive conditions where n was found varied between 5 and 8. Owing to the fact that most alloys have lower values for n (4, 5), threshold stress was estimated for studied conditions. The creep governing mechanisms for different conditions are discussed here, with a particular attention to the effect of phosphorous addition on the microstructural features, including number of primary silicon particles, mean primary silicon spacing, and morphology and distribution of eutectic silicon.

  16. Influence of atomic ordering on elastocaloric and magnetocaloric effects of a Ni–Cu–Mn–Ga ferromagnetic shape memory alloy

    International Nuclear Information System (INIS)

    Highlights: • Ni51Cu4Mn20Ga25 alloy exhibits normal elastocaloric and magnetocaloric effects. • L21 atomic order of the alloy is increased after annealing at 773 K for 10 h. • Increasing L21 atomic order improves its elastocaloric and magnetocaloric effects. • Atomic ordering modifies the magnetic and martensitic transitions of the system. - Abstract: The coexisting elastocaloric and magnetocaloric effects in ferromagnetic shape memory alloys have attracted much attention for the potential application in solid state refrigeration. Previous studies show that the L21 atomic ordering of Heusler ferromagnetic shape memory alloys plays important role on their magnetocaloric effect. However, no research work investigates the effect of atomic ordering on their elastocaloric effect yet. In this study, we investigated the influence of atomic ordering on the elastocaloric and magnetocaloric effects of a Ni51Cu4Mn20Ga25 ferromagnetic shape memory alloy. The alloy exhibits normal elastocaloric effect and normal magnetocaloric effect near room temperature. Moreover, we found that the enhancement of atomic order in this alloy can greatly increase the entropy change and refrigeration capacity of its elastocaloric and magnetocaloric effects. This is attributed to that the atomic ordering modifies the magnetic and martensitic transitions of the system

  17. Influence of atomic ordering on elastocaloric and magnetocaloric effects of a Ni–Cu–Mn–Ga ferromagnetic shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chonghui [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Yu, E-mail: yuwang@mail.xjtu.edu.cn [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Tang, Zhao; Liao, Xiaoqi; Yang, Sen; Song, Xiaoping [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China)

    2015-05-05

    Highlights: • Ni{sub 51}Cu{sub 4}Mn{sub 20}Ga{sub 25} alloy exhibits normal elastocaloric and magnetocaloric effects. • L2{sub 1} atomic order of the alloy is increased after annealing at 773 K for 10 h. • Increasing L2{sub 1} atomic order improves its elastocaloric and magnetocaloric effects. • Atomic ordering modifies the magnetic and martensitic transitions of the system. - Abstract: The coexisting elastocaloric and magnetocaloric effects in ferromagnetic shape memory alloys have attracted much attention for the potential application in solid state refrigeration. Previous studies show that the L2{sub 1} atomic ordering of Heusler ferromagnetic shape memory alloys plays important role on their magnetocaloric effect. However, no research work investigates the effect of atomic ordering on their elastocaloric effect yet. In this study, we investigated the influence of atomic ordering on the elastocaloric and magnetocaloric effects of a Ni{sub 51}Cu{sub 4}Mn{sub 20}Ga{sub 25} ferromagnetic shape memory alloy. The alloy exhibits normal elastocaloric effect and normal magnetocaloric effect near room temperature. Moreover, we found that the enhancement of atomic order in this alloy can greatly increase the entropy change and refrigeration capacity of its elastocaloric and magnetocaloric effects. This is attributed to that the atomic ordering modifies the magnetic and martensitic transitions of the system.

  18. Effect of porosity on the tensile properties of low ductility aluminum alloys

    Directory of Open Access Journals (Sweden)

    Gustavo Waldemar Mugica

    2004-06-01

    Full Text Available The literature contains reports of several studies correlating the porosity and mechanical properties of aluminum alloys. Most of these studies determine this correlation based on the parameter of global volumetric porosity. These reports, however, fail to separate the effects of microstructural features and porosity on alloys, though recognizing the influence of the latter on their mechanical properties. Thus, when the decrease in tensile strength due to the porosity effect is taken into account, the findings are highly contradictory. An analysis was made of the correlation between mechanical properties and global volumetric porosity and volumetric porosity in the fracture, as well as of the beta-Al5FeSi phase present in 380 aluminum alloy. Our findings indicate that mechanical properties in tension relating to global volumetric porosity lead to overestimations of the porosity effect in detriment to the mechanical properties. Moreover, the proposed models that take into account the effects of particles, both Si and beta-Al5FeSi, are unapplicable to low ductility alloys.

  19. Effect of recovery on the recrystallization texture of an Al-Mg alloy

    International Nuclear Information System (INIS)

    The effect of recovery on the recrystallization texture of an Al-Mg alloy was investigated by X-ray diffraction. It was found that the recovery of cold-rolled sheets prior to recrystallization annealing promoted the formation of the R texture, but restrained the formation of the cube texture

  20. Effect of recovery on the recrystallization texture of an Al-Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.C. [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)], E-mail: wcliu@ysu.edu.cn; Li, J.; Yuan, H.; Yang, Q.X. [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2007-11-15

    The effect of recovery on the recrystallization texture of an Al-Mg alloy was investigated by X-ray diffraction. It was found that the recovery of cold-rolled sheets prior to recrystallization annealing promoted the formation of the R texture, but restrained the formation of the cube texture.

  1. Effects of surface finishing conditions on the biocompatibility of a nickel-chromium dental casting alloy.

    LENUS (Irish Health Repository)

    McGinley, Emma Louise

    2011-07-01

    To assess the effects of surface finishing condition (polished or alumina particle air abraded) on the biocompatibility of direct and indirect exposure to a nickel-chromium (Ni-Cr) d.Sign®10 dental casting alloy on oral keratinocytes. Biocompatibility was performed by assessing cellular viability and morphology, metabolic activity, cellular toxicity and presence of inflammatory cytokine markers.

  2. Effects of neutron irradiation in magnetic properties of metals and alloys

    International Nuclear Information System (INIS)

    The effects of neutron irradiation on the magnetic properties of metals and alloys, namely magnetic anisotropy, hysteresis loop, initial magnetic permeability, which are sensitives to structural changes, are studied. First a short review is made, followed by experimentals results and the plot of the vacancies supersaturation, which are obtained in the reactor of the Instituto de Pesquisas Energeticas e Nucleares. (Author)

  3. Trace elements in flue gas desulfurization environments and their effect on corrosion of alloys

    International Nuclear Information System (INIS)

    A literature survey has been performed to determine what trace elements are prevalent in the environments of various flue gas desulfurization (FGD) components. The potential effect of these elements on the corrosion of alloys is discussed. Thermodynamic calculations demonstrated that certain elements in the flue gas can complex fluoride, thereby inhibiting corrosion significantly

  4. Configurational energies and effective cluster interactions in substitutionally disordered binary alloys

    International Nuclear Information System (INIS)

    The determination of configurational energies in terms of effective cluster interactions in substitutionally disordered alloys from a knowledge of the alloy electronic structure is examined within the methods of concentration waves (CW) and the generalized perturbation method (GPM), and for the first time within the embedded-cluster method (ECM). It is shown that the ECM provides the exact summation to all orders of the effective cluster interaction expansions obtained in the partially renormalized GPM. The connection between the various methods (CW, GPM, and ECM) is discussed and illustrated by means of numerical calculations for model one-dimensional tight-binding (TB) systems and for TB Hamiltonians chosen to describe Pd-V alloys. These calculations, and the formal considerations presented in the body of the paper, show the complete equivalence of converged GPM summations within specific clusters and the ECM. In addition, it is shown that an exact expansion of the configurational energy can be obtained in terms of fully renormalized effective cluster interactions. In principle, these effective cluster interactions can be used in conjunction with statistical models to determine stable ordered structures at low temperatures and alloy phase diagrams

  5. Effects of coolant chemistry on corrosion of 3003 aluminum alloy in automotive cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Cheng, Y.F. [Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta (Canada)

    2010-07-15

    In this work, effects of coolant chemistry, including concentrations of chloride ions and ethylene glycol and addition of various ions, on corrosion of 3003 Al alloy were investigated by electrochemical impedance spectroscopy measurements and scanning electron microscopy characterization. In chloride-free, ethylene glycol-water solution, a layer of Al-alcohol film is proposed to form on the electrode surface. With the increase of ethylene glycol concentration, more Al-alcohol film is formed, resulting in the increase in film resistance and charge-transfer resistance. In the presence of Cl{sup -} ions, they would be involved in the film formation, decreasing the stability of the film. In 50% ethylene glycol-water solution, the threshold value of Cl{sup -} concentration for pitting initiation is within the range of 100 ppm to 0.01 M. When the ethylene glycol concentration increases to 70%, the threshold Cl{sup -} concentration for pitting is from 0.01 to 0.1 M. In 100% ethylene glycol, there is no pitting of 3003 Al alloy even at 0.1 M of Cl{sup -}. Even a trace amount of impurity cation could affect significantly the corrosion behavior of 3003 Al alloy in ethylene glycol-water solution. Addition of Zn{sup 2+} is capable of increasing the corrosion resistance of Al alloy electrode, while Cu{sup 2+} ions containing in the solution would enhance corrosion, especially pitting corrosion, of Al alloy. The effect of Mg{sup 2+} on Al alloy corrosion is only slight. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Effects of biodegradable Mg–6Zn alloy extracts on apoptosis of intestinal epithelial cells

    International Nuclear Information System (INIS)

    Highlights: ► We evaluated the effects of Mg–6Zn alloys on apoptosis of IEC-6 cells. ► The apoptosis was evaluated by investigating the expression of caspase-1 and Bcl-2. ► The IEC-6 cells displayed better cell functions in 60% or 20% extract. ► The conspicuous alkaline environment is disadvantageous to apoptosis of IEC cells. ► The excessive Mg concentration is disadvantageous to apoptosis of IEC-6 cells. - Abstract: In this study, intestinal epithelial cells (IEC)-6 were cultured in different concentration extracts of Mg–6Zn alloys for different time periods. To achieve a total of three concentrations (100%, 60% and 20% concentration), the extracts were serially diluted with Dulbecco's modified Eagle medium High Glucose to observe a dose–response relationship. We studied the indirect effects of Mg–6Zn alloys on IEC-6 cells apoptosis. The apoptosis of IEC-6 cells was measured using flow cytometry. And the apoptosis of IEC-6 cells was evaluated by investigating the expression of caspase-1and Bcl-2 using real-time polymerase chain reaction (PCR) and Western blotting tests. It was found that the levels of apoptosis in IEC-6 cells cultured in 100% Mg–6Zn alloy extracts were significantly higher than those in 60% and 20% extracts; the 100% extract can down-regulate expression of Bcl-2 after culture. The in vitro results indicated that the conspicuous alkaline environment and excessive Mg concentration, even Zn concentration caused by rapid corrosion of Mg–6Zn alloys promote IEC-6 cells apoptosis, although further experiments will be necessary to formally prove our conclusions. Therefore, the adjustment of the degradation rate is needed for using Mg–Zn alloy as a surgical suture material.

  7. Effect of alloying on carbon formation during ethane dehydrogenation

    DEFF Research Database (Denmark)

    Rovik, Anne; Kegnæs, Søren; Dahl, Søren;

    2009-01-01

    The structure sensitivity of different transition metals in the hydrogenolysis, dehydrogenation, and coking reactions during ethane conversion has been investigated. The investigated metals, Ni, Ru, Rh, and Pd, are co-impregnated with Ag onto an inactive MgAl2O4 spinel support and tested in the...... coke during the initial period where after dehydrogenation of ethane is observed. It has previously been predicted in surface science studies that Ag covers the steps of certain transition metals. Here it is documented that the hydrogenolysis and coking reactions are significantly suppressed by co......-Pd/spinel due to an alloy formation of Ag and Pd at these conditions. From our results it can therefore be concluded that hydrogenolysis mainly takes place on the steps and kinks of the transition metal particles, dehydrogenation reactions mainly takes place on the terraces, and coking is significantly reduced...

  8. Silicidation of Mo-alloyed ytterbium: Mo alloying effects on microstructure evolution and contact properties

    International Nuclear Information System (INIS)

    In this study, we investigated the effects of Mo addition to Yb as a contact material with Si for metal–oxide-semiconductor field-effect transistors (MOSFETs) to mitigate oxidation problems, a persistent problem for rare-earth metal-based contacts (such as Yb/Si and Er/Si). Our thorough materials characterization using transmission electron microscopy and X-ray diffraction unravels Mo segregation during silicidation and its effect against oxidation. I–V characteristics, measured from Schottky diodes produced from the samples, reflect such microstructure evolution and demonstrate a strong improvement in contact properties at high temperatures

  9. Small-crack effects in high-strength aluminum alloys

    Science.gov (United States)

    Newman, J. C., Jr.; Wu, X. R.; Venneri, S. L.; Li, C. G.

    1994-01-01

    The National Aeronautics and Space Administration and the Chinese Aeronautical Establishment participated in a Fatigue and Fracture Mechanics Cooperative Program. The program objectives were to identify and characterize crack initiation and growth of small cracks (10 microns to 2 mm long) in commonly used US and PRC aluminum alloys, to improve fracture mechanics analyses of surface- and corner-crack configurations, and to develop improved life-prediction methods. Fatigue and small-crack tests were performed on single-edgenotch tension (SENT) specimens and large-crack tests were conducted on center-crack tension specimens for constant-amplitude (stress ratios of -1, 0, and 0.5) and Mini-TWIST spectrum loading. The plastic replica method was used to monitor the initiation and growth of small fatigue cracks at the semicircular notch. Crack growth results from each laboratory on 7075-T6 bare and LC9cs clad aluminum alloys agreed well and showed that fatigue life was mostly crack propagation from a material defect (inclusion particles or void) or from the cladding layer. Finite-element and weight-function methods were used to determine stress intensity factors for surface and corner cracks in the SENT specimens. Equations were then developed and used in a crack growth and crack-closure model to correlate small- and large-crack data and to make life predictions for various load histories. The cooperative program produced useful experimental data and efficient analysis methods for improving life predictions. The results should ultimately improve aircraft structural reliability and safety.

  10. Comparative study of the Portevin-Le Chatelier effect in interstitial and substitutional alloy

    OpenAIRE

    A. Sarkar; Chatterjee, A; Barat, P.; Mukherjee, P.

    2006-01-01

    Tensile tests were carried out by deforming polycrystalline samples of an interstitial alloy, low carbon steel at room temperature in a wide range of strain rates where the Portevin-Le Chatelier (PLC) effect was observed. The observed stress time series data were analyzed using the nonlinear dynamical methods. From the analyses, we could establish the presence of marginal deterministic chaos in the PLC effect of the low carbon steel. Moreover, we made a comparative study of the PLC effect of ...

  11. An Investigation into the Effect of Alloying Elements on the Recrystallization Behavior of 70/30 Brass

    Science.gov (United States)

    Shafiei M, A.; Roshanghias, A.; Abbaszadeh, H.; Akbari, G. H.

    2010-06-01

    An Artificial Neural Network (ANN) model has been designed for predicting the effects of alloying elements (Fe, Si, Al, Mn) on the recrystallization behavior and microstructural changes of 70/30 brass. The model introduced here considers the content of alloying elements, temperature, and time of recrystallization as inputs while percent of recrystallization is presented as output. It is shown that the designed model is able to predict the effect of alloying elements well. It is also shown that all alloying elements strongly affect the recrytallization kinetics, and all slow down the recrystallization process. The effect of alloying elements on the activation energy for recrystallization has also been investigated. The results show that Si is the element which increases the activation energy.

  12. Effects of Mm(NiCoAlMn)5 hydrogen storage alloy coated with Ni-Co-P alloy by electroless plating on electrochemical properties of hydride electrodes

    Institute of Scientific and Technical Information of China (English)

    孙春文; 郭占成; 唐致远; 郭鹤桐

    2003-01-01

    The effect of chemical plating with Ni-Co-P alloy on the properties of MH electrodes is investigated. The results show that the efficiency of storage alloy and the activation of MH electrode have been improved by introducing 1.74% cobalt in the Ni-Co-P alloy coating. The initial discharge capacity is 208 mAh/g. The maximum discharge capacity gets to 298.5 mAh/g. At the same time the cycle life of MH electrodes is improved. The discharge capacity of MH electrodes coated with Ni-Co-P is 88% of the maximum discharge capacity after 300 cycles. Whereas the discharge capacity of bare alloy electrodes retains 62% of the maximum capacity after 300 cycles. An increment of discharge capacity is mainly due to the superposition of the oxidation current of Co as well as improved efficiency of microcurrent collection. The effect of Ni-Co-P alloy coating by electroless plating on the kinetic properties of hydride electrode has been systematically investigated by electrochemical techniques. The results indicate that the kinetic properties of MH electrodes, including exchange current density, limiting current density, have been improved markedly. This improvement of kinetic properties leads to the decrease of the overpotential of anodic and cathodic polarization.

  13. Effect of alloying on microstructure and precipitate evolution in ferritic weld metal

    Science.gov (United States)

    Narayanan, Badri Kannan

    The effect of alloying on the microstructure of ferritic weld metal produced with an self-shielded flux cored arc welding process (FCAW-S) has been studied. The welding electrode has a flux core that is intentionally alloyed with strong deoxidizers and denitriding elements such as aluminum, titanium and zirconium in addition to austenite formers such as manganese and nickel. This results in formation of microstructure consisting of carbide free bainite, retained austenite and twinned martensite. The work focuses on characterization of the microstructures and the precipitates formed during solidification and the allotropic phase transformation of the weld metal. Aluminum, manganese and nickel have significant solubility in iron while aluminum, titanium and zirconium have very strong affinity for nitrogen and oxygen. The effect of these alloying elements on the phase transformation and precipitation of oxides and nitrides have been studied with various characterization techniques. In-situ X-ray synchrotron diffraction has been used to characterize the solidification path and the effect of heating and cooling rates on microstructure evolution. Scanning Transmission Electron Microscopy (STEM) in conjunction with Energy Dispersive Spectroscopy (EDS) and Electron energy loss spectroscopy (EELS) was used to study the effect of micro-alloying additions on inclusion evolution. The formation of core-shell structure of oxide/nitride is identified as being key to improvement in toughness of the weld metal. Electron Back Scattered Diffraction (EBSD) in combination with Orientation Imaging Microscopy (OIM) and Transmission electron microscopy (TEM) has been employed to study the effect of alloying on austenite to ferrite transformation modes. The prevention of twinned martensite has been identified to be key to improving ductility for achieving high strength weld metal.

  14. Effect of simulated HTGR primary circuit helium on properties of structural alloys

    International Nuclear Information System (INIS)

    The effect of exposure to simulated HTGR primary circuit helium (400 μatm H2/2 μatm H2O/40 μatm CO/0.2 μ atm CO2/20 μatm CH4 in He at 2 atm total pressure) on the properties of structural alloys is studied over the temperature range of 750 to 10500C (1382 to 19220F). Creep-rupture testing is being performed using both single specimen and multispecimen equipment. Specimens are also being exposed unstressed for post-exposure evaluation of oxidation, thermal aging effects and carburization and for evaluating changes in tensile, impact and fatigue properties due to exposure. Some air tests are being performed for comparison. The results to date (exposure times to approximately 10,000 hours) are discussed for a variety of wrought iron- and nickel-based austentic alloys, cast nickel-based alloys, and oxide dispersion strengthened alloys. It generally appears that the environmental effect is significant only in the highest temperature range: thermal aging appears to be the cause of most of the changes seen during lower temperature exposures accomplished to date

  15. Compressive strength, plastic flow properties, and surface frictional effects of 1100, 3003 and 6061 aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pinkerton, G.W.

    1993-12-31

    The purpose of this study is to find aluminum alloys that are effective for use as wire vacuum seals in the 800MeV particle accelerator located at the Louis Anderson Meson Physics Facility (LAMPF) in Los Alamos, NM. Three alloys, Al 1100, Al 3003, and Al 6061, are investigated under uniaxial compression to determine stresses for a given height reduction from 0 to 70 percent, and to find plastic flow and surface interaction effects. Right-circular cylindrical specimens are compressed on-end (cylindrically) and radially (for modeling as compressed wire). Aluminum 1100 and 3003 alloys are compared for length to diameter ratios of 1 and 2 for both compression types, and are then compared to results of radial compression of annealed small diameter Al 1100 wire currently used at LAMPE. The specimens are also compressed between three different platen surfaces, polished steel, etched steel, and aluminum 6061-T6, to determine effects of friction. The Al 3003 alloy exhibits 20 to 25% lower stresses at all height reductions than Al 1100 for both cylindrical and radial compression.

  16. Effect of natural and magnetic convections on the structure of electrodeposited zinc-nickel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Levesque, A., E-mail: alexandra.levesque@univ-reims.fr [LACMDTI URCA, BP 1039, 51687 Reims Cedex2 (France); Chouchane, S. [Faculte des Sciences, Universite Badji Mokhtar, Annaba (Algeria); Douglade, J. [LACMDTI URCA, BP 1039, 51687 Reims Cedex2 (France); Rehamnia, R. [Faculte des Sciences, Universite Badji Mokhtar, Annaba (Algeria); Chopart, J.-P. [LACMDTI URCA, BP 1039, 51687 Reims Cedex2 (France)

    2009-06-30

    The effects of a magnetic field applied in a direction parallel or perpendicular to the cathode substrate plane, during electrodeposition process of Zn-Ni alloy have been investigated by means of chronoamperometric measurements, X-ray diffraction and EDX analysis. The modification of crystal orientation of the alloy by the superimposition of a high magnetic field is discussed for alloys with a content of nickel range 6-13 at%. Whatever the phase composition obtained without magnetic field, either {gamma}-Ni{sub 5}Zn{sub 21} or a mixture of the {gamma} and zinc phases, which depends on the concentration of Ni{sup 2+} in the electrolyte bath, the preferential orientation (1 0 1) of the zinc phase is always favoured with perpendicular and parallel magnetic field. There is no saturation of this effect with amplitude of B up to 8 T. A study of different geometric configurations of the cathode, which induce more or less natural convection, consolidates these results. The structural modifications of Zn-Ni alloy electrodeposits are thus probably due to a magnetohydrodynamic effect. An additional phenomenon is observed in presence of a perpendicular applied magnetic field since the (3 3 0) preferential orientation of the {gamma}-Ni{sub 5}Zn{sub 21} disappears with high values of B.

  17. Compressive strength, plastic flow properties, and surface frictional effects of 1100, 3003 and 6061 aluminum alloys

    International Nuclear Information System (INIS)

    The purpose of this study is to find aluminum alloys that are effective for use as wire vacuum seals in the 800MeV particle accelerator located at the Louis Anderson Meson Physics Facility (LAMPF) in Los Alamos, NM. Three alloys, Al 1100, Al 3003, and Al 6061, are investigated under uniaxial compression to determine stresses for a given height reduction from 0 to 70 percent, and to find plastic flow and surface interaction effects. Right-circular cylindrical specimens are compressed on-end (cylindrically) and radially (for modeling as compressed wire). Aluminum 1100 and 3003 alloys are compared for length to diameter ratios of 1 and 2 for both compression types, and are then compared to results of radial compression of annealed small diameter Al 1100 wire currently used at LAMPE. The specimens are also compressed between three different platen surfaces, polished steel, etched steel, and aluminum 6061-T6, to determine effects of friction. The Al 3003 alloy exhibits 20 to 25% lower stresses at all height reductions than Al 1100 for both cylindrical and radial compression

  18. Effect of precipitation on strength and ductility in a Mg-Zn-Y alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rosalie, Julian M. [Microstructure Design Group, Structural Materials Unit, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Somekawa, Hidetoshi [Toughness Design Group, Structural Materials Unit, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Singh, Alok, E-mail: alok.singh@nims.go.jp [Microstructure Design Group, Structural Materials Unit, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Mukai, Toshiji [Dept. Mechanical Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe City 657-8501 (Japan)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer Strain and ageing used to control {beta}{sub 1}{sup Prime} precipitate size and distribution. Black-Right-Pointing-Pointer Precipitate size and distribution are correlated with strength and ductility. Black-Right-Pointing-Pointer Larger volume fraction of {beta}{sub 1}{sup Prime} precipitates introduced by solute re-partitioning. Black-Right-Pointing-Pointer 32% increase in yield strength achieved by 5% pre-ageing deformation. - Abstract: The effect of pre-ageing deformation on the size and distribution of {beta}{sub 1}{sup Prime} precipitates and subsequently on the resulting strength and ductility have been measured in a Mg-3.0at.%Zn-0.5at.%Y alloy. The alloy was extruded and then subjected to a T8 heat treatment comprised of a solution-treatment, cold-work and artificial ageing. Extrusion was used to introduce texture, ensuring that deformation occurred via slip rather than twinning. Samples were subjected to controlled uniaxial deformation and then isothermally aged to peak hardness. Precipitate length, diameter and number density were measured and evaluated in terms of the strength and ductility of the alloy. The nucleation of the {beta}{sub 1}{sup Prime} precipitates in peak-aged condition without pre-ageing deformation (i.e. T6 treatment) was poor, with only 0.5% volume fraction, compared to approximately 3.5% in T6 treated binary Mg-3.0at.%Zn alloy. The microstructure of the Mg-Zn-Y alloy was less refined, with larger diameter precipitates and lower {beta}{sub 1}{sup Prime} number densities than a binary Mg-3.0at.%Zn alloy. Deformation to 5% plastic strain increased the volume fraction of {beta}{sub 1}{sup Prime} precipitates to approximately 2.3% and refined the {beta}{sub 1}{sup Prime} precipitate length and diameter. The combination of these effects increased the yield strength after isothermal ageing from 217 MPa (0% cold-work) to 287 MPa (5% cold-work). The yield stress increased linearly with reciprocal

  19. Effect of Ca, RE elements and semi-solid processing on the microstructure and creep properties of AZ91 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nami, B. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Shabestari, S.G., E-mail: shabestari@iust.ac.ir [Center of Excellence for Advanced Materials and Processing (CEAMP), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Razavi, H. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Mirdamadi, Sh. [Center of Excellence for Advanced Materials and Processing (CEAMP), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Miresmaeili, S.M. [Department of Mechanical Engineering, Shahid Rajaee Teacher Training University (SRTTU), Lavizan, Tehran (Iran, Islamic Republic of)

    2011-01-25

    Research highlights: {yields} The size of solid globular {alpha}(Mg) particles decreases in semi-solid slurries of AZ91 alloy by adding Ca and RE elements, whereas it has no considerable effect on the shape factor of the solid particles. {yields} Particle growth in semi-solid slurries of AZ91 and AZRC91 alloys takes place by Ostwald ripening mechanism. {yields} The coarsening rate of solid particles in semi-solid slurries of AZRC91 alloy is lower than that of AZ91 alloy. {yields} Creep properties of AZ91 alloy was improved by adding Ca and RE elements. The thixoformed specimens exhibit the better creep resistance than the as-cast specimens. - Abstract: The effects of calcium and rare earth elements (RE) on the microstructure and creep properties of as-cast and thixoformed AZ91 magnesium alloy have been investigated. It has been shown that the amount of {beta}(Mg{sub 17}Al{sub 12}) intermetallic compound decreases by adding Ca and RE elements into AZ91 alloy and new Al{sub 11}RE{sub 3} and Al{sub 2}Ca intermetallic compounds form in the microstructure. The coarsening of primary {alpha}(Mg) particles in AZ91 alloy and in the Ca and RE containing (AZRC91) alloy takes place by Ostwald ripening mechanism. Adding Ca and RE elements into AZ91 alloy results in a decrease in the coarsening rate of solid particles in semi-solid slurry, whereas it has no visible effect on the shape factor of the solid-particles. The creep properties of AZ91 alloy are improved by adding Ca and RE elements particularly, in the thixoformed condition.

  20. Effect of Ca, RE elements and semi-solid processing on the microstructure and creep properties of AZ91 alloy

    International Nuclear Information System (INIS)

    Research highlights: → The size of solid globular α(Mg) particles decreases in semi-solid slurries of AZ91 alloy by adding Ca and RE elements, whereas it has no considerable effect on the shape factor of the solid particles. → Particle growth in semi-solid slurries of AZ91 and AZRC91 alloys takes place by Ostwald ripening mechanism. → The coarsening rate of solid particles in semi-solid slurries of AZRC91 alloy is lower than that of AZ91 alloy. → Creep properties of AZ91 alloy was improved by adding Ca and RE elements. The thixoformed specimens exhibit the better creep resistance than the as-cast specimens. - Abstract: The effects of calcium and rare earth elements (RE) on the microstructure and creep properties of as-cast and thixoformed AZ91 magnesium alloy have been investigated. It has been shown that the amount of β(Mg17Al12) intermetallic compound decreases by adding Ca and RE elements into AZ91 alloy and new Al11RE3 and Al2Ca intermetallic compounds form in the microstructure. The coarsening of primary α(Mg) particles in AZ91 alloy and in the Ca and RE containing (AZRC91) alloy takes place by Ostwald ripening mechanism. Adding Ca and RE elements into AZ91 alloy results in a decrease in the coarsening rate of solid particles in semi-solid slurry, whereas it has no visible effect on the shape factor of the solid-particles. The creep properties of AZ91 alloy are improved by adding Ca and RE elements particularly, in the thixoformed condition.

  1. Effect of Alloying Elements in Hot-Rolled Metastable β-Titanium Alloys. Part II: Mechanical Properties

    Science.gov (United States)

    Manda, Premkumar; Chakkingal, Uday; Singh, A. K.

    2016-07-01

    This paper describes the tensile properties, flow and work-hardening behavior of four metastable β-titanium alloys Ti-5Al-5Mo-5V-3Cr (A1), Ti-5Al-3.5Mo-7.2V-3Cr (A2), Ti-5Al-5Mo-8.6V-1.5Cr (A3), and Ti-5Al-3.5Mo-5V-3.94Cr (A4) in α+β hot-rolled condition. The decreasing order of average strength parameters ( σ YS and σ UTS) is A4, A2, A1, and A3. The maximum strength observed in alloy A4 is due to the presence of highest wt. fraction of Cr. The elongation is the maximum and minimum in alloys A3 and A4, respectively. These alloys display moderate to high percent in-plane anisotropy ( A IP) and reasonably low anisotropic index ( δ) values. Both the A IP and δ values are maximum and minimum in alloys A1 and A3, respectively. The yield locus plots also exhibit the presence of anisotropy due to relatively large differences in yield strength values along tension and compression directions. The flow behavior of alloys A1, A2, and A4 follows Swift equation, while the alloy A3 displays best fit with Holloman equation. The presence of prestrain ( ɛ 0) in hot-rolled materials before tensile testing has an important bearing on the flow curves of A1, A2, and A4 alloys. The instantaneous work-hardening rate curves of the alloys A1, A2, and A3 exhibit all the three typical stages (stage I, stage II, and stage III) in RD samples, while the alloy A4 shows the presence of only stage I and stage III. The 45 deg to RD and TD samples of alloys A1, A2, and A4 display only stage I. The stages I and III as well as I and II are present in alloy A3 in 45 deg to RD and TD samples, respectively. Dislocation-controlled strain hardening occurs in all the three stages of these alloys in the absence of stress-induced martensitic transformation (α″) and twinning. Slip is the predominant deformation mechanism during tensile testing. Three types of slip lines, i.e., planar, wavy, and intersecting have been observed close to fracture surfaces of post tensile-tested specimens.

  2. Effect of Alloying Elements in Hot-Rolled Metastable β-Titanium Alloys. Part II: Mechanical Properties

    Science.gov (United States)

    Manda, Premkumar; Chakkingal, Uday; Singh, A. K.

    2016-04-01

    This paper describes the tensile properties, flow and work-hardening behavior of four metastable β-titanium alloys Ti-5Al-5Mo-5V-3Cr (A1), Ti-5Al-3.5Mo-7.2V-3Cr (A2), Ti-5Al-5Mo-8.6V-1.5Cr (A3), and Ti-5Al-3.5Mo-5V-3.94Cr (A4) in α+β hot-rolled condition. The decreasing order of average strength parameters (σ YS and σ UTS) is A4, A2, A1, and A3. The maximum strength observed in alloy A4 is due to the presence of highest wt. fraction of Cr. The elongation is the maximum and minimum in alloys A3 and A4, respectively. These alloys display moderate to high percent in-plane anisotropy (A IP) and reasonably low anisotropic index (δ) values. Both the A IP and δ values are maximum and minimum in alloys A1 and A3, respectively. The yield locus plots also exhibit the presence of anisotropy due to relatively large differences in yield strength values along tension and compression directions. The flow behavior of alloys A1, A2, and A4 follows Swift equation, while the alloy A3 displays best fit with Holloman equation. The presence of prestrain (ɛ 0) in hot-rolled materials before tensile testing has an important bearing on the flow curves of A1, A2, and A4 alloys. The instantaneous work-hardening rate curves of the alloys A1, A2, and A3 exhibit all the three typical stages (stage I, stage II, and stage III) in RD samples, while the alloy A4 shows the presence of only stage I and stage III. The 45 deg to RD and TD samples of alloys A1, A2, and A4 display only stage I. The stages I and III as well as I and II are present in alloy A3 in 45 deg to RD and TD samples, respectively. Dislocation-controlled strain hardening occurs in all the three stages of these alloys in the absence of stress-induced martensitic transformation (α″) and twinning. Slip is the predominant deformation mechanism during tensile testing. Three types of slip lines, i.e., planar, wavy, and intersecting have been observed close to fracture surfaces of post tensile-tested specimens.

  3. Effect of cobalt content on electrochemical performance of La-Mg-Ni system (Ce2Ni7-type) electrode alloys

    Institute of Scientific and Technical Information of China (English)

    WANG Xinlin; DONG Xiaoping; ZHANG Yanghuan; GUO Shihai; Lü Fanxiu

    2008-01-01

    In order to improve the cyclic stability of La-Mg-Ni system (Ce2Ni7-type) alloy electrode, small amount of Co was added in La0.75Mg0.25Ni3.5 alloy. The effect of Co on electrochemical performance and microstructure of the alloys were investigated in detail. XRD results showed that the alloys had multiphase structure composed of (La, Mg)2Ni7, LaNi5 and small amount of LaNi2 phases. The discharge capacity of the alloys first increased and then decreased with increasing Co content. At a discharge current density of 900 mA/g, the HRD of the alloy electrodes increased from 81.3% (x=0) to 89.2 % (x=0.2), and then reduced to 87.8 % (x=0.6). After 60 charge/discharge cycles, the capacity retention rate of the alloys enhanced from 52.67% to 61.32%, and the capacity decay rate of the alloys decreased from 2.60 to 2.05 mAh/g per cycle with increasing Co content. The obtained results by XPS and XRD showed that the fundamental reasons for the capacity decay of the La-Mg-Ni system (Ce2Ni7-type) alloy electrodes were corrosion and oxidation as well as passivation of Mg and La in alkaline solution.

  4. Effects of cerium on as-cast microstructure and mechanical properties of Mg-3Sn-2Ca magnesium alloy

    International Nuclear Information System (INIS)

    The Mg-3Sn-2Ca-xCe (x = 0-2.0 wt.%) alloys were prepared by permanent mould casting method, the effects of Ce on the as-cast microstructure and mechanical properties of the alloys were investigated. The results indicated that the volume fraction and size of CaMgSn phase in the Mg-3Sn-2Ca alloy respectively were decreased by adding 0.5-2.0 wt.%Ce, and the average size of CaMgSn phase in the Mg-3Sn-2Ca alloys added 1.5 or 2.0 wt.%Ce was relatively smaller. The main phases in the as-cast Mg-3Sn-2Ca alloys with and without adding Ce were α-Mg, CaMgSn and Mg2Ca phases, and Mg12Ce phase were found in the alloys added more than 1.0 wt.%Ce. The addition of Ce improved the tensile and creep properties of Mg-3Sn-2Ca alloy, and the mechanical properties of Mg-3Sn-2Ca alloys added 1.5 or 2.0 wt.%Ce were relatively higher. The strengthening mechanism of Ce-containing Mg-3Sn-2Ca alloys was mainly attributed to the refinement of CaMgSn phase.

  5. Effects of minor yttrium addition on hot deformability of lamellar Ti-45Al-5Nb alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-yong; LI Bao-hui; KONG Fan-tao

    2007-01-01

    The effects of 0.3%(molar fraction, the same below) yttrium addition on hot deformability of lamellar Ti-45Al-5Nb alloy were investigated by simulated isothermal forging tests. The ingots with the nominal compositions of Ti-45Al-5Nb and Ti-45Al-5Nb-0.3Y were prepared by induction skull melting. Simulated isothermal forging tests were conducted on Gleeble 1500D thermo-simulation machine using a 6 mm in diameter and 10 mm in length compressive specimen at the deformation temperatures of 1 100, 1 150, 1 200 ℃ and strain rates of 1.0, 0.1, 0.01 s-1. The results show that yttrium addition remarkably improves hot deformability of Ti-45Al-5Nb alloy. An appropriate hot deformation processing parameter of Ti-45Al-5Nb-0.3Y alloy is determined as 1 200 ℃, 0.01 s-1. The flow stresses are decreased by yttrium addition under the same compressive conditions. The activation energies of deformation Q are calculated as 448.6 and 399.5 kJ/mol for Y-free and Y-containing alloys, respectively. The deformed microstructure observation under 1 200 ℃, 0.01 s-1 condition indicates that Ti-45Al-5Nb-0.3Y alloy shows more dynamic recrystallization. The improvement of hot deformability of Ti-45Al-5Nb-0.3Y alloy induced by yttrium addition should be attributed to that the smaller the original lamellar colonies, the lower the deformation resistance and activation energy of deformation are, and the more the dynamic recrystallization is.

  6. Effect of interfacial solute segregation on ductile fracture of Al–Cu–Sc alloys

    International Nuclear Information System (INIS)

    Three-dimensional atom probe analysis is employed to characterize the Sc segregation at θ′/α-Al interfaces in Al–2.5 wt.% Cu–0.3 wt.% Sc alloys aged at 473, 523 and 573 K, respectively. The interfacial Sc concentration is quantitatively evaluated and the change in interfacial energy caused by Sc segregation is assessed, which is in turn correlated to yield strength and ductility of the alloys. The strongest interfacial Sc segregation is generated in the 523 K-aged alloy, resulting in an interfacial Sc concentration about 10 times greater than that in the matrix and a reduction of ∼25% in interfacial energy. Experimental results show that the interfacial Sc segregation promotes θ′ precipitation and enhances the strengthening response. A scaling relationship between the interfacial energy and precipitation strengthening increment is proposed to account for the most notable strengthening effect observed in the 523 K-aged alloy, which is ∼2.5 times that in its Sc-free counterpart and ∼1.5 times that in the 473 and 573 K-aged Al–Cu–Sc alloys. The interfacial Sc segregation, however, causes a sharp drop in the ductility when the precipitate radius is larger than ∼200 nm in the 523 K-aged alloy, indicative of a transition in fracture mechanisms. The underlying fracture mechanism for the low ductility regime, revealed by in situ transmission electron microscopy tensile testing, is that interfacial decohesion occurs at the θ′ precipitates ahead of crack tip and favorably aids the crack propagation. A micromechanical model is developed to rationalize the precipitate size-dependent transition in fracture mechanisms by taking into account the competition between interfacial voiding and matrix Al rupture that is tailored by interfacial Sc segregation

  7. On the effect of Nb-based compounds on the microstructure of Al–12Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, L., E-mail: leandro.bolzoni@brunel.ac.uk; Nowak, M.; Hari Babu, N.

    2015-07-15

    Cast Al alloys are important structural materials for the lightweighting of cars and, consequently, reduction of greenhouse gases emission and pollution. The microstructure and properties of cast Al alloys could be further improved by means of grain refinement, practise which cannot efficiently be performed with common Al–Ti–B grain refiners used for wrought Al alloys. In this work we proposed the employment of Nb+B inoculation as an alternative for the refinement of the primary α-Al dendrites of cast Al–Si alloy by studying the grain refinement induced by the Nb+B inoculants as a function of key aspects such as cooling rate, fading behaviour and simulated recyclability tests. It is found that the grain size of the Nb+B inoculated material is noticeably less sensitive to the cooling rate. Nb+B inoculants are still present and promote the refinement of the Al–12Si alloy even after few hours of contact time, although some fading is detected. Furthermore, Nb+B inoculants are also still effective for enhancing heterogeneous nucleation after three remelting of the inoculated alloy. The fading behaviour and ability to retain grain refining potency after remelting are highly relevant to industrial scale applications. - Highlights: • The influence of Nb+B inoculation on Al–12SSi is assessed. • The grain size decreases along with the amount of Nb+B compounds. • Nb+B inoculation makes the grain size less sensitive from the cooling rate. • Grain refinement is obtained via heterogeneous nucleation.

  8. Investigation of alloying effects in aluminum dispersion strengthened with Al2O3

    International Nuclear Information System (INIS)

    Two types of alloying elements were investigated to determine if the room-temperature strength could be improved and if, through lowering the oxide content, the high-temperature ductility could be improved. Mg was investigated for its solid solution strengthening in one type alloy. The other type alloy involved further dispersion strengthening through adding Fe, Mo, Zr, Cr, V, and Ti which form highly stable intermetallic compounds with Al. Fabrication techniques were developed which produced uniform and reproducible rods for testing. Prealloyed powders were produced by atomizing the molten alloys and collecting the powders in water. This procedure produced uniform powders with a very fine distribution of the intermetallic compounds. Fabrication into rods then included ball-milling, vacuum hot pressing, vacuum heat treating, and hot extrusion. Mg additions improved strengths up to 2000C with little effect above that temperature. Room-temperature tensile strengths up to 77,000 psi were obtained which are comparable to the strengths obtained in conventional aluminum alloys. The additional dispersion strengthening of the intermetallic compounds is additive to that of the oxide from room temperature to 4500C. No significant improvements in ductility are obtained by reducing the oxide content since even at very low ball-milling times (i.e., low oxide contents) the uniform elongation at 4500C is typically 0.5 percent. Good combinations of strength and ductility at 4500C were obtained in some of the alloys containing intermetallic compounds with no ball-milling. Typical properties at this temperature were tensile strengths of 7,000 psi, uniform elongation of 3 percent, and total elongation of 35 percent. (21 tables, 33 fig, 43 references) (auth)

  9. Electrochemical characteristics of a carbon fibre composite and the associated galvanic effects with aluminium alloys

    International Nuclear Information System (INIS)

    Highlights: • Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation in NaCl electrolyte. • The exposed carbon fibres on the side and front regions are responsible for a high cathodic current density. • The NaCl + CuSO4 electrolyte was used to investigate the cathodic polarization behaviour of the exposed carbon fibres. • Galvanic coupling behaviour between the composite and aluminium alloys (AA7075-T6 and AA1050) was measured in NaCl electrolyte. • The higher galvanic current density measured on AA1050 alloy introduced a higher dissolution rate than the AA7075-T6 alloy. - Abstract: The electrochemical behaviour of a carbon fibre reinforced epoxy matrix composite in 3.5% NaCl and 3.5% NaCl + 0.5 M CuSO4 electrolytes was examined by potentiodynamic polarisation, potentiostatic polarisation and scanning electron microscopy. Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation. The large size of the exposed carbon fibres on the side region is responsible for a higher cathodic current density than the front region in the NaCl electrolyte. The deposition of copper on the front surface of composite confirmed that the significantly higher cathodic current resulted from the exposure of the fibres to the NaCl electrolyte. Galvanic coupling between the composite and individual aluminium alloys (AA7075-T6 and AA1050) was used to measure galvanic potentials and galvanic current densities. The highly alloyed AA7075-T6 alloy and its high population density of cathodic sites compared to the AA1050 acted to reduce the galvanic effect when coupled to the composite front or side regions

  10. Cathodic cycling effects in the oxide films formed on zirconium alloys type AB2

    International Nuclear Information System (INIS)

    The passive behavior of ZrNi alloys near the rest potential is studied through in situ voltammetry, ellipsometry, and microscopic observation.A significant oxide layer growth is observed in aqueous 1 M KOH during the application of different potential programs currently used in the activation processes of the alloy.The understanding of both the alloy activation process and the hydrogen absorption process is important in the strategies employed for the design of electrodes for nickel metal hydride batteries.The kinetics of the oxide layer formation, under potential cycling in the cathodic region related to the rest potential, plays a significant role in the activation process of metal alloy.Cathodic potential cycling increases the thickness and decreases the compactness of the passive oxide layer.The protonation of the oxide decreases the barrier effect and makes the anodic polarization more effective.Potential cycling gives rise to increasing surface oxidation, hydrogen absorption and hydride formation, and produces the consequent fragmentation of the material mainly through grain limits (J.Solid State Eletrochem. in press)

  11. Effect of Co addition on crystallization and magnetic properties of FeSiBPCu alloy

    Institute of Scientific and Technical Information of China (English)

    Rui Xiang; Shaoxiong Zhou; Bangshao Dong; Guangqiang Zhang; Zongzhen Li; Yanguo Wang; Chuntao Chang

    2014-01-01

    The effects of Co addition on the microstructure, crystallization processes and soft magnetic properties of (Fe1-xCox)83Si4B8P4Cu1 (x=0.35, 0.5, 0.65) alloys were investigated. The experimental results demonstrated that the addition of Co decreased the thermal stability against crystallization of the amorphous phase, and thus improved the heat treatment temperature of this alloy. FeCoSiBPCu nanocrystalline alloys with a dispersedα'-FeCo phase were obtained by appropriately annealing the as-quenched ribbons at 763 K for 10 min. Theα'-FeCo with grains size ranging from 9 to 28 nm was identified in primary crystallization. The coercivity (Hc) markedly increased with increasing x and exhibited a minimum value at x=0.35, while the saturation magnetic flux density (Bs) shows a slight decrease. The (Fe0.65Co0.35)83Si4B8P4Cu1 nanocrystalline alloy exhibited a high saturation magnetic flux density Bs of 1.68 T, a low coercivity, Hc of 5.4 A/m and a high effective permeability μe of 29,000 at 1 kHz.

  12. A study on the combined effect of forging and aging in Mg–Y–RE alloy

    International Nuclear Information System (INIS)

    Highlights: ► For the first time a combination of forging and aging has been explored for a magnesium alloy. ► Objective was to maximize the strength-ductility combination of a Mg–Y–RE alloy. ► An excellent combination of high strength (388 MPa) and high ductility (23%) was obtained. - Abstract: The combined effect of forging and aging on microstructural evolution and mechanical properties of a Mg–Y–RE alloy was studied in the present work by employing hardness measurements, tensile tests, optical microscopy (OM), scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) analysis. The -F temper treated bulk Mg–Y–RE alloy samples were subjected to forging for microstructural refinement and subsequent aging to maximize the strength-ductility combination. The forged samples combined with peak aging treatment (60 h at 180 °C) exhibited an excellent combination of high strength (388 MPa) and high ductility (23%). The combined effect of grain refinement, work hardening, precipitation strengthening and recovery is responsible for the simultaneous improvement of both strength and ductility. A comparative study of age hardening response of forged samples and as received samples showed higher hardenability in forged samples.

  13. A study on the combined effect of forging and aging in Mg-Y-RE alloy

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, S.K.; Yuan, W. [Centre for Friction Stir Processing and Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Mishra, R.S., E-mail: rsmishra@mst.edu [Centre for Friction Stir Processing and Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); DeLorme, R.; Davis, B. [Magnesium Elektron North America Inc., Madison, IL 62060 (United States); Howell, R.A.; Cho, K. [Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Grounds, MD 21005 (United States)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer For the first time a combination of forging and aging has been explored for a magnesium alloy. Black-Right-Pointing-Pointer Objective was to maximize the strength-ductility combination of a Mg-Y-RE alloy. Black-Right-Pointing-Pointer An excellent combination of high strength (388 MPa) and high ductility (23%) was obtained. - Abstract: The combined effect of forging and aging on microstructural evolution and mechanical properties of a Mg-Y-RE alloy was studied in the present work by employing hardness measurements, tensile tests, optical microscopy (OM), scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) analysis. The -F temper treated bulk Mg-Y-RE alloy samples were subjected to forging for microstructural refinement and subsequent aging to maximize the strength-ductility combination. The forged samples combined with peak aging treatment (60 h at 180 Degree-Sign C) exhibited an excellent combination of high strength (388 MPa) and high ductility (23%). The combined effect of grain refinement, work hardening, precipitation strengthening and recovery is responsible for the simultaneous improvement of both strength and ductility. A comparative study of age hardening response of forged samples and as received samples showed higher hardenability in forged samples.

  14. Effect of high density electropulsing treatment on formability of TC4 titanium alloy sheet

    Institute of Scientific and Technical Information of China (English)

    SONG Hui; WANG Zhong-jin; GAO Tie-jun

    2007-01-01

    An annealed TC4 titanium alloy sheet was treated by high density electropulsing (Jmax=(5.09-5.26)×103A/mm2, tp=110 μs) under ambient conditions. The effect of electropulsing treatment(EPT) on the plastic deformation behavior of TC4 titanium alloy sheet was studied using uniaxial tension tests. The experimental results indicate that electropulsing treatment significantly changes the mechanical properties of sheet metal: the uniform elongation is increased by 35%, the yield stress is decreased by 19.8% and the yield to tensile ratio is decreased by 17.6%. It is of significant meaning to improve the formability of TC4 titanium alloy sheet. The optical microscope and scanning electron microscope(SEM) were used to examine the changes of the microstructure and the fracture morphology before and after the electropulsing treatment. It is found that recrystallization occurs in the sheet metal and dimples in fracture surface are large and deep after the electropulsing treatment. The research results show that the electropulsing treatment is an effective method to improve the formability of titanium alloy sheets.

  15. Effects of alloy heat treatment on oxidation kinetics and scale morphology for Crofer 22 APU

    Science.gov (United States)

    Magdefrau, Neal J.; Chen, Lei; Sun, Ellen Y.; Aindow, Mark

    2013-11-01

    The effect of alloy heat treatment on the oxidation kinetics and oxide scale microstructure of Crofer 22 APU has been studied. Parabolic oxidation rate constants were measured for the as-received alloy and after pre-oxidation heat treatment in argon at 1050 °C for 1 and 4 h. The oxide scale microstructure was investigated using scanning electron microscopy, focused ion beam milling and transmission electron microscopy. It was found that the alloy forms a two-layer scale with a continuous chromia layer and a discontinuous MnCr2O4 overlayer. Two forms of internal oxides were also formed: subscale pockets of spinel and isolated TiOx precipitates in the underlying alloy. The pre-oxidation heat treatment had a profound effect on the grain size and morphology of the Cr2O3 and MnCr2O4 layers in the scale. The heat-treated samples exhibit a 3.5× lower parabolic oxidation rate constant than the as-received Crofer 22 APU. This improvement in oxidation resistance is attributed to the dramatic differences in the morphology of the oxide scale that forms during the earliest stages of oxidation (<5 h). The implications of these findings for oxidation mechanisms and long-term SOFC performance are discussed.

  16. Effect of the Degree of Plastic Deformation on the Electrical Resistance and Thermal Conductivity of Al-Mg-Si Alloy

    Directory of Open Access Journals (Sweden)

    Joseph Ajibade OMOTOYINBO

    2014-02-01

    Full Text Available Experiments have been conducted to investigate the effect of the degree of plastic deformation on the electrical resistance and thermal conductivity of Al-Mg-Si (6063 alloy. Thirty six samples of the 6063 alloy were used in all for the experiments (three samples constituted a group and twelve groups were instituted in the experiment with each group corresponding to a particular degree of deformation. Eleven groups were cold deformed plastically by subjecting the groups to different percentages of cold work starting from 5% to 55%, with 5% intervals. It was observed that there was no appreciable increase in the electrical resistance of the alloy as the degree of deformation increased. However, cold deformed 6063-Aluminium alloy appeared to be thermally unstable as the degree of plastic deformation increased. It was concluded that plastic deformation has no deleterious effect on the electrical resistance of the alloy but rendered the material thermally unstable in terms of thermal conductivity.

  17. The effect of mechanical alloying on microstructure and mechanical properties of MoSi2 prepared by spark plasma sintering

    International Nuclear Information System (INIS)

    Highlights: • Powders of Mo and Si according to MoSi2 stoichiometry were mechanically alloyed. • The as milled powder mixture was sintered using spark plasma sintering. • We investigated the microstructure and mechanical properties of samples. - Abstract: In this research the effect of mechanical alloying on the in situ synthesis–sintering behavior and mechanical properties of MoSi2 has been investigated. The Mo and Si powders according to MoSi2 stoichiometric composition were mechanically alloyed at different times. Then, the powders were subjected to spark plasma sintering process for preparing monolithic MoSi2. X-ray diffraction pattern of the sintered samples showed that by increasing the mechanical alloying time, Mo5Si3 has been formed. It seems that the formation of Mo5Si3 is due to the effect of mechanical alloying on microstructure and thermodynamic condition of the reaction

  18. The effect of nitrogen on the glass-forming ability and micro-hardness of Fe-Cr-Mn-N amorphous alloys prepared by mechanical alloying

    International Nuclear Information System (INIS)

    In this research, the effect of nitrogen on the thermal behavior and micro-hardness of Fe-Cr-Mn-N amorphous alloys synthesized by mechanical alloying under a nitrogen atmosphere has been considered. The characterization of the as-milled powders by X-ray diffraction, scanning and transmission electron microscopy showed that a fully amorphous structure has been developed by the mechanical alloying process. Differential scanning calorimetry results revealed that the glass transition temperatures and onset crystallization temperatures are in the ranges of 764-766 K and 855-861 K, respectively, for the alloys containing 3.45-3.95 wt.% nitrogen, giving considerable supercooled liquid regions of 91-95 K. The amorphous alloys exhibited an increase in the glass-forming ability by increasing the nitrogen amount. Furthermore, the as-milled amorphous powders showed high micro-hardness values of nearly 1015-1070 HV with an elastic-plastic deformation feature during the indentations. A decrease in the micro-hardness values was found by increasing the nitrogen content.

  19. Effect of overheating temperature on the microstructure and creep behavior of HP40Nb alloy

    International Nuclear Information System (INIS)

    Highlights: → Effect of overheating temperature on the microstructure of HP40Nb is investigated. → We measure the creep properties of HP40Nb (ε) through using impression creep testing. → Effect of overheating temperature on ε is investigated. → The content of inter-dendritic carbides is the main influencing factor on ε. -- Abstract: HP40Nb alloy has been widely used as a high temperature material in petrochemical plants. However, overheating or local temperature excursion occurs occasionally in service and leads to serious damage on the material. Effect of temperature on the microstructure and creep performance of the HP40Nb alloy is investigated in the present work. Several specimens are cut from serviced components of the alloy and heat-treated at different temperatures from 900 oC to 1250 oC for its possible working conditions, in which the temperature of 1200 or 1250 oC is used to simulate the overheating condition of HP40Nb tubes. The microstructure of specimens is examined by scanning electron microscope (SEM) and transmission electron microscope (TEM). The creep behavior is evaluated through using impression creep tests with a flat-ended cylindrical indenter. The content of inter- and intra-dendritic carbides in the specimens is represented by the surface fraction of each phase, which has been estimated by image processing method. The results show that the total of the surface fraction of inter- and intra-dendritic carbides in the HP40Nb alloy does not significantly change at the temperature lower than 1100 oC. However, the surface fraction of inter-dendritic carbides reaches the maximum at 1100 oC. A maximal steady state impression rate is also observed at 1100 oC. The results suggest that the content of inter-dendritic carbides is the main influencing factor on the creep performance of HP40Nb alloys comparing with that of the intra-dendritic carbides.

  20. Effects of porosity on corrosion resistance of Mg alloy foam produced by powder metallurgy technology

    International Nuclear Information System (INIS)

    Magnesium alloy foams have the potential to serve as structural material for regular light-weight applications as well as for biodegradable scaffold implants. However, their main disadvantage relates to the high reactivity of magnesium and consequently their natural tendency to corrode in regular service conditions and in physiological environments. The present study aims at evaluating the effect of porosity on the corrosion resistance of MRI 201S magnesium alloy foams in 0.9% NaCl solution and in phosphate buffer saline solution as a simulated physiological electrolyte. The magnesium foams were produced by powder metallurgy technology using space-holding particles to control the porosity content. Machined chips were used as raw material for the production of Mg alloy powder by milling process. The microstructure of the foams was examined using optical and scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analysis. The corrosion behavior was evaluated by immersion test and potentiodynamic polarization analysis. The results obtained clearly demonstrate that the porosity has a significant effect on the corrosion resistance of the tested foams. Foams with 14–19% porosity have a corrosion rate of 4–10 mcd and 7–15 mcd in NaCl and phosphate buffer saline solution, respectively, compared to only 0.10 mcd for the same alloy in as cast conditions. This increased corrosion degradation of the Mg foams by more than one order of magnitude compared to the cast alloy may limit their potential application in regular and physiological environments. - Highlights: • Porosity has a detrimental effect on corrosion resistance of MRI 201S Mg foams. • 14–19% porosity increases the corrosion rate by more than one order of magnitude. • Accelerated corrosion limits the use of foams in regular/physiological environments

  1. Influence of alloying effect on X-ray fluorescence parameters of Co and Cu in CoCuAg alloy films

    Science.gov (United States)

    Aylikci, Nuray Kup; Tiraşoğlu, Engin; Apaydin, Gökhan; Cengiz, Erhan; Aylikci, Volkan; Bakkaloğlu, Ömer Faruk

    2009-06-01

    In this study, K β/K α X-ray intensity ratios, σ, σ production cross-sections and ωK fluorescence yields of Co and Cu and L β/L α X-ray intensity ratios, σ, σ production cross-sections and ϖ average fluorescence yields of Ag in pure metals and in different alloy compositions were measured. In this study, alloying effects on the σ production cross-sections of Co and Cu were investigated and changes interpreted according to the rearrangement of valance state electrons and the charge transfer process between the 3d elements (Co and Cu) and Ag.

  2. Effect of laser treatment on the surface of copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Garbacz, Halina, E-mail: hgarbacz@inmat.pw.edu.pl [Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02-507 Warsaw (Poland); Fortuna-Zalesna, Elzbieta [Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02-507 Warsaw (Poland); Marczak, Jan [Military University of Technology, Institute of Optoelectronics, Gen. S. Kaliskiego 2, 00-908 Warsaw (Poland); Koss, Andrzej; Zatorska, Anna [Academy of Fine Arts in Warsaw, Inter-Academy Institute for Conservation and Restoration of Works of Art, Wybrzeze Kosciuszkowskie 37, 00-379 Warsaw (Poland); Zukowska, Grazyna Z. [Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664 Warsaw (Poland); Onyszczuk, Tomasz; Kurzydlowski, Krzysztof J. [Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02-507 Warsaw (Poland)

    2011-06-15

    The paper presents the results of laser cleaning of the archaeological metal objects using two time widths of pulsed laser radiation, which are around 150 {mu}s and around 120 ns. Two archaeological objects made of copper alloys were studied: a bow and a ring. Both objects came from a cemetery which is located in the garden complex of Wilanow Palace in Warsaw and are dated from XII to XIII century. The bow and bronze ring had ornamental longitudinal grooving and were part of burial jewellery. The materials of which these artefacts were made of, as well as corrosion products on these objects, were studied by using a variety of analytical techniques. The phase composition of the corrosion layers was determined by using Raman spectroscopy. The surface topography as well as the chemical composition of the deposits and cleaned surfaces were investigated. The samples were examined using scanning electron microscopes equipped with EDS. The investigations included observations in SE and BSE modes and point analyses of the chemical composition by EDS.

  3. Mitigation of harmful effects of welds in zirconium alloy components

    International Nuclear Information System (INIS)

    Welding produces local residual tensile stresses and changes in texture in components made from zirconium alloys. In the heat-affected zone in tubes or plates, the basal plane normals are rotated into the plane of the component and perpendicular to the direction of the weld. Thin-walled zircaloy-2 tubes containing an axial weld do not reach their full strength, because they always fail prematurely in the weld when pressurised to failure in a fixed-end burst test. Reinforcing the weld by increasing its thickness by 25% moves the failure to the parent metal, improves the biaxial strength of the tube by 20 to 25%, and increases the total elongation by 200 to 450%. In components made from Zr-2.5Nb, the texture in the heat-affected zone promotes delayed hydride cracking (DHC) driven by tensile residual stress. Although the texture is not much affected by heat-treatments below 630 degrees celsius and large grain interaction stresses remain as a result of mixed textures, macro-residual tensile stresses can be relieved by heat-treatment to the point where the probability of cracking is very low

  4. Mitigation of harmful effects of welds in zirconium alloy components

    International Nuclear Information System (INIS)

    Welding produces local residual tensile stresses and changes in texture in components made from zirconium alloys. In the heat-affected zone in tubes or plates, the basal plane normals are rotated into the plane of the component and perpendicular to the direction of the weld. Thin-walled Zircaloy-2 tubes containing an axial weld do not reach their full strength because they always fail prematurely in the weld when pressurized to failure in a fixed-end burst test. Reinforcing the weld by increasing its thickness by 25% moves the failure to the parent metal and improves the biaxial strength of the tube by 20 to 25% and increases the total elongation by 200 to 450%. In components made from Zr-2.5Nb, the texture in the heat-affected zone promotes delayed hydride cracking (DHC) driven by tensile residual stress. Although the texture is not much affected by heat-treatments below 630oC and large grain interaction stresses remain as a result of mixed textures, macro-residual tensile stresses can be relieved by heat treatment to the point where the probability of cracking is very low. (author)

  5. Effect of strain rate and temperature at high strains on fatigue behavior of SAP alloys

    DEFF Research Database (Denmark)

    Blucher, J.T.; Knudsen, Per; Grant, N.J.

    1968-01-01

    Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased with...... decreasing strain rate, above 500 F, and with increasing temperature; ductility at fracture in tension test is shown to be important factor in determining life under conditions of test. (20318)...

  6. Effect of Triple Annealing Treatment on Stress Relaxation of Ti-6Al-4V Alloy

    Institute of Scientific and Technical Information of China (English)

    Yong LIU; Jingchuan ZHU; Zhongda YIN; Mingwei LI

    2004-01-01

    The effect of triple annealing on stress relaxation of Ti-6Al-4V alloy as well as the microstructure after stress relaxation were studied. The results showed that triple annealing treatment enhanced the resistance of stress relaxation performance, and when the temperature was rising, this effect became notable. The stress relaxation deformation mechanism is of dislocation creep at 400℃ and recovery creep at 600℃.

  7. Effects of strain and trapping on hydrogen-induced cracking in high strength low alloy steels

    OpenAIRE

    Bosch, Cédric; Delafosse, David; Longaygue, Xavier

    2010-01-01

    International audience In pearlitic steels, hydrogen trapping at interphase boundaries may induce hydrogen- cracking in the absence of external applied stress such as in blistering and Hydrogen Induced Cracking. However, in low alloy steels containing a much lower density of such trapping sites and/or when hydrogen activity is reduced, most instances of hydrogen-induced cracking involve strong interactions between local plasticity and hydrogen effects. We investigated the effects of these ...

  8. Effect of Nb on the Microstructure, Mechanical Properties, Corrosion Behavior, and Cytotoxicity of Ti-Nb Alloys

    Directory of Open Access Journals (Sweden)

    Mi-Kyung Han

    2015-09-01

    Full Text Available In this paper, the effects of Nb addition (5–20 wt % on the microstructure, mechanical properties, corrosion behavior, and cytotoxicity of Ti-Nb alloys were investigated with the aim of understanding the relationship between phase/microstructure and various properties of Ti-xNb alloys. Phase/microstructure was analyzed using X-ray diffraction (XRD, SEM, and TEM. The results indicated that the Ti-xNb alloys (x = 10, 15, and 20 wt % were mainly composed of α + β phases with precipitation of the isothermal ω phase. The volume percentage of the ω phase increased with increasing Nb content. We also investigated the effects of the alloying element Nb on the mechanical properties (including Vickers hardness and elastic modulus, oxidation protection ability, and corrosion behavior of Ti-xNb binary alloys. The mechanical properties and corrosion behavior of Ti-xNb alloys were found to be sensitive to Nb content. These experimental results indicated that the addition of Nb contributed to the hardening of cp-Ti and to the improvement of its oxidation resistance. Electrochemical experiments showed that the Ti-xNb alloys exhibited superior corrosion resistance to that of cp-Ti. The cytotoxicities of the Ti-xNb alloys were similar to that of pure titanium.

  9. Effect of Heat Treatment on the In-Plane Anisotropy of As-Rolled 7050 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Huie Hu

    2016-04-01

    Full Text Available Tensile tests were conducted on both as-quenched and over-aged 7050 aluminum alloy to investigate the effect of heat treatment on the in-plane anisotropy of as-rolled 7050 aluminum alloy. The results showed that the tensile direction has limited effect on mechanical properties of the as-quenched 7050 aluminum alloy. The in-plane anisotropy factors (IPA factor of tensile strength, yield strength, and elongation in as-rolled 7050 aluminum alloy fluctuate in the vicinity of 5%. The anisotropy of the as-quenched 7050 aluminum alloy is mainly affected by the texture according to single crystal analysis based on the Schmid factor method. Besides, the IPA factor of the elongation in the over-aged 7050 aluminum alloy reaches 11.6%, illustrating that the anisotropy of the over-aged 7050 aluminum alloy is more prominent than that of the as-quenched. The occurrence of the anisotropy in the over-aged 7050 aluminum alloy is mainly attributed to the microstructures. which are characterized by visible precipitate free zones (PFZs and coarse precipitates in (subgrain boundaries.

  10. Effects of iron on intermetallic compound formation in scandium modified Al–Si–Mg Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [National Metal and Materials Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@mail.kmutt.ac.th [Production Engineering Department, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2014-12-15

    Highlights: • Iron reduces the modification effects of scandium in Al–Si–Mg alloys. • Morphologies of Sc-rich intermetallic phases vary with Fe and Sc contents and the cooling rates. • Sc neutralizes effects of Fe by changing Fe-rich intermetallic phases from platelets to more cubic. - Abstract: In general, iron has a strong tendency to dissolve in molten aluminum. Iron has very low solid solubility in aluminum–silicon casting alloys, so it will form intermetallic compounds that cause detrimental effects on mechanical properties. In this work, the effects of iron on intermetallic compound formations in scandium modified Al–Si–Mg alloys were studied. There were two levels of iron addition (0.2 and 0.4 wt.%) and two levels of scandium addition (0.2 and 0.4 wt.%). We found that the effects of scandium modification decreased with increasing iron addition. The morphologies of the complex intermetallic compounds were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. It was found that scandium changes the morphology of Fe-rich intermetallic compounds from β-phase (plate-like) to α-phase, which reduces the harmful effects of β-phase.

  11. Influences of different degassing processes on refining effect and properties of 4004 Al alloy

    Directory of Open Access Journals (Sweden)

    Wang Liping

    2013-03-01

    Full Text Available In order to improve the plasticity of 4004 Al alloy and subsequently the productivity of 4004 Al foil, the research studied in detail the influence of the rotary impeller degassing process on the refining effect of 4004 Al alloy, in which the impacts of four major parameters: gas flow, rotational speed, refining time, and stewing time, on degassing rate of 4004 Al alloy was systematically studied by using an orthogonal experiment methodology. Results show that the rotational speed has the greatest impact on the degassing of 4004 Al alloy, followed by gas flow and refining time; stewing time has the least impact. The optimum purification parameters obtained by current orthogonal analysis were: rotor speed of 500 r·min-1, inert gas flow of 0.4 mL·h-1, refining time of 15 min, and stewing time of 6 min. Degassing rate using the optimum parameters reaches 68%. In addition, the comparison experiments among C2Cl6 refining, rotary impeller degassing, and combined treatment of C2Cl6 refining and rotary impeller degassing for 4004 Al alloy were performed. The experimental data indicated that the combined treatment of C2Cl6 refining and rotary impeller degassing has the best degassing effect. Degassing rate of C2Cl6 refining, rotary impeller degassing and combined refining treatment is 39%, 69.1% and 76.9%, respectively. The mechanical properties of the specimen refined by rotary impeller degassing were higher than those by C2Cl6 refining, but lower than those by combined refining treatment.

  12. The Effects of Water Vapor and Hydrogen on the High-Temperature Oxidation of Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mu, N; Jung, K; Yanar, N M; Pettit, F S; Holcomb, G R; Howard, B H; Meier, G H

    2013-06-01

    Essentially all alloys and coatings that are resistant to corrosion at high temperature require the formation of a protective (slowly-growing and adherent) oxide layer by a process known as selective oxidation. The fundamental understanding of this process has been developed over the years for exposure in pure oxygen or air. However, the atmospheres in most applications contain significant amounts of water vapor which can greatly modify the behavior of protective oxides. The development of oxy-fuel combustion systems in which fossil fuels are burned in a mixture of recirculated flue gas and oxygen, rather than in air, has caused renewed interest in the effects of water vapor and steam on alloy oxidation. The focus of this paper is on the ways the presence of water vapor can directly alter the selective oxidation process. The paper begins with a brief review of the fundamentals of selective oxidation followed by a description of recent experimental results regarding the effect of water vapor on the oxidation of a variety of chromia-forming alloys (Fe- and Ni-base) in the temperature range 600 to 700 °C. The atmospheres include air, air-H{sub 2}O, Ar-H{sub 2}O and Ar-H{sub 2}O-O{sub 2}. Then the behavior of alumina-forming alloys in H{sub 2}O-containing atmospheres is briefly described. As hydrogen is produced during oxidation of alloys in H{sub 2}O, it can be released back into the gas phase or injected into the metal (where it can diffuse through to the other side). Experiments in which hydrogen concentrations have been measured on both sides of thin specimens during oxidation by H{sub 2}O on only one side are described. Finally, it is attempted to catalogue the various experimental observations under a few general principles.

  13. Corrosion of alloy 22 in phosphate ions effect and chloride containing solutions

    International Nuclear Information System (INIS)

    Alloy 22 belongs to Ni-Cr-Mo family. This alloy resists the most aggressive environments for industrial applications, in oxidizing as well as reducing conditions, because exhibits an excellent uniform and localized corrosion resistance in aqueous solution. Because of its outstanding corrosion resistant, this alloy is one of the candidate to be considered for the outer shell of the canister that would contain high level radioactive nuclear wastes in a geological repository. The aim of this work is to study ion phosphate influence over Alloy 22 corrosion behavior under aggressive conditions, such as high temperature and high ion chloride concentration, where this material might be susceptible to crevice corrosion. Two different types of samples were used: cylinder specimens for uniform corrosion behavior studies and Prismatic Crevice Assembly (PCA) specimens for localized corrosion studies. Electrochemical tests were performed in deaerated aqueous solution of 1 M NaCl and 1 M NaCl with different phosphate additions at 90 C degrees and pH near neutral. The anodic film and corrosion products obtained were studied by SEM/EDS. Cyclic Potentiodynamic Polarization (CPP) curves obtained for uniform corrosion studies, showed an increase of the passivity range in phosphate containing solutions. The passive current value was 1 μA/cm2 approximately in all the tests. PCA electrochemical tests, that combined a CPP with a potentiostatic polarization step for 2 hours in between the forward and reverse scan, showed crevice corrosion development in some cases. The repassivation potential value, determined by the intersection of the forward and the reverse scan, increased with phosphate addition. A complete crevice corrosion inhibition effect was found for phosphate concentration higher than 0.3 M. These results indicate that the passivity potential range depend on phosphate presence and might be related with the incorporation of the anion in the passive film. Results of the tests

  14. Modeling of effects of matrix on actuation characteristics of embedded shape memory alloy wires

    Institute of Scientific and Technical Information of China (English)

    CUI Xiao-long; ZHENG Yan-jun; CUI Li-shan

    2005-01-01

    Effects of matrix properties on the actuation characteristics of embedded shape memory alloy wires were studied. The coefficient of thermal expansion and the modulus of matrix have significant effect on the maximum recovery stress. The thermal strain rate of the SMA wires upon heating is more sensitive to the matrix properties than the stress rate does. Additional fibers embedded in the matrix have significant effect on the stress distribution between the SMA wires and the matrix, and thus affect the interface quality significantly. Fibers with negative thermal expansion coefficient are beneficial to the interface between shape memory alloy wires and the epoxy matrix. All conclusions based on the numerical modeling can find experimental supports.

  15. Bauschinger effect in haynes 230 alloy: Influence of strain rate and temperature

    Science.gov (United States)

    Thakur, Aniruddha; Vecchio, Kenneth S.; Nemat-Nasser, Sia

    1996-07-01

    Quasistatic and dynamic Bauschinger behavior in HAYNES 230 alloy is examined. At low strain rate (10-3/s), the as- received 230 alloy does not show a drop in flow stress, i.e., no Bauschinger effect is displayed. At high strain rate (103/s), a drop in flow stress of 240 MPa was observed upon stress reversal. In contrast, the precipitation- strengthened condition exhibited a Bauschinger effect in both low and high strain rate stress-reversal experiments. The magnitude of the Bauschinger effect was found to increase with increasing strain rate, forward strain, and decreasing temperature. The substructure evolution accompanying the forward loading cycles was investigated by transmission electron microscopy and is related to the back stresses that developed. The increased Bauschinger stress drop observed at high strain rate and/or low temperature was correlated to an increased degree of planar slip under these conditions.

  16. Effect of steady and time-harmonic magnetic fields on macrosegragation in alloy solidification

    Energy Technology Data Exchange (ETDEWEB)

    Incropera, F.P.; Prescott, P.J. [Purdue Univ., West Lafayette, IN (United States)

    1995-12-31

    Buoyancy-induced convection during the solidification of alloys can contribute significantly to the redistribution of alloy constituents, thereby creating large composition gradients in the final ingot. Termed macrosegregation, the condition diminishes the quality of the casting and, in the extreme, may require that the casting be remelted. The deleterious effects of buoyancy-driven flows may be suppressed through application of an external magnetic field, and in this study the effects of both steady and time-harmonic fields have been considered. For a steady magnetic field, extremely large field strengths would be required to effectively dampen convection patterns that contribute to macrosegregation. However, by reducing spatial variations in temperature and composition, turbulent mixing induced by a time-harmonic field reduces the number and severity of segregates in the final casting.

  17. Magnetocaloric effect of Gd5Si2Ge2 alloys in low magnetic field

    Indian Academy of Sciences (India)

    Hong Zeng; Chunjiang Kuang; Jiuxing Zhang; Ming Yue

    2011-07-01

    The magnetocaloric effect of Gd5Si2Ge2 alloys under heat treatment conditions are investigated in low magnetic fields. The magnetocaloric effect (MCE) is studied by measuring magnetic entropy change ( M) and adiabatic temperature change ( ad) in a magnetic field of 1.5 T using a vibrating sample magnetometer (VSM) and a home-made magnetocaloric effect measuring apparatus, respectively. The maximum M of the alloys increases by 200% from 4.38 to 13.32 J kg-1 K-1, the maximum ad increases by 105% from 1.9 to 3.9 K when compared to the as-cast due to the homogeneous composition distribution and microstructure, while the magnetic ordering temperature is slightly reduced. These results indicate that the annealed Gd5Si2Ge2 compounds are promising as high-performance magnetic refrigerants working room temperature in relatively low magnetic fields.

  18. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

    Science.gov (United States)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-12-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. PMID:27612770

  19. Alloying effects on the hydrogen-storage capability of Pd–TM–H (TM = Cu, Au, Pt, Ir) systems

    International Nuclear Information System (INIS)

    Highlights: • Magnetic susceptibilities and hydrogen capabilities for Pd–TM–H were simultaneously measured. • Magnetic susceptibilities of Pd–Pt–H and Pd–Ir–H exhibited different behavior from Pd–H. • Hydrogen capabilities of Pd–TM were decreased with increasing TM content. • Alloying Pd with Pt and Ir reduced more its hydrogen capability than alloying with Cu and Au. • These results were explained by change on band structure above Fermi level by alloying. - Abstract: Pressure–composition isotherms and the magnetic susceptibilities of Pd–TM–H (TM = Cu, Au, Pt, and Ir) systems were measured at ambient temperature, and the effects of alloying between Pd and transition metals on the hydrogen storage capability of these Pd–TM alloys were investigated by considering their electronic band structures. All of the magnetic susceptibilities for the Pd–TM–H systems decreased linearly with hydrogen uptake. For the Pd–Cu alloy, the magnetic susceptibility was nearly zero at the terminal composition of hydrogen in the plateau region obtained from the pressure–composition isotherm, and the terminal composition decreased with increasing Cu substitution. These results indicated that the hydrogen-storage capability was proportional to the amount of unoccupied d states in the electronic band structure of the Pd–Cu alloy. The Pd–Au–H system exhibited substantially the same behavior as the Pd–Cu–H system. For the Pd–Pt and Pd–Ir alloys, the magnetic susceptibility at the terminal composition of hydrogen in the plateau exhibited a finite positive value, indicating that the unoccupied d states in the Pd–Pt and Pd–Ir alloys were not filled when the maximum quantity of hydrogen was stored in the alloys. These finite magnetic susceptibilities at the terminal composition of hydrogen in the plateau region were explained by the structural modification of the unoccupied d states in the electronic band structures due to alloying

  20. Effect Of Milling Time On Microstructure Of AA6061 Composites Fabricated Via Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Tomiczek B.

    2015-06-01

    Full Text Available The aim of this work is to determine the effect of manufacturing conditions, especially milling time, on the microstructure and crystallite size of a newly developed nanostructural composite material with the aluminium alloy matrix reinforced with halloysite nanotubes. Halloysite, being a clayey mineral of volcanic origin, is characterized by high porosity and large specific surface area. Thus it can be used as an alternative reinforcement in metal matrix composite materials. In order to obtain this goal, composite powders with fine microstructures were fabricated using high-energy mechanical alloying, cold compacting and hot extrusion techniques. The obtained composite powders of aluminium alloy reinforced with 5, 10 and 15 wt% of halloysite nanotubes were characterized with SEM, TEM and XRD analysis. It has been proven that the use of mechanical alloying leads to a high degree of deformation, which, coupled with a decreased grain size below 100 nm and the dispersion of the refined reinforcing particles–reinforces the material very well.

  1. Effect of benzaldehyde on the electrodeposition and corrosion properties of Ni–W alloys

    Institute of Scientific and Technical Information of China (English)

    U. Pramod Kumar; C. Joseph Kennady

    2015-01-01

    The effect of different concentrations of benzaldehyde on the electrodeposition of Ni–W alloy coatings on a mild steel substrate from a citrate electrolyte was investigated in this study. The electrolytic alkaline bath (pH 8.0) contained stoichiometric amounts of nickel sulfate, sodium tungstate, and trisodium citrate as precursors. The corrosion resistance of the Ni–W-alloy-coated specimens in 0.2 mol/L H2SO4 was studied using various electrochemical techniques. Tafel polarization studies reveal that the alloy coatings obtained from the bath containing 50 ppm benzaldehyde exhibit a protection efficiency of 95.33%. The corrosion rate also decreases by 21.5 times compared with that of the blank. A higher charge-transfer resistance of 1159.40?·cm2 and a lower double-layer capacitance of 29.4 μF·cm?2 further confirm the better corrosion resistance of the alloy coating. X-ray diffraction studies reveal that the deposits on the mild steel surface are consisted of nanocrystals. A lower surface roughness value (Rmax) of the deposits is confirmed by atomic force microscopy.

  2. EFFECT OF CASTING MOULD ON MECHANICAL PROPERTIES OF 6063 ALUMINUM ALLOY

    Directory of Open Access Journals (Sweden)

    WASIU AJIBOLA AYOOLA

    2012-02-01

    Full Text Available Modern production methods for casting articles include the use of sand- mould, metal-mould, die, and centrifugal castings. Castings produced using sand mould is known to have peculiar microstructures depending on average size, distribution and shape of the moulding sand grains and the chemical composition of the alloy. These affect the surface finish, permeability and refractoriness of all the castings. In this paper, the effect of using CO2 process, metal mould, cement-bonded sand mould and naturally-bonded sand mould on the hardness, tensile and impact strengths of as-cast 6063 Aluminum alloy is presented. The results show that there is significant increase in hardness(33.7 HB of the alloy when naturally-bonded sand mould is used for its production over that of metal, CO2 and cement moulds. The stress-strain curves behaviour of the samples also indicated that sample from naturally bonded sand has highest tensile strength with superior ductility. The alloy shows highest impact strength when metal mould is used for sample preparation in comparison with other moulds.

  3. Effect of equal channel angular pressing on aging treatment of Al-7075 alloy

    Directory of Open Access Journals (Sweden)

    M.H. Shaeri

    2015-04-01

    Full Text Available The effect of aging treatment on microstructure and mechanical properties of equal channel angular pressed Al-7075 alloy was examined. Commercial Al-7075 alloy in the solid solution heat-treated condition was processed by equal channel angular pressing through route BC at both the room temperature and 120 °C. Only three passes of equal channel angular pressing was possible due to the low ductility of the alloy at both temperatures. Followed by equal channel angular pressing, the specimens have been aged at 120 °C for different aging times. Mechanical properties were measured by Vickers microhardness and tensile tests and microstructural observations were undertaken using transmission electron microscopy, X-ray diffractometer as well as optical microscopy. Microstructural investigations showed that ultrafine-grained materials with grain size in the range of 200–350 nm and 300–500 nm could be obtained after three passes of equal channel angular pressing at room temperature and 120 °C, respectively. Equal channel angular pressing of solid solution heat-treated Al-7075 alloy accelerates precipitation rate and subsequently leads to a significant decrease in aging time to attain maximum mechanical properties. Furthermore, it is possible to achieve maximum mechanical properties during equal channel angular pressing at 120 °C as a result of dynamic aging and formation of small ɳ´ phase.

  4. Effect of Alloying Interlayer on Interfacial Bond Strength of CuW/CuCr Integral Materials

    International Nuclear Information System (INIS)

    The effects of Fe alloying interlayers with different content on microstructures and mechanical properties of dissimilar CuW/CuCr joints prepared by sintering-infiltration method were studied. Microhardness (HV) and tensile tests were used to evaluate the mechanical properties of the resulting joints. Additionally, optical, scanning electron microscopy examinations and energy dispersive spectrometry elemental analyses were applied to determine the interfacial characteristics of CuW/CuCr integral materials. The results show element Fe in the alloying interlayers is mostly diffused to the Cu-W composite side, the Cu/W interphase has achieved the metallurgical bond, and the CuW/CuCr integrated material with Cu-5wt%Fe alloy interlayer exhibits higher interfacial bond strength. However, when the Fe content in the interlayers is above 5wt%, the W skeletons near the interface are dissolved and eroded by element Fe addition, the amount of eutectic phase is increased and the microhardness on copper matrix is decreased for the Cu-Cr alloy side near the interlayer, and the interfacial strength of CuW/CuCr integrated materials is also decreased.

  5. Effect of modification and heat treatment operations on impact strength of the EN AC-46000 alloy

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2010-10-01

    Full Text Available More and more stringent requirements concerning mechanical and technological properties, which are imposed on materials used tocastings of heavy duty machinery components extort implementation of modern selection methods of alloying additives (synthesis ofalloys, modifying agents and heat treatment. Obtainment of optimal results, i.e. improvement of mechanical properties of processed alloyas well as its economic aspect are connected with selection of a suitable temperatures and durations of solution heat treatment and ageing operations. In the paper is present an effect of modification and heat treatment processes on KCV impact strength of the EN AC-46000alloy. Investigated alloy underwent typical treatments of refining and modification, and next heat treatment. Temperatures’ range for heat treatment operations was evaluated with used of the ATD method. Obtained results concern registered curves of melting and solidification with use of the ATD method and the impact strength. On base of performed tests one has determined a range of heat treatment parameters which create conditions to suitable impact strength of the EN AC-46000 alloy.

  6. Effect of Residual Strain Induced by Cold Working on PWSCC of Alloy 690

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Woo; Hwang, Seong Sik; Lim, Yun Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    PWSCC has been widely reported to occur in the inside of the steam generator (SG) tubing, and in other instrumentation nozzles such as the control rod drive mechanism (CRDM) penetrations, especially on those surfaces having a dissimilar metal welds (DMW) or those heavily machined. Under an abnormal working procedure or without a sufficient post-heat treatment for stress relaxation, a high tensile stress can persist after welding or cold working of the alloys. Variation of a strain field is also accompanied by the cold working or machining process. The conventional method for measuring the residual strain is a micro-hardness test, which has a limitation owing to the presence of precipitates and grain boundaries in the matrix of the test specimen. A new technique of electron backscatter diffraction (EBSD) has recently been applied to residual strain analysis on a micro-scale to overcome this limitation. This work is concerning a quantitative analysis of the local residual strain by EBSD and its effect on the PWSCC of Alloy 690 CRDM materials. In this work, the local residual strain of Alloy 690 CRDM materials cold-worked at various plastic strain levels was quantitatively evaluated using an EBSD analysis. From KAM maps, it was confirmed that the residual strain increased with cold-working, and a higher strain was concentrated at the grain boundary than in the matrix. The severe strain field localized at the grain boundary accelerated the inter-grannular growth of PWSCC of Alloy 690.

  7. The effect of extension twinning on the electrochemical corrosion properties of Mg–Y alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Guodong [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Peng, Qiuming, E-mail: pengqiuming@gmail.com [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Wang, Yanan [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, Baozhong, E-mail: bzliu@hpu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000 (China)

    2015-01-05

    Highlights: • {101"¯2} extension twins form in a Mg–1 wt.% Y alloy with a true strain of 1%. • Extension twins improves electrochemical corrosion properties of a Mg–1 wt.% Y alloy. • {101"¯2} twins vary pitting potential, film formation and charge transfer resistance. • The reasons root in a preferential oxide layer and low twin boundary energy. - Abstract: The effect of extension twinning formed during compression deformation on the corrosion properties of an Mg–1 wt.% Y alloy was investigated using electrochemical tests. The corrosion morphology evolution after immersion in 0.9 wt.% NaCl aqueous solutions for various times has been analyzed by scanning electron microscope. The electron back-scatter diffraction result shows the {101"¯2} extension twins appear in the deformed Mg–1 wt.% Y alloy with a true strain of 1%. The extension twinning accelerates the formation of oxide film and increases charge transfer resistance, resulting in the improvement of corrosion properties. However, it hardly affects the occurrence of microcracks in grain boundaries. The main reasons root in a preferred formation of homogeneous oxide layer in twinning area and low twin boundary energy.

  8. The effect of extension twinning on the electrochemical corrosion properties of Mg–Y alloys

    International Nuclear Information System (INIS)

    Highlights: • {101¯2} extension twins form in a Mg–1 wt.% Y alloy with a true strain of 1%. • Extension twins improves electrochemical corrosion properties of a Mg–1 wt.% Y alloy. • {101¯2} twins vary pitting potential, film formation and charge transfer resistance. • The reasons root in a preferential oxide layer and low twin boundary energy. - Abstract: The effect of extension twinning formed during compression deformation on the corrosion properties of an Mg–1 wt.% Y alloy was investigated using electrochemical tests. The corrosion morphology evolution after immersion in 0.9 wt.% NaCl aqueous solutions for various times has been analyzed by scanning electron microscope. The electron back-scatter diffraction result shows the {101¯2} extension twins appear in the deformed Mg–1 wt.% Y alloy with a true strain of 1%. The extension twinning accelerates the formation of oxide film and increases charge transfer resistance, resulting in the improvement of corrosion properties. However, it hardly affects the occurrence of microcracks in grain boundaries. The main reasons root in a preferred formation of homogeneous oxide layer in twinning area and low twin boundary energy

  9. Effect of Residual Strain Induced by Cold Working on PWSCC of Alloy 690

    International Nuclear Information System (INIS)

    PWSCC has been widely reported to occur in the inside of the steam generator (SG) tubing, and in other instrumentation nozzles such as the control rod drive mechanism (CRDM) penetrations, especially on those surfaces having a dissimilar metal welds (DMW) or those heavily machined. Under an abnormal working procedure or without a sufficient post-heat treatment for stress relaxation, a high tensile stress can persist after welding or cold working of the alloys. Variation of a strain field is also accompanied by the cold working or machining process. The conventional method for measuring the residual strain is a micro-hardness test, which has a limitation owing to the presence of precipitates and grain boundaries in the matrix of the test specimen. A new technique of electron backscatter diffraction (EBSD) has recently been applied to residual strain analysis on a micro-scale to overcome this limitation. This work is concerning a quantitative analysis of the local residual strain by EBSD and its effect on the PWSCC of Alloy 690 CRDM materials. In this work, the local residual strain of Alloy 690 CRDM materials cold-worked at various plastic strain levels was quantitatively evaluated using an EBSD analysis. From KAM maps, it was confirmed that the residual strain increased with cold-working, and a higher strain was concentrated at the grain boundary than in the matrix. The severe strain field localized at the grain boundary accelerated the inter-grannular growth of PWSCC of Alloy 690

  10. Effects of Fe, Co and Ni elements on the ductility of TiAl alloy

    International Nuclear Information System (INIS)

    Highlights: • Effect of Fe/Co/Ni on the ductility of TiAl was studied by theory and experiments. • Ni exists in the form of NiTi, which is detrimental to the ductility of TiAl. • Fe Co change electronic and elastic properties to improve ductility of TiAl. - Abstract: The Ni atom is difficult to occupy the Ti or Al site in TiAl, it exists in the form of NiTi phase at the grain boundary of TiAl alloy, which is detrimental to the ductility of the TiAl alloy. The Fe and Co atoms preferentially occupy the Al sites and can improve the electronic structures and elastic properties of TiAl, leading to the improvement of the ductility of TiAl alloy. With the addition of 3 at.% Fe and Co, the tested average fracture strain of TiAl alloy increases from 17.3% to 19.1% and 18.0%, respectively

  11. Effect of mold temperature on the microstructure and corrosion properties of a 14-karat gold alloy.

    Science.gov (United States)

    Koiso, Kazuo; Saito, Takahiro; Kawashima, Isao

    2012-01-01

    The objective of this research was to investigate the effect of mold temperature on grain interior and grain boundary reactions in a14-karat gold alloy. The alloy (Au-15%Ag-3%Pd-24 mass%Cu) was cast into an investment with different mold temperatures (22, 250,400, and 700°C) and then analyzed using SEM, X-ray diffraction, and potentiodynamic polarization tests. Lower mold temperatures(22 and 250°C) retarded a grain boundary reaction evidently present when using higher mold temperatures (400 and 700°C). Phase separation, which was manifested as a dual phase grain boundary nodular formation, was observed at a higher degree at 400°C mold temperature than at 700°C. The corrosion potentials of alloys cast at lower mold temperatures were more noble than those cast at higher mold temperatures, suggesting improved corrosion properties. Results of this study showed that the microstructure, crystalline phases present, and corrosion properties of 14-karat gold alloy were keenly influenced by the mold temperature, which controls and influences the cooling rate. PMID:22864223

  12. Effects of pH and chloride concentration on pitting corrosion of AA6061 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zaid, B. [Division de Technologie du Combustible, Departement de Metallurgie, Centre de Recherche Nucleaire de Draria, BP. 43 Seballa, Draria (Algeria)], E-mail: zaidbachir@yahoo.com; Saidi, D. [Division de Technologie du Combustible, Departement de Metallurgie, Centre de Recherche Nucleaire de Draria, BP. 43 Seballa, Draria (Algeria); Benzaid, A. [Divisionde Physique et Application Nucleaires, Departement Application Nucleaires, Centre de Recherche Nucleaire de Draria, BP. 43 Seballa, Draria (Algeria); Hadji, S. [Division de Technologie du Combustible, Departement du combustible, Centre de Recherche Nucleaire de Draria, BP. 43 Seballa, Draria (Algeria)

    2008-07-15

    Effects of pH solution and chloride (Cl{sup -}) ion concentration on the corrosion behaviour of alloy AA6061 immersed in aqueous solutions of NaCl have been investigated using measurements of weight loss, potentiodynamic polarisation, linear polarisation, cyclic polarisation experiment combined with open circuit potential transient technique and optical or scanning electron microscopy. The corrosion behaviour of the AA6061 aluminum alloy was found to be dependant on the pH and chloride concentration [NaCl] of solution. In acidic or slightly neutral solutions, general and pitting corrosion occurred simultaneously. In contrast, exposure to alkaline solutions results in general corrosion. Experience revealed that the alloy AA6061 was susceptible to pitting corrosion in all chloride solution of concentration ranging between 0.003 wt% and 5.5 wt% NaCl and an increase in the chloride concentration slightly shifted both the pitting E{sub pit} and corrosion E{sub cor} potentials to more active values. In function of the conditions of treatment, the sheets of the alloy AA6061 undergo two types of localised corrosion process, leading to the formation of hemispherical and crystallographic pits. Polarisation resistance measurements in acidic (pH = 2) and alkaline chloride solutions (pH = 12) which are in good agreement with those of weight loss, show that the corrosion kinetic is minimised in slightly neutral solutions (pH = 6)

  13. De Haas-van Alphen effect study of electronic structures of niobium-based molybdenum alloys

    International Nuclear Information System (INIS)

    The electronic structures of dilute niobium-based molybdenum alloys have been studied by using the de Haas-van Alphen effect. The rate of increase of the Dingle temperature (ΔTsub(D)* on alloying is found to be fairly small compared with that of noble-metal alloys and to be anisotropic over the Fermi surfaces, that is, 3 K (at% Mo)-1 for ν oscillations arising from the ellipsoids, and 7 K (at% Mo)-1 for α and eta oscillations arising from the jungle gym. The change in frequency of the ν3456 oscillation is about 2/3 that predicted by the rigid band model. Applying the partial-wave analysis to these experimental facts, the following results are obtained. (i) T/e d wave phase shift dominates over s, p and f wave phase shifts in this alloy system and the anisotropy in ΔTsub(D)* results from the anisotropy in the amount of d component of the wavefunction over the Fermi surfaces. (ii) The non-rigid band-like behaviour of the ν3456 oscillation arises from the same origin as ΔTsub(D)*. (iii) The significantly small ΔTsub(D)* found in the present experiment is related to a small electron group velocity on the Fermi surfaces in niobium. (author)

  14. Effects in Mg-Zn-based alloys strengthened by quasicrystalline phase

    Science.gov (United States)

    Vlček, M.; Čížek, J.; Lukáč, F.; Melikhova, O.; Hruška, P.; Procházka, I.; Vlach, M.; Stulíková, I.; Smola, B.; Jäger, A.

    2016-01-01

    Magnesium Mg-based alloys are promising lightweight structural materials for automotive, aerospace and biomedical applications. Recently Mg-Zn-Y system attracted a great attention due to a stable icosahedral phase (I-phase) with quasicrystalline structure which is formed in these alloys. Positron lifetime spectroscopy and in situ synchrotron X-ray diffraction were used to study thermal stability of I-phase and precipitation effects in Mg-Zn-Y and Mg- Zn-Al alloys. All alloys containing quasicrystalline I-phase exhibit misfit defects characterized by positron lifetime of ∼ 300 ps. These defects are associated with the interfaces between I- phase particles and Mg matrix. The quasicrystalline I-phase particles were found to be stable up to temperatures as high as ∼ 370°C. The W-phase is more stable and melts at ∼ 420°C. Concentration of defects associated with I-phase decreases after annealing at temperatures above ∼ 300°C.

  15. Effect of benzaldehyde on the electrodeposition and corrosion properties of Ni-W alloys

    Science.gov (United States)

    Pramod Kumar, U.; Kennady, C. Joseph

    2015-10-01

    The effect of different concentrations of benzaldehyde on the electrodeposition of Ni-W alloy coatings on a mild steel substrate from a citrate electrolyte was investigated in this study. The electrolytic alkaline bath (pH 8.0) contained stoichiometric amounts of nickel sulfate, sodium tungstate, and trisodium citrate as precursors. The corrosion resistance of the Ni-W-alloy-coated specimens in 0.2 mol/L H2SO4 was studied using various electrochemical techniques. Tafel polarization studies reveal that the alloy coatings obtained from the bath containing 50 ppm benzaldehyde exhibit a protection efficiency of 95.33%. The corrosion rate also decreases by 21.5 times compared with that of the blank. A higher charge-transfer resistance of 1159.40 Ω·cm2 and a lower double-layer capacitance of 29.4 μF·cm-2 further confirm the better corrosion resistance of the alloy coating. X-ray diffraction studies reveal that the deposits on the mild steel surface are consisted of nanocrystals. A lower surface roughness value ( R max) of the deposits is confirmed by atomic force microscopy.

  16. Effect of Neodymium on Microstructure and Mechanical Properties of Mg-Sb Alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of Nd on the microstructure and mechanical properties of Mg-Sb3 alloy were studied with the 0~0.15% addition content. The addition of Nd makes the grain of Mg-Sb3 alloy obviously refined, where the grain size decreases from 100~200 μm to 0.2~10 μm. And the typical dendrite characteristic turns into the equiaxed grain microstructure with the addition of 0.05%~0.1% Nd. The reason for grain refinement is from the supercooling theory. The mechanical properties tested indicate that the tensile strength and especially elongation of the alloys are improved with the addition of Nd and their maximum enhancing rates based on the Nd-free Mg-Sb3 alloy are 20% and 10% at 0.1% Nd, respectively. The main reason is attributed to the grain refinement by Nd. The tensile strength and especially elongation decline when Nd addition is over 0.1%, owing to the number and size increase of the needle-shaped phases on the grain boundaries with the Nd addition increasing.

  17. Effects of Compression Parameters on Deformation Behaviors of Semi-Solid ZA27 Alloys

    Institute of Scientific and Technical Information of China (English)

    CHEN Ti-jun; HAO Yuan; SUN Jun

    2003-01-01

    An investigation was performed on the effects of semi-solid compression parameters,such as strain rate,compression temperature and heating time at these temperatures on deformation behaviors of two kinds of ZA27 alloys,one was modified by Zr and the other was unmodified.The results indicate that with the increasing of the strain,the stress of the modified composite first sharply increases to a peak value,then dramatically decreases to a plateau value,and again increases till the end of deformation.But for the unmodified,after being up to a peak value,the stress only decreases slowly.As the compression temperature or the heating time decreases,or the strain rate increases,the stress level and the cracking degree of these two kinds of alloys increase.Under the same deformation conditions,the stress level and the cracking degree of the unmodified alloy are higher than those of the modified one.But there is an exception that the stress level of the unmodified alloy is minimum and smaller than that of the modified one when deformed at the low temperature of 450℃.These phenomena were mainly discussed through analyzing the microstructures under different conditions and the deformation mechanisms at different deformation stages.

  18. Effect of nanostructuring on the elastic properties of aluminum alloy AMg6

    International Nuclear Information System (INIS)

    We experimentally investigated the nanostructuring effect on the elastic properties of aluminum alloy AMg6 (Al–Mg–Mn system). The n-AMg6 nanostuctured specimens were prepared from a commercial polycrystalline alloy by refining and homogenizing a mixture of small chips of the alloy in a planetary mill. The resulting product consists of 200-500-micron agglomerates of nanoparticles with average nanoparticle size ∼ 40–60 nanometer according to the X-ray analysis. The compacted nanopowder was extruded at a temperature of 300°C with a reduction of cross-sectional area at least 4 times to 90 mm diameter. High resolution transmission electron microscopy studies confirmed the presence of the nanostructure with a grain size of ∼60 nanometers. For the experiments, nine parallelepiped shape specimens of 20×20×40 mm3 size were cut from the central and peripheral parts of the n-AMg6 rod. We measured of the second-order and third-order elastic coefficients of the obtained samples by ultrasonic method. The same measurements were made on specimens of the primary AMg6 alloy for comparison

  19. Effect of cryorolling and warm rolling on precipitation evolution in Al 6061 alloy

    International Nuclear Information System (INIS)

    In the present investigation, the effect of deformation on precipitation sequence and microstructural evolution in Al 6061 alloy was studied using low temperature differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The precipitation sequence was greatly influenced by deformation in cryorolled and warm rolled samples. At low temperatures (<150 °C), two distinct cluster peaks have been observed upon cryorolling (CR). At high temperatures (>150 °C), the peak corresponding to β′ formation has disappeared in the deformed alloy as compared to undeformed coarse grained material. TEM investigation of the deformed alloy revealed bimodal distribution of precipitate sizes with both very fine and coarse structures. Pre-deformation of the alloy led to the simultaneous formation of β″ and β′ precipitates. Activation energies of clusters and major strengthening phase formation were calculated for the cryorolled and warm rolled materials and compared with the undeformed coarse grained material. The reduction of free energy for the formation of strengthening phase has occurred in the deformed material as compared to undeformed bulk material

  20. The effect of neutron irradiation on the electrical resistivity of high-strength copper alloys

    International Nuclear Information System (INIS)

    The effects of neutron irradiation on the electrical resistivity of precipitation hardened (PH) and dispersion strengthened (DS) copper alloys are discussed. The analysis is based on the experimental study of radiation damage of PH and DS copper alloys, irradiated in the fast neutron reactor BOR-60 with doses of 8-16 x 1025 n/m2 and in the mixed spectrum neutron reactor SM-2 with doses of 3.7-5.5 x 1025 n/m2. The experimental data on the change Δρ in electrical resistivity of DS-type copper alloys irradiated in the BOR-60 reactor show that irradiation to 7-10 dpa at T=340-450 C causes a drop in electrical conductivity by not more than 20%. The obtained results show that in mixed-spectrum reactors the rate of Δρ normalized to the dpa is about 20 times as high as in fast neutron reactors. The conclusion is made that the calculations performed for ITER must take into account the presence of appreciable fluxes of thermal neutrons in certain components of the reactor. The latter will play a decisive role in the drop in thermal conductivity of copper alloys in these components. (orig.)