Internal friction in iron-aluminium alloys having a high aluminium content

International Nuclear Information System (INIS)

Hillairet, J.; Delaplace, J.; Silvent, A.

1966-01-01

By using a torsion pendulum to measure the internal friction of iron-aluminium alloys containing between 25 and 50 atom per cent of aluminium, it has been possible to show the existence of three damping peaks due to interstitial carbon. Their evolution is followed as a function of the carbon content, of the thermal treatment and of the aluminium content. A model based on the preferential occupation of tetrahedral sites is proposed as an interpretation of the results. A study of the Zener peak in these substitution alloys shows also that a part of the short distance disorder existing at high temperatures can be preserved by quenching. (author) [fr

Borated aluminum alloy manufacturing technology

International Nuclear Information System (INIS)

Shimojo, Jun; Taniuchi, Hiroaki; Kajihara, Katsura; Aruga, Yasuhiro

2003-01-01

Borated aluminum alloy is used as the basket material of cask because of its light weight, thermal conductivity and superior neutron absorbing abilities. Kobe Steel has developed a unique manufacturing process for borated aluminum alloy using a vacuum induction melting method. In this process, aluminum alloy is melted and agitated at higher temperatures than common aluminum alloy fabrication methods. It is then cast into a mold in a vacuum atmosphere. The result is a high quality aluminum alloy which has a uniform boron distribution and no impurities. (author)

Iron-chrome-aluminum alloy cladding for increasing safety in nuclear power plants

Science.gov (United States)

Rebak, Raul B.

2017-12-01

After a tsunami caused plant black out at Fukushima, followed by hydrogen explosions, the US Department of Energy partnered with fuel vendors to study safer alternatives to the current UO2-zirconium alloy system. This accident tolerant fuel alternative should better tolerate loss of cooling in the core for a considerably longer time while maintaining or improving the fuel performance during normal operation conditions. General electric, Oak ridge national laboratory, and their partners are proposing to replace zirconium alloy cladding in current commercial light water power reactors with an iron-chromium-aluminum (FeCrAl) cladding such as APMT or C26M. Extensive testing and evaluation is being conducted to determine the suitability of FeCrAl under normal operation conditions and under severe accident conditions. Results show that FeCrAl has excellent corrosion resistance under normal operation conditions and FeCrAl is several orders of magnitude more resistant than zirconium alloys to degradation by superheated steam under accident conditions, generating less heat of oxidation and lower amount of combustible hydrogen gas. Higher neutron absorption and tritium release effects can be minimized by design changes. The implementation of FeCrAl cladding is a near term solution to enhance the safety of the current fleet of commercial light water power reactors.

Study on Explosive Forming of Aluminum Alloy

Directory of Open Access Journals (Sweden)

H Iyama

2016-09-01

Full Text Available Now, the aluminum alloy is often used as auto parts, for example, body, engine. For example, there are the body, a cylinder block, a piston, a connecting rod, interior, exterior parts, etc. These are practical used the characteristic of a light and strong aluminum alloy efficiently. However, although an aluminum alloy is lighter than steel, the elongation is smaller than that. Therefore, in press forming, some problems often occur. We have proposed use of explosive forming, in order to solve this problem. In the explosive forming, since a blank is formed at high speed, a strain rate effect becomes large and it can be made the elongation is larger. Then, in order to clarify this feature, we carried out experimental research and numerical analysis. In this paper, these contents will be discussed.

Effects of alloying elements on nodular and uniform corrosion resistance of zirconium-based alloys

International Nuclear Information System (INIS)

Abe, Katsuhiro

1992-01-01

The effects of alloying and impurity elements (tin, iron, chromium, nickel, niobium, tantalum, oxygen, aluminum, carbon, nitrogen, silicon, and phosphorus) on the nodular and uniform corrosion resistance of zirconium-based alloys were studied. The improving effect of iron, nickel and niobium in nodular corrosion resistance were observed. The uniform corrosion resistance was also improved by nickel, niobium and tantalum. The effects of impurity elements, nitrogen, aluminum and phosphorus were negligibly small but increasing the silicon content seemed to improve slightly the uniform corrosion resistance. Hydrogen pick-up fraction were not changed by alloying and impurity elements except nickel. Nickel addition increased remarkably hydrogen pick-up fraction. Although the composition of secondary precipitates changed with contents of alloying elements, the correlation of composition of secondary precipitates to corrosion resistance was not observed. (author)

In-situ reactions in hybrid aluminum alloy composites during incorporating silica sand in aluminum alloy melts

Directory of Open Access Journals (Sweden)

Benjamin F. Schultz

2016-07-01

Full Text Available In order to gain a better understanding of the reactions and strengthening behavior in cast aluminum alloy/silica composites synthesized by stir mixing, experiments were conducted to incorporate low cost foundry silica sand into aluminum composites with the use of Mg as a wetting agent. SEM and XRD results show the conversion of SiO2 to MgAl2O4 and some Al2O3 with an accompanying increase in matrix Si content. A three-stage reaction mechanism proposed to account for these changes indicates that properties can be controlled by controlling the base Alloy/SiO2/Mg chemistry and reaction times. Experimental data on changes of composite density with increasing reaction time and SiO2 content support the three-stage reaction model. The change in mechanical properties with composition and time is also described.

Modification of Sr on 4004 Aluminum Alloy

Science.gov (United States)

Guo, Erjun; Cao, Guojian; Feng, Yicheng; Wang, Liping; Wang, Guojun; Lv, Xinyu

2013-05-01

As a brazing foil, 4004 Al alloy has good welding performance. However, the high Si content decreases the plasticity of the alloy. To improve the plasticity of 4004 Al alloy and subsequently improve the productivity of 4004 Al foil or 434 composite foil, 4004 Al alloy was modified by Al-10%Sr master alloy. Modification effects of an additional amount of Sr, modification temperature, and holding time on 4004 aluminum alloy were studied by orthogonal design. The results showed that the greatest impact parameter of 4004 aluminum alloy modification was the additional amount of Sr, followed by holding time and modification temperature. The optimum modification parameters obtained by orthogonal design were as follows: Sr addition of 0.04%, holding time of 60 min, and modification temperature of 760°C. The effect of Sr addition on modification was analyzed in detail based on orthogonal results. With increasing of Sr addition, elongation of 4004 alloy increased at first, and decreased after reaching the maximum value.

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.

X-ray thickness measurement of aluminum alloys

International Nuclear Information System (INIS)

Albert, J.J.

1976-01-01

The theory of x-ray thickness gauging is extended to reveal the conditions under which a fixed anode voltage is ideal. A mathematical model of an alloy and computations reveal that two voltages can be used to measure the aluminum alloys with an error of roughly 1 percent, determined by the tolerance on manganese content rather than the large errors ordinarily a consequence of the tolerances on copper and zinc content. Implementation is discussed

Characterization of ion-implanted aluminum and iron by spectroscopic ellipsometry

International Nuclear Information System (INIS)

Brodkin, J.S.; Franzen, W.; Culbertson, R.J.

1990-01-01

The change in the optical constants of aluminum alloy and iron samples caused by implantation with nitrogen and chromium ions has been investigated by spectroscopic ellipsometry. The objective is to develop a method for simple, non-destructive characterization of ion-implanted metals. 5 refs., 6 figs

Phases in lanthanum-nickel-aluminum alloys

International Nuclear Information System (INIS)

Mosley, W.C.

1992-01-01

Lanthanum-nickel-aluminum (LANA) alloys will be used to pump, store and separate hydrogen isotopes in the Replacement Tritium Facility (RTF). The aluminum content (y) of the primary LaNi 5 -phase is controlled to produce the desired pressure-temperature behavior for adsorption and desorption of hydrogen. However, secondary phases cause decreased capacity and some may cause undesirable retention of tritium. Twenty-three alloys purchased from Ergenics, Inc. for development of RTF processes have been characterized by scanning electron microscopy (SEM) and by electron microprobe analysis (EMPA) to determine the distributions and compositions of constituent phases. This memorandum reports the results of these characterization studies. Knowledge of the structural characteristics of these alloys is a useful first step in selecting materials for specific process development tests and in interpreting results of those tests. Once this information is coupled with data on hydrogen plateau pressures, retention and capacity, secondary phase limits for RTF alloys can be specified

PREPARATION OF ACTINIDE-ALUMINUM ALLOYS

Science.gov (United States)

Moore, R.H.

1962-09-01

BS>A process is given for preparing alloys of aluminum with plutonium, uranium, and/or thorium by chlorinating actinide oxide dissolved in molten alkali metal chloride with hydrochloric acid, chlorine, and/or phosgene, adding aluminum metal, and passing air and/or water vapor through the mass. Actinide metal is formed and alloyed with the aluminum. After cooling to solidification, the alloy is separated from the salt. (AEC)

Scientific Background for Processing of Aluminum Waste

Science.gov (United States)

Kononchuk, Olga; Alekseev, Alexey; Zubkova, Olga; Udovitsky, Vladimir

2017-11-01

Changing the source of raw materials for producing aluminum and the emergence of a huge number of secondary alumina waste (foundry slag, sludge, spent catalysts, mineral parts of coal and others that are formed in various industrial enterprises) require the creation of scientific and theoretical foundations for their processing. In this paper, the aluminum alloys (GOST 4784-97) are used as an aluminum raw material component, containing the aluminum component produced as chips in the machine-building enterprises. The aluminum waste is a whole range of metallic aluminum alloys including elements: magnesium, copper, silica, zinc and iron. Analysis of the aluminum waste A1- Zn-Cu-Si-Fe shows that depending on the content of the metal the dissolution process of an aluminum alloy should be treated as the result of the chemical interaction of the metal with an alkaline solution. It is necessary to consider the behavior of the main components of alloys in an alkaline solution as applied to the system Na2O - Al2O3 - SiO2 - CO2 - H2O.

High-strength and high-RRR Al-Ni alloy for aluminum-stabilized superconductor

CERN Document Server

Wada, K; Sakamoto, H; Yamamoto, A; Makida, Y

2000-01-01

The precipitation type aluminum alloys have excellent performance as the increasing rate in electric resistivity with additives in the precipitation state is considerably low, compared to that of the aluminum alloy with additives in the solid-solution state. It is possible to enhance the mechanical strength without remarkable degradation in residual resistivity ratio (RRR) by increasing content of selected additive elements. Nickel is the suitable additive element because it has very low solubility in aluminum and low increasing rate in electric resistivity, and furthermore, nickel and aluminum form intermetallic compounds which effectively resist the motion of dislocations. First, Al-0.1wt%Ni alloy was developed for the ATLAS thin superconducting solenoid. This alloy achieved high yield strength of 79 MPa (R.T.) and 117 MPa (4.2 K) with high RRR of 490 after cold working of 21% in area reduction. These highly balanced properties could not be achieved with previously developed solid-solution aluminum alloys. ...

Vapor corrosion of aluminum cladding alloys and aluminum-uranium fuel materials in storage environments

International Nuclear Information System (INIS)

Lam, P.; Sindelar, R.L.; Peacock, H.B. Jr.

1997-04-01

An experimental investigation of the effects of vapor environments on the corrosion of aluminum spent nuclear fuel (A1 SNF) has been performed. Aluminum cladding alloys and aluminum-uranium fuel alloys have been exposed to environments of air/water vapor/ionizing radiation and characterized for applications to degradation mode analysis for interim dry and repository storage systems. Models have been developed to allow predictions of the corrosion response under conditions of unlimited corrodant species. Threshold levels of water vapor under which corrosion does not occur have been identified through tests under conditions of limited corrodant species. Coupons of aluminum 1100, 5052, and 6061, the US equivalent of cladding alloys used to manufacture foreign research reactor fuels, and several aluminum-uranium alloys (aluminum-10, 18, and 33 wt% uranium) were exposed to various controlled vapor environments in air within the following ranges of conditions: Temperature -- 80 to 200 C; Relative Humidity -- 0 to 100% using atmospheric condensate water and using added nitric acid to simulate radiolysis effects; and Gamma Radiation -- none and 1.8 x 10 6 R/hr. The results of this work are part of the body of information needed for understanding the degradation of the A1 SNF waste form in a direct disposal system in the federal repository. It will provide the basis for data input to the ongoing performance assessment and criticality safety analyses. Additional testing of uranium-aluminum fuel materials at uranium contents typical of high enriched and low enriched fuels is being initiated to provide the data needed for the development of empirical models

Ultrasonic texture characterization of aluminum, zirconium and titanium alloys

International Nuclear Information System (INIS)

Anderson, A.J.

1997-01-01

This work attempts to show the feasibility of nondestructive characterization of non-ferrous alloys. Aluminum alloys have a small single crystal anisotropy which requires very precise ultrasonic velocity measurements for derivation of orientation distribution coefficients (ODCs); the precision in the ultrasonic velocity measurement required for aluminum alloys is much greater than is necessary for iron alloys or other alloys with a large single crystal anisotropy. To provide greater precision, some signal processing corrections need to be applied to account for the inherent, half-bandwidth offset in triggered pulses when using a zero-crossing technique for determining ultrasonic velocity. In addition, alloys with small single crystal anisotropy show a larger dependence on the single crystal elastic constants (SCECs) when predicting ODCs which require absolute velocity measurements. Attempts were made to independently determine these elastics constants in an effort to improve correlation between ultrasonically derived ODCs and diffraction derived ODCs. The greater precision required to accurately derive ODCs in aluminum alloys using ultrasonic nondestructive techniques is easily attainable. Ultrasonically derived ODCs show good correlation with derivations made by Bragg diffraction techniques, both neutron and X-ray. The best correlation was shown when relative velocity measurements could be used in the derivations of the ODCs. Calculation of ODCs in materials with hexagonal crystallites can also be done. Because of the crystallite symmetries, more information can be extracted using ultrasonic techniques, but at a cost of requiring more physical measurements. Some industries which use materials with hexagonal crystallites, e.g. zirconium alloys and titanium, have traditionally used texture parameters which provide some specialized measure of the texture. These texture parameters, called Kearns factors, can be directly related to ODCs

Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

Science.gov (United States)

Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.

2016-05-03

A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

Corrosion mechanisms of aluminum alloys in waters of low conductivity

International Nuclear Information System (INIS)

Haddad, Roberto E; Lanazani, Liliana; Rodriguez, Sebastian

2006-01-01

After completing their burn cycle, nuclear fuels in experimental reactors made with aluminum alloys have to remain for long periods in distilled water, in interim storage. While aluminum alloys are resistant to corrosion in pure water, severe deterioration occurs in elements that have been immersed for periods of up to 30 years. Pitting-like surface alterations can even occur in nuclear quality waters (conductivity below 5 μS/cm and dissolved ions content below detection thresholds) in time periods of less than one year. An important factor that could become a potential promoter of this phenomena is the presence of dust particles and others, that could settle on the metallic surface, generating a locally aggressive medium. A simple immersion experiment demonstrates that these points can become initiation sites for pitting with very low concentrations of chlorides (under 10 ppm), especially if the electrochemical potential is increased by contact with another metallic material, even staying below the pitting potential in this medium. There are several corrosion mechanisms acting simultaneously, depending on the nature of the deposits. Pitting under glass particles has been detected, which may be related to a simple crevice corrosion process. In the case of iron oxides, however, the results depend on the type of oxide. Pits more than 100 microns deep have been obtained in 7 day immersion tests, so in spent fuel storage sites these mechanisms could easily cause penetration of the 500 micron aluminum plates during the time covering the interim storage under water, which could be decades, with similar chemical conditions (CW)

Fast LIBS Identification of Aluminum Alloys

Directory of Open Access Journals (Sweden)

Tawfik W.

2007-04-01

Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

Aluminum alloy for cladding excellent in sacrificial anode property and erosion-corrosion resistance

International Nuclear Information System (INIS)

Imaizumi, S.; Mikami, K.; Yamada, K.

1980-01-01

An aluminum alloy for cladding excellent in sacrificial anode property and erosion-corrosion resistance, which consists essentially of, in weight percentage: zinc - 0.3 to 3.0%, magnesium - 0.2 to 4.0%, manganese - 0.3 to 2.0%, and, the balance aluminum and incidental impurities; said alloy including an aluminum alloy also containing at least one element selected from the group consisting of, in weight percentage: indium - 0.005 to 0.2%, tin - 0.01 to 0.3%, and, bismuth - 0.01 to 0.3%; provided that the total content of indium, tin and bismuth being up to 0.3%

Study of the pyrophoric characteristics of uranium-iron alloys

International Nuclear Information System (INIS)

Duplessis, X.

2000-01-01

The objective of the study is to understand the pyrophoric characteristics of uranium-iron alloys. In order to carry out this research we have elected to use uranium-iron alloy powder with granules of 200 μm and 1000 μm diameter with 4%, 10.8% and 14% iron content. The experiments were performed on small samples of few milligrams and on larger quantities of few hundred grams. The main conclusions obtained are the followings: -The reaction start at 453 K (180 deg. C) and the ignition at 543 K (270 deg. C) - The influence of the specific area seems more important than the iron concentration in the alloys - When the alloy ignites, the fire spreads quickly and the alloy rapidly consumes. (author)

Beryllium-aluminum alloys for investment castings

International Nuclear Information System (INIS)

Nachtrab, W.T.; Levoy, N.

1997-01-01

Beryllium-aluminum alloys containing greater than 60 wt % beryllium are very favorable materials for applications requiring light weight and high stiffness. However, when produced by traditional powder metallurgical methods, these alloys are expensive and have limited applications. To reduce the cost of making beryllium-aluminum components, Nuclear Metals Inc. (NMI) and Lockheed Martin Electronics and Missiles have recently developed a family of patented beryllium-aluminum alloys that can be investment cast. Designated Beralcast, the alloys can achieve substantial weight savings because of their high specific strength and stiffness. In some cases, weight has been reduced by up to 50% over aluminum investment casting. Beralcast is now being used to make thin wall precision investment castings for several advanced aerospace applications, such as the RAH-66 Comanche helicopter and F-22 jet fighter. This article discusses alloy compositions, properties, casting method, and the effects of cobalt additions on strength

Fast LIBS Identification of Aluminum Alloys

Directory of Open Access Journals (Sweden)

Tawfik W.

2007-04-01

Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T(e and N(e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T(e and N(e for the aluminum in aluminum alloys using an optical fiber probe.

Some properties of aluminum-uranium alloys in the cast, rolled and annealed conditions

International Nuclear Information System (INIS)

Jones, T.I.; McGee, I.J.; Norlock, L.R.

1960-06-01

The metallographic and hardness changes associated with the rolling and subsequent. annealing of aluminum alloys containing up to 30-wt.% uranium have been described. The alloys possessed good rolling properties. However the richer alloys were unusual in that after an initial reduction,, further cold rolling caused softening. In the alloy range examined, increasing uranium contents caused reduced preferred orientation. Qualitative explanations have been proposed to account for the observations on roll softening and preferred orientation. Heat-treating and ageing experiments confirmed that the solid solubility of uranium in aluminum is negligible. (author)

Corrosion resistance of sodium sulfate coated cobalt-chromium-aluminum alloys at 900 C, 1000 C, and 1100 C

Science.gov (United States)

Santoro, G. J.

1979-01-01

The corrosion of sodium sulfate coated cobalt alloys was measured and the results compared to the cyclic oxidation of alloys with the same composition, and to the hot corrosion of compositionally equivalent nickel-base alloys. Cobalt alloys with sufficient aluminum content to form aluminum containing scales corrode less than their nickel-base counterparts. The cobalt alloys with lower aluminum levels form CoO scales and corrode more than their nickel-base counterparts which form NiO scales.

Precision forging technology for aluminum alloy

Science.gov (United States)

Deng, Lei; Wang, Xinyun; Jin, Junsong; Xia, Juchen

2018-03-01

Aluminum alloy is a preferred metal material for lightweight part manufacturing in aerospace, automobile, and weapon industries due to its good physical properties, such as low density, high specific strength, and good corrosion resistance. However, during forging processes, underfilling, folding, broken streamline, crack, coarse grain, and other macro- or microdefects are easily generated because of the deformation characteristics of aluminum alloys, including narrow forgeable temperature region, fast heat dissipation to dies, strong adhesion, high strain rate sensitivity, and large flow resistance. Thus, it is seriously restricted for the forged part to obtain precision shape and enhanced property. In this paper, progresses in precision forging technologies of aluminum alloy parts were reviewed. Several advanced precision forging technologies have been developed, including closed die forging, isothermal die forging, local loading forging, metal flow forging with relief cavity, auxiliary force or vibration loading, casting-forging hybrid forming, and stamping-forging hybrid forming. High-precision aluminum alloy parts can be realized by controlling the forging processes and parameters or combining precision forging technologies with other forming technologies. The development of these technologies is beneficial to promote the application of aluminum alloys in manufacturing of lightweight parts.

Electrochemical behaviour of aluminum alloy containing various stanum concentration tested in tropical seawater

International Nuclear Information System (INIS)

Siti Radiah Mohd Kamarudin; Muhamad Daud; Mohd Shariff Satar

2004-01-01

A study has been carried out to investigate the electrochemical behaviour of sacrificial anodes with different Sh concentration in tropical seawater environment. In this work, samples of Aluminum alloy with the addition of Sn in a range of 1. 0% - 1. 7% were tested in tropical seawater at room temperature. Tafel technique was used to produce a graph of the measured current versus potential for each different Sh concentration of aluminum alloy. The results show that the variation in alloy compositions affected the values of corrosion rate, corrosion current density and potential compared to alloy without Sn content. Furthermore, it was found that small addition of Sn successfully increased aluminum ion dissolution into seawater by producing a higher value of corrosion current density and corrosion rate. (Author)

Electrosynthesized polyaniline for the corrosion protection of aluminum alloy 2024-T3

Directory of Open Access Journals (Sweden)

Huerta-Vilca Domingo

2003-01-01

Full Text Available Adherent polyaniline films on aluminum alloy 2024-T3 have been prepared by electrodeposition from aniline containing oxalic acid solution. The most appropriate method to prepare protective films was a successive galvanostatic deposition of 500 seconds. With this type of film, the open circuit potential of the coating shifted around 0.065V vs. SCE compared to the uncoated alloy. The polyaniline coatings can be considered as candidates to protect copper-rich (3 - 5% aluminum alloys by avoiding the galvanic couple between re-deposited copper on the surface and the bulk alloy. The performance of the polyaniline films was verified by immersion tests up to 2.5 months. It was good with formation of some aluminum oxides due to electrolyte permeation so, in order to optimize the performance a coating formulation would content an isolation topcoat.

NASA-427: A New Aluminum Alloy

Science.gov (United States)

Nabors, Sammy A.

2015-01-01

NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

Aluminum alloy and associated anode and battery

International Nuclear Information System (INIS)

Tarcy, G.P.

1990-01-01

This patent describes an aluminum alloy. It comprises: eutectic amounts of at least two alloying elements selected from the group consisting of bismuth, cadmium, scandium, gallium, indium, lead, mercury, thallium, tin, and zinc with the balance being aluminum and the alloying elements being about 0.01 to 3.0 percent by weight of the alloy

[Microbiological corrosion of aluminum alloys].

Science.gov (United States)

Smirnov, V F; Belov, D V; Sokolova, T N; Kuzina, O V; Kartashov, V R

2008-01-01

Biological corrosion of ADO quality aluminum and aluminum-based construction materials (alloys V65, D16, and D16T) was studied. Thirteen microscopic fungus species and six bacterial species proved to be able to attack aluminum and its alloys. It was found that biocorrosion of metals by microscopic fungi and bacteria was mediated by certain exometabolites. Experiments on biocorrosion of the materials by the microscopic fungus Alternaria alternata, the most active biodegrader, demonstrated that the micromycete attack started with the appearance of exudate with pH 8-9 on end faces of the samples.

An all aluminum alloy UHV components

International Nuclear Information System (INIS)

Sugisaki, Kenzaburo

1985-01-01

An all aluminum components was developed for use with UHV system. Aluminum alloy whose advantage are little discharge gas, easy to bake out, light weight, little damage against radieactivity radiation is used. Therefore, as it is all aluminum alloy, baking is possible. Baking temperature is 150 deg C in case of not only ion pump, gate valve, angle valve but also aluminum components. Ion pump have to an ultrahigh vacuum of order 10 -9 torr can be obtained without baking, 10 -10 torr order can be obtained after 24 hour of baking. (author)

Advanced powder metallurgy aluminum alloys via rapid solidification technology

Science.gov (United States)

Ray, R.

1984-01-01

Aluminum alloys containing 10 to 11.5 wt. pct. of iron and 1.5 to 3 wt. pct. of chromium using the technique of rapid solidification powder metallurgy were studied. Alloys were prepared as thin ribbons (.002 inch thick) rapidly solidified at uniform rate of 10(6) C/second by the melt spinning process. The melt spun ribbons were pulverized into powders (-60 to 400 mesh) by a rotating hammer mill. The powders were consolidated by hot extrusion at a high reduction ratio of 50:1. The powder extrusion temperature was varied to determine the range of desirable processing conditions necessary to yield useful properties. Powders and consolidated alloys were characterized by SEM and optical metallography. The consolidated alloys were evaluated for (1) thermal stability, (2) tensile properties in the range, room temperature to 450 F, and (3) notch toughness in the range, room temperature to 450 F.

Stress corrosion in high-strength aluminum alloys

Science.gov (United States)

Dorward, R. C.; Hasse, K. R.

1980-01-01

Report describes results of stress-corrosion tests on aluminum alloys 7075, 7475, 7050, and 7049. Tests compare performance of original stress-corrosion-resistant (SCR) aluminum, 7075, with newer, higher-strength SCR alloys. Alloys 7050 and 7049 are found superior in short-transverse cross-corrosion resistance to older 7075 alloy; all alloys are subject to self-loading effect caused by wedging of corrosion products in cracks. Effect causes cracks to continue to grow, even at very-low externally applied loads.

Aluminum stimulates uptake of non-transferrin bound iron and transferrin bound iron in human glial cells

International Nuclear Information System (INIS)

Kim, Yongbae; Olivi, Luisa; Cheong, Jae Hoon; Maertens, Alex; Bressler, Joseph P.

2007-01-01

Aluminum and other trivalent metals were shown to stimulate uptake of transferrin bound iron and nontransferrin bound iron in erytholeukemia and hepatoma cells. Because of the association between aluminum and Alzheimer's Disease, and findings of higher levels of iron in Alzheimer's disease brains, the effects of aluminum on iron homeostasis were examined in a human glial cell line. Aluminum stimulated dose- and time-dependent uptake of nontransferrin bound iron and iron bound to transferrin. A transporter was likely involved in the uptake of nontransferrin iron because uptake reached saturation, was temperature-dependent, and attenuated by inhibitors of protein synthesis. Interestingly, the effects of aluminum were not blocked by inhibitors of RNA synthesis. Aluminum also decreased the amount of iron bound to ferritin though it did not affect levels of divalent metal transporter 1. These results suggest that aluminum disrupts iron homeostasis in Brain by several mechanisms including the transferrin receptor, a nontransferrin iron transporter, and ferritin

Research On Technology Of Making Rare Earth Alloy Having Rare Earth Content ≽30% From Ore (≽40% REO) Using Aluminum Thermal Technology In Arc Furnace

International Nuclear Information System (INIS)

Ngo Xuan Hung; Ngo Trong Hiep; Tran Duy Hai; Nguyen Huu Phuc

2014-01-01

Arc furnace was used to smelt materials consisting of rare earth ore having rare earth content of ≽40% REO, aluminum as the reducing agent and additives. Rare earth alloy was obtained with rare earth metal content of more than 30%. (author)

Fatigue crack propagation in aluminum-lithium alloys

Science.gov (United States)

Rao, K. T. V.; Ritchie, R. O.; Piascik, R. S.; Gangloff, R. P.

1989-01-01

The principal mechanisms which govern the fatigue crack propagation resistance of aluminum-lithium alloys are investigated, with emphasis on their behavior in controlled gaseous and aqueous environments. Extensive data describe the growth kinetics of fatigue cracks in ingot metallurgy Al-Li alloys 2090, 2091, 8090, and 8091 and in powder metallurgy alloys exposed to moist air. Results are compared with data for traditional aluminum alloys 2024, 2124, 2618, 7075, and 7150. Crack growth is found to be dominated by shielding from tortuous crack paths and resultant asperity wedging. Beneficial shielding is minimized for small cracks, for high stress ratios, and for certain loading spectra. While water vapor and aqueous chloride environments enhance crack propagation, Al-Li-Cu alloys behave similarly to 2000-series aluminum alloys. Cracking in water vapor is controlled by hydrogen embrittlement, with surface films having little influence on cyclic plasticity.

Corrosion resistance and electrochemical potentiokinetic reactivation testing of some iron-base hardfacing alloys

International Nuclear Information System (INIS)

Cockeram, B.V.

1999-01-01

Hardfacing alloys are weld deposited on a base material to provide a wear resistant surface. Commercially available iron-base hardfacing alloys are being evaluated for replacement of cobalt-base alloys to reduce nuclear plant activation levels. Corrosion testing was used to evaluate the corrosion resistance of several iron-base hardfacing alloys in highly oxygenated environments. The corrosion test results indicate that iron-base hardfacing alloys in the as-deposited condition have acceptable corrosion resistance when the chromium to carbon ratio is greater than 4. Tristelle 5183, with a high niobium (stabilizer) content, did not follow this trend due to precipitation of niobium-rich carbides instead of chromium-rich carbides. This result indicates that iron-base hardfacing alloys containing high stabilizer contents may possess good corrosion resistance with Cr:C < 4. NOREM 02, NOREM 01, and NoCo-M2 hardfacing alloys had acceptable corrosion resistance in the as-deposited and 885 C/4 hour heat treated condition, but rusting from sensitization was observed in the 621 C/6 hour heat treated condition. The feasibility of using an Electrochemical Potentiokinetic Reactivation (EPR) test method, such as used for stainless steel, to detect sensitization in iron-base hardfacing alloys was evaluated. A single loop-EPR method was found to provide a more consistent measurement of sensitization than a double loop-EPR method. The high carbon content that is needed for a wear resistant hardfacing alloy produces a high volume fraction of chromium-rich carbides that are attacked during EPR testing. This results in inherently lower sensitivity for detection of a sensitized iron-base hardfacing alloy than stainless steel using conventional EPR test methods

A mechanism for the formation of equiaxed grains in welds of aluminum-lithium alloy 2090

International Nuclear Information System (INIS)

Lin, D.C.; Wang, G.-X.; Srivatsan, T.S.

2003-01-01

In this technical note, the formation and presence of a zone of equiaxed grains (EQZ) along the fusion boundary of welded aluminum-lithium alloy 2090 using filler metals containing zirconium and lithium is presented and discussed. However, no EQZ was evident in welded joints of alloy 2090 using the commercial filler metals: aluminum alloy 2319 and 4145. Under identical conditions, aluminum-lithium alloy 2090 was fusion welded using several new filler metals containing various amounts of zirconium and lithium. Results reveal an increase in the width of the zone of equiaxed grains with an increase in zirconium and lithium content in the filler metal. A viable mechanism for the formation of equiaxed grains and its relationship to filler metal composition is highlighted

Improvement of magnetocaloric properties of Gd-Ge-Si alloys by alloying with iron

Directory of Open Access Journals (Sweden)

Erenc-Sędziak T.

2013-01-01

Full Text Available The influence of annealing of Gd5Ge2Si2Fex alloys at 1200°C and of alloying with various amount of iron on structure as well as thermal and magnetocaloric properties is investigated. It was found that annealing for 1 to 10 hours improves the entropy change, but reduces the temperature of maximum magnetocaloric effect by up to 50 K. Prolonged annealing of the Gd5Ge2Si2 alloy results in the decrease of entropy change due to the reduction of Gd5Ge2Si2 phase content. Addition of iron to the ternary alloy enhances the magnetocaloric effect, if x = 0.4 – 0.6, especially if alloying is combined with annealing at 1200°C: the peak value of the isothermal entropy change from 0 to 2 T increases from 3.5 to 11 J/kgK. Simultaneously, the temperature of maximum magnetocaloric effect drops to 250 K. The changes in magnetocaloric properties are related to the change in phase transformation from the second order for arc molten ternary alloy to first order in the case of annealed and/or alloyed with iron. The results of this study indicate that the minor addition of iron and heat treatment to Gd-Ge-Si alloys may be useful in improving the materials’ magnetocaloric properties..

Reduction of Oxidative Melt Loss of Aluminum and Its Alloys

Energy Technology Data Exchange (ETDEWEB)

Dr. Subodh K. Das; Shridas Ningileri

2006-03-17

This project led to an improved understanding of the mechanisms of dross formation. The microstructural evolution in industrial dross samples was determined. Results suggested that dross that forms in layers with structure and composition determined by the local magnesium concentration alone. This finding is supported by fundamental studies of molten metal surfaces. X-ray photoelectron spectroscopy data revealed that only magnesium segregates to the molten aluminum alloy surface and reacts to form a growing oxide layer. X-ray diffraction techniques that were using to investigate an oxidizing molten aluminum alloy surface confirmed for the first time that magnesium oxide is the initial crystalline phase that forms during metal oxidation. The analytical techniques developed in this project are now available to investigate other molten metal surfaces. Based on the improved understanding of dross initiation, formation and growth, technology was developed to minimize melt loss. The concept is based on covering the molten metal surface with a reusable physical barrier. Tests in a laboratory-scale reverberatory furnace confirmed the results of bench-scale tests. The main highlights of the work done include: A clear understanding of the kinetics of dross formation and the effect of different alloying elements on dross formation was obtained. It was determined that the dross evolves in similar ways regardless of the aluminum alloy being melted and the results showed that amorphous aluminum nitride forms first, followed by amorphous magnesium oxide and crystalline magnesium oxide in all alloys that contain magnesium. Evaluation of the molten aluminum alloy surface during melting and holding indicated that magnesium oxide is the first crystalline phase to form during oxidation of a clean aluminum alloy surface. Based on dross evaluation and melt tests it became clear that the major contributing factor to aluminum alloy dross was in the alloys with Mg content. Mg was

Charge-density-shear-moduli relationships in aluminum-lithium alloys.

Science.gov (United States)

Eberhart, M

2001-11-12

Using the first principles full-potential linear-augmented-Slater-type orbital technique, the energies and charge densities of aluminum and aluminum-lithium supercells have been computed. The experimentally observed increase in aluminum's shear moduli upon alloying with lithium is argued to be the result of predictable changes to aluminum's total charge density, suggesting that simple rules may allow the alloy designer to predict the effects of dilute substitutional elements on alloy elastic response.

Thin wall ductile iron casting as a substitute for aluminum alloy casting in automotive industry

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M. Górny

2009-01-01

Full Text Available In paper it is presented thin wall ductile iron casting (TWDI as a substitute of aluminium alloy casting. Upper control arm made of ductile iron with wall thickness ranging from 2 – 3.7 mm was produced by inmold process. Structure, mechanical properties and computer simulations were investigated. Structural analysis of TWDI shows pearlitic-ferritic matrix free from chills and porosity. Mechanical testing disclose superior ultimate tensile strength (Rm, yield strength (Rp0,2 and slightly lower elongation (E of TWDI in comparison with forged control arm made of aluminium alloy (6061-T6. Moreover results of computer simulation of static loading for tested control arms are presented. Analysis show that the light-weight ductile iron casting can be loaded to similar working conditions as the forged Al alloy without any potential failures.

Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers for Aluminum Alloys

Directory of Open Access Journals (Sweden)

Michael D. Blanton

2012-09-01

Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

High strength corrosion-resistant zirconium aluminum alloys

International Nuclear Information System (INIS)

Schulson, E.M.; Cameron, D.J.

1976-01-01

A zirconium-aluminum alloy is described possessing superior corrosion resistance and mechanical properties. This alloy, preferably 7.5-9.5 wt% aluminum, is cast, worked in the Zr(Al)-Zr 2 Al region, and annealed to a substantially continuous matrix of Zr 3 Al. (E.C.B.)

Functional aluminum alloys for ultra high vacuum use

International Nuclear Information System (INIS)

Kato, Yutaka; Tsukamoto, Kenji; Isoyama, Eizo

1985-01-01

Ultra high vacuum systems made of aluminum alloys are actively developed. The reasons for using aluminum alloys are low residual radioactivity, light weight, good machinability, good thermal conductivity, non-magnetism. The important function required for ultra high vacuum materials is low outgassing rate, but surface gas on ordinary aluminum is much. Then the research on aluminum surface structure with low outgassing rate has been made and the special extrusion method, that is, extrusion method with the conditions of preventing air from entering inside of pipe and of taking in mixture gas of Ar + O 2 , was developed. 6063 alloy obtained by special extrusion method showed low outgassing rate (2 x 10 -13 Torr. 1/s. cm 2 ) by only 150 deg C, 24 h baking. For the future it will be important to develop aluminum alloys with low dynamic outgassing rate as well as low static outgassing rate. (author)

Phosphorus effect on structure and physical properties of iron-nickel alloys

International Nuclear Information System (INIS)

Berseneva, F.N.; Kalinin, V.M.; Rybalko, O.F.

1982-01-01

The structure and properties of iron-nickel alloys (30-50 % Ni) containing from 0.02 to 0.5 wt. % P have been investigated. It has been found that phosphorus solubility in iron-nickel alloys at most purified from impurities exceeds limiting solubility values usually observed for commercial alloys. Phosphide eutectics precipitation over the grain boundaries of studied alloys occurs but with phosphorus content equal 0.45 wt. %. The 0.4 wt. % P addition in invar alloys increases saturation magnetization and the Curie point and leads to a more homogeneous structure

Microstructures and properties of aluminum die casting alloys

Energy Technology Data Exchange (ETDEWEB)

M. M. Makhlouf; D. Apelian; L. Wang

1998-10-01

This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

Advanced powder metallurgy aluminum alloys and composites

Science.gov (United States)

Lisagor, W. B.; Stein, B. A.

1982-01-01

The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

Anisotropic behavior studies of aluminum alloy 5083-H0 using a micro-tensile test stage in a FEG-SEM

CSIR Research Space (South Africa)

Motsi, GT

2016-02-01

Full Text Available stream_source_info Motsi_18197_2016.pdf.txt stream_content_type text/plain stream_size 1246 Content-Encoding UTF-8 stream_name Motsi_18197_2016.pdf.txt Content-Type text/plain; charset=UTF-8 Materials Science... & Engineering A, vol. 656: 266-274 Anisotropic behavior studies of aluminum alloy 5083-H0 using a micro-tensile test stage in a FEG-SEM Motsi GT Shongwe MB Sono TJ Olubambi PA ABSTRACT: The plastic anisotropic characteristics of aluminum alloy 5083-H...

High-strength laser welding of aluminum-lithium scandium-doped alloys

Science.gov (United States)

Malikov, A. G.; Ivanova, M. Yu.

2016-11-01

The work presents the experimental investigation of laser welding of an aluminum alloy (system Al-Mg-Li) and aluminum alloy (system Al-Cu-Li) doped with Sc. The influence of nano-structuring of the surface layer welded joint by cold plastic deformation on the strength properties of the welded joint is determined. It is founded that, regarding the deformation degree over the thickness, the varying value of the welded joint strength is different for these aluminum alloys. The strength of the plastically deformed welded joint, aluminum alloys of the Al-Mg-Li and Al-Cu-Li systems reached 0.95 and 0.6 of the base alloy strength, respectively.

Influence of Nickel Addition on Properties of Secondary AlSi7Mg0.3 Alloy

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Richtárech L.

2015-06-01

Full Text Available This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by nickel. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich intermetallic phases. It is impossible to remove iron from melt by standard operations. Some elements eliminates iron by changing iron intermetallic phase morphology, decreasing its extent and by improving alloy properties. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of nickel as iron corrector of iron based phases.

Stress Corrosion Cracking of Certain Aluminum Alloys

Science.gov (United States)

Hasse, K. R.; Dorward, R. C.

1983-01-01

SC resistance of new high-strength alloys tested. Research report describes progress in continuing investigation of stress corrosion (SC) cracking of some aluminum alloys. Objective of program is comparing SC behavior of newer high-strength alloys with established SC-resistant alloy.

Electron-beam welding of aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Brillant, Marcel; de Bony, Yves

1980-08-15

The objective of this article is to describe the status of the application of electron-beam welding to aluminum alloys. These alloys are widely employed in the aeronautics, space and nuclear industries.

Corrosion resistance properties of enamels with high B2O3-P2O5 content to molten aluminum

International Nuclear Information System (INIS)

Zhou, M.; Li, K.; Shu, D.; Sun, B.D.; Wang, J.

2003-01-01

Anticorrosive properties of borophosphate and boron-free enamels to molten aluminum were investigated using SEM and electron probe. Carbonates of alkali metal and alkaline earth metal were added in an appropriate weight ratio to achieve desired melting temperature of the enamels. SEM examination on the solidified interface between the enamels and aluminum alloy show that the enamels can spread slightly on aluminum alloy. For anticorrosive sample of borophosphate enamel, phosphorus was not detected by electron probe at the side of aluminum alloy near the interface, but silicon was detected in the silica-free enamels side. For the sample of boron-free enamels, however, phosphorus was found at the side of aluminum alloy near the interface. It was revealed that the enamels with high B 2 O 3 -P 2 O 5 content have high corrosion resistance to molten aluminum

Radiation corrosion in aluminum alloy bellows

International Nuclear Information System (INIS)

Konno, Osamu

1987-01-01

Testing was carried out in which materials for vacuum devices (Al, Ti, Cu, SUS) are exposed to electron beams (50 MeV, average current 80 μA) to determine the changes in the quantity, partial pressure and composition of the gases released from the materials. The test appratus used are made of Al alloys alone. During the test, vacuum leak is found in the Al alloy bellows used in the drive device. The leak is found to result from corrosion caused by water. The surface structure is analyzed by SEM, EPMA, ESCA and IMA. It is confirmed that the Al alloy used as material for the bellows if highly resistant to corrosion. It is concluded that it is necessary to use high purity cooling water to prevent the cooling water from causing corrosion. It has been reported that high purity aluminum is very high in resistance to corrosion. Based on these measurements and considerations, it is suggested that when aluminum is to be used as material for vacuum devices in an accelerator, it is required to provide protection film on its surface to prevent corrosion or to use cooling water pipes cladded with pure aluminum and an aluminum alloy. In addition, the temperature of the cooling water should be set after adequately considering the environmental conditions in the room. (Nogami, K.)

Study on tribological behaviors of Fe+ ion implanted in 2024 aluminum alloy

International Nuclear Information System (INIS)

Zhang Aimin; Chen Jianmin; Shi Weidong; Liu Zhenmin

2000-01-01

2024 aluminum alloy was implanted with Fe + ions at a dose of 7x10 16 -3 x 10 17 Fe + /cm 2 . The depth profile of Fe element was investigated by Auger electron spectroscopy (AES). The composition of the surface layer was investigated by XRD with sample-tilting diffraction (STD) mode. The worn out surface was observed by scanning electron microscopy (SEM). Micro-hardness, friction and wear properties have been studied before and after Fe + implantation. An AES analysis shows Fe display Gaussian shape distributions. STD shows Al 5 Fe 2 formed during the implantation. Micro-hardness of surface layer was reduced after implantation, but it did not simply decrease with the increasing implantation doses. The friction and wear tests of implanted and unimplanted samples were carried out on a static-dynamic friction precise measuring apparatus. After implantation, the friction coefficient was reduced from 0.7 to 0.1; the wear resistance was improved remarkably, but decreased with increasing implantation dose. The wear mechanism of the unimplanted sample was adhesive wear, abrasive wear and plastic deformation. The wear reducing effect of Fe + ion induced on 2024 aluminum alloy is mainly attributed to tribooxidation of iron and transfixion of line defect. These two factors prevent the adhesive wear, abrasive wear and plastic deformation of 2024 aluminum alloy

Phase Diagram of Al-Ca-Mg-Si System and Its Application for the Design of Aluminum Alloys with High Magnesium Content

Directory of Open Access Journals (Sweden)

Nikolay A. Belov

2017-10-01

Full Text Available The phase transformations in the Al-Ca-Mg-Si system have been studied using thermodynamic calculations and experimental methods. We show that at 10% Magnesium (Mg, depending on the concentrations of calcium (Ca and silicon (Si, the following phases crystallize first (apart from the aluminum (Al solid solution: Al4Ca, Mg2Si, and Al2CaSi2. We have found that the major part of the calculated concentration range is covered by the region of the primary crystallization of the Al2CaSi2 phase. Regardless of the Ca and Si content, the solidification of the aluminum-magnesium alloys ends with the following nonvariant eutectic reaction: L → (Al + Al4Ca + Mg2Si + Al3Mg2. With respect to the temperature and composition of the liquid phase, this reaction is close to the eutectic reaction in the Al-Mg binary system. The addition of Ca and Si to the Al-10% Mg base alloy increases its hardness, reduces its density, and has no negative influence on its corrosion resistance. We have also established that the near-eutectic alloy containing about 3% Ca and 1% Si has the optimum structure.

Environment assisted degradation mechanisms in aluminum-lithium alloys

Science.gov (United States)

Gangloff, Richard P.; Stoner, Glenn E.; Swanson, Robert E.

1988-01-01

Section 1 of this report records the progress achieved on NASA-LaRC Grant NAG-1-745 (Environment Assisted Degradation Mechanisms in Al-Li Alloys), and is based on research conducted during the period April 1 to November 30, 1987. A discussion of work proposed for the project's second year is included. Section 2 provides an overview of the need for research on the mechanisms of environmental-mechanical degradation of advanced aerospace alloys based on aluminum and lithium. This research is to provide NASA with the basis necessary to permit metallurgical optimization of alloy performance and engineering design with respect to damage tolerance, long term durability and reliability. Section 3 reports on damage localization mechanisms in aqueous chloride corrosion fatigue of aluminum-lithium alloys. Section 4 reports on progress made on measurements and mechanisms of localized aqueous corrosion in aluminum-lithium alloys. Section 5 provides a detailed technical proposal for research on environmental degradation of Al-Li alloys, and the effect of hydrogen in this.

Seacoast stress corrosion cracking of aluminum alloys

Science.gov (United States)

Humphries, T. S.; Nelson, E. E.

1981-01-01

The stress corrosion cracking resistance of high strength, wrought aluminum alloys in a seacoast atmosphere was investigated and the results were compared with those obtained in laboratory tests. Round tensile specimens taken from the short transverse grain direction of aluminum plate and stressed up to 100 percent of their yield strengths were exposed to the seacoast and to alternate immersion in salt water and synthetic seawater. Maximum exposure periods of one year at the seacoast, 0.3 or 0.7 of a month for alternate immersion in salt water, and three months for synthetic seawater were indicated for aluminum alloys to avoid false indications of stress corrosion cracking failure resulting from pitting. Correlation of the results was very good among the three test media using the selected exposure periods. It is concluded that either of the laboratory test media is suitable for evaluating the stress corrosion cracking performance of aluminum alloys in seacoast atmosphere.

Aluminum alloy excellent in neutron absorbing performance

International Nuclear Information System (INIS)

Iida, Tetsuya; Tamamura, Tadao; Morimoto, Hiroyuki; Ouchi, Ken-ichiro.

1987-01-01

Purpose: To obtain structural materials made of aluminum alloys having favorable neutron absorbing performance and excellent in the performance as structural materials such as processability and strength. Constitution: Powder of Gd 2 O 3 as a gadolinium compound or metal gadolinium is uniformly mixed with the powder of aluminum or aluminum alloy. The amount of the gadolinium compound added is set to 0.1 - 30 % by weight. No sufficient neutron absorbing performance can be obtained if it is less than 0.1 % by weight, whereas the processability and mechanical property of the alloy are degraded if it exceeds 30 % by weight. Further, the grain size is set to less about 50 μm. Further, since the neutron absorbing performance varies greatly if the aluminum powder size exceeds 100 μm, the diameter is set to less than about 100 μm. These mixtures are molded in a hot press. This enables to obtain aimed structural materials. (Takahashi, M.)

Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

Science.gov (United States)

Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

2003-01-01

Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg- 0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300 F for 24 hours. In this study, a two-step aging treatment was developed through a comprehensive 24 full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175 F and 250 F. The second step aging temperatures was

Microstructure and Properties of Selected Magnesium-Aluminum Alloys Prepared for SPD Processing Technology

Directory of Open Access Journals (Sweden)

Cizek L.

2017-12-01

Full Text Available A growing interest in wrought magnesium alloys has been noticed recently, mainly due to development of various SPD (severe plastic deformation methods that enable significant refinement of the microstructure and – as a result – improvement of various functional properties of products. However, forming as-cast magnesium alloys with the increased aluminum content at room temperature is almost impossible. Therefore, application of heat treatment before forming or forming at elevated temperature is recommended for these alloys. The paper presents the influence of selected heat treatment conditions on the microstructure and the mechanical properties of the as-cast AZ91 alloy. Deformation behaviour of the as-cast AZ61 alloy at elevated temperatures was analysed as well. The microstructure analysis was performed by means of both light microscopy and SEM. The latter one was used also for fracture analysis. Moreover, the effect of chemical composition modification by lithium addition on the microstructure of the AZ31-based alloy is presented. The test results can be helpful in preparation of the magnesium-aluminum alloys for further processing by means of SPD methods.

Mechanical properties of friction stir welded aluminum alloys 5083 and 5383

Directory of Open Access Journals (Sweden)

Jeom Kee Paik

2009-09-01

Full Text Available The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW, laser welding and friction stir welding (FSW, FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009, jointly funded by its member agencies.

Chemical Reduction Synthesis of Iron Aluminum Powders

Science.gov (United States)

Zurita-Méndez, N. N.; la Torre, G. Carbajal-De; Ballesteros-Almanza, L.; Villagómez-Galindo, M.; Sánchez-Castillo, A.; Espinosa-Medina, M. A.

In this study, a chemical reduction synthesis method of iron aluminum (FeAl) nano-dimensional intermetallic powders is described. The process has two stages: a salt reduction and solvent evaporation by a heat treatment at 1100°C. The precursors of the synthesis are ferric chloride, aluminum foil chips, a mix of Toluene/THF in a 75/25 volume relationship, and concentrated hydrochloric acid as initiator of the reaction. The reaction time was 20 days, the product obtained was dried at 60 °C for 2 h and calcined at 400, 800, and 1100 °C for 4 h each. To characterize and confirm the obtained synthesis products, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques were used. The results of morphology and chemical characterization of nano-dimensional powders obtained showed a formation of agglomerated particles of a size range of approximately 150 nm to 1.0 μm. Composition of powders was identified as corundum (Al2O3), iron aluminide (FeAl3), and iron-aluminum oxides (Fe0. 53Al0. 47)2O3 phases. The oxide phases formation were associated with the reaction of atmospheric concentration-free oxygen during synthesis and sintering steps, reducing the concentration of the iron aluminum phase.

Thermoelectrical power analysis of precipitation in 6013 aluminum alloy

International Nuclear Information System (INIS)

Abdala, M.R.W.S.; Garcia de Blas, J.C.; Barbosa, C.; Acselrad, O.

2008-01-01

The 6013 aluminum alloy was first developed for application in the aircraft industry and, more recently, as a replacement option for the use of the 6061 alloy in the automotive industry. The present work describes the evolution of the process of formation and dissolution of different kinds of precipitates in 6013 aluminum alloy, subjected to different conditions of heat treatment, using for this purpose measurements of thermoelectrical power, Vickers microhardness and differential scanning calorimeter (DSC). Although in the last years many works have been published on the use of thermoelectrical power (TEP) measurements for the analysis of precipitation process in traditional alloys such as 6061, there is still little information related to 6013 alloy. The results obtained are compared with a previous characterization work on the same alloy using transmission electron microscopy. It was observed that TEP measurements are very sensitive to precipitation phenomena in this alloy, and it has been found that there is an inverse relation between TEP and Vickers microhardness values, which allowed proposing a precipitation sequence for 6013 aluminum alloy

Determination of small amounts of aluminum in iron and steel by x-ray fluorescence analysis

International Nuclear Information System (INIS)

Ito, Minao; Sato, Shoki; Narita, Masanao

1981-01-01

The accuracy of X-ray fluorescence analysis for determining aluminum in steel is generally poor when the aluminum content is below 0.1%. In this study, it is confirmed that the existence of inhomogeneous acid-insoluble aluminum causes the poor accuracy of X-ray fluorescence analysis. The accuracy can be improved by adding granular ferro-zirconium to molten steel when sampling. By using this method, the accuracy of determining aluminum was 0.0024% for low alloy steels and 0.0022% for stainless steels as the standard deviation obtained for a series of differences between an analytical result and a standard value. Corrections for overlapping of the chromium spectrum, and for absorption and enhancement effects of co-existent elements are not necessary for the analysis of low alloy steels, whereas these corrections are necessary for the analysis of stainless steels. (author)

Lost foam casting of aluminum alloy-SiCp composite material

International Nuclear Information System (INIS)

Baalasuburamaniam, R.; Cvetnic, C.; Ravindran, C.

2002-01-01

Metal matrix composites are a viable alternative to cast irons in automotive components with possible increase in strength-to-weight ratio. Lost foam casting of aluminum alloy matrix composite containing 20 volume percent SiC was carried out at 690, 730, and 770 o C with a view to determining the effects of cooling rate on microstructure, particle distribution, microporosity and mechanical properties. These results were compared with those for the matrix material cast under similar conditions. The results and the correlations are of particular interest as there is no published literature on lost foam casting of composite materials. (author)

Using Neural Networks to Predict the Hardness of Aluminum Alloys

Directory of Open Access Journals (Sweden)

B. Zahran

2015-02-01

Full Text Available Aluminum alloys have gained significant industrial importance being involved in many of the light and heavy industries and especially in aerospace engineering. The mechanical properties of aluminum alloys are defined by a number of principal microstructural features. Conventional mathematical models of these properties are sometimes very complex to be analytically calculated. In this paper, a neural network model is used to predict the correlations between the hardness of aluminum alloys in relation to certain alloying elements. A backpropagation neural network is trained using a thorough dataset. The impact of certain elements is documented and an optimum structure is proposed.

An Influence of Ageing on the Structure, Corrosion Resistance and Hardness of High Aluminum ZnAl40Cu3 Alloy

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Michalik R.

2016-03-01

Full Text Available Zn-Al-Cu alloys are used primarily because of their tribological properties as an alternative material for bronze, cast iron and aluminum alloy bearings and as a construction material. Particularly interesting are high aluminum zinc alloys. Monoeutectic zinc and aluminum alloys are characterized by the highest hardness, tensile strength and wear resistance of all of the zinc alloys. A significant problem with the use of the Zn-Al-Cu alloys is their insufficient resistance to electrochemical corrosion. Properties of Zn-Al-Cu alloys can be improved by heat treatment. The purpose of examination was to determine the effect of heat treatment (aging at various temperatures on the microstructure and corrosion resistance of the ZnAl40Cu3 alloy. The scope of the examination included: structural examinations, determination of hardness using Brinell’s method and corrosion resistance examinations. Ageing at higher temperatures causes a creation of areas where is an eutectoid mixture. The study showed that ageing causes a decrease in hardness of ZnAl40Cu3 alloy. This decrease is even greater, when the temperature of ageing is lower. The studies have shown a significant influence of ageing on the corrosion resistance of the alloy ZnAl40Cu3. Maximum corrosion resistance were characterized by the sample after ageing at higher temperatures.

Chemical interactions and thermodynamic studies in aluminum alloy/molten salt systems

Science.gov (United States)

Narayanan, Ramesh

The recycling of aluminum and aluminum alloys such as Used Beverage Container (UBC) is done under a cover of molten salt flux based on (NaCl-KCl+fluorides). The reactions of aluminum alloys with molten salt fluxes have been investigated. Thermodynamic calculations are performed in the alloy/salt flux systems which allow quantitative predictions of the equilibrium compositions. There is preferential reaction of Mg in Al-Mg alloy with molten salt fluxes, especially those containing fluorides like NaF. An exchange reaction between Al-Mg alloy and molten salt flux has been demonstrated. Mg from the Al-Mg alloy transfers into the salt flux while Na from the salt flux transfers into the metal. Thermodynamic calculations indicated that the amount of Na in metal increases as the Mg content in alloy and/or NaF content in the reacting flux increases. This is an important point because small amounts of Na have a detrimental effect on the mechanical properties of the Al-Mg alloy. The reactions of Al alloys with molten salt fluxes result in the formation of bluish purple colored "streamers". It was established that the streamer is liquid alkali metal (Na and K in the case of NaCl-KCl-NaF systems) dissipating into the melt. The melts in which such streamers were observed are identified. The metal losses occurring due to reactions have been quantified, both by thermodynamic calculations and experimentally. A computer program has been developed to calculate ternary phase diagrams in molten salt systems from the constituting binary phase diagrams, based on a regular solution model. The extent of deviation of the binary systems from regular solution has been quantified. The systems investigated in which good agreement was found between the calculated and experimental phase diagrams included NaF-KF-LiF, NaCl-NaF-NaI and KNOsb3-TINOsb3-LiNOsb3. Furthermore, an insight has been provided on the interrelationship between the regular solution parameters and the topology of the phase

Long term immersion test of aluminum alloy AA 6061 used for fuel cladding in MTR type reactors

International Nuclear Information System (INIS)

Linardi, Evelina M.; Rodriguez, Sebastian; Haddad, Roberto; Lanzani, Liliana

2009-01-01

In this work we present the results of long term immersion tests performed in the aluminum alloy AA 6061, used for fuel cladding in MTR type reactors. The tests were performed at open circuit potential in high purity water (ρ = 18.2 MΩ.cm) and in 10 -3 M NaCl solution. Two kinds of assemblies were studied: simple sheets and artificial crevices, immersed during 6, 12 and 18 months at room temperature. In both media and both assemblies, the aluminum hydroxide phases crystalline bayerite and bohemite were identified. It was found that a kind of localized attack named alkaline attack occurs around the iron-rich intermetallics. These particles were confirmed to control the corrosion of the AA 6061 alloy in an aerated medium. Immersion times for up to 18 months did not increase the oxide growth or the alkaline attack on the AA 6061 alloy. (author)

High strength cast aluminum alloy development

Science.gov (United States)

Druschitz, Edward A.

The goal of this research was to understand how chemistry and processing affect the resulting microstructure and mechanical properties of high strength cast aluminum alloys. Two alloy systems were investigated including the Al-Cu-Ag and the Al-Zn-Mg-Cu systems. Processing variables included solidification under pressure (SUP) and heat treatment. This research determined the range in properties that can be achieved in BAC 100(TM) (Al-Cu micro-alloyed with Ag, Mn, Zr, and V) and generated sufficient property data for design purposes. Tensile, stress corrosion cracking, and fatigue testing were performed. CuAl2 and Al-Cu-Fe-Mn intermetallics were identified as the ductility limiting flaws. A solution treatment of 75 hours or longer was needed to dissolve most of the intermetallic CuAl 2. The Al-Cu-Fe-Mn intermetallic was unaffected by heat treatment. These results indicate that faster cooling rates, a reduction in copper concentration and a reduction in iron concentration might increase the ductility of the alloy by decreasing the size and amount of the intermetallics that form during solidification. Six experimental Al-Zn-Mg-Cu series alloys were produced. Zinc concentrations of 8 and 12wt% and Zn/Mg ratios of 1.5 to 5.5 were tested. Copper was held constant at 0.9%. Heat treating of the alloys was optimized for maximum hardness. Al-Zn-Mg-Cu samples were solution treated at 441°C (826°F) for 4 hours before ramping to 460°C (860°F) for 75 hours and then aged at 120°C (248°F) for 75 hours. X-ray diffraction showed that the age hardening precipitates in most of these alloys was the T phase (Mg32Zn 31.9Al17.1). Tensile testing of the alloys showed that the best mechanical properties were obtained in the lowest alloy condition. Chilled Al-8.2Zn-1.4Mg-0.9Cu solidified under pressure resulted in an alloy with a yield strength of 468MPa (68ksi), tensile strength of 525MPa (76ksi) and an elongation of 9%.

Effect of Contact Time on Interface Reaction between Aluminum Silicon (7% and 11% Alloy and Steel Dies SKD 61

Directory of Open Access Journals (Sweden)

Bambang Suharno

2010-10-01

Full Text Available Die soldering (die sticking is a defect of metal casting in which molten metal “welds” to the metallic die mold surface during casting process. Die soldering is the result of an interface reaction between the molten aluminum and the die material. Aluminum alloy with 7 and 11% silicon and SKD 61 die steel are the most common melt and die material used in aluminum die casting. This research is done to study the morphology and the characteristics of the formed AlxFeySiz intermetallic layer during interface reaction at dipping test. The samples of as-anneal SKD 61 tool steel was dipped into the molten of Al-7%Si held at temperature 680oC and into molten Al-11%Si held at temperature 710oC with the different contact time of 10 minutes; 30 minutes; and 50 minutes. The research results showed that the interface reaction can form a compact intermetallic layer with AlxFey phase and a broken intermetallic layer with AlxFeySiz phase on the surface of SKD 61 tool steel. The increasing of the contact time by the immersion of material SKD 61 tool steel in both of molten Al-7%Si and Al-11%Si will increase the thickness of the AlxFeySiz intermetallic layer until an optimum point and then decreasing. The micro hardness of the AlxFeySiz intermetallic layer depends on the content of the iron. Increasing of the iron content in intermetallic layer will increase the micro hardness of the AlxFeySiz. This condition happened because the increasing of Fe content will cause forming of intermetallic AlxFeySiz phase becomes quicker.

Silicon effects on formation of EPO oxide coatings on aluminum alloys

International Nuclear Information System (INIS)

Wang, L.; Nie, X.

2006-01-01

Electrolytic plasma processes (EPP) can be used for cleaning, metal-coating, carburizing, nitriding, and oxidizing. Electrolytic plasma oxidizing (EPO) is an advanced technique to deposit thick and hard ceramic coatings on a number of aluminum alloys. However, the EPO treatment on Al-Si alloys with a high Si content has rarely been reported. In this research, an investigation was conducted to clarify the effects of silicon contents on the EPO coating formation, morphology, and composition. Cast hypereutectic 390 alloys (∼ 17% Si) and hypoeutectic 319 alloys (∼ 7% Si) were chosen as substrates. The coating morphology, composition, and microstructure of the EPO coatings on those substrates were investigated using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). A stylus roughness tester was used for surface roughness measurement. It was found that the EPO process had four stages where each stage was corresponding to various coating surface morphology, composition, and phase structures, characterised by different coating growth mechanisms

Acceptability and use of iron and iron-alloy cooking pots: implications for anaemia control programmes.

Science.gov (United States)

Tripp, Katherine; Mackeith, Nancy; Woodruff, Bradley A; Talley, Leisel; Mselle, Laurent; Mirghani, Zahra; Abdalla, Fathia; Bhatia, Rita; Seal, Andrew J

2010-01-01

To evaluate the acceptability of iron and iron-alloy cooking pots prior to an intervention trial and to investigate factors affecting retention and use. Pre-trial research was conducted on five types of iron and iron-alloy pots using focus group discussions and a laboratory evaluation of Fe transfer during cooking was undertaken. Usage and retention during the subsequent intervention trial were investigated using focus group discussions and market monitoring. Three refugee camps in western Tanzania. Refugee health workers were selected for pre-trial research. Mothers of children aged 6-59 months participated in the investigation of retention and use. Pre-trial research indicated that the stainless steel pot would be the only acceptable type for use in this population due to excessive rusting and/or the high weight of other types. Cooking three typical refugee dishes in stainless steel pots led to an increase in Fe content of 3.2 to 17.1 mg/100 g food (P basic acceptability criteria. The relatively low usage reported during the trial highlights the limitations of using high-value iron-alloy cooking pots as an intervention in populations where poverty and the availability of other pots may lead to selling.

Acoustic emission from a solidifying aluminum-lithium alloy

Science.gov (United States)

Henkel, D. P.; Wood, J. D.

1992-01-01

Physical phenomena associated with the solidification of an AA2090 Al-Li alloy have been characterized by AE methods. Repeatable patterns of AE activity as a function of solidification time are recorded and explained for ultrahigh-purity (UHP) aluminum and an Al-4.7 wt pct Cu binary alloy, in addition to the AA2090 Al-Li alloy, by the complementary utilization of thermal, AE, and metallographic methods. One result shows that the solidification of UHP aluminum produces one discrete period of high AE activity as the last 10 percent of solid forms.

Semi-solid metal forming of beryllium-reinforced aluminum alloys

International Nuclear Information System (INIS)

Haws, W.; Lane, L.; Marder, J.; Nicholas, N.

1995-01-01

A Powder Metallurgy (PM) based, Semi-Solid Metal (SSM) forming process has been developed to produce low cost near-net shapes of beryllium-reinforced aluminum alloys. Beryllium acts as a reinforcing additive to the aluminum, in which there is nearly no mutual solid solubility. The modulus of elasticity of the alloy dramatically increases, while the density and thermal expansion coefficient decrease with increasing beryllium content. The material is suitable for complex thermal management and vibration resistance applications, as well as for airborne components which are density and stiffness sensitive. The forming process involves heating a blank of the material to a temperature at which the aluminum is semi-solid and the beryllium is solid. The semi-solid blank is then injected without turbulence into a permanent mold. High quality, near net shape components can be produced which are functionally superior to those produced by other permanent mold processes. Dimensional accuracy is equivalent to or better than that obtained in high pressure die casting. Cost effectiveness is the primary advantage of this technique compared to other forming processes. The advantages and limitations of the process are described. Physical and mechanical property data are presented, as well as directions for future investigation

Carbon Dissolution Using Waste Biomass—A Sustainable Approach for Iron-Carbon Alloy Production

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Irshad Mansuri

2018-04-01

Full Text Available This paper details the characterisation of char obtained by high-temperature pyrolysis of waste macadamia shell biomass and its application as carbon source in iron-carbon alloy production. The obtained char was characterised by ultimate and proximate analysis, X-ray diffraction (XRD, Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR, X-ray photon spectroscopy (XPS, Brunauer-Emmett-Teller (BET surface area via N2 isothermal adsorption and scanning electron microscopy (SEM. The results indicated that obtained char is less porous, low in ash content, and high in carbon content. Investigation of iron-carbon alloy formation through carbon dissolution at 1550 °C was carried out using sessile drop method by using obtained char as a carbon source. Rapid carbon pickup by iron was observed during first two minutes of contact and reached a saturation value of ~5.18 wt % of carbon after 30 min. The carbon dissolution rate using macadamia char as a source of carbon was comparatively higher using than other carbonaceous materials such as metallurgical coke, coal chars, and waste compact discs, due to its high percentage of carbon and low ash content. This research shows that macadamia shell waste, which has a low content of ash, is a valuable supplementary carbon source for iron-carbon alloy industries.

Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys

International Nuclear Information System (INIS)

Chemin, Aline; Marques, Denys; Bisanha, Leandro; Motheo, Artur de Jesus; Bose Filho, Waldek Wladimir; Ruchert, Cassius Olivio Figueiredo

2014-01-01

Highlights: • The corrosion on new aerospace aluminum alloy is studied. • Al 7 Cu 2 Fe precipitate was detected in the 7475-T7351 and 7081 T73511 alloy by scanning electron microscopy. • Al 7 Cu 2 Fe particles have different morphologies depending on the forming process. • Corrosion pitting occurs around Al 7 Cu 2 Fe precipitates in 7475-T7351 and 7081-T73511 alloys. - Abstract: The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al 7 Cu 2 Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al 7 Cu 2 Fe precipitate in both alloys, revealing the anodic behavior of the matrix

Effect of direct contact with iron on gas evolution behavior of aluminum

International Nuclear Information System (INIS)

Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka

1998-01-01

Dry Low-Level Radioactive Waste (LLW), incombustible solid LLW, generated from nuclear power stations is planed to be solidified with cement backfill in drums. The solidified dry LLW will be buried to shallow underground at Rokkasyo LLW Disposal Center. It is well known that corrosion of aluminum and hydrogen gas evolution occur in high pH environments such as mortar. Gas evolution from aluminum is likely to effect the leachability of solidified dry LLW with mortar. Though aluminum removal from dry LLW is planed, a small amount of aluminum will be actually included in dry LLW. Large effects of pH and temperature on corrosion rate of aluminum and gas evolution were recognized in our previous study. It was also found that 1.5 mole hydrogen gas evolves while 1 mole aluminum corrodes under 60degC. Actually aluminum in drums is likely to contact with carbon steel of which main element is iron. The gas evolution behavior of aluminum is expected to be affected by its direct contact with iron. Therefore, effect of direct contact with iron on gas evolution behavior of aluminum was studied. The corrosion rate of aluminum increased by contacting it with iron in simulating mortar environments. The amount of gas evolution from aluminum was reduced by contacting with iron. The reduction in gas evolution was considered to result from the change of cathode reaction from hydrogen evolution to oxygen reduction. When aluminum contacts with iron, the corrosion and gas evolution behavior of aluminum is significantly affected oxygen in environment. (author)

Retention and release of tritium in aluminum clad, Al-Li alloys

International Nuclear Information System (INIS)

Louthan, M.R. Jr.

1991-01-01

Tritium retention in and release from aluminum clad, aluminum-lithium alloys is modeled from experimental and operational data developed during the thirty plus years of tritium production at the Savannah River Site. The model assumes that tritium atoms, formed by the 6 Li(n,α) 3 He reaction, are produced in solid solution in the Al-Li alloy. Because of the low solubility of hydrogen isotopes in aluminum alloys, the irradiated Al-Li rapidly becomes supersaturated in tritium. Newly produced tritium atoms are trapped by lithium atoms to form a lithium tritide. The effective tritium pressure required for trap or tritide stability is the equilibrium decomposition pressure of tritium over a lithium tritide-aluminum mixture. The temperature dependence of tritium release is determined by the permeability of the cladding to tritium and the local equilibrium at the trap sites. This model is used to calculate tritium release from aluminum clad, aluminum-lithium alloys. 9 refs., 3 figs

Iron-titanium-mischmetal alloys for hydrogen storage

Science.gov (United States)

Sandrock, Gary Dale

1978-01-01

A method for the preparation of an iron-titanium-mischmetal alloy which is used for the storage of hydrogen. The alloy is prepared by air-melting an iron charge in a clay-graphite crucible, adding titanium and deoxidizing with mischmetal. The resultant alloy contains less than about 0.1% oxygen and exhibits a capability for hydrogen sorption in less than half the time required by vacuum-melted, iron-titanium alloys.

Biaxial Testing of 2195 Aluminum Lithium Alloy Using Cruciform Specimens

Science.gov (United States)

Johnston, W. M.; Pollock, W. D.; Dawicke, D. S.; Wagner, John A. (Technical Monitor)

2002-01-01

A cruciform biaxial test specimen was used to test the effect of biaxial load on the yield of aluminum-lithium alloy 2195. Fifteen cruciform specimens were tested from 2 thicknesses of 2195-T8 plate, 0.45 in. and 1.75 in. These results were compared to the results from uniaxial tensile tests of the same alloy, and cruciform biaxial tests of aluminum alloy 2219-T87.

Surface treatment of new type aluminum lithium alloy and fatigue crack behaviors of this alloy plate bonded with Ti–6Al–4V alloy strap

International Nuclear Information System (INIS)

Sun, Zhen-Qi; Huang, Ming-Hui; Hu, Guo-Huai

2012-01-01

Highlights: ► A new generation aluminum lithium alloy which special made for Chinese commercial plane was investigated. ► Pattern of aluminum lithium alloy and Ti alloy were shown after anodization. ► Crack propagation of samples bonded with different wide Ti straps were studied in this paper. -- Abstract: Samples consisting of new aluminum lithium alloy (Al–Li alloy) plate developed by the Aluminum Company of America and Ti–6Al–4V alloy (Ti alloy) plate were investigated. Plate of 400 mm × 140 mm × 2 mm with single edge notch was anodized in phosphoric solution and Ti alloy plate of 200 mm × 20 (40) mm × 2 mm was anodized in alkali solution. Patterns of two alloys were studied at original/anodized condition. And then, aluminum alloy and Ti alloy plates were assembled into a sample with FM 94 film adhesive. Fatigue crack behaviors of the sample were investigated under condition of nominal stress σ = 36 MPa and 54 MPa, stress ratio of 0.1. Testing results show that anodization treatment modifies alloys surface topography. Ti alloy bonding to Al–Li alloy plate effectively retards crack growth than that of Al–Li alloy plate. Fatigue life of sample bonded with Ti alloy strap improves about 62.5% than that of non-strap plate.

Characterization of 2024-T3: An aerospace aluminum alloy

International Nuclear Information System (INIS)

Huda, Zainul; Taib, Nur Iskandar; Zaharinie, Tuan

2009-01-01

The 2024-T3 aerospace aluminum alloy, reported in this investigation, was acquired from a local aerospace industry: Royal Malaysian Air Force (RMAF). The heat treatable 2024-T3 aluminum alloy has been characterized by use of modern metallographic and material characterization techniques (e.g. EPMA, SEM). The microstructural characterization of the metallographic specimen involved use of an optical microscope linked with a computerized imaging system using MSQ software. The use of EPMA and electron microprobe elemental maps enabled us to detect three types of inclusions: Al-Cu, Al-Cu-Fe-Mn, and Al-Cu-Fe-Si-Mn enriched regions. In particular, the presence of Al 2 CuMg (S-phase) and the CuAl 2 (θ') phases indicated precipitation strengthening in the aluminum alloy

High temperature Moessbauer study of order-disorder transformation in iron-aluminum alloys

International Nuclear Information System (INIS)

Oki, Kensuke; Yamamura, Akihiko; Kudo, Kazunao; Eguchi, Tetsuo

1979-01-01

Ordering process of iron rich Fe-Al alloys has been investigated at elevated temperatures by mean of Moessbauer spectroscopy. The observed spectra are analyzed to obtain the temperature dependences of the internal field, isomer shift and line width, and the results are discussed in connection with the ordering process. The alloy with 24.7 at% Al exhibits spectra, which are characteristic of the superposition of a single-line spectrum and a six-line one, originating from the ordered paramagnetic B2 or DO 3 state and disordered ferromagnetic α, respectively, and the results confirm the coexistence of α phase with B2 or DO 3 . The isomer shift of the paramagnetic component of the spectra shows discontinuous changes at the temperatures of transformation α reversible B2 and B2 reversible DO 3 . (author)

Superplasticity in powder metallurgy aluminum alloys and composites

International Nuclear Information System (INIS)

Mishra, R.S.; Bieler, T.R.; Mukherjee, A.K.

1995-01-01

Superplasticity in powder metallurgy Al alloys and composites has been reviewed through a detailed analysis. The stress-strain curves can be put into 4 categories: classical well-behaved type, continuous strain hardening type, continuous strain softening type and complex type. The origin of these different types of is discussed. The microstructural features of the processed material and the role of strain have been reviewed. The role of increasing misorientation of low angle boundaries to high angle boundaries by lattice dislocation absorption is examined. Threshold stresses have been determined and analyzed. The parametric dependencies for superplastic flow in modified conventional aluminum alloys, mechanically alloyed alloys and Al alloy matrix composites is determined to elucidate the superplastic mechanism at high strain rates. The role of incipient melting has been analyzed. A stress exponent of 2, an activation energy equal to that for grain boundary diffusion and a grain size dependence of 2 generally describes superplastic flow in modified conventional Al alloys and mechanically alloyed alloys. The present results agree well with the predictions of grain boundary sliding models. This suggests that the mechanism of high strain rate superplasticity in the above-mentioned alloys is similar to conventional superplasticity. The shift of optimum superplastic strain rates to higher values is a consequence of microstructural refinement. The parametric dependencies for superplasticity in aluminum alloy matrix composites, however, is different. A true activation energy of superplasticity in aluminum alloy matrix composites, however, is different. A true activation energy of 313 kJ/mol best describes the composites having SiC reinforcements. The role of shape of the reinforcement (particle or whisker) and processing history is addressed. The analysis suggests that the mechanism for superplasticity in composites is interface diffusion controlled grain boundary sliding

Effect of aluminum content on the passivation behavior of Fe-Al alloys in sulfuric acid solution

DEFF Research Database (Denmark)

Chiang, Wen-Chi; Luu, W.C.; Wu, J.K.

2006-01-01

-Al alloys, which the Al content of alloy exceeds 19 at %, have wide passivation regions with low passivation current. However, when the Al content of Fe-Al alloys exceeds this range, the increment of Al content has slight influence on passivation behavior compared with ternary Cr addition....

Iron Intermetallic Phases in the Alloy Based on Al-Si-Mg by Applying Manganese

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Podprocká R.

2017-09-01

Full Text Available Manganese is an effective element used for the modification of needle intermetallic phases in Al-Si alloy. These particles seriously degrade mechanical characteristics of the alloy and promote the formation of porosity. By adding manganese the particles are being excluded in more compact shape of “Chinese script” or skeletal form, which are less initiative to cracks as Al5FeSi phase. In the present article, AlSi7Mg0.3 aluminium foundry alloy with several manganese content were studied. The alloy was controlled pollution for achieve higher iron content (about 0.7 wt. % Fe. The manganese were added in amount of 0.2 wt. %, 0.6 wt. %, 1.0 wt. % and 1.4 wt. %. The influence of the alloying element on the process of crystallization of intermetallic phases were compared to microstructural observations. The results indicate that increasing manganese content (> 0.2 wt. % Mn lead to increase the temperature of solidification iron rich phase (TAl5FeSi and reduction this particles. The temperature of nucleation Al-Si eutectic increase with higher manganese content also. At adding 1.4 wt. % Mn grain refinement and skeleton particles were observed.

Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy

Energy Technology Data Exchange (ETDEWEB)

Terry, Brandon C., E-mail: terry13@purdue.edu [School of Aeronautics and Astronautics, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States); Sippel, Travis R. [Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011 (United States); Pfeil, Mark A. [School of Aeronautics and Astronautics, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States); Gunduz, I.Emre; Son, Steven F. [School of Mechanical Engineering, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States)

2016-11-05

Highlights: • Al-Li alloy propellant has increased ideal specific impulse over neat aluminum. • Al-Li alloy propellant has a near complete reduction in HCl acid formation. • Reduction in HCl was verified with wet bomb experiments and DSC/TGA-MS/FTIR. - Abstract: Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (I{sub SP}). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal I{sub SP} by ∼7 s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5 ± 4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.

Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy

International Nuclear Information System (INIS)

Terry, Brandon C.; Sippel, Travis R.; Pfeil, Mark A.; Gunduz, I.Emre; Son, Steven F.

2016-01-01

Highlights: • Al-Li alloy propellant has increased ideal specific impulse over neat aluminum. • Al-Li alloy propellant has a near complete reduction in HCl acid formation. • Reduction in HCl was verified with wet bomb experiments and DSC/TGA-MS/FTIR. - Abstract: Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (I_S_P). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal I_S_P by ∼7 s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5 ± 4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.

Soft x-ray emission studies of several aluminum alloys

International Nuclear Information System (INIS)

Tsang, K.L.; Zhang, C.H.; Callcott, T.A.; Arakawa, E.T.; Ederer, D.L.; Biancaniello, F.; Curelaru, I.

1986-01-01

During the first few months of operation of our soft x-ray spectrometer at the NSLS, we have measured the L emission spectrum for three classes of aluminum alloys: dilute aluminum-magnesium alloys to extend the Al-Mg system to the impurity limit; a 50-50 alloy of aluminum-lithium to characterize the band structure of bulk samples of this potential battery electrolite; and the icosahedral and normal Al-Mn alloys to see if the two phases had measurably different density of states which have been predicted. All spectra shown are produced when core holes generated by energetic electrons or photons are filled by radiative transitions from conduction band states. Dipole selection rules govern the transitions. Thus, K spectra provide a measure of the p-symmetic partial density of states (DOS) near the atom. Similarly, L spectra produced by transitions to p-core holes map the s and d symmetric DOS in the vicinity of the atom with the core hole

Soft x-ray emission studies of several aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Tsang, K.L.; Zhang, C.H.; Callcott, T.A.; Arakawa, E.T.; Ederer, D.L.; Biancaniello, F.; Curelaru, I.

1986-09-23

During the first few months of operation of our soft x-ray spectrometer at the NSLS, we have measured the L emission spectrum for three classes of aluminum alloys: dilute aluminum-magnesium alloys to extend the Al-Mg system to the impurity limit; a 50-50 alloy of aluminum-lithium to characterize the band structure of bulk samples of this potential battery electrolite; and the icosahedral and normal Al-Mn alloys to see if the two phases had measurably different density of states which have been predicted. All spectra shown are produced when core holes generated by energetic electrons or photons are filled by radiative transitions from conduction band states. Dipole selection rules govern the transitions. Thus, K spectra provide a measure of the p-symmetic partial density of states (DOS) near the atom. Similarly, L spectra produced by transitions to p-core holes map the s and d symmetric DOS in the vicinity of the atom with the core hole.

Vanadium Influence on Iron Based Intermetallic Phases in AlSi6Cu4 Alloy

Directory of Open Access Journals (Sweden)

Bolibruchová D.

2014-10-01

Full Text Available Negative effect of iron in Al-Si alloys mostly refers with iron based intermetallic phases, especially Al5FeSi phases. These phases are present in platelet-like forms, which sharp edges are considered as main cracks initiators and also as contributors of porosity formation. In recent times, addition of some elements, for example Mn, Co, Cr, Ni, V, is used to reduce influence of iron. Influence of vanadium in aluminium AlSi6Cu4 alloy with intentionally increased iron content is presented in this article. Vanadium amount has been graduated and chemical composition of alloy has been analysed by spectral analysis. Vanadium influence on microstructural changes was evaluated by microstructural analysis and some of intermetallic particles were reviewed by EDX analysis.

Thermodynamic Properties of Alloys of Iron and Silicon

International Nuclear Information System (INIS)

Vecher, R.A.; Gejderih, V.A.; Gerasimov, Ja.I.

1966-01-01

The Fe-Si phase diagram is complex. At 1000°K there are FeSi 2 (β) and FeSi phases and solid solutions of silicon in α and α' iron. EMF measurements were made on the electrochemical cells: Fe|Fe 2+ , KI + Nal|Fe-Si at 600-800°C molten The alloys were prepared from particularly pure components by powder metallurgy and protracted annealing. Studies were made of ten alloys with silicon content between 85 and 4% in all the phase fields in the diagram section at 1000°K. We calculated the integral thermodynamic quantities ΔG, ΔH and ΔS for the formation of the silicides FeSi 2 (β), FeSi and Fe 3 Si at the mean temperature for the experimental range (1000°K), and also (using the thermal capacity of the silicides, the iron and the silicon) at 298, 1188 and 1798°K. The heats of formation of the silicides mentioned at 298°K (kcal/mole) are -19.4, -17.6 and -22.4 respectively. The data existing in the literature enable us to calculate the heat of formation of FeSi 2.33 (α-leboite) at 298°K and this is found to be -14.4 kcal/mole. The heats calculated by us are 1.5-3 kcal higher than the experimental values of Corber and Olsen. The heats of mixing calculated by us for liquid alloys agree well with data in the literature. The data obtained can be regarded as due to the change in the character of the bond in silicides from metallic to covalent when the silicon content is increased. From the data for alloy solutions of silicon in a-iron, the iron activities were calculated. It was found that the α ⇌ α' transformation observed is a real phase transformation. The two-phase range is wider than shown in the phase diagram (from data in the literature). Conversion of the iron activities in solid solution to liquid solution gives good agreement with the data of Chipman. (author) [fr

Etching Behavior of Aluminum Alloy Extrusions

Science.gov (United States)

Zhu, Hanliang

2014-11-01

The etching treatment is an important process step in influencing the surface quality of anodized aluminum alloy extrusions. The aim of etching is to produce a homogeneously matte surface. However, in the etching process, further surface imperfections can be generated on the extrusion surface due to uneven materials loss from different microstructural components. These surface imperfections formed prior to anodizing can significantly influence the surface quality of the final anodized extrusion products. In this article, various factors that influence the materials loss during alkaline etching of aluminum alloy extrusions are investigated. The influencing variables considered include etching process parameters, Fe-rich particles, Mg-Si precipitates, and extrusion profiles. This study provides a basis for improving the surface quality in industrial extrusion products by optimizing various process parameters.

Comments on process of duplex coatings on aluminum alloys

Institute of Scientific and Technical Information of China (English)

Samir H.A.; QIAN Han-cheng(钱翰城); XIA Bo-cai(夏伯才); WU Shi-ming(吴仕明)

2004-01-01

Despite the great achievements made in improvement of wear resistance properties of aluminum alloys,their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on aluminum alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

Characterization of 2024-T3: An aerospace aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Huda, Zainul [Department of Mechanical Engineering, University of Malaya, Kuala Lumpur (Malaysia)], E-mail: drzainulhuda@hotmail.com; Taib, Nur Iskandar [Department of Geology, University of Malaya, Kuala Lumpur (Malaysia)], E-mail: ntaib@alumni.indiana.edu; Zaharinie, Tuan [Department of Mechanical Engineering, University of Malaya, Kuala Lumpur (Malaysia)], E-mail: rinie_3483@hotmail.com

2009-02-15

The 2024-T3 aerospace aluminum alloy, reported in this investigation, was acquired from a local aerospace industry: Royal Malaysian Air Force (RMAF). The heat treatable 2024-T3 aluminum alloy has been characterized by use of modern metallographic and material characterization techniques (e.g. EPMA, SEM). The microstructural characterization of the metallographic specimen involved use of an optical microscope linked with a computerized imaging system using MSQ software. The use of EPMA and electron microprobe elemental maps enabled us to detect three types of inclusions: Al-Cu, Al-Cu-Fe-Mn, and Al-Cu-Fe-Si-Mn enriched regions. In particular, the presence of Al{sub 2}CuMg (S-phase) and the CuAl{sub 2} ({theta}') phases indicated precipitation strengthening in the aluminum alloy.

Method to increase the toughness of aluminum-lithium alloys at cryogenic temperatures

Science.gov (United States)

Sankaran, Krishnan K. (Inventor); Sova, Brian J. (Inventor); Babel, Henry W. (Inventor)

2006-01-01

A method to increase the toughness of the aluminum-lithium alloy C458 and similar alloys at cryogenic temperatures above their room temperature toughness is provided. Increasing the cryogenic toughness of the aluminum-lithium alloy C458 allows the use of alloy C458 for cryogenic tanks, for example for launch vehicles in the aerospace industry. A two-step aging treatment for alloy C458 is provided. A specific set of times and temperatures to age the aluminum-lithium alloy C458 to T8 temper is disclosed that results in a higher toughness at cryogenic temperatures compared to room temperature. The disclosed two-step aging treatment for alloy 458 can be easily practiced in the manufacturing process, does not involve impractical heating rates or durations, and does not degrade other material properties.

Study of the pyrophoric characteristics of uranium-iron alloys; Etude du caractere pyrophorique des alliages uranium fer

Energy Technology Data Exchange (ETDEWEB)

Duplessis, X

2000-02-23

The objective of the study is to understand the pyrophoric characteristics of uranium-iron alloys. In order to carry out this research we have elected to use uranium-iron alloy powder with granules of 200 {mu}m and 1000 {mu}m diameter with 4%, 10.8% and 14% iron content. The experiments were performed on small samples of few milligrams and on larger quantities of few hundred grams. The main conclusions obtained are the followings: -The reaction start at 453 K (180 deg. C) and the ignition at 543 K (270 deg. C) - The influence of the specific area seems more important than the iron concentration in the alloys - When the alloy ignites, the fire spreads quickly and the alloy rapidly consumes. (author)

Corrosion Resistance of 7475-T7351 Aluminum Alloy Plate for Aviation

OpenAIRE

LIU Ming; LI Hui-qu; CHEN Jun-zhou; LI Guo-ai; CHEN Gao-hong

2017-01-01

The intergranular corrosion and exfoliation corrosion properties of 7475-T7351 aluminum alloy plate for aviation were investigated, and the corrosion behaviors of the alloy were analyzed by metallographic analysis(MA) and transmission electron microscope(TEM). The results show that no obvious intergranular corrosion is observed, but exfoliation corrosion grade of 7475-T7351 aluminum alloy increases from EA on surface to EC in the core. The exfoliation corrosion of 7475 alloy plate is mainly b...

Precipitation hardenable iron-nickel-chromium alloy having good swelling resistance and low neutron absorbence

International Nuclear Information System (INIS)

Korenko, M.K.; Merrick, H.F.; Gibson, R.C.

1982-01-01

An iron-nickel-chromium age-hardenable alloy suitable for use in fast breeder reactor ducts and cladding utilizes the gamma-double prime strengthening phase and has a morphology of the gamma-double prime phase enveloping the gamma-prime phase and delta phase distributed at or near the grain boundaries. The alloy consists essentially of about 40-50 percent nickel, 7.5-14 percent chromium, 1.5-4 percent niobium, .25-.75 percent silicon, 1-3 percent titanium, .1-.5 percent aluminum, .02-1 percent carbon, .002-.015 percent boron, and the balance iron. Up to 2 percent manganese and up to .01 percent magnesium may be added to inhibit trace element effects; up to .1 percent zirconium may be added to increase radiation swelling resistance; and up to 3 percent molybdenum may be added to increase strength

Hydrogen effects in aluminum alloys

International Nuclear Information System (INIS)

Louthan, M.R. Jr.; Caskey, G.R. Jr.; Dexter, A.H.

1976-01-01

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 D 2 / = 1.9 x 10 -2 exp (--22,400/RT) cc (NTP)atm/sup -- 1 / 2 / s -1 cm -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

Environmental fatigue in aluminum-lithium alloys

Science.gov (United States)

Piascik, Robert S.

1992-01-01

Aluminum-lithium alloys exhibit similar environmental fatigue crack growth characteristics compared to conventional 2000 series alloys and are more resistant to environmental fatigue compared to 7000 series alloys. The superior fatigue crack growth behavior of Al-Li alloys 2090, 2091, 8090, and 8091 is due to crack closure caused by tortuous crack path morphology and crack surface corrosion products. At high R and reduced closure, chemical environment effects are pronounced resulting in accelerated near threshold da/dN. The beneficial effects of crack closure are minimized for small cracks resulting in rapid growth rates. Limited data suggest that the 'chemically small crack' effect, observed in other alloy system, is not pronounced in Al-Li alloys. Modeling of environmental fatigue in Al-Li-Cu alloys related accelerated fatigue crack growth in moist air and salt water to hydrogen embrittlement.

Properties of welded joints in laser welding of aeronautic aluminum-lithium alloys

Science.gov (United States)

Malikov, A. G.; Orishich, A. M.

2017-01-01

The work presents the experimental investigation of the laser welding of the aluminum-lithium alloys (system Al-Mg-Li) and aluminum alloy (system Al-Cu-Li) doped with Sc. The influence of the nano-structuring of the surface layer welded joint by the cold plastic deformation method on the strength properties of the welded joint is determined. It is founded that, regarding the deformation degree over the thickness, the varying value of the welded joint strength is different for these aluminum alloys.

An electrochemical investigation of the corrosion behavior of aluminum alloys in chloride containing solutions

International Nuclear Information System (INIS)

Campos Filho, Jorge Eustaquio de

2005-01-01

Aluminum alloys have been used as cladding materials for nuclear fuel in research reactors due to its corrosion resistance. Aluminum owes its good corrosion resistance to a protective barrier oxide film formed and strongly bonded to its surface. In pool type TRIGA IPR-R1 reactor, located at Centro de Desenvolvimento da Tecnologia Nuclear in Belo Horizonte, previous immersion coupon tests revealed that aluminum alloys suffer from pitting corrosion, in spite of high quality of water control. Corrosion attack is initiated by breaking the protective oxide film on aluminum alloy surface. Chloride ions can break this oxide film and stimulate metal dissolution. In this study the aluminum alloys 1050, 5052 and 6061 were used to evaluate their corrosion behavior in chloride containing solutions. The electrochemical techniques used were potentiodynamic anodic polarization and cyclic polarization. Results showed that aluminum alloys 5052 and 6061 present similar corrosion resistance in low chloride solutions (0,1 ppm NaCl) and in reactor water but both alloys are less resistant in high chloride solution (1 ppm NaCl). Aluminum alloy 1050 presented similar behavior in the three electrolytes used, regarding to pitting corrosion, indicating that the concentration of the chloride ions was not the only variable to influence its corrosion susceptibility. (author)

Electrochemistry of vanadium(II and the electrodeposition of aluminum-vanadium alloys in the aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt

Directory of Open Access Journals (Sweden)

Tsuda T.

2003-01-01

Full Text Available The electrochemical behavior of vanadium(II was examined in the 66.7-33.3 mole percent aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt containing dissolved VCl2 at 353 K. Voltammetry experiments revealed that V(II could be electrochemically oxidized to V(III and V(IV. However at slow scan rates the V(II/V(III electrode reaction is complicated by the rapid precipitation of V(III as VCl3. The reduction of V(II occurs at potentials considerably negative of the Al(III/Al electrode reaction, and Al-V alloys cannot be electrodeposited from this melt. However electrodeposition experiments conducted in VCl2-saturated melt containing the additive, 1-ethyl-3-methylimidazolium tetrafluoroborate, resulted in Al-V alloys. The vanadium content of these alloys increased with increasing cathodic current density or more negative applied potentials. X-ray analysis of Al-V alloys that were electrodeposited on a rotating copper wire substrate indicated that these alloys did not form or contain an intermetallic compound, but were non-equilibrium or metastable solid solutions. The chloride-pitting corrosion properties of these alloys were examined in aqueous NaCl by using potentiodynamic polarization techniques. Alloys containing ~10 a/o vanadium exhibited a pitting potential that was 0.3 V positive of that for pure aluminum.

First-principles surface interaction studies of aluminum-copper and aluminum-copper-magnesium secondary phases in aluminum alloys

Science.gov (United States)

da Silva, Thiago H.; Nelson, Eric B.; Williamson, Izaak; Efaw, Corey M.; Sapper, Erik; Hurley, Michael F.; Li, Lan

2018-05-01

First-principles density functional theory-based calculations were performed to study θ-phase Al2Cu, S-phase Al2CuMg surface stability, as well as their interactions with water molecules and chloride (Cl-) ions. These secondary phases are commonly found in aluminum-based alloys and are initiation points for localized corrosion. Density functional theory (DFT)-based simulations provide insight into the origins of localized (pitting) corrosion processes of aluminum-based alloys. For both phases studied, Cl- ions cause atomic distortions on the surface layers. The nature of the distortions could be a factor to weaken the interlayer bonds in the Al2Cu and Al2CuMg secondary phases, facilitating the corrosion process. Electronic structure calculations revealed not only electron charge transfer from Cl- ions to alloy surface but also electron sharing, suggesting ionic and covalent bonding features, respectively. The S-phase Al2CuMg structure has a more active surface than the θ-phase Al2Cu. We also found a higher tendency of formation of new species, such as Al3+, Al(OH)2+, HCl, AlCl2+, Al(OH)Cl+, and Cl2 on the S-phase Al2CuMg surface. Surface chemical reactions and resultant species present contribute to establishment of local surface chemistry that influences the corrosion behavior of aluminum alloys.

Investigation on effect of iron and corundum content on corrosion resistance of the NiFe-Al2O3 coatings

International Nuclear Information System (INIS)

Starosta, R.; Zielinski, A.

1999-01-01

The alloy NiFe and composite NiFe-Al 2 O 3 coatings, obtained by electrodeposition on the base of cast iron, were investigated. The iron content in alloy coatings was dependent on iron content in galvanic bath, and was estimated by means of X-ray microanalysis at 18.5 wt. pct. and 41.2 wt. pct. No existence of ordered Ni 3 Fe phase was found by diffraction technique. Both potentiodynamic and impedance measurements disclosed that a presence of Al 2 O 3 or increasing iron content in the layer caused the decrease in corrosion resistance. (author)

Roentgenoelectronic investigation into oxidation of iron-chromium and iron-chromium-nickel alloys

International Nuclear Information System (INIS)

Akimov, A.G.; Rozenfel'd, I.L.; Kazanskij, L.P.; Machavariani, G.V.

1978-01-01

Kinetics of iron-chromium and iron-chromium-nickel alloy oxidation (of the Kh13 and Kh18N10T steels) in oxygen was investigated using X-ray electron spectroscopy. It was found that according to X-ray electron spectra chromium oxidation kinetics in the iron-chromium alloy differs significantly from oxidation kinetics of chromium pattern. Layer by layer X-ray electron analysis showed that chromium is subjected to a deeper oxidation as compared to iron, and accordingly, Cr 2 O 3 layer with pure iron impregnations is placed between the layer of mixed oxide (Fe 3 O 4 +Cr 2 O 3 ) and metal. A model of the iron-chromium alloy surface is suggested. The mixed oxide composition on the steel surface is presented as spinel Fesub(2+x)Crsub(1-x)Osub(y)

Studies on neutron irradiation effects of iron alloys and nickel-base heat resistant alloys

International Nuclear Information System (INIS)

Watanabe, Katsutoshi

1987-09-01

The present paper describes the results of neutron irradiation effects on iron alloys and nickel-base heat resistant alloys. As for the iron alloys, irradiation hardening and embrittlement were investigated using internal friction measurement, electron microscopy and tensile testings. The role of alloying elements was also investigated to understand the irradiation behavior of iron alloys. The essential factors affecting irradiation hardening and embrittlement were thus clarified. On the other hand, postirradiation tensile and creep properties were measured of Hastelloy X alloy. Irradiation behavior at elevated temperatures is discussed. (author)

The corrosion behavior of iron and aluminum under waste disposal conditions

International Nuclear Information System (INIS)

Fujisawa, R.; Cho, T.; Sugahara, K.; Takizawa, Y.; Hironaga, M.

1997-01-01

The generation of hydrogen gas from metallic waste in corrosive disposal environment is an important issue for the safety analysis of low-level radioactive waste disposal facilities in Japan. In particular iron and aluminum are the possibly important elements regarding the gas generation. However, the corrosion behavior of these metals has not been sufficiently investigated under the highly alkaline non-oxidizing disposal conditions yet. The authors studied the corrosion behavior of iron and aluminum under simulated disposal environments. The quantity of hydrogen gas generated from iron was measured in a closed cell under highly alkaline non-oxidizing conditions. The observed corrosion rate of iron in the initial period of immersion was 4 nm/year at 15 C, 20 nm/year at 30 C, and 200 nm/year at 45 C. The activation energy was found to be 100 kJ/mol from Arrhenius plotting of the above corrosion rates. The corrosion behavior of aluminum was studied under an environment simulating conditions in which aluminum was solidified with mortar. In the initial period aluminum corroded rapidly with a corrosion rate of 20 mm/year. However, the corrosion rate decreased with time, and after 1,000 hours the rate reached 0.001 to 0.01 mm/year. Thus the authors obtained data on hydrogen gas generation from iron and aluminum under the disposal environment relevant to the safety analysis of low-level radioactive disposal facilities in Japan

Progress in development of iron base alloys

International Nuclear Information System (INIS)

Zackay, V.V.; Parker, E.R.

1980-01-01

The ways of development of new iron base high-strength alloys are considered. Perspectiveness of ferritic steel strengthening with intermetallides (TaFe 2 , for instance) is shown. Favourable combination of plasticity, strength and fracture toughness in nickel-free iron-manganese alloys (16-20%) is also pointed out. A strength level of alloyed maraging steels can be achieved by changes in chemical composition and by proper heat treatments of low- and medium-alloyed steels

Investigation of the Precipitation Behavior in Aluminum Based Alloys

KAUST Repository

Khushaim, Muna S.

2015-11-30

The transportation industries are constantly striving to achieve minimum weight to cut fuel consumption and improve overall performance. Different innovative design strategies have been placed and directed toward weight saving combined with good mechanical behavior. Among different materials, aluminum-based alloys play a key role in modern engineering and are widely used in construction components because of their light weight and superior mechanical properties. Introduction of different nano-structure features can improve the service and the physical properties of such alloys. For intelligent microstructure design in the complex Al-based alloy, it is important to gain a deep physical understanding of the correlation between the microstructure and macroscopic properties, and thus atom probe tomography with its exceptional capabilities of spatially resolution and quantitative chemical analyses is presented as a sophisticated analytical tool to elucidate the underlying process of precipitation phenomena in aluminum alloys. A complete study examining the influence of common industrial heat treatment on the precipitation kinetics and phase transformations of complex aluminum alloy is performed. The qualitative evaluation results of the precipitation kinetics and phase transformation as functions of the heat treatment conditions are translated to engineer a complex aluminum alloy. The study demonstrates the ability to construct a robust microstructure with an excellent hardness behavior by applying a low-energy-consumption, cost-effective method. The proposed strategy to engineer complex aluminum alloys is based on both mechanical strategy and intelligent microstructural design. An intelligent microstructural design requires an investigation of the different strengthen phases, such as T1 (Al2CuLi), θ′(Al2Cu), β′(Al3Zr) and δ′(Al3Li). Therefore, the early stage of phase decomposition is examined in different binary Al-Li and Al-Cu alloys together with different

Corrosion of alloys of the niobium--titanium--aluminium system

International Nuclear Information System (INIS)

Andreeva, V.V.; Alekseeva, E.L.; Dontsov, S.N.; Moiseeva, I.S.

The mechanical properties and corrosion resistance of niobium--titanium--aluminum alloys in 20 percent HCl and 40--75 percent H 2 SO 4 at 40 and 100 0 C are considered. Current density vs potential and corrosion rate vs potential potentiostatic curves plotted in 75 percent H 2 SO 4 at 140 0 C for the alloys with different titanium contents at a constant content of aluminum and also for alloys with a constant titanium content at different contents of aluminum are given. It was shown that the corrosion resistance of the alloys in 75 percent H 2 SO 4 at 140 0 C is an exponential function of the atomic content of the alloying components (Ti, Al) in them; aluminum vitiates the corrosion resistance very strongly

Creep Aging Behavior Characterization of 2219 Aluminum Alloy

Directory of Open Access Journals (Sweden)

Lingfeng Liu

2016-06-01

Full Text Available In order to characterize the creep behaviors of 2219 aluminum alloy at different temperatures and stress levels, a RWS-50 Electronic Creep Testing Machine (Zhuhai SUST Electrical Equipment Company, Zhuhai, China was used for creep experiment at temperatures of 353~458 k and experimental stresses of 130~170 MPa. It was discovered that this alloy displayed classical creep curve characteristics in its creep behaviors within the experimental parameters, and its creep value increased with temperature and stress. Based on the creep equation of hyperbolic sine function, regression analysis was conducted of experimental data to calculate stress exponent, creep activation energy, and other related variables, and a 2219 aluminum alloy creep constitutive equation was established. Results of further analysis of the creep mechanism of the alloy at different temperatures indicated that the creep mechanism of 2219 aluminum alloy differed at different temperatures; and creek characteristics were presented in three stages at different temperatures, i.e., the grain boundary sliding creep mechanism at a low temperature stage (T < 373 K, the dislocation glide creep mechanism at a medium temperature stage (373 K ≤ T < 418 K, and the dislocation climb creep mechanism at a high temperature stage (T ≥ 418 K. By comparative analysis of the fitting results and experiment data, they were found to be in agreement with the experimental data, revealing that the established creep constitutive equation is suitable for different temperatures and stresses.

Advanced powder metallurgy aluminum alloys via rapid solidification technology, phase 2

Science.gov (United States)

Ray, Ranjan; Jha, Sunil C.

1987-01-01

Marko's rapid solidification technology was applied to processing high strength aluminum alloys. Four classes of alloys, namely, Al-Li based (class 1), 2124 type (class 2), high temperature Al-Fe-Mo (class 3), and PM X7091 type (class 4) alloy, were produced as melt-spun ribbons. The ribbons were pulverized, cold compacted, hot-degassed, and consolidated through single or double stage extrusion. The mechanical properties of all four classes of alloys were measured at room and elevated temperatures and their microstructures were investigated optically and through electron microscopy. The microstructure of class 1 Al-Li-Mg alloy was predominantly unrecrystallized due to Zr addition. Yield strengths to the order of 50 Ksi were obtained, but tensile elongation in most cases remained below 2 percent. The class 2 alloys were modified composition of 2124 aluminum alloy, through addition of 0.6 weight percent Zr and 1 weight percent Ni. Nickel addition gave rise to a fine dispersion of intermetallic particles resisting coarsening during elevated temperature exposure. The class 2 alloy showed good combination of tensile strength and ductility and retained high strength after 1000 hour exposure at 177 C. The class 3 Al-Fe-Mo alloy showed high strength and good ductility both at room and high temperatures. The yield and tensile strength of class 4 alloy exceeded those of the commercial 7075 aluminum alloy.

Structural and magnetic properties of Fe{sub x}Ni{sub 100−x} alloys synthesized using Al as a reducing metal

Energy Technology Data Exchange (ETDEWEB)

Srakaew, N. [Department of Physics, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand); Jantaratana, P., E-mail: fscipsj@ku.ac.th [Department of Physics, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand); Nipakul, P. [Department of Physics, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand); Sirisathitkul, C. [Molecular Technology Research Unit, School of Science, Walailak University, Nakhon Si Thammarat 80161 (Thailand)

2017-08-01

Highlights: • Reduction by aluminum is a simple and safe route to synthesize iron-nickel alloys. • Alloy compositions with up to 90 at.% Fe can be obtained with minimal oxidation. • Morphology and magnetic properties are varied with the alloy composition. - Abstract: Iron-nickel (Fe-Ni) alloys comprising nine different compositions were rapidly synthesized from the redox reaction using aluminum foils as the reducing metal. Compared with conventional chemical syntheses, this simple approach is relatively safe and allows control over the alloy morphology and magnetic behavior as a function of the alloy composition with minimal oxidation. For alloys having low (10%–30%) Fe content the single face-centered cubic (FCC) FeNi{sub 3} phase was formed with nanorods aligned in the (1 1 1) crystalline direction on the cluster surface. This highly anisotropic morphology gradually disappeared as the Fe content was raised to 40%–70% with the alloy structure possessing a mixture of FCC FeNi{sub 3} and body-centered cubic (BCC) Fe{sub 7}Ni{sub 3}. The FCC phase was entirely replaced by the BCC structure upon further increase the Fe content to 80%–90%. The substitution of Ni by Fe in the crystals and the dominance of the BCC phase over the FCC structure gave rise to enhanced magnetization. By contrast, the coercive field decreased as a function of increasing Fe because of the reduction in shape anisotropy and the rise of saturation magnetization.

Influence of Iron in AlSi10MgMn Alloy

Directory of Open Access Journals (Sweden)

Žihalová M.

2014-12-01

Full Text Available Presence of iron in Al-Si cast alloys is common problem mainly in secondary (recycled aluminium alloys. Better understanding of iron influence in this kind of alloys can lead to reduction of final castings cost. Presented article deals with examination of detrimental iron effect in AlSi10MgMn cast alloy. Microstructural analysis and ultimate tensile strength testing were used to consider influence of iron to microstructure and mechanical properties of selected alloy.

Corrosion of aluminum alloys in simulated dry storage environments

International Nuclear Information System (INIS)

Peacock, H.B. Jr.; Sindelar, R.L.; Lam, P.S.

1996-01-01

The effect of temperature and relative humidity on the high temperature (up to 150 degrees C) corrosion of aluminum alloys was investigated for dry storage of spent nuclear fuels in a closed or sealed system. A dependency on alloy type, temperature and initial humidity was determined for 1100, 5052 and 6061 aluminum alloys. Results after 4500 hours of environmental testing show that for a closed system, corrosion tends to follow a power law with the rate decreasing with increasing exposure. As corrosion takes place, two phenomena occur: (1) a hydrated layer builds up to resist corrosion, and (2) moisture is depleted from the system and the humidity slowly decreases with time. At a critical level of relative humidity, corrosion reactions stop, and no additional corrosion occurs if the system remains closed. The results form the basis for the development of an acceptance criteria for the dry storage of aluminum clad spent nuclear fuels

Effects of silicon, copper and iron on static and dynamic properties of alloy 206 (aluminum-copper) in semi-solids produced by the SEED process

Science.gov (United States)

Lemieux, Alain

The advantages of producing metal parts by rheocasting are generally recognised for common foundry alloys of Al-Si. However, other more performing alloys in terms of mechanical properties could have a great interest in specialized applications in the automotive industry, while remaining competitive in the forming. Indeed, the growing demand for more competitive products requires the development of new alloys better suited to semi-solid processes. Among others, Al-Cu alloys of the 2XX series are known for their superior mechanical strength. However, in the past, 2XX alloys were never candidates for pressure die casting. The main reason is their propensity to hot tearing. Semi-solid processes provide better conditions for molding with the rheological behavior of dough and molding temperatures lower reducing this type of defect. In the initial phase, this research has studied factors that reduce hot tearing susceptibility of castings produced by semi-solid SEED of alloy 206. Subsequently, a comparative study on the tensile properties and fatigue was performed on four variants of the alloy 206. The results of tensile strength and fatigue were compared with the specifications for applications in the automotive industry and also to other competing processes and alloys. During this study, several metallurgical aspects were analyzed. The following main points have been validated: i) the main effects of compositional variations of silicon, iron and copper alloy Al-Cu (206) on the mechanical properties, and ii) certain relationships between the mechanism of hot cracking and the solidification rate in semi-solid. Parts produced from the semi-solid paste coming from the SEED process combined with modified 206 alloys have been successfully molded and achieved superior mechanical properties than the requirements of the automotive industry. The fatigue properties of the two best modified 206 alloys were higher than those of A357 alloy castings and are close to those of the

Cast and hipped gamma titanium aluminum alloys modified by chromium, boron, and tantalum

International Nuclear Information System (INIS)

Huang, Shyhchin.

1993-01-01

A cast body is described of a chromium, boron, and tantalum modified titanium aluminum alloy, said alloy consisting essentially of titanium, aluminum, chromium, boron, and tantalum in the following approximate atomic ratio: Ti-Al 45-50 Cr 1-3 Ta 1-8 B 0.1-0.3 , and said alloy having been prepared by casting the alloy to form said cast body and by HIPping said body

Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

Science.gov (United States)

Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

2016-11-05

Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption. Copyright © 2016 Elsevier B.V. All rights reserved.

Corrosion of aluminum alloys in a reactor disassembly basin

International Nuclear Information System (INIS)

Howell, J.P.; Zapp, P.E.; Nelson, D.Z.

1992-01-01

This document discusses storage of aluminum clad fuel and target tubes of the Mark 22 assembly takes place in the concrete-lined, light-water-filled, disassembly basins located within each reactor area at the Savannah River Site (SRS). A corrosion test program has been conducted in the K-Reactor disassembly basin to assess the storage performance of the assemblies and other aluminum clad components in the current basin environment. Aluminum clad alloys cut from the ends of actual fuel and target tubes were originally placed in the disassembly water basin in December 1991. After time intervals varying from 45--182 days, the components were removed from the basin, photographed, and evaluated metallographically for corrosion performance. Results indicated that pitting of the 8001 aluminum fuel clad alloy exceeded the 30-mil (0.076 cm) cladding thickness within the 45-day exposure period. Pitting of the 1100 aluminum target clad alloy exceeded the 30-mil (0.076 cm) clad thickness in 107--182 days exposure. The existing basin water chemistry is within limits established during early site operations. Impurities such as Cl - , NO 3 - and SO 4 - are controlled to the parts per million level and basin water conductivity is currently 170--190 μmho/cm. The test program has demonstrated that the basin water is aggressive to the aluminum components at these levels. Other storage basins at SRS and around the US have successfully stored aluminum components for greater than ten years without pitting corrosion. These basins have impurity levels controlled to the parts per billion level (1000X lower) and conductivity less than 1.0 μmho/cm

Effects of Be, Sr, Fe and Mg interactions on the microstructure and mechanical properties of aluminum based aeronautical alloys

Science.gov (United States)

Ibrahim, Mohamed Fawzy

The present work was carried out on a series of heat-treatable aluminum-based aeronautical alloys containing various amounts of magnesium (Mg), iron (Fe), strontium (Sr) and beryllium (Be). Tensile test bars (dendrite arm spacing ~ 24mum) were solutionized for either 5 or 12 hours at 540°C, followed by quenching in warm water (60°C). Subsequently, these quenched samples were aged at 160°C for times up to 12 hours. Microstructural assessment was performed. All heat-treated samples were pulled to fracture at room temperature using a servo-hydraulic tensile testing machine. The results show that Be causes partial modification of the eutectic silicon (Si) particles similar to that reported for Mg addition. Addition of 0.8 wt.% Mg reduced the eutectic temperature by ~10°C. During solidification of alloys containing high levels of Fe and Mg, without Sr, a peak corresponding to the formation of a Be-Fe phase (Al8Fe2BeSi) was detected at 611°C. The Be-Fe phase precipitates in a script-like morphology. A new quinary eutectic-like reaction was observed to take place near the end of solidification of high Mg, high Fe, Be-containing alloys. This new reaction is composed mainly of fine particles of Si, Mg2Si, pi-Al 8Mg3FeSi6 and (Be-Fe) phases. The volume fraction of this reaction decreased with the addition of Sr. The addition of Be has a noticeable effect on decreasing the beta-phase length, or volume fraction, this effect may be limited by adding Sr. Beryllium addition also results in the precipitation of the beta-phase in a nodular form, which reduces the harmful effects of these intermetallics on the alloy mechanical properties. Increasing both Mg and Fe levels led to an increase in the amount of the pi-phase; increasing the iron content led to an increase in the volume fraction of the partially soluble beta- and pi-phases, while Mg2Si particles were completely dissolved. The beta-phase platelets were observed to undergo changes in their morphology due to the

Pore structure and mechanical properties of directionally solidified porous aluminum alloys

Directory of Open Access Journals (Sweden)

Komissarchuk Olga

2014-01-01

Full Text Available Porous aluminum alloys produced by the metal-gas eutectic method or GASAR process need to be performed under a certain pressure of hydrogen, and to carry over melt to a tailor-made apparatus that ensures directional solidification. Hydrogen is driven out of the melt, and then the quasi-cylindrical pores normal to the solidification front are usually formed. In the research, the effects of processing parameters (saturation pressure, solidification pressure, temperature, and holding time on the pore structure and porosity of porous aluminum alloys were analyzed. The mechanical properties of Al-Mg alloys were studied by the compressive tests, and the advantages of the porous structure were indicated. By using the GASAR method, pure aluminum, Al-3wt.%Mg, Al-6wt.%Mg and Al-35wt.%Mg alloys with oriented pores have been successfully produced under processing conditions of varying gas pressure, and the relationship between the final pore structure and the solidification pressure, as well as the influences of Mg quantity on the pore size, porosity and mechanical properties of Al-Mg alloy were investigated. The results show that a higher pressure of solidification tends to yield smaller pores in aluminum and its alloys. In the case of Al-Mg alloys, it was proved that with the increasing of Mg amount, the mechanical properties of the alloys sharply deteriorate. However, since Al-3%Mg and Al-6wt.%Mg alloys are ductile metals, their porous samples have greater compressive strength than that of the dense samples due to the existence of pores. It gives the opportunity to use them in industry at the same conditions as dense alloys with savings in weight and material consumption.

Interactions between drops of a molten aluminum-lithium alloy and liquid water

International Nuclear Information System (INIS)

Nelson, L.S.

1994-01-01

In certain hypothesized nuclear reactor accident scenarios, 1- to 10-g drops of molten aluminum-lithium alloys might contact liquid water. Because vigorous steam explosions have occurred when large amounts of molten aluminum-lithium alloys were released into water or other coolants, it becomes important to know whether there will be explosions if smaller amounts of these molten alloys similarly come into contact with water. Therefore, the authors released drops of molten Al-3.1 wt pct Li alloy into deionized water at room temperature. The experiments were performed at local atmospheric pressure (0.085 MPa) without pressure transient triggers applied to the water. The absence of these triggers allowed them to (a) investigate whether spontaneous initiation of steam explosions would occur with these drops and (b) study the alloy-water chemical reactions. The drop sizes and melt temperatures were chosen to simulate melt globules that might form during the hypothesized melting of the aluminum-lithium alloy components

Corrosion properties of aluminum based alloys deposited by ion beam assisted deposition

International Nuclear Information System (INIS)

Enders, B.; Krauss, S.; Wolf, G.K.

1994-01-01

The replacement of cadmium coatings by other protective measures is an important task because of the environmentally detrimental properties of cadmium. Therefore, aluminum and aluminum alloy coatings containing elements such as silicon or magnesium with more positive or negative positions in the galvanic series in relation to pure aluminum were deposited by ion beam assisted deposition onto glass and low carbon steel. Pure aluminum films were deposited onto low carbon steel in order to study the influence of the ion-to-atom arrival ratio and the angle of ion incidence on the corrosion properties. For examination of the pitting behavior as a function of the concentration of alloying element, quasipotentiostatic current-potential and potentiostatic current-time plots were measured in chlorine-containing acetate buffer. It is shown that these alloys can protect steel substrates under uniform and pitting corrosion conditions considerably better than pure aluminum coatings. ((orig.))

Effect of diluted alloying elements on mechanical properties of iron

International Nuclear Information System (INIS)

Hassan, A.A.S.

1996-01-01

Iron and its alloys have extensive applications. The effect of solute additions on mechanical properties of iron was investigated to check the efficiency of solute atoms on strength and surface e life. Additions in the range of 0.1 wt.% and 0.3 wt.% of alloying elements of Cu,Ni and Si were used. Samples of grains size ranged from 6-40 m which have been prepared by annealing followed by furnace cooling. The recrystallization temperature increases with alloying addition (475 degree C for Fe-0.3 wt. % C alloy compared to 375 degree C for pure iron). Si and Cu additions inhibit grain growth of iron whereas Ni addition enhances it.Addition of Si or Ni to iron induced softening below room temperature whereas addition of Cu caused hardening. The work hardening parameters decreased due to alloying additions. The strength coefficient K was 290 M N/m2 for Fe-03 wt % Ni compared to 340 M N/m2 for pure iron. The work hardening exponent n is 0.12 for fe-0.3 wt. Cu alloy compared to 0.17 for pure iron. All the investigated alloys fulfilled the Hall-Petch relation at liquid Nitrogen and at room temperature. Alloying addition which caused softening addition which caused hardening increased the Half-Petch parameters. Ni addition favors ductility of iron whereas Cu addition reduces it. Alloying additions generally lead to brittle fracture and decrease the crack resistance of iron. 9 tabs., 55 figs., 103 refs

Microarc Oxidation of the High-Silicon Aluminum AK12D Alloy

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S. K. Kiseleva

2015-01-01

Full Text Available The aim of work is to study how the high-silicon aluminum AK12D alloy microstructure and MAO-process modes influence on characteristics (microhardness, porosity and thickness of the oxide layer of formed surface layer.Experimental methods of study:1 MAO processing of AK12D alloy disc-shaped samples. MAO modes features are concentration of electrolyte components – soluble water glass Na2SiO3 and potassium hydroxide (KOH. The content of two components both the soluble water glass and the potassium hydroxide was changed at once, with their concentration ratio remaining constant;2 metallographic analysis of AK12D alloy structure using an optical microscope «Olympus GX51»;3 image analysis of the system "alloy AK12D - MAO - layer" using a scanning electron microscope «JEOL JSM 6490LV»;4 hardness evaluation of the MAO-layers using a micro-hardness tester «Struers Duramin».The porosity, microhardness and thickness of MAO-layer formed on samples with different initial structures are analyzed in detail. Attention is paid to the influence of MAO process modes on the quality layer.It has been proved that the MAO processing allows reaching quality coverage with high microhardness values of 1200-1300HV and thickness up to 114 μm on high-silicon aluminum alloy. It has been found that the initial microstructure of alloy greatly affects the thickness of the MAO - layer. The paper explains the observed effect using the physical principles of MAO process and the nature of silicon particles distribution in the billet volume.It has been shown that increasing concentration of sodium silicate and potassium hydroxide in the electrolyte results in thicker coating and high microhardness.It has been revealed that high microhardness is observed in the thicker MAO-layers.Conclusions:1 The microstructure of aluminum AK12D alloy and concentration of electrolyte components - liquid glass Na2SiO3 and potassium hydroxide affect the quality of coating resulted from MAO

Phosphorus, iron, and aluminum losses in runoff from a rotationally-grazed pasture in Georgia, USA

Science.gov (United States)

Pastures can be a source of phosphorus (P) contributing to eutrophication and impairment of water resources. Phosphorus is tightly held in soils that are highly weathered, acidic, and with high iron (Fe) and aluminum (Al) content like the Ultisols of southeastern USA. We used 11-yr (1999-2009) of da...

Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy

Science.gov (United States)

Li, Song-mei; Li, Ying-dong; Zhang, You; Liu, Jian-hua; Yu, Mei

2015-02-01

Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.

Aerospace Patented High-Strength Aluminum Alloy Used in Commercial Industries

Science.gov (United States)

2004-01-01

NASA structural materials engineers at Marshall Space Flight Center (MSFC) in Huntsville, Alabama developed a high-strength aluminum alloy for aerospace applications with higher strength and wear-resistance at elevated temperatures. The alloy is a solution to reduce costs of aluminum engine pistons and lower engine emissions for the automobile industry. The Boats and Outboard Engines Division at Bombardier Recreational Products of Sturtevant, Wisconsin is using the alloy for pistons in its Evinrude E-Tec outboard, 40-90 horsepower, engine line. The alloy pistons make the outboard motor quieter and cleaner, while improving fuel mileage and increasing engine durability. The engines comply with California Air resources Board emissions standards, some of the most stringent in the United States. (photo credit: Bombardiier Recreational Products)

A modified Johnson–Cook model of dynamic tensile behaviors for 7075-T6 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ding-Ni, E-mail: siping4840@126.com [The College of Information, Mechanical and Electrical Engineering, Shanghai Normal University, Shanghai 200234 (China); Shangguan, Qian-Qian [The College of Information, Mechanical and Electrical Engineering, Shanghai Normal University, Shanghai 200234 (China); Xie, Can-Jun [Commercial Aircraft Corporation of China, Ltd., Shanghai 200120 (China); Liu, Fu [Shanghai Aircraft Design and Research Institute of COMAC, Shanghai 201210 (China)

2015-01-15

Highlights: • The dynamic mechanical behaviors at various strain rates were measured. • The strain rate hardening effect of 7075-T6 aluminum alloy is significant. • A new Johnson–Cook constitutive model of 7075-T6 aluminum alloy was obtained. • Numerical simulations of tensile tests at different rates were conducted. • Accuracy of the modified Johnson–Cook constitutive equation was proved. - Abstract: The dynamic mechanical behaviors of 7075-T6 aluminum alloy at various strain rates were measured by dynamic tensile tests using the electronic universal testing machine, high velocity testing system and split Hopkinson tensile bar (SHTB). Stress–strain curves at different rates were obtained. The results show that the strain rate hardening effect of 7075-T6 aluminum alloy is significant. By modifying the strain rate hardening term in the Johnson–Cook constitutive model, a new Johnson–Cook (JC) constitutive model of 7075-T6 aluminum alloy was obtained. The improved Johnson–Cook model matched the experiment results very well. With the Johnson–Cook constitutive model, numerical simulations of tensile tests at different rates for 7075-T6 aluminum alloy were conducted. According to tensile loading and stress–strain relation of 7075-T6 aluminum alloy, calculation results were compared with experimental results. Accuracy of the modified Johnson–Cook constitutive equation was further proved.

A modified Johnson–Cook model of dynamic tensile behaviors for 7075-T6 aluminum alloy

International Nuclear Information System (INIS)

Zhang, Ding-Ni; Shangguan, Qian-Qian; Xie, Can-Jun; Liu, Fu

2015-01-01

Highlights: • The dynamic mechanical behaviors at various strain rates were measured. • The strain rate hardening effect of 7075-T6 aluminum alloy is significant. • A new Johnson–Cook constitutive model of 7075-T6 aluminum alloy was obtained. • Numerical simulations of tensile tests at different rates were conducted. • Accuracy of the modified Johnson–Cook constitutive equation was proved. - Abstract: The dynamic mechanical behaviors of 7075-T6 aluminum alloy at various strain rates were measured by dynamic tensile tests using the electronic universal testing machine, high velocity testing system and split Hopkinson tensile bar (SHTB). Stress–strain curves at different rates were obtained. The results show that the strain rate hardening effect of 7075-T6 aluminum alloy is significant. By modifying the strain rate hardening term in the Johnson–Cook constitutive model, a new Johnson–Cook (JC) constitutive model of 7075-T6 aluminum alloy was obtained. The improved Johnson–Cook model matched the experiment results very well. With the Johnson–Cook constitutive model, numerical simulations of tensile tests at different rates for 7075-T6 aluminum alloy were conducted. According to tensile loading and stress–strain relation of 7075-T6 aluminum alloy, calculation results were compared with experimental results. Accuracy of the modified Johnson–Cook constitutive equation was further proved

Microcapillary Features in Silicon Alloyed High-Strength Cast Iron

Directory of Open Access Journals (Sweden)

R.K. Hasanli

2017-04-01

Full Text Available Present study explores features of silicon micro capillary in alloyed high-strength cast iron with nodular graphite (ductile iron produced in metal molds. It identified the nature and mechanism of micro liquation of silicon in a ductile iron alloyed with Nickel and copper, and demonstrated significant change of structural-quality characteristics. It was concluded that the matrix of alloyed ductile iron has a heterogeneous structure with cross reinforcement and high-silicon excrement areas.

Evaluation of Sc-Bearing Aluminum Alloy C557 for Aerospace Applications

Science.gov (United States)

Domack, Marcia S.; Dicus, Dennis L.

2002-01-01

The performance of the Al-Mg-Sc alloy C557 was evaluated to assess its potential for a broad range of aerospace applications, including airframe and launch vehicle structures. Of specific interest were mechanical properties at anticipated service temperatures and thermal stability of the alloy. Performance was compared with conventional airframe aluminum alloys and with other emerging aluminum alloys developed for specific service environments. Mechanical properties and metallurgical structure were evaluated for commercially rolled sheet in the as-received H116 condition and after thermal exposures at 107 C. Metallurgical analyses were performed to de.ne grain morphology and texture, strengthening precipitates, and to assess the effect of thermal exposure.

Anti-icing/frosting and self-cleaning performance of superhydrophobic aluminum alloys

Science.gov (United States)

Feng, Libang; Yan, Zhongna; Shi, Xueting; Sultonzoda, Firdavs

2018-02-01

Ice formation and frost deposition on cryogenic equipment and systems can result in serious problems and huge economic loss. Hence, it is quite necessary to develop new materials to prevent icing and frosting on cold surfaces in engineering fields. Here, a superhydrophobic aluminum alloy with enhanced anti-frosting, anti-icing, and self-cleaning performance has been developed by a facile one-step method. The anti-frosting/icing performance of superhydrophobic aluminum alloys is confirmed by frosting/icing time delay, consolidating and freezing temperature reduction, and lower amount of frost/ice adhesion. Meanwhile, the excellent self-cleaning performance is authenticated by the fact that simulated pollution particles can be cleaned out by rolling water droplets completely. Finally, based on the classical nucleation theory, anti-icing and anti-frosting mechanisms of the superhydrophobic aluminum alloys are deduced. Results show that grounded on "air cushion" and "heat insulation" effect, a larger nucleation barrier and a lower crystal growth rate can be observed, which, hence, inhibit ice formation and frost deposition. It can be concluded that preparing superhydrophobic surfaces would be an effective strategy for improving anti-icing, anti-frosting, and self-cleaning performance of aluminum alloys.

Preparation of rare earth and other metal alloys containing aluminum and silicon

International Nuclear Information System (INIS)

Mitchell, A.; Goldsmith, J.R.; Gray, M.

1981-01-01

A method is provided for making alloys of aluminum and silicon with a third metal which may be a rare earth or a member of groups 4b, 5b, or 6b of the periodic table. The flux system CaF 2 -CaO-Al 2 O 3 is used as a solvent to provide a reactive medium for the alloy-forming reactions. Aluminum is supplied as a reducing agent, and silicon is added as a sink for the alloying metal. The resulting alloy may be used in steels. (L.L.)

Addition of iron for the removal of the {beta}-AlFeSi intermetallic by refining of {alpha}-AlFeSi phase in an Al-7.5Si-3.6Cu alloy

Energy Technology Data Exchange (ETDEWEB)

Belmares-Perales, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Zaldivar-Cadena, A.A., E-mail: azaldiva70@hotmail.com [Facultad de Ingenieria Civil, Departamento de Ecomateriales y Energia, Instituto de Ingenieria Civil, Av. Fidel Velasquez and Av. Universidad S/N, Cd. Universitaria, San Nicolas de los Garza, N.L. 66450 (Mexico)

2010-10-25

Addition of iron into the molten metal for the removal of the {beta}-AlFeSi intermetallic by refining of {alpha}-AlFeSi phase has been studied. Solidification conditions and composition determine the final microstructure and mechanical properties of a casting piece. It is known that increasing the iron content will produce an increasing of the {alpha}-AlFeSi and {beta}-AlFeSi phases. This phenomenon was confirmed with calculations made by Thermo-Calc{sup TM} software and validated with experimental results, however, the technique of iron addition in this study plays an important role on the solidification kinetics of these iron phases because the refining of {alpha}-AlFeSi and removal of {beta}-AlFeSi phases can be improved. Final results showed an improvement in mechanical properties by removal and refining of {beta}-AlFeSi and {alpha}-AlFeSi phases, respectively. This study shows a new method of removal of {beta}-AlFeSi that could be adopted in the aluminum smelting industry in aluminum alloys with a low cooling rate with a secondary dendritic spacing of about 37 {mu}m.

Addition of iron for the removal of the β-AlFeSi intermetallic by refining of α-AlFeSi phase in an Al-7.5Si-3.6Cu alloy

International Nuclear Information System (INIS)

Belmares-Perales, S.; Zaldivar-Cadena, A.A.

2010-01-01

Addition of iron into the molten metal for the removal of the β-AlFeSi intermetallic by refining of α-AlFeSi phase has been studied. Solidification conditions and composition determine the final microstructure and mechanical properties of a casting piece. It is known that increasing the iron content will produce an increasing of the α-AlFeSi and β-AlFeSi phases. This phenomenon was confirmed with calculations made by Thermo-Calc TM software and validated with experimental results, however, the technique of iron addition in this study plays an important role on the solidification kinetics of these iron phases because the refining of α-AlFeSi and removal of β-AlFeSi phases can be improved. Final results showed an improvement in mechanical properties by removal and refining of β-AlFeSi and α-AlFeSi phases, respectively. This study shows a new method of removal of β-AlFeSi that could be adopted in the aluminum smelting industry in aluminum alloys with a low cooling rate with a secondary dendritic spacing of about 37 μm.

Iron aluminide useful as electrical resistance heating elements

Science.gov (United States)

Sikka, V.K.; Deevi, S.C.; Fleischhauer, G.S.; Hajaligol, M.R.; Lilly, A.C. Jr.

1997-04-15

The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, {=}0.05% Zr or ZrO{sub 2} stringers extending perpendicular to an exposed surface of the heating element or {>=}0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, {<=}2% Ti, {<=}2% Mo, {<=}1% Zr, {<=}1% C, {<=}0.1% B, {<=}30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, {<=}1% rare earth metal, {<=}1% oxygen, {<=}3% Cu, balance Fe. 64 figs.

Study of aluminum content in a welding metal by thermoelectric measurements

Science.gov (United States)

Carreón, H.; Ramirez, S.; Coronado, C.; Salazar, M.

2018-03-01

This work investigates the effect caused by the aluminum content in a welding metal and its variation in mechanical properties through the use of a non-destructive thermoelectric technique. It is known that aluminum has positive effects as deoxidizer in low percentages and alloying element together with Niobium and Vanadium. Aluminum has a positive and negative effect, initially improves the mechanical properties of the metal, as it acts as a grain refiner, increasing the yield strength, but in larger quantities, important mechanical properties such as hardness and toughness are seriously affected. For this purpose, HSLA ASTM 572 Gr. 50 steel was used as the base metal, where the weld metal was deposited, after which the specimens were fabricated and the mechanical tests and non-destructive tests were carried out. The sensitivity of the thermoelectric potential technique to microstructural and chemical composition changes was confirmed. The evolution of absolute thermoelectric potential (TEP) values with respect to the percentage of aluminum added to the weld was observed, being also quite sensitive to defects such as micro-cracks.

Laser Surface Alloying of Aluminum for Improving Acid Corrosion Resistance

Science.gov (United States)

Jiru, Woldetinsay Gutu; Sankar, Mamilla Ravi; Dixit, Uday Shanker

2018-04-01

In the present study, laser surface alloying of aluminum with magnesium, manganese, titanium and zinc, respectively, was carried out to improve acid corrosion resistance. Laser surface alloying was conducted using 1600 and 1800 W power source using CO2 laser. Acid corrosion resistance was tested by dipping the samples in a solution of 2.5% H2SO4 for 200 h. The weight loss due to acid corrosion was reduced by 55% for AlTi, 41% for AlMg alloy, 36% for AlZn and 22% for AlMn alloy. Laser surface alloyed samples offered greater corrosion resistance than the aluminum substrate. It was observed that localized pitting corrosion was the major factor to damage the surface when exposed for a long time. The hardness after laser surface alloying was increased by a factor of 8.7, 3.4, 2.7 and 2 by alloying with Mn, Mg, Ti and Zn, respectively. After corrosion test, hardness was reduced by 51% for AlTi sample, 40% for AlMg sample, 41.4% for AlMn sample and 33% for AlZn sample.

Mechanical behavior of aluminum-lithium alloys at cryogenic temperatures

International Nuclear Information System (INIS)

Glazer, J.; Verzasconi, S.L.; Sawtell, R.R.; Morris, J.W. Jr.

1987-01-01

The cryogenic mechanical properties of aluminum-lithium alloys are of interest because these alloys are attractive candidate materials for cryogenic tankage. Previous work indicates that the strength-toughness relationship for alloy 2090-T81 (Al-2.7Cu-2.2Li-0.12Zr by weight) improves significantly as temperature decreases. The subject of this investigation is the mechanism of this improvement. Deformation behavior was studied since the fracture morphology did not change with temperature. Tensile failures in 2090-T81 and -T4 occur at plastic instability. In contrast, in the binary aluminum-lithium alloy studied here they occur well before plastic instability. For all three materials, the strain hardening rate in the longitudinal direction increases as temperature decreases. This increase is associated with an improvement in tensile elongation at low temperatures. In alloy 2090-T4, these results correlate with a decrease in planar slip at low temperatures. The improved toughness at low temperatures is believed to be due to increased stable deformation prior to fracture

A study of hydrogen permeation in aluminum alloy treated by various oxidation processes

International Nuclear Information System (INIS)

Song Wenhai; Long Bin

1997-01-01

A set of oxide coatings was formed on the surface of an Al alloy (wt%: Fe, 0.24; Si, 1.16; Cu, 0.05-0.2; Zn, 0.1; Al, residual) by means of various oxidation processes. The hydrogen permeability through the aluminum alloy and its coating materials was determined by a vapor phase permeation technique at temperatures ranging from 400 to 500 C using high-purity H 2 (99.9999%) gas with an upstream hydrogen pressure of 10 4 -10 5 Pa. The experimental results show that the hydrogen permeability through aluminum oxide coating is 100-2000 times lower than that through the aluminum alloy substrate. This means that the aluminum oxide is a significant hydrogen permeation barrier. A high hydrogen permeation resistance was observed in an oxide layer prefilmed in 200 C water, while an anodized aluminum oxide film had a less obstructive effect, possibly caused by the porous structure of the anodic oxide. The hydrogen permeability through films of aluminum oxide was not a simple function of the aluminum-oxide phase configuration. (orig.)

Effect of alloying elements on characteristics of iron passive state in sulfuric acid

International Nuclear Information System (INIS)

Rejes Jola, O.; Mustafa-Zade, F.M.; Sukhotin, A.M.; Tchannikova, O.A.

1981-01-01

The curves of anodic polarization of iron binary alloys with Cr, Mo, W, Ni, Si, Co, Mn, Re, Ti, Al, Cu, Bi, Zn, In, V, Sb, Ta, Hf, Pb, Sn, Zr, Nb, Ce, B, P, S in 0.5 MH 2 SO 4 are studied. Passivation potentials, potentials of total passivation, transpassivity and current density are determined in the passivity region. All alloys had alpha-structure, the content of alloying elements was close to solubility in solid solution. Elements are classified according to the type of their effect on passive state of iron. Character of this effect does not have a direct connection with passivation ability the elements themselves, it is determined, probably, by a possibility to form stable passivating ruixed oxides of the ferrospinel type [ru

Solidification paths of multicomponent monotectic aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Mirkovic, Djordje; Groebner, Joachim [Clausthal University of Technology, Institute of Metallurgy, Robert-Koch-Street 42, D-38678 Clausthal-Zellerfeld (Germany); Schmid-Fetzer, Rainer [Clausthal University of Technology, Institute of Metallurgy, Robert-Koch-Street 42, D-38678 Clausthal-Zellerfeld (Germany)], E-mail: schmid-fetzer@tu-clausthal.de

2008-10-15

Solidification paths of three ternary monotectic alloy systems, Al-Bi-Zn, Al-Sn-Cu and Al-Bi-Cu, are studied using thermodynamic calculations, both for the pertinent phase diagrams and also for specific details concerning the solidification of selected alloy compositions. The coupled composition variation in two different liquids is quantitatively given. Various ternary monotectic four-phase reactions are encountered during solidification, as opposed to the simple binary monotectic, L' {yields} L'' + solid. These intricacies are reflected in the solidification microstructures, as demonstrated for these three aluminum alloy systems, selected in view of their distinctive features. This examination of solidification paths and microstructure formation may be relevant for advanced solidification processing of multicomponent monotectic alloys.

The characteristics of aluminum-scandium alloys processed by ECAP

International Nuclear Information System (INIS)

Venkateswarlu, K.; Rajinikanth, V.; Ray, Ajoy Kumar; Xu Cheng; Langdon, Terence G.

2010-01-01

Aluminum-scandium alloys were prepared having different scandium additions of 0.2, 1.0 and 2.0 wt.% and these alloys were processed by equal-channel angular pressing (ECAP) at 473 K. The results show the grain refinement of the aluminum matrix and the morphology of the Al 3 Sc precipitates depends strongly on the scandium concentration. The tensile properties were evaluated after ECAP by pulling to failure at initial strain rates from 1.0 x 10 -3 to 1.0 x 10 -1 s -1 . The Al-1% Sc alloy exhibited the highest tensile strength of ∼250 MPa at a strain rate of 1.0 x 10 -1 s -1 . This alloy also exhibited a superior grain refinement of ∼0.4 μm after ECAP where this is attributed to a smaller initial grain size and an optimum volume fraction of dispersed Al 3 Sc precipitates having both micrometer and nanometer sizes.

Friction stir welding process to repair voids in aluminum alloys

Science.gov (United States)

Rosen, Charles D. (Inventor); Litwinski, Edward (Inventor); Valdez, Juan M. (Inventor)

1999-01-01

The present invention provides an in-process method to repair voids in an aluminum alloy, particularly a friction stir weld in an aluminum alloy. For repairing a circular void or an in-process exit hole in a weld, the method includes the steps of fabricating filler material of the same composition or compatible with the parent material into a plug form to be fitted into the void, positioning the plug in the void, and friction stir welding over and through the plug. For repairing a longitudinal void (30), the method includes machining the void area to provide a trough (34) that subsumes the void, fabricating filler metal into a strip form (36) to be fitted into the trough, positioning the strip in the trough, and rewelding the void area by traversing a friction stir welding tool longitudinally through the strip. The method is also applicable for repairing welds made by a fusing welding process or voids in aluminum alloy workpieces themselves.

Odontologic use of copper/aluminum alloys: mitochondrial respiration as sensitive parameter of biocompatibility

Directory of Open Access Journals (Sweden)

Rodrigues Luiz Erlon A.

2003-01-01

Full Text Available Copper/aluminum alloys are largely utilized in odontological restorations because they are less expensive than gold or platinum. However, tarnishing and important corrosion in intrabuccal prostheses made with copper/aluminum alloys after 28 days of use have been reported. Several kinds of food and beverage may attack and corrode these alloys. Copper is an essential component of several important enzymes directly involved in mitochondrial respiratory metabolism. Aluminum, in contrast, is very toxic and, when absorbed, plasma values as small as 1.65 to 21.55 mg/dl can cause severe lesions to the nervous system, kidneys, and bone marrow. Because mitochondria are extremely sensitive to minimal variation of cellular physiology, the direct relationship between the mitocondrial respiratory chain and cell lesions has been used as a sensitive parameter to evaluate cellular aggression by external agents. This work consisted in the polarographic study of mitochondrial respiratory metabolism of livers and kidneys of rabbits with femoral implants of titanium or copper/aluminum alloy screws. The experimental results obtained did not show physiological modifications of hepatic or renal mitochondria isolated from animals of the three experimental groups, which indicate good biocompatibility of copper/aluminum alloys and suggest their odontological use.

Microstructure Development and Characteristics of Semisolid Aluminum Alloys; FINAL

International Nuclear Information System (INIS)

Merton Flemings; Srinath Viswanathan

2001-01-01

A drop forge viscometer was employed to investigate the flow behavior under very rapid compression rates of A357, A356 diluted with pure aluminum and Al-4.5%Cu alloys. The A357 alloys were of commercial origin (MHD and SIMA) and the rheocast, modified A356 and Al-4.5Cu alloys were produced by a process developed at the solidification laboratory of MIT

Grain refinement of permanent mold cast copper base alloys. Final report

Energy Technology Data Exchange (ETDEWEB)

Sadayappan, M.; Thomson, J. P.; Elboujdaini, M.; Gu, G. Ping; Sahoo, M.

2004-04-29

Grain refinement behavior of copper alloys cast in permanent molds was investigated. This is one of the least studied subjects in copper alloy castings. Grain refinement is not widely practiced for leaded copper alloys cast in sand molds. Aluminum bronzes and high strength yellow brasses, cast in sand and permanent molds, were usually fine grained due to the presence of more than 2% iron. Grain refinement of the most common permanent mold casting alloys, leaded yellow brass and its lead-free replacement EnviroBrass III, is not universally accepted due to the perceived problem of hard spots in finished castings and for the same reason these alloys contain very low amounts of iron. The yellow brasses and Cu-Si alloys are gaining popularity in North America due to their low lead content and amenability for permanent mold casting. These alloys are prone to hot tearing in permanent mold casting. Grain refinement is one of the solutions for reducing this problem. However, to use this technique it is necessary to understand the mechanism of grain refinement and other issues involved in the process. The following issues were studied during this three year project funded by the US Department of Energy and the copper casting industry: (1) Effect of alloying additions on the grain size of Cu-Zn alloys and their interaction with grain refiners; (2) Effect of two grain refining elements, boron and zirconium, on the grain size of four copper alloys, yellow brass, EnviroBrass II, silicon brass and silicon bronze and the duration of their effect (fading); (3) Prediction of grain refinement using cooling curve analysis and use of this method as an on-line quality control tool; (4) Hard spot formation in yellow brass and EnviroBrass due to grain refinement; (5) Corrosion resistance of the grain refined alloys; (6) Transfer the technology to permanent mold casting foundries; It was found that alloying elements such as tin and zinc do not change the grain size of Cu-Zn alloys

Kinetic characterization and of recrystallization of the aluminum alloy 6063 after S work hardening treatment

International Nuclear Information System (INIS)

Esposito, Iara Maria

2006-01-01

The aluminum 6063 alloy possesses a great industrial interest, presenting characteristics that justify its frequent use, when compared to the other aluminum alloys: the precipitation hardening and high cold work capacity. These alloys present high ductility, that allows their use in operations with high deformation degrees, as the cold work. The objective of this work is to show comparative analysis of the hardness Vickers of the commercial aluminum 6063 alloy, after cold work with different area reduction degree and thermal treatment. Considering the frequent utilization aluminium 6063 alloy, this work studies the characterization and recrystallization of this alloy, after the plastic deformation in different area reduction degrees, thermal treatment and convenient treatment times - Thermo mechanic Treatments. (author)

Evaluation of microstructure of A356 aluminum alloy casting ...

Indian Academy of Sciences (India)

The objective of this investigation was to evaluate the effect of vibrations (during solidification) on the metallurgical properties of A356 aluminum casting. Mechanical vibrations were applied to A356 aluminum alloy through set up. A356 melt has been subjected to mechanical vibration with the frequency range from 0 to 400 ...

An improved stress corrosion test medium for aluminum alloys

Science.gov (United States)

Humphries, T. S.; Coston, J. E.

1981-01-01

A laboratory test method that is only mildly corrosive to aluminum and discriminating for use in classifying the stress corrosion cracking resistance of aluminum alloys is presented along with the method used in evaluating the media selected for testing. The proposed medium is easier to prepare and less expensive than substitute ocean water.

Method of preparing an electrode material of lithium-aluminum alloy

Science.gov (United States)

Settle, Jack L.; Myles, Kevin M.; Battles, James E.

1976-01-01

A solid compact having a uniform alloy composition of lithium and aluminum is prepared as a negative electrode for an electrochemical cell. Lithium losses during preparation are minimized by dissolving aluminum within a lithium-rich melt at temperatures near the liquidus temperatures. The desired alloy composition is then solidified and fragmented. The fragments are homogenized to a uniform composition by annealing at a temperature near the solidus temperature. After comminuting to fine particles, the alloy material can be blended with powdered electrolyte and pressed into a solid compact having the desired electrode shape. In the preparation of some electrodes, an electrically conductive metal mesh is embedded into the compact as a current collector.

Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y., E-mail: jean-yves.hihn@univ-fcomte.fr

2015-11-15

Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

International Nuclear Information System (INIS)

Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y.

2015-01-01

Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

Microstructure and Mechanical Properties of Al-5Mg-0.8Mn Alloys with Various Contents of Fe and Si Cast under Near-Rapid Cooling

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Yulin Liu

2017-10-01

Full Text Available Al-5Mg-0.8Mn alloys (AA5083 with various iron and silicon contents were cast under near-rapid cooling and rolled into sheets. The aim was to study the feasibility of minimizing the deteriorating level of the harmful Fe-rich phases on the mechanical properties through refining the intermetallics by significantly increasing the casting rate. The results showed that the size and density of the intermetallic particles that remained in the hot bands and the cold rolled sheets increased as the contents of iron and silicon in the alloys were increased. However, the increment of the particle sizes was limited due to the significant refinement of the intermetallics formed during casting under near-rapid cooling. The mechanical properties of the alloys reduced as the contents of iron and silicon in the alloys increased. However, the decrement of tensile strengths and ductility was quite small. Therefore, higher contents of iron and silicon could be used in the Al-5Mg-0.8Mn alloy (AA5083 alloy when the material is cast under near-rapid cooling, such as in the continuous strip casting process.

Role of iron and aluminum coagulant metal residuals and lead release from drinking water pipe materials.

Science.gov (United States)

Knowles, Alisha D; Nguyen, Caroline K; Edwards, Marc A; Stoddart, Amina; McIlwain, Brad; Gagnon, Graham A

2015-01-01

Bench-scale experiments investigated the role of iron and aluminum residuals in lead release in a low alkalinity and high (> 0.5) chloride-to-sulfate mass ratio (CSMR) in water. Lead leaching was examined for two lead-bearing plumbing materials, including harvested lead pipe and new lead: tin solder, after exposure to water with simulated aluminum sulfate, polyaluminum chloride and ferric sulfate coagulation treatments with 1-25-μM levels of iron or aluminum residuals in the water. The release of lead from systems with harvested lead pipe was highly correlated with levels of residual aluminum or iron present in samples (R(2) = 0.66-0.88), consistent with sorption of lead onto the aluminum and iron hydroxides during stagnation. The results indicate that aluminum and iron coagulant residuals, at levels complying with recommended guidelines, can sometimes play a significant role in lead mobilization from premise plumbing.

Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

Energy Technology Data Exchange (ETDEWEB)

Liu Wenyong, E-mail: lwy@iccas.ac.cn [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Luo Yuting; Sun Linyu [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Wu Ruomei, E-mail: cailiaodian2004@126.com [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Jiang Haiyun [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Liu Yuejun [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China)

2013-01-01

Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: Black-Right-Pointing-Pointer Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. Black-Right-Pointing-Pointer Superhydrophobic surfaces with a high water contact angle of 162 Degree-Sign and a low rolling angle of 2 Degree-Sign were obtained. Black-Right-Pointing-Pointer The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162 Degree-Sign and the sliding angle of 2 Degree-Sign was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed

Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

International Nuclear Information System (INIS)

Liu Wenyong; Luo Yuting; Sun Linyu; Wu Ruomei; Jiang Haiyun; Liu Yuejun

2013-01-01

Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: ► Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. ► Superhydrophobic surfaces with a high water contact angle of 162° and a low rolling angle of 2° were obtained. ► The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low

Coprecipitation of arsenate with metal oxides. 3. Nature, mineralogy, and reactivity of iron(III)-aluminum precipitates.

Science.gov (United States)

Violante, Antonio; Pigna, Massimo; Del Gaudio, Stefania; Cozzolino, Vincenza; Banerjee, Dipanjan

2009-03-01

Coprecipitation involving arsenic with aluminum or iron has been studied because this technique is considered particularly efficient for removal of this toxic element from polluted waters. Coprecipitation of arsenic with mixed iron-aluminum solutions has received scant attention. In this work we studied (i)the mineralogy, surface properties, and chemical composition of mixed iron-aluminum oxides formed at initial Fe/Al molar ratio of 1.0 in the absence or presence of arsenate [As/ Fe+Al molar ratio (R) of 0, 0.01, or 0.1] and at pH 4.0, 7.0, and 10.0 and aged for 30 and 210 days at 50 degrees C and (ii) the removal of arsenate from the coprecipitates after addition of phosphate. The amounts of short-range ordered precipitates (ferrihydrite, aluminous ferrihydrite and/or poorly crystalline boehmite) were greater than those found in iron and aluminum systems (studied in previous works), due to the capacity of both aluminum and arsenate to retard or inhibitthe transformation of the initially formed precipitates into well-crystallized oxides (gibbsite, bayerite, and hematite). As a consequence, the surface areas of the iron-aluminum oxides formed in the absence or presence of arsenate were usually much larger than those of aluminum or iron oxides formed under the same conditions. Arsenate was found to be associated mainly into short-range ordered materials. Chemical composition of all samples was affected by pH, initial R, and aging. Phosphate sorption was facilitated by the presence of short-range ordered materials, mainly those richer in aluminum, but was inhibited by arsenate present in the samples. The quantities of arsenate replaced by phosphate, expressed as percentages of its total amount present in the samples, were particularly low, ranging from 10% to 26%. A comparison of the desorption of arsenate by phosphate from aluminum-arsenate and iron-arsenate (studied in previous works) and iron-aluminum-arsenate coprecipitates evidenced that phosphate has a greater

Reshock Response of 2A12 Aluminum Alloy at High Pressures

International Nuclear Information System (INIS)

Ri-Li, Hou; Jian-Xiang, Peng; Fu-Qian, Jing; Jian-Hua, Zhang; Ping, Zhou

2009-01-01

By means of mounting the specimen on a low-impedance buffer, reshock experiments were carried out on a 2A12 aluminum alloy up to shock stresses of 67.6 GPa. Reshock wave profiles from the initial shock stresses of 60.9–67.6 GPa were measured with a velocity interferometer, and it shows that the 2A12 aluminum alloy characterizes as quasi-elastic response during recompression process. The Lagrange longitudinal velocities along the reloading path from initial shock state were obtained from two shots of experiments, while the bulk velocities at corresponding shock stresses were determined via extrapolating from the public reported unloading plastic sound velocities. Combining the reshock and the release experimental results, the yield strength of 2A12 aluminum alloy at shock stress of 60.9 GPa was estimated to be about 1.7 GPa

Fluoride Removal From Drinking Water by Electrocoagulation Using Iron and Aluminum Electrodes

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Takdastan

2014-07-01

Full Text Available Background Existence of fluoride in drinking water above the permissible level causes human skeletal fluorosis. Objectives Electrocoagulation by iron and aluminum electrodes was proposed for removing fluoride from drinking water. Materials and Methods Effects of different operating conditions such as treatment time, initial pH, applied voltage, type and number of electrodes, the spaces between aluminum and iron electrodes, and energy consumption during electrocoagulation were investigated in the batch reactor. Variable concentrations of fluoride solution were prepared by mixing proper amounts of sodium fluoride with deionized water. Results Experimental results showed that aluminum electrode is more effective in fluoride removal than iron, as in 40 minutes and initial pH of 7.5 at 20 V, the fluoride removal process reached to 97.86%. The final recommendable limit of fluoride (1.5 mg/L was obtained in 10 minutes at 20 V with the aluminum electrode. Conclusions In electrocoagulation with iron and aluminum electrodes, increase of voltage, number of electrodes and reaction time as well as decrease of the spaces between electrodes, enhanced the fluoride removal efficiency from drinking water. In addition the effect of pH and initial concentration of fluoride varied with types of electrodes.

Structure and mechanical properties of TiZr binary alloy after Al addition

International Nuclear Information System (INIS)

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

2013-01-01

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

Relation between feeding mechanisms and solidification mode in 380 aluminium alloy with different iron contents; Relacion entre los mecanismos de alimentacion y el modo de solidificacion en una aleacion de aluminio 380 con distintos contenidos de hierro

Energy Technology Data Exchange (ETDEWEB)

Tovio, D. O.; Gonzalez, A.C.; Mugica, G. W.; Cuyas, J. C.

2003-07-01

In the present work the effect of iron (0.15, 0.42 and 0.86%) content in feeding mechanisms for 380 aluminium alloy has been studied. The feeding capacity has been evaluated by a device that produces a barrier removable to allowing the movement of the inter dendritic liquid. The results show the flow of different quantity of liquid, it depends of the temperature of operating the device and of the iron content. For minimum and maximum iron content, the inter dendritic and bursts feeding mechanisms are fundamentally involved, for 0.42% of iron the feeding mechanisms was the inter dendritic. The authors establish this behavior by the solidification mode of alloy, which promotes the presence of particles of Si or plates of b-Al{sub 3}FeDi phase, in the inter dendritic channels and produce the different feeding mechanisms. (Author) 15 refs.

Study of nanodispersed aluminum and iron alcosols by photoacoustic spectroscopy

Science.gov (United States)

An, Vladimir; de Izarra, Charles; Saveliev, Gennady

2011-06-01

Nanodispersed aluminum and iron alcosols were prepared by ultrasonic dispersion of nanodispersed aluminum and iron powders in absolute ethanol. The photoacoustic signal (PAS) produced in modulated CO2 laser irradiation (1.026 and 1.096 kHz) of alcosols depends on the nature and method of nanoparticle fabrication and does not depend on their concentration in ethanol (within 1-5 g/l). Chemical interaction between metal nanoparticles and ethanol activated by laser irradiation or/and ultrasound is considered as the cause of the PAS.

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

Science.gov (United States)

McNamara, Cameron T.

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

Elastic and plastic properties of iron-aluminium alloys. Special problems raised by the brittleness of alloys of high aluminium content

International Nuclear Information System (INIS)

Mouturat, P.

1966-06-01

The present study embodies the results obtained with iron-aluminium alloys whose composition runs from 0 to nearly 50 atoms per cent aluminium. Conditions of elaboration and transformation have been studied successively, as well as the Young's modulus and the flow stress; the last chapter embodies, a study of the Portevin-le-Chatelier effect in alloys of 40 atoms per cent of aluminium. I) The principal difficulty to clear up consisted in the intergranular brittleness of ordered alloys; this brittleness has been considerably reduced with appropriate conditions of elaboration and transformation. II) The studies upon the Young's modulus are in connection with iron-aluminium alloys; transformation temperatures are well shown up. The formation of covalent bonds on and after 25 atoms per cent show the highest values of the modulus. III) The analysis of variations of the flow stress according to the temperature show some connection with ordered structures, the existence of antiphase domains and the existence of sur-structure dislocations. IV) In the ordered Fe Al domain the kinetics of the Portevin-le-Chatelier effect could be explained by a mechanism of diffusion of vacancies. The role they play has been specified by the influence they exert upon the dislocations; this has led us to the inhomogeneous Rudman order; this inhomogeneous order could explain the shape of the traction curves. (author) [fr

Molten aluminum alloy fuel fragmentation experiments

International Nuclear Information System (INIS)

Gabor, J.D.; Purviance, R.T.; Cassulo, J.C.; Spencer, B.W.

1992-01-01

Experiments were conducted in which molten aluminum alloys were injected into a 1.2 m deep pool of water. The parameters varied were (i) injectant material (8001 aluminum alloy and 12.3 wt% U-87.7 wt% Al), (ii) melt superheat (O to 50 K), (iii) water temperature (313, 343 and 373 K) and (iv) size and geometry of the pour stream (5, 10 and 20 mm diameter circular and 57 mm annular). The pour stream fragmentation was dominated by surface tension with large particles (∼30 mm) being formed from varicose wave breakup of the 10-mm circular pours and from the annular flow off a 57 mm diameter tube. The fragments produced by the 5 mm circular et were smaller (∼ mm), and the 20 mm jet which underwent sinuous wave breakup produced ∼100 mm fragments. The fragments froze to form solid particles in 313 K water, and when the water was ≥343 K, the melt fragments did not freeze during their transit through 1.2 m of water

Study of localized corrosion in aluminum alloys by the scanning reference electrode technique

Science.gov (United States)

Danford, M. D.

1995-01-01

Localized corrosion in 2219-T87 aluminum (Al) alloy, 2195 aluminum-lithium (Al-Li) alloy, and welded 2195 Al-Li alloy (4043 filler) have been investigated using the relatively new scanning reference electrode technique (SRET). Anodic sites are more frequent and of greater strength in the 2195 Al-Li alloy than in the 2219-T87 Al alloy, indicating a greater tendency toward pitting for the latter. However, the overall corrosion rates are about the same for these two alloys, as determined using the polarization resistance technique. In the welded 2195 Al-Li alloy, the weld bean is entirely cathodic, with rather strongly anodic heat affected zones (HAZ) bordering both sides, indicating a high probability of corrosion in the HAZ parallel to the weld bead.

Effect of the AlCr20 Addition on the Microstructure of Secondary AlSi7Mg0.3 Alloy

Directory of Open Access Journals (Sweden)

Bolibruchová D.

2014-06-01

Full Text Available This paper deals with influence of chrome addition and heat treatment on segregation of iron based phases in the secondary alloy AlSi7Mg0.3 microstructure by chrome and heat treatment. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich intermetallic phases. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate its negative influence by addition some other elements that affect the segregation of intermetallics in less harmful type or by heat treatment. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of chrome as iron corrector of iron based phases.

Study of the alloying additives and alkaline zincate solution effects on the commercial aluminum as galvanic anode for use in alkaline batteries

International Nuclear Information System (INIS)

Rashvand avei, M.; Jafarian, M.; Moghanni Bavil Olyaei, H.; Gobal, F.; Hosseini, S.M.; Mahjani, M.G.

2013-01-01

The corrosion behavior of different grades of commercial aluminum such as AA1040, AA5083, AA6060 and AA7075 in ZnO-containing 4 M NaOH has been determined by using open circuit potential-time measurements (OCP), galvanostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) reveal that ZnO produces the inhibition effect by the formation of a zinc-containing deposit layer on the surface of aluminum electrodes. Although the influence of zincating on the performance of aluminum alloys and considering the amount of alloying elements such as zinc, magnesium and manganese in AA7075 and AA5083 alloys is much more than AA6060 one, the AA6060 aluminum exhibits negligible corrosion rate. Alloying aluminum with other elements and modifying the composition of the electrolyte is a necessary condition for reducing the self-corrosion of the aluminum anodes, whereas the proportion of the amount of additive elements is sufficient and important condition. As AA6060 with a low amount of Zn and Mg, but the high value of the ratio of (Mg/Zn) content (>400) can serve as a good galvanic anode in the alkaline media. - Highlights: • Decreasing the corrosion rate of tested alloys in 4 M NaOH solution specially AA6060. • Lowering the extent of anodic polarization at a current density of 50 mA cm −2 . • High inhibitor efficiency about 97% for AA6060

Study of the alloying additives and alkaline zincate solution effects on the commercial aluminum as galvanic anode for use in alkaline batteries

Energy Technology Data Exchange (ETDEWEB)

Rashvand avei, M. [Department of Chemistry, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Jafarian, M., E-mail: mjafarian@kntu.ac.ir [Department of Chemistry, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Moghanni Bavil Olyaei, H. [Department of Chemistry, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Gobal, F. [Department of Chemistry, Sharif University of Technology, P.O. Box 11365-8516, Tehran (Iran, Islamic Republic of); Hosseini, S.M. [Jahad Organization – Science and Technology Center, Tehran (Iran, Islamic Republic of); Mahjani, M.G. [Department of Chemistry, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of)

2013-12-16

The corrosion behavior of different grades of commercial aluminum such as AA1040, AA5083, AA6060 and AA7075 in ZnO-containing 4 M NaOH has been determined by using open circuit potential-time measurements (OCP), galvanostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) reveal that ZnO produces the inhibition effect by the formation of a zinc-containing deposit layer on the surface of aluminum electrodes. Although the influence of zincating on the performance of aluminum alloys and considering the amount of alloying elements such as zinc, magnesium and manganese in AA7075 and AA5083 alloys is much more than AA6060 one, the AA6060 aluminum exhibits negligible corrosion rate. Alloying aluminum with other elements and modifying the composition of the electrolyte is a necessary condition for reducing the self-corrosion of the aluminum anodes, whereas the proportion of the amount of additive elements is sufficient and important condition. As AA6060 with a low amount of Zn and Mg, but the high value of the ratio of (Mg/Zn) content (>400) can serve as a good galvanic anode in the alkaline media. - Highlights: • Decreasing the corrosion rate of tested alloys in 4 M NaOH solution specially AA6060. • Lowering the extent of anodic polarization at a current density of 50 mA cm{sup −2}. • High inhibitor efficiency about 97% for AA6060.

Friction stir welding of T joints of dissimilar aluminum alloy: A review

Science.gov (United States)

Thakare, Shrikant B.; Kalyankar, Vivek D.

2018-04-01

Aluminum alloys are preferred in the mechanical design due to their advantages like high strength, good corrosion resistance, low density and good weldability. In various industrial applications T joints configuration of aluminum alloys are used. In different fields, T joints having skin (horizontal sheet) strengthen by stringers (vertical sheets) were used to increase the strength of structure without increasing the weight. T joints are usually carried out by fusion welding which has limitations in joining of aluminum alloy due to significant distortion and metallurgical defects. Some aluminum alloys are even non weldable by fusion welding. The friction stir welding (FSW) has an excellent replacement of conventional fusion welding for T joints. In this article, FSW of T joints is reviewed by considering aluminum alloy and various joint geometries for defect analysis. The previous experiments carried out on T joints shows the factors such as tool geometry, fixturing device and joint configurations plays significant role in defect free joints. It is essential to investigate the material flow during FSW to know joining mechanism and the formation of joint. In this study the defect occurred in the FSW are studied for various joint configurations and parameters. Also the effect of the parameters and defects occurs on the tensile strength are studied. It is concluded that the T-joints of different joint configurations can be pretended successfully. Comparing to base metal some loss in tensile strength was observed in the weldments as well as overall reduction of the hardness in the thermos mechanically affected zone also observed.

Replacement of steel parts with extruded aluminum alloys in an automobile

Science.gov (United States)

Daggula, Manikantha Reddy

Over the past years, vehicle emissions have shown a negative impact on environment and human health. A new strategy has been used by automakers to reduce a vehicle's weight which significantly reduce fuel consumption and C02 emissions. A very light car consumes very less fuel as it needs to overcome less inertia, decreasing the required power to movie the vehicle. Reducing weight is the easiest way to increase fuel economy and making it by just 10% can increase its efficiency 6 to 8 percent. For a normal scale 80% of vehicles weight is shared among chassis, power train and other exterior components. Almost 60% of the vehicles weight is comprised of steel and the remaining is with cast and extruded aluminum and magnesium alloys. Our main aim is to look for the parts like Fuel tank holder, Fuel filler neck, Turbo inlet assembly, and Brake lines, Dash board frame which are made from steel and replace them with extruded aluminum alloys, to analyze a conventional rear wheel aluminum drive shaft and replace it with a new design and with a new aluminum alloy. The current project involves dismantling an automobile and looking for feasible steel parts and making samples, analyzing the hardness of the samples. These parts are optimally analyzed using Ansys Finite element analysis tool, these parts are subjected to the constraints such as three-point bending, tensile testing, hydrostatic pressure and also torsional stress action on the drive shaft, the deformation and stress are observed in these parts. The results show the current steel parts can be replaced with 3000 series aluminum alloy and the drive shaft can be replaced with new design with 6061-T6 Al-alloy which decreases 25% of the shaft weight.

A Study on Zinc-Iron Alloy Electrodeposition from a Chloride Electrolyte

DEFF Research Database (Denmark)

Jensen, Jens Dahl

1998-01-01

The electrodeposition of zinc-iron alloys from a chloride-based electrolyte has been studied using electrochemical polarisation techniques, Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDXA) and Computer Assisted Pulse Plating (CAPP...... this system ideal for production of compositional modulated alloy (CMA) electrodeposits. Chloride content, pH and agitation of the electrolyte have been observed to have a strong influence on the reaction at the cathode surface, just as the use of pulse reversal current during electrodeposition. A theory...

Fatigue Strength Estimation Based on Local Mechanical Properties for Aluminum Alloy FSW Joints

Directory of Open Access Journals (Sweden)

Kittima Sillapasa

2017-02-01

Full Text Available Overall fatigue strengths and hardness distributions of the aluminum alloy similar and dissimilar friction stir welding (FSW joints were determined. The local fatigue strengths as well as local tensile strengths were also obtained by using small round bar specimens extracted from specific locations, such as the stir zone, heat affected zone, and base metal. It was found from the results that fatigue fracture of the FSW joint plate specimen occurred at the location of the lowest local fatigue strength as well as the lowest hardness, regardless of microstructural evolution. To estimate the fatigue strengths of aluminum alloy FSW joints from the hardness measurements, the relationship between fatigue strength and hardness for aluminum alloys was investigated based on the present experimental results and the available wide range of data from the references. It was found as: σa (R = −1 = 1.68 HV (σa is in MPa and HV has no unit. It was also confirmed that the estimated fatigue strengths were in good agreement with the experimental results for aluminum alloy FSW joints.

The intermetallic bonding between a ring carrier and aluminum piston alloy

Directory of Open Access Journals (Sweden)

Manasijevic, Srećko

2015-09-01

Full Text Available This paper presents the results of investigating the formation of intermetallic bond between a ring carrier and aluminum piston alloy. The ring carrier is made of austenitic cast iron (Ni-Resist in order to increase the wear resistance of the first ring groove and applied in highly loaded diesel engines. Metallographic examination of the quality of alfin bond was done. A metallographic investigation using an optical microscope in combination with the SEM/EDS analysis of the quality of the intermetallic bonding layer was done. The test results show that can be made successfully as well as the formation of metal connection (alfin bond between the ring carrier and aluminum piston alloy.El artículo presenta los resultados de la investigación sobre la formación de una unión intermetálica entre el portasegmento y la aleación de aluminio del pistón. El portasegmento es una fundición de hierro austenítico (Ni-Resist con el fin de aumentar la resistencia al desgaste de la unión Al-fin del primer segmento y se utiliza en motores diésel altamente cargados. Se realizó un examen metalográfico de la unión intermetálica, mediante un microscopio óptico en combinación con SEM/EDS. Los satisfactorios resultados obtenidos muestran la formación de contacto metálico (unión Al-fin del primer segmento entre el portasegmento y la aleación de aluminio del pistón.

Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys

Directory of Open Access Journals (Sweden)

Thomas Gietzelt

2016-11-01

Full Text Available Normally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation, leading to an annihilation of temperature stress at the microscopic scale, preventing hot cracks even for alloys with extreme melting range. In this paper, several spray-compacted hypereutectic aluminum alloys were laser welded. Besides different silicon contents, additional alloying elements like copper, iron and nickel were present in some alloys, affecting the microstructure. The microstructure was investigated at the delivery state of spray-compacted material as well as for a wide range of welding speeds ranging from 0.5 to 10 m/min, respectively. The impact of speed on phase composition and morphology was studied at different disequilibrium solidification conditions. At high welding velocity, a close-meshed network of eutectic Al-Si-composition was observed, whereas the matrix is filled with nearly pure aluminum, helping to diminish the thermal stress during accelerated solidification. Primary solidified silicon was found, however, containing considerable amounts of aluminum, which was not expected from phase diagrams obtained at the thermodynamic equilibrium.

Finite Element Analysis and Die Design of Non-specific Engineering Structure of Aluminum Alloy during Extrusion

International Nuclear Information System (INIS)

Chen, D.-C.; Lu, Y.-Y.

2010-01-01

Aluminum extension applies to industrial structure, light load, framework rolls and conveyer system platform. Many factors must be controlled in processing the non-specific engineering structure (hollow shape) of the aluminum alloy during extrusion, to obtain the required plastic strain and desired tolerance values. The major factors include the forming angle of the die and temperature of billet and various materials. This paper employs rigid-plastic finite element (FE) DEFORM 3D software to investigate the plastic deformation behavior of an aluminum alloy (A6061, A5052, A3003) workpiece during extrusion for the engineering structure of the aluminum alloy. This work analyzes effective strain, effective stress, damage and die radius load distribution of the billet under various conditions. The analytical results confirm the suitability of the current finite element software for the non-specific engineering structure of aluminum alloy extrusion.

Iron aluminide useful as electrical resistance heating elements

Science.gov (United States)

Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier S.; Hajaligol, Mohammad R.; Lilly, Jr., A. Clifton

1997-01-01

The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, .ltoreq.1% Cr and either .gtoreq.0.05% Zr or ZrO.sub.2 stringers extending perpendicular to an exposed surface of the heating element or .gtoreq.0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B, .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, .ltoreq.1% oxygen, .ltoreq.3% Cu, balance Fe.

Austenitic stainless steel alloys with high nickel contents in high temperature liquid metal systems

International Nuclear Information System (INIS)

Konvicka, H.R.; Schwarz, N.F.

1981-01-01

Fe-Cr-Ni base alloys (nickel content: from 15 to 70 wt%, Chromium content: 15 wt%, iron: balance) together with stainless steel (W.Nr. 1.4981) have been exposed to flowing liquid sodium at 730 0 C in four intervals up to a cumulative exposure time of 1500 hours. Weight change data and the results of post-exposition microcharacterization of specimens are reported. The corrosion rates increase with increasing nickel content and tend to become constant after longer exposure times for each alloy. The corrosion rate of stainless steel is considerably reduced due to the presence of the base alloys. Different kinetics of nickel poor (up to 35% nickel) and nickel rich (> 50% nickel) alloys and nickel transport from nickel rich to nickel poor material is observed. (orig.)

Study of Henna (Lawsonia inermis) as Natural Corrosion Inhibitor for Aluminum Alloy in Seawater

International Nuclear Information System (INIS)

Nik, W B Wan; Zulkifli, F; Sulaiman, O; Samo, K B; Rosliza, R

2012-01-01

Commercial henna (Lawsonia inermis) was investigated to inhibit the corrosion of aluminum alloy through immersion in seawater. The aluminum alloy (5083) was prepared in size of 25mm × 25mm × 3mm. The immersion test was conducted in seawater with different concentration of henna, 100ppm, 300ppm, 500ppm for duration of 60 days. Four characterizations were performed in this study which was weight loss study, Fourier Transform Infrared (FTIR), Electrochemical Impedance Spectroscopy (EIS) and adsorption isotherm. The results indicated that henna has major constituents of lawsone which contributed to the chemisorptions or adsorption process by forming an isolation layers on the aluminum alloy surface which follows the Langmuir adsorption isotherm. It was found that the protection layer attached on metal was not permanent and precipitation occurred as the time increases. The highest inhibition efficiency was found at 88% (500ppm). This research found that henna is an excellent natural inhibitor for aluminum alloy in seawater.

The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminum Alloy

Directory of Open Access Journals (Sweden)

E.P. Georgiou

2017-10-01

Full Text Available This work focuses in investigating the effect of cold deformation on the cathodic hydrogen charging of 5083 aluminum alloy. The aluminium alloy was submitted to a cold rolling process, until the average thickness of the specimens was reduced by 7% and 15%, respectively. A study of the structure, microhardness, and tensile properties of the hydrogen charged aluminium specimens, with and without cold rolling, indicated that the cold deformation process led to an increase of hydrogen susceptibility of this aluminum alloy.

Russian aluminum-lithium alloys for advanced reusable spacecraft

International Nuclear Information System (INIS)

Charette, Ray O.; Leonard, Bruce G.; Bozich, William F.; Deamer, David A.

1998-01-01

Cryotanks that are cost-affordable, robust, fuel-compatible, and lighter weight than current aluminum design are needed to support next-generation launch system performance and operability goals. The Boeing (McDonnell Douglas Aerospace-MDA) and NASA's Delta Clipper-Experimental Program (DC-XA) flight demonstrator test bed vehicle provided the opportunity for technology transfer of Russia's extensive experience base with weight-efficient, highly weldable aluminum-lithium (Al-Li) alloys for cryogenic tank usage. As part of NASA's overall reusable launch vehicle (RLV) program to help provide technology and operations data for use in advanced RLVs, MDA contracted with the Russian Academy of Sciences (RAS/IMASH) for design, test, and delivery of 1460 Al-Li alloy liquid oxygen (LO 2 ) cryotanks: one for development, one for ground tests, and one for DC-XA flight tests. This paper describes the development of Al-Li 1460 alloy for reusable LO 2 tanks, including alloy composition tailoring, mechanical properties database, forming, welding, chemical milling, dissimilar metal joining, corrosion protection, completed tanks proof, and qualification testing. Mechanical properties of the parent and welded materials exceeded expectations, particularly the fracture toughness, which promise excellent reuse potential. The LO 2 cryotank was successfully demonstrated in DC-XA flight tests

TEM investigation of ductile iron alloyed with vanadium.

Science.gov (United States)

Dymek, S; Blicharski, M; Morgiel, J; Fraś, E

2010-03-01

This article presents results of the processing and microstructure evolution of ductile cast iron, modified by an addition of vanadium. The ductile iron was austenitized closed to the solidus (1095 degrees C) for 100 h, cooled down to 640 degrees C and held on at this temperature for 16 h. The heat treatment led to the dissolution of primary vanadium-rich carbides and their subsequent re-precipitation in a more dispersed form. The result of mechanical tests indicated that addition of vanadium and an appropriate heat treatment makes age hardening of ductile iron feasible. The precipitation processes as well as the effect of Si content on the alloy microstructure were examined by scanning and transmission electron microscopy. It was shown that adjacent to uniformly spread out vanadium-rich carbides with an average size of 50 nm, a dispersoid composed of extremely small approximately 1 nm precipitates was also revealed.

Study of the thermal and kinetic parameters during directional solidification of zinc-aluminum eutectic alloys

International Nuclear Information System (INIS)

Gueijman, Sergio Fabian; Ares, Alicia Esther; Schvezov, Carlos Enrique

2008-01-01

Much work has been done recently on investigating zinc-based binary alloys, with different aluminum content, and modified or not with small amounts of other alloying elements. Some of these alloys have interesting properties, such as, the ZA alloys that have properties similar to some bronzes that are used in applications that require pieces with enough resistance to mechanical stresses. The longitudinal thermal gradients, the minimal gradients, the velocities of the liquid interphases, the velocities of the solid interphases and the accelerations of both interphases as a function of time and position were determined for each diluted alloy of the eutectic concentration considered (Zn-5%Al, % in weight), solidified horizontally with caloric extraction from both ends of the test pieces. The values obtained from the horizontal solidification with two directions of predominant caloric extraction are compared to previous values obtained for the same vertically solidified alloy system with a predominantly caloric extraction direction

Precipitation behavior of aluminum alloy 2139 fabricated using additive manufacturing

Energy Technology Data Exchange (ETDEWEB)

Brice, Craig, E-mail: craig.a.brice@lmco.com [NASA Langley Research Center, Hampton, VA 23681 (United States); Shenoy, Ravi [Northrop Grumman Corporation Technical Services, Hampton, VA 23681 (United States); Kral, Milo; Buchannan, Karl [University of Canterbury, Christchurch (New Zealand)

2015-11-11

Additive manufacturing (AM) is an emerging technology capable of producing near net shape structures in a variety of materials directly from a computer model. Standard metallic alloys that were developed for cast or wrought processing have largely been adopted for AM feedstock. In many applications, these legacy alloys are quite acceptable. In the aluminum alloy family, however, there is a significant performance gap between the casting alloys currently being used in AM processes and the high strength/toughness capability available in certain wrought alloys. The precipitation hardenable alloys, most often used in high performance structures, present challenges for processing by AM. The near net shape nature of AM processes does not allow for mechanical work prior to the heat treatment that is often necessary to develop a uniform distribution of precipitates and give peak mechanical performance. This paper examines the aluminum (Al) alloy 2139, a composition that is strengthened by homogeneous precipitation of Ω (Al{sub 2}Cu) plates and thus ideally suited for near net shape processes like AM. Transmission electron microscopy, microhardness, and tensile testing determined that, with proper processing conditions, Al 2139 can be additively manufactured and subsequently heat treated to strength levels comparable to those of peak aged wrought Al 2139.

Precipitation behavior of aluminum alloy 2139 fabricated using additive manufacturing

International Nuclear Information System (INIS)

Brice, Craig; Shenoy, Ravi; Kral, Milo; Buchannan, Karl

2015-01-01

Additive manufacturing (AM) is an emerging technology capable of producing near net shape structures in a variety of materials directly from a computer model. Standard metallic alloys that were developed for cast or wrought processing have largely been adopted for AM feedstock. In many applications, these legacy alloys are quite acceptable. In the aluminum alloy family, however, there is a significant performance gap between the casting alloys currently being used in AM processes and the high strength/toughness capability available in certain wrought alloys. The precipitation hardenable alloys, most often used in high performance structures, present challenges for processing by AM. The near net shape nature of AM processes does not allow for mechanical work prior to the heat treatment that is often necessary to develop a uniform distribution of precipitates and give peak mechanical performance. This paper examines the aluminum (Al) alloy 2139, a composition that is strengthened by homogeneous precipitation of Ω (Al_2Cu) plates and thus ideally suited for near net shape processes like AM. Transmission electron microscopy, microhardness, and tensile testing determined that, with proper processing conditions, Al 2139 can be additively manufactured and subsequently heat treated to strength levels comparable to those of peak aged wrought Al 2139.

Influence of iron and beryllium additions on heat resistance of silicide coatings on TsMB-30 molybdenum alloy

International Nuclear Information System (INIS)

Zajtseva, A.L.; Fedorchuk, N.M.; Lazarev, Eh.M.; Korotkov, N.A.

1985-01-01

Alloying of titanium modified silicide coatings on TsMB-30 molybdenum alloy with iron or beryllium is stated to improve their protective properties. Coatings with low content of alloying elements have the best protective properties. Service life of coatings is determined by the formed oxide film and phase transformations taking place in the coating

Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy

Directory of Open Access Journals (Sweden)

Patricia Gómez

2016-05-01

Full Text Available The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe, Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe, Al Si9Cu3(Fe(Zn and Al Si9 has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10−1 pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe(Zn, with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy.

Science.gov (United States)

Gómez, Patricia; Elduque, Daniel; Sarasa, Judith; Pina, Carmelo; Javierre, Carlos

2016-05-25

The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe), Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe), Al Si9Cu3(Fe)(Zn) and Al Si9) has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA) with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10 -1 pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe)(Zn), with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe) cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

INFLUENCE OF IRON CONTENT AND PLASTIC DEFORMATION ...

African Journals Online (AJOL)

eobe

MECHANICAL PROPERTIES OF 8011-TYPE Al-Fe-Si ALLOY. O. H. Yakubu1, I. ... properties such as formability, corrosion, light weight and also ... In aluminium alloy, a large number of iron-containing intermetallic ... conditions and alloy composition. Although ... and tensile behaviour of 7075 aluminium alloy [8] observed ...

Investigation of alloying effects in aluminum dispersion strengthened with Al2O3

International Nuclear Information System (INIS)

Copeland, G.L.

1975-10-01

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 200 0 C 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 450 0 C. 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 450 0 C is typically 0.5 percent. Good combinations of strength and ductility at 450 0 C 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)

Superior light metals by texture engineering: Optimized aluminum and magnesium alloys for automotive applications

International Nuclear Information System (INIS)

Hirsch, J.; Al-Samman, T.

2013-01-01

Aluminum and magnesium are two highly important lightweight metals used in automotive applications to reduce vehicle weight. Crystallographic texture engineering through a combination of intelligent processing and alloying is a powerful and effective tool to obtain superior aluminum and magnesium alloys with optimized strength and ductility for automotive applications. In the present article the basic mechanisms of texture formation of aluminum and magnesium alloys during wrought processing are described and the major aspects and differences in deformation and recrystallization mechanisms are discussed. In addition to the crystal structure, the resulting properties can vary significantly, depending on the alloy composition and processing conditions, which can cause drastic texture and microstructure changes. The elementary mechanisms of plastic deformation and recrystallization comprising nucleation and growth and their orientation dependence, either within the homogeneously formed microstructure or due to inhomogeneous deformation, are described along with their impact on texture formation, and the resulting forming behavior. The typical face-centered cubic and hexagonal close-packed rolling and recrystallization textures, and related mechanical anisotropy and forming conditions are analyzed and compared for standard aluminum and magnesium alloys. New aspects for their modification and advanced strategies of alloy design and microstructure to improve material properties are derived

Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

International Nuclear Information System (INIS)

Kim, Jong Cheon; Cheong, Seong Kyun

2012-01-01

The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue

Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Cheon; Cheong, Seong Kyun [Seoul Nat' l Univ. of Science and Technology, Seoul (Korea, Republic of)

2012-11-15

The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue.

Auger electron spectroscopy study of surface segregation in the binary alloys copper-1 atomic percent indium, copper-2 atomic percent tin, and iron-6.55 atomic percent silicon

Science.gov (United States)

Ferrante, J.

1973-01-01

Auger electron spectroscopy was used to examine surface segregation in the binary alloys copper-1 at. % indium, copper-2 at. % tin and iron-6.55 at. % silicon. The copper-tin and copper-indium alloys were single crystals oriented with the /111/ direction normal to the surface. An iron-6.5 at. % silicon alloy was studied (a single crystal oriented in the /100/ direction for study of a (100) surface). It was found that surface segregation occurred following sputtering in all cases. Only the iron-silicon single crystal alloy exhibited equilibrium segregation (i.e., reversibility of surface concentration with temperature) for which at present we have no explanation. McLean's analysis for equilibrium segregation at grain boundaries did not apply to the present results, despite the successful application to dilute copper-aluminum alloys. The relation of solute atomic size and solubility to surface segregation is discussed. Estimates of the depth of segregation in the copper-tin alloy indicate that it is of the order of a monolayer surface film.

Effect of Fe-Content on the Mechanical Properties of Recycled Al Alloys during Hot Compression

Directory of Open Access Journals (Sweden)

Hongzhou Lu

2017-07-01

Full Text Available It is unavoidable that Fe impurities will be mixed into Al alloys during recycling of automotive aluminum parts, and the Fe content has a significant effect on the mechanical properties of the recycled Al alloys. In this work, hot compression tests of two Fe-containing Al alloys were carried out at elevated temperatures within a wide strain rate range from 0.01 s−1 to 10 s−1. The effect of Fe content on the peak stress of the stress vs. strain curves, strain rate sensitivity and activation energy for dynamic recrystallization are analyzed. Results show that the recycled Al alloy containing 0.5 wt % Fe exhibits higher peak stresses and larger activation energy than the recycled Al alloy containing 0.1 wt % Fe, which results from the fact that there are more dispersed AlMgFeSi and/or AlFeSi precipitates in the recycled Al alloy containing 0.5 wt % Fe as confirmed by SEM observation and energy spectrum analysis. It is also shown that the Fe content has little effect on the strain rate sensitivity of the recycled Al alloys.

Physical Modeling of Plastic Working Conditions for Rods of 7xxx Series Aluminum Alloys

Directory of Open Access Journals (Sweden)

Dyja H.

2017-06-01

Full Text Available The continuing high level of demand for lightweight structural materials is the reason for the ever-growing interest in aluminum alloys. The main areas of application for aluminum alloys products are the aerospace and automotive industries. Production of profiles and structural elements from lightweight alloys gives possibility to reduce the curb weight of construction, which directly translates into among other reduction of fuel consumption and lower amount of generated exhaust gas.

Development Program for Natural Aging Aluminum Casting Alloys

Energy Technology Data Exchange (ETDEWEB)

Dr. Geoffrey K. Sigworth

2004-05-14

A number of 7xx aluminum casting alloys are based on the ternary Al-Zn-Mg system. These alloys age naturally to high strength at room temperature. A high temperature solution and aging treatment is not required. Consequently, these alloys have the potential to deliver properties nearly equivalent to conventional A356-T6 (Al-Si-Mg) castings, with a significant cost saving. An energy savings is also possible. In spite of these advantages, the 7xx casting alloys are seldom used, primarily because of their reputation for poor castibility. This paper describes the results obtained in a DOE-funded research study of these alloys, which is part of the DOE-OIT ''Cast Metals Industries of the Future'' Program. Suggestions for possible commercial use are also given.

Microstructure, hardness and tensile properties of A380 aluminum alloy with and without Li additions

International Nuclear Information System (INIS)

Karamouz, Mostafa; Azarbarmas, Mortaza; Emamy, Masoud; Alipour, Mohammad

2013-01-01

In this work, the effects of lithium (Li) on the microstructure, hardness and mechanical properties of A380 aluminum alloy have been investigated. The alloy was produced by conventional casting. Microstructures of the samples were investigated using the optical and scanning electron microscopy. The results showed that with increase of Li content up to 0.1%, the morphology of β-Al 5 FeSi and eutectic Si phases changed from intersected and branched coarse platelets into fine and independent ones. Li decreased hardness values of the alloy. Also, it was revealed from tensile tests that with addition of 0.6% Li, the ultimate tensile strength (UTS) and elongation values increased from 274 to 300 MPa and 3.8% to 6%, respectively. Fractographic examination of the fracture surfaces indicated that the alloys with Li addition had more ductile dimple and fewer brittle cleavage surfaces

Stress corrosion cracking of an aluminum alloy used in external fixation devices.

Science.gov (United States)

Cartner, Jacob L; Haggard, Warren O; Ong, Joo L; Bumgardner, Joel D

2008-08-01

Treatment for compound and/or comminuted fractures is frequently accomplished via external fixation. To achieve stability, the compositions of external fixators generally include aluminum alloy components due to their high strength-to-weight ratios. These alloys are particularly susceptible to corrosion in chloride environments. There have been several clinical cases of fixator failure in which corrosion was cited as a potential mechanism. The aim of this study was to evaluate the effects of physiological environments on the corrosion susceptibility of aluminum 7075-T6, since it is used in orthopedic external fixation devices. Electrochemical corrosion curves and alternate immersion stress corrosion cracking tests indicated aluminum 7075-T6 is susceptible to corrosive attack when placed in physiological environments. Pit initiated stress corrosion cracking was the primary form of alloy corrosion, and subsequent fracture, in this study. Anodization of the alloy provided a protective layer, but also caused a decrease in passivity ranges. These data suggest that once the anodization layer is disrupted, accelerated corrosion processes occur. (c) 2007 Wiley Periodicals, Inc.

Thermomechanical treatment of welded joints of aluminum-lithium alloys modified by scandium

Science.gov (United States)

Malikov, A. G.

2017-12-01

At present, the aeronautical equipment manufacture involves up-to-date high-strength aluminum alloys of decreased density resulting from the lithium admixture. Various technologies of fusible welding of these alloys are being developed. The paper presents experimental investigations of the optimization of the laser welding of aluminum alloys with the scandium-modified welded joint after thermomechanical treatment. The effect of scandium on the micro- and macrostructure is studied along with strength characteristics of the welded joint. It is found that thermomechanical treatment allows us to obtain the strength of the welded joint 0.89 for the Al-Mg-Li system and 0.99 for the Al-Cu-Li system with the welded joint modified by scandium in comparison with the base alloy after treatment.

Characterization of Aluminum Magnesium Alloy Reverse Sensitized via Heat Treatment

Science.gov (United States)

2016-09-01

when magnesium comes out of solution as a second phase, Al3Mg2, on the grain boundaries, eventually forming a continuous network and increasing...alloys. Al-Mg alloys can become sensitized when magnesium comes out of solution as a second phase, Al3Mg2, on the grain boundaries, eventually...THIS PAGE INTENTIONALLY LEFT BLANK 1 I. INTRODUCTION A. MOTIVATION Aluminum alloys are attractive ship-building materials. They are lightweight

Yield and flow properties of aluminum alloy AA 8001

International Nuclear Information System (INIS)

Lyons, J.S.; Johnson, H.W.; Han, E.G.

1995-01-01

Aluminum alloy AA 8001 is being used at the Westinghouse Savannah River Company (WSRC) for nuclear reactor fuel and target components. The objective of this research was to determine parameters for predictive models of the compressive flow properties of AA 8001. Seventy-five true strain-rate, hot compression tests were performed. New, quantitative information about the yield and flow behavior of aluminum alloy AA 8001 was determined. Parameters were determined to use in a hyperbolic sine constitutive law so that the yield stress, the peak stress, and the peak strain can be predicted from the temperature-compensated strain-rate, Z. It was found that the onset of strain softening was more strongly dependent on Z than the onset of yielding was

Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques

Directory of Open Access Journals (Sweden)

Abou Bakr Elshalakany

2014-01-01

Full Text Available A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM and scanning electron microscopy (SEM equipped with an energy dispersive X-ray analysis (EDX. This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt% of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs.

Magnetic composites based on hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides

International Nuclear Information System (INIS)

Braga, Tiago P.; Vasconcelos, Igor F.; Sasaki, Jose M.; Fabris, J.D.; Oliveira, Diana Q.L. de; Valentini, Antoninho

2010-01-01

Materials containing hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides were obtained from a chemical precursor prepared by admixing chitosan and iron and aluminum hydroxides. The oxides were first characterized with scanning electron microscopy, X-ray diffraction, and Moessbauer spectroscopy. Scanning electron microscopy micrographs showed the size distribution of the resulting spheres to be highly homogeneous. The occurrence of nano-composites containing aluminum oxides and iron oxides was confirmed from powder X-ray diffraction patterns; except for the sample with no aluminum, the superparamagnetic relaxation due to iron oxide particles were observed from Moessbauer spectra obtained at 298 and 110 K; the onset six line-spectrum collected at 20 K indicates a magnetic ordering related to the blocking relaxation effect for significant portion of small spheres in the sample with a molar ratio Al:Fe of 2:1.

The influence of various cooling rates during laser alloying on nodular iron surface layer

Science.gov (United States)

Paczkowska, Marta; Makuch, Natalia; Kulka, Michał

2018-06-01

The results of research referring to modification of the nodular iron surface layer by laser alloying with cobalt were presented. The aim of this study was to analyze the possibilities of cobalt implementation into the surface layer of nodular iron in various laser heat treatment conditions (by generating different cooling rates of melted surface layer). The modified surface layer of nodular iron was analyzed with OM, SEM, TEM, XRD, EDS and Vickers microhardness tester. The modified surface layer of nodular iron after laser alloying consisted of: the alloyed zone (melted with cobalt), the transition zone and the hardened zone from solid state. The alloyed zone was characterized by higher microstructure homogeneity - in contrast to the transition and the hardened zones. All the alloyed zones contained a dendritic microstructure. Dendrites consisted of martensite needles and retained austenite. Cementite was also detected. It was stated, that due to similar dimension of iron and cobalt atoms, their mutual replacement in the crystal lattice could occur. Thus, formation of phases based on α solution: Co-Fe (44-1433) could not be excluded. Although cobalt should be mostly diluted in solid solutions (because of its content in the alloyed zone), the other newly formed phases as Co (ε-hex.), FeC and cobalt carbides: Co3C, CoC0.25 could be present in the alloyed zones as a result of unique microstructure creation during laser treatment. Pearlite grains were observed in the zone, formed using lower power density of the laser beam and its longer exposition time. Simply, such conditions resulted in the cooling rate which was lower than critical cooling rate. The alloyed zones, produced at a higher cooling rate, were characterized by better microstructure homogeneity. Dendrites were finer in this case. This could result from a greater amount of crystal nuclei appearing at higher cooling rate. Simultaneously, the increased amount of γ-Fe and Fe3C precipitates was expected in

Three-body abrasive wear behaviour of metastable spheroidal carbide cast irons with different chromium contents

Energy Technology Data Exchange (ETDEWEB)

Efremenko, Vasily; Pastukhova, Tatiana; Chabak, Yuliia; Efremenko, Alexey [Pryazovskyi State Technical Univ., Mariupol (Ukraine); Shimizu, Kazumichi; Kusumoto, Kenta [Muroran Institute of Technology, Hokkaido (Japan); Brykov, Michail [Zaporozhye National Technical Univ., Zaporozhye (Ukraine)

2018-02-15

The effect of heat treatment and chromium contents (up to 9.1 wt.%) on the wear resistance of spheroidal carbide cast iron (9.5 wt.% V) was studied using optical and scanning electron microscopy, X-ray diffractometry, dilatometry and three-body abrasive testing. It was found that quenching from 760 C and 920 C improved the alloys' wear resistance compared to the as-cast state due to the formation of metastable austenite transforming into martensite under abrasion. The wear characteristics of alloys studied are 1.6 - 2.3 times higher than that of reference cast iron (12 wt.% V) having stable austenitic matrix. Chromium addition decreases surface damage due to the formation of M{sub 7}C{sub 3} carbides, while it reduces wear resistance owing to austenite stabilization to abrasion-induced martensite transformation. The superposition of these factors results in decreasing the alloys' wear behaviour with chromium content increase.

Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

Science.gov (United States)

Liu, Wenyong; Luo, Yuting; Sun, Linyu; Wu, Ruomei; Jiang, Haiyun; Liu, Yuejun

2013-01-01

We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low surface free energy, the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

Spray rolling aluminum alloy strip

Energy Technology Data Exchange (ETDEWEB)

McHugh, Kevin M.; Delplanque, J.-P.; Johnson, S.B.; Lavernia, E.J.; Zhou, Y.; Lin, Y

2004-10-10

Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant.

Investigation of the Precipitation Behavior in Aluminum Based Alloys

KAUST Repository

Khushaim, Muna S.

2015-01-01

A complete study examining the influence of common industrial heat treatment on the precipitation kinetics and phase transformations of complex aluminum alloy is performed. The qualitative evaluation results of the precipitation

Effect of iron and silicon in aluminium and its alloys

International Nuclear Information System (INIS)

Kovacs, I.

1990-01-01

The iron and silicon are the main impurities in aluminium, they are always present in alloys made from commercially pure base material. The solid solubility of iron in aluminium is very low, therefore its largest amount forms intermetallic compounds the kind of which depends strongly on the other impurities of alloying elements. Although the solid solubility of silicon is much larger than that of the iron, it is the constituent of both the primary and the secondary particles, the structure of which depends in general on the iron-silicon concentration ratio. These Fe and Si containing particles can cause various and basic changes in the macroscopic properties of the alloy. Since commercially pure aluminium has extensive consumer and industrial use, it is very important to know, not only from scientific but also from practical point of view, the effect of iron and silicon on the physical and mechanical properties of aluminium and its alloys. The aim of the ''International Workshop on the Effect of Iron and Silicon in Aluminium and its Alloys'' was to clarify the present knowledge on this subject. The thirty papers presented at the Workshop and collected in this Proceedings cover many important fields of the subject. I hope that they will contribute to both the deeper understanding of the related phenomena and the improvement of technologies for producing better aluminium alloys

Corrosion and nanomechanical behaviors of plasma electrolytic oxidation coated AA7020-T6 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Venugopal, A., E-mail: arjun_venu@hotmail.com [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Srinath, J. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Rama Krishna, L. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad 500005 (India); Ramesh Narayanan, P.; Sharma, S.C.; Venkitakrishnan, P.V. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India)

2016-04-13

Alumina coating was deposited on AA7020 aluminum alloy by plasma electrolytic oxidation (PEO) method. The corrosion, stress corrosion cracking (SCC) and nano-mechanical behaviors were examined by means of potentiodynamic polarization, slow strain rate test (SSRT) and nano-indentation tests. Potentiodynamic polarization (PP) was used to evaluate the corrosion resistance of the coating and slow strain rate test (SSRT) was used for evaluating the environmental cracking resistance in 3.5% NaCl solution. The mechanical properties (hardness and elastic modulus) were obtained from each indentation as a function of the penetration depth across the coating cross section. The above results were compared with similar PEO coated aluminum and magnesium alloys. Results indicated that PEO coating on AA7020 alloy significantly improved the corrosion resistance. However the environmental cracking resistance was found to be only marginal. The hardness and elastic modulus values were found to be much higher when compared to the base metal and similar PEO coated 7075 aluminum alloys. The fabricated coating also exhibited good adhesive strength with the substrate similar to other PEO coated aluminum alloys reported in the literature.

Preparation of three-dimensional shaped aluminum alloy foam by two-step foaming

International Nuclear Information System (INIS)

Shang, J.T.; Xuming, Chu; Deping, He

2008-01-01

A novel method, named two-step foaming, was investigated to prepare three-dimensional shaped aluminum alloy foam used in car industry, spaceflight, packaging and related areas. Calculations of thermal decomposition kinetics of titanium hydride showed that there is a considerable amount of hydrogen releasing when the titanium hydride is heated at a relatively high temperature after heated at a lower temperature. The hydrogen mass to sustain aluminum alloy foam, having a high porosity, was also estimated by calculations. Calculations indicated that as-received titanium hydride without any pre-treatment can be used as foaming agents in two-step foaming. The processes of two-step foaming, including preparing precursors and baking, were also studied by experiments. Results showed that, low titanium hydride dispersion temperature, long titanium hydride dispersion time and low precursors porosity are beneficial to prepare three-dimensional shaped aluminum alloy foams with uniform pores

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.

Mechanical Properties of Titanium and Aluminum Alloys at Cryogenic Temperatures

Science.gov (United States)

1962-03-01

aluminum alloys. Table I is a tabulation of the chemical composition of the tita - nium alloys. The bar was 5/8 inch in diameter and the sheet 0.060 inch...Ti-6AI-4V Tensile azid yield strength data for both bar and sheet of this tita - nium alloy are shown in Figure A-3. Bar and sheet data show approxi...not recommended for low temperature applications. The remainder of the tita - nium alloys were tested from room temperature to -452 F. In general, Ti

Fusion boundary microstructure evolution in aluminum alloys

Science.gov (United States)

Kostrivas, Anastasios Dimitrios

2000-10-01

A melting technique was developed to simulate the fusion boundary of aluminum alloys using the GleebleRTM thermal simulator. Using a steel sleeve to contain the aluminum, samples were heated to incremental temperatures above the solidus temperature of a number of alloys. In alloy 2195, a 4wt%Cu-1wt%Li alloy, an equiaxed non-dendritic zone (EQZ) could be formed by heating in the temperature range from approximately 630 to 640°C. At temperatures above 640°C, solidification occurred by the normal epitaxial nucleation and growth mechanism. Fusion boundary behavior was also studied in alloys 5454-H34, 6061-T6, and 2219-T8. Additionally, experimental alloy compositions were produced by making bead on plate welds using an alloy 5454-H32 base metal and 5025 or 5087 filler metals. These filler metals contain zirconium and scandium additions, respectively, and were expected to influence nucleation and growth behavior. Both as-welded and welded/heat treated (540°C and 300°C) substrates were tested by melting simulation, resulting in dendritic and EQZ structures depending on composition and substrate condition. Orientation imaging microscopy (OIM(TM)) was employed to study the crystallographic character of the microstructures produced and to verify the mechanism responsible for EQZ formation. OIM(TM) proved that grains within the EQZ have random orientation. In all other cases, where the simulated microstructures were dendritic in nature, it was shown that epitaxy was the dominant mode of nucleation. The lack of any preferred crystallographic orientation relationship in the EQZ supports a theory proposed by Lippold et al that the EQZ is the result of heterogeneous nucleation within the weld unmixed zone. EDS analysis of the 2195 on STEM revealed particles with ternary composition consisted of Zr, Cu and Al and a tetragonal type crystallographic lattice. Microdiffraction line scans on EQZ grains in the alloy 2195 showed very good agreement between the measured Cu

A detailed investigation of the strain hardening response of aluminum alloyed Hadfield steel

Science.gov (United States)

Canadinc, Demircan

The unusual strain hardening response exhibited by Hadfield steel single and polycrystals under tensile loading was investigated. Hadfield steel, which deforms plastically through the competing mechanisms slip and twinning, was alloyed with aluminum in order to suppress twinning and study the role of slip only. To avoid complications due to a grained structure, only single crystals of the aluminum alloyed Hadfield steel were considered at the initial stage of the current study. As a result of alloying with aluminum, twinning was suppressed; however a significant increase in the strain hardening response was also present. A detailed microstructural analysis showed the presence of high-density dislocation walls that evolve in volume fraction due to plastic deformation and interaction with slip systems. The very high strain hardening rates exhibited by the aluminum alloyed Hadfield steel single crystals was attributed to the blockage of glide dislocations by the high-density dislocation walls. A crystal plasticity model was proposed, that accounts for the volume fraction evolution and rotation of the dense dislocation walls, as well as their interaction with the active slip systems. The novelty of the model lies in the simplicity of the constitutive equations that define the strain hardening, and the fact that it is based on experimental data regarding the microstructure. The success of the model was tested by its application to different crystallographic orientations, and finally the polycrystals of the aluminum alloyed Hadfield steel. Meanwhile, the capability of the model to predict texture was also observed through the rotation of the loading axis in single crystals. The ability of the model to capture the polycrystalline deformation response provides a venue for its utilization in other alloys that exhibit dislocation sheet structures.

In vitro and in vivo corrosion evaluation of nickel-chromium- and copper-aluminum-based alloys.

Science.gov (United States)

Benatti, O F; Miranda, W G; Muench, A

2000-09-01

The low resistance to corrosion is the major problem related to the use of copper-aluminum alloys. This in vitro and in vivo study evaluated the corrosion of 2 copper-aluminum alloys (Cu-Al and Cu-Al-Zn) compared with a nickel-chromium alloy. For the in vitro test, specimens were immersed in the following 3 corrosion solutions: artificial saliva, 0.9% sodium chloride, and 1.0% sodium sulfide. For the in vivo test, specimens were embedded in complete dentures, so that one surface was left exposed. The 3 testing sites were (1) close to the oral mucosa (partial self-cleaning site), (2) surface exposed to the oral cavity (self-cleaning site), and (3) specimen bottom surface exposed to the saliva by means of a tunnel-shaped perforation (non-self-cleaning site). Almost no corrosion occurred with the nickel-chromium alloy, for either the in vitro or in vivo test. On the other hand, the 2 copper-aluminum-based alloys exhibited high corrosion in the sulfide solution. These same alloys also underwent high corrosion in non-self-cleaning sites for the in vivo test, although minimal attack was observed in self-cleaning sites. The nickel-chromium alloy presented high resistance to corrosion. Both copper-aluminum alloys showed considerable corrosion in the sulfide solution and clinically in the non-self-cleaning site. However, in self-cleaning sites these 2 alloys did not show substantial corrosion.

Modeling mechanical properties of cast aluminum alloy using artificial neural network

International Nuclear Information System (INIS)

Jokhio, M.H.; Panhwar, M.I.

2009-01-01

Modeling is widely used to investigate the mechanical properties of engineering materials due to increasing demand of low cost and high strength to weight ratio for many engineering applications. The aluminum casting alloys are cost competitive material and possess the desired properties. The mechanical properties largely depend upon composition of alloys and their processing method. Alloy design involves controlling mechanical properties via optimization of the composition and processing parameters. For optimization the possible root is empirical modeling and its more refined version is the analysis of the wide range of data using ANN (Artificial Neural Networks) modeling. The modeling of mechanical properties of the aluminum alloys are the main objective of present work. For this purpose, some data were collected and experimentally prepared using conventional casting method. A MLP (Multilayer Perceptron) network was developed, which is trained by using the error back propagation algorithm. (author)

Aluminum alloy analysis using microchip-laser induced breakdown spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Freedman, Andrew [Center for Sensor Systems and Technologies, Aerodyne Research, Inc., 45 Manning Road Billerica, MA, 01821-3976 (United States)]. E-mail: af@aerodyne.com; Iannarilli, Frank J. [Center for Sensor Systems and Technologies, Aerodyne Research, Inc., 45 Manning Road Billerica, MA, 01821-3976 (United States); Wormhoudt, Joda C. [Center for Sensor Systems and Technologies, Aerodyne Research, Inc., 45 Manning Road Billerica, MA, 01821-3976 (United States)

2005-08-31

A laser induced breakdown spectroscopy-based apparatus for the analysis of aluminum alloys which employs a microchip laser and a handheld spectrometer with an ungated, non-intensified CCD array has been built and tested. The microchip laser, which emits low energy pulses (4-15 {mu}J) at high repetition rates (1-10 kHz) at 1064 nm, produces, when focused, an ablation crater with a radius on the order of only 10 {mu}m. The resulting emission is focused onto an optical fiber connected to 0.10 m focal length spectrometer with a spectral range of 275-413 nm. The apparatus was tested using 30 different aluminum alloy reference samples. Two techniques for constructing calibration curves from the data, peak integration and partial least squares regression, were quantitatively evaluated. Results for Fe, Mg, Mn, Ni, Si, and Zn indicated limits of detection (LOD) that ranged from 0.05 to 0.14 wt.% and overall measurement errors which varied from 0.06 to 0.18 wt.%. Higher limits of detection and overall error for Cu (> 0.3 wt.%) were attributed to analysis problems associated with the presence of optically thick lines and a spectral interference from Zn. Improvements in design and component sensitivity should increase overall performance by at least a factor of 2, allowing for dependable aluminum alloy classification.

Stress Corrosion Cracking Behavior of LD10 Aluminum Alloy in UDMH and N2O4 propellant

Science.gov (United States)

Zhang, Youhong; Chang, Xinlong; Liu, Wanlei

2018-03-01

The LD10 aluminum alloy double cantilever beam specimens were corroded under the conditions of Unsymmetric Uimethyl Hydrazine (UDMH), Dinitrogen Tetroxide (N2O4), and 3.5% NaCl environment. The crack propagation behavior of the aluminum alloy in different corrosion environment was analyzed. The stress corrosion cracking behavior of aluminum alloy in N2O4 is relatively slight and there are not evident stress corrosion phenomenons founded in UDMH.

Effect of aluminum coatings on corrosion properties of AZ31 magnesium alloy

Energy Technology Data Exchange (ETDEWEB)

Chiu Liuho; Lin Hsingan; Chen Chunchin; Yang Chihfu [Dept. of materials engineering, Tatung Univ., Taipei (Taiwan); Chang Chiahua; Wu Jenchin [Physical chemistry section, chemical systems research div., Chung-Shan Inst. of Science and Technology, Tao-Yuan (Taiwan)

2003-07-01

This investigation aimed to increase the corrosion resistance of an AZ31 magnesium alloy by an aluminum arc spray coating and a post-treatment consisted of hot pressing and anodizing. It was found that the aluminum arc spraying alone was incapable of protection against corrosion due to the high amount of pores present in the coating layer. In order to solve the problem, densification of the Al arc-sprayed layer was carried out by hot pressing the coated AZ31 Mg alloy plate under an appropriate range of temperature, time and pressure. After hot pressing the Al coated AZ31 Mg alloy plate exhibited a much improved corrosion resistance. A final anodizing treatment applied to the AZ31 alloy with the dense Al coating further improved its resisting to corrosion. The results showed that, by adopting the Al arc spraying, hot pressing and anodizing process, the corrosion current density of the AZ31 alloy in a 3.5 wt% NaCl solution was from 2.1 x 10{sup -6} A/cm{sup 2} (original AZ31) to 3.7 x 10{sup -7} A/cm{sup 2} (after the surface treatment), which value is close to that of an anodized aluminum plate. (orig.)

The stress-corrosion cracking behavior of high-strength aluminum powder metallurgy alloys

Science.gov (United States)

Pickens, J. R.; Christodoulou, L.

1987-01-01

The susceptibility to stress-corrosion cracking (SCC) of rapidly solidified (RS) aluminum powder metallurgy (P/M) alloys 7090 and 7091, mechanically alloyed aluminum P/M alloy IN* 9052, and ingot metallurgy (I/M) alloys of similar compositions was compared using bolt-loaded double cantilever beam specimens. In addition, the effects of aging, grain size, grain boundary segregation, pre-exposure embrittlement, and loading mode on the SCC of 7091 were independently assessed. Finally, the data generated were used to elucidate the mechanisms of SCC in the three P/M alloys. The IN 9052 had the lowest SCC susceptibility of all alloys tested in the peak-strength condition, although no SCC was observed in the two RS alloys in the overaged condition. The susceptibility of the RS alloys was greater in the underaged than the peak-aged temper. We detected no significant differences in susceptibility of 7091 with grain sizes varying from 2 to 300 μm. Most of the crack advance during SCC of 7091 was by hydrogen embrittlement (HE). Furthermore, both RS alloys were found to be susceptible to preexposure embrittlement—also indicative of HE. The P/M alloys were less susceptible to SCC than the I/M alloys in all but one test.

Characterization of B4C-composite-reinforced aluminum alloy composites

Science.gov (United States)

Singh, Ram; Rai, R. N.

2018-04-01

Dry sliding wear tests conducted on Pin-on-disk wear test machine. The rotational speed of disc is ranging from (400-600rpm) and under loads ranging from (30-70 N) the contact time between the disc and pin is constant for each pin specimen of composites is 15 minute. In all manufacturing industries the uses of composite materials has been increasing globally, In the present study, an aluminum 5083 alloy is used as the matrix and 5% of weight percentage of Boron Carbide (B4C) as the reinforcing material. The composite is produced using stir casting technique. This is cost effective method. The aluminum 5083 matrix can be strengthened by reinforcing with hard ceramic particles like silicon carbide and boron carbide. In this experiment, aluminum 5083 alloy is selected as one of main material for making parts of the ship it has good mechanical properties, good corrosion resistance and it is can welded very easily and does have good strength. The samples are tested for hardness and tensile strength. The mechanical properties like Hardness can be increased by reinforcing aluminum 5083alloy 5% boron carbide (B4C) particles and tensile strength. Finally the Scanning Electron Microscope (SEM) analysis and EDS is done, which helps to study topography of composites and it produces images of a sample by scanning it with a focused beam of electrons and the presence of composition found in the matrix.

Development of low activation aluminum alloys for reacting plasma experiment

International Nuclear Information System (INIS)

Matsumoto, K.; Kawai, H.; Saida, T.; Onozuka, M.

1986-01-01

In the advanced fusion devices aiming at D-T burning, structural components such as vacuum vessels, coil casings are exposed to high energy neutrons produced by D-T reaction. From a view point of maintenability of accessibility, low radioactive structural materials are strongly preferred. The authors have developed two types of improved alloys of reduced radioactivity based on 5083 aluminum alloy: Al-Mg-Bi . Cr and Al-Mg-Cu . Zr. Both of the alloys of 50mm thickness have been proved to have excellent material properties virtually equivalent to those of 5083 alloy

Microstructure, hardness and tensile properties of A380 aluminum alloy with and without Li additions

Energy Technology Data Exchange (ETDEWEB)

Karamouz, Mostafa [Research Center of Materials engineering, University of Kerman Industrial Graduate, Kerman (Iran, Islamic Republic of); Research Center of Materials engineering, University of Kerman Industrial Graduate, Kerman (Iran, Islamic Republic of); Azarbarmas, Mortaza, E-mail: mazarbarmas@ut.ac.ir [Faculty of Mechanical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Emamy, Masoud [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Alipour, Mohammad [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2013-10-10

In this work, the effects of lithium (Li) on the microstructure, hardness and mechanical properties of A380 aluminum alloy have been investigated. The alloy was produced by conventional casting. Microstructures of the samples were investigated using the optical and scanning electron microscopy. The results showed that with increase of Li content up to 0.1%, the morphology of β-Al{sub 5}FeSi and eutectic Si phases changed from intersected and branched coarse platelets into fine and independent ones. Li decreased hardness values of the alloy. Also, it was revealed from tensile tests that with addition of 0.6% Li, the ultimate tensile strength (UTS) and elongation values increased from 274 to 300 MPa and 3.8% to 6%, respectively. Fractographic examination of the fracture surfaces indicated that the alloys with Li addition had more ductile dimple and fewer brittle cleavage surfaces.

Plasma spraying of beryllium and beryllium-aluminum-silver alloys

International Nuclear Information System (INIS)

Castro, R.G.; Stanek, P.W.; Elliott, K.E.; Jacobson, L.A.

1994-01-01

A preliminary investigation on plasma-spraying of beryllium and a beryllium-aluminum-4% silver alloy was done at the Los Alamos National Laboratory's Beryllium Atomization and Thermal Spray Facility (BATSF). Spherical Be and Be-Al-4%Ag powders, which were produced by centrifugal atomization, were used as feedstock material for plasma-spraying. The spherical morphology of the powders allowed for better feeding of fine (<38 μm) powders into the plasma-spray torch. The difference in the as-deposited densities and deposit efficiencies of the two plasma-sprayed powders will be discussed along with the effect of processing parameters on the as-deposited microstructure of the Be-Al-4%Ag. This investigation represents ongoing research to develop and characterize plasma-spraying of beryllium and beryllium-aluminum alloys for magnetic fusion and aerospace applications

Plasma spraying of beryllium and beryllium-aluminum-silver alloys

International Nuclear Information System (INIS)

Castro, R.G.; Stanek, P.W.; Elliott, K.E.; Jacobson, L.A.

1993-01-01

A preliminary investigation on plasma-spraying of beryllium and a beryllium-aluminum 4% silver alloy was done at the Los Alamos National Laboratory's Beryllium Atomization and Thermal Spray Facility (BATSF). Spherical Be and Be-Al-4%Ag powders, which were produced by centrifugal atomization, were used as feedstock material for plasma-spraying. The spherical morphology of the powders allowed for better feeding of fine (<38 μm) powders into the plasma-spray torch. The difference in the as-deposited densities and deposit efficiencies of the two plasma-sprayed powders will be discussed along with the effect of processing parameters on the as-deposited microstructure of the Be-Al-4%Ag. This investigation represents ongoing research to develop and characterize plasma-spraying of beryllium and beryllium-aluminum alloys for magnetic fusion and aerospace applications

Method of forming magnetostrictive rods from rare earth-iron alloys

Science.gov (United States)

McMasters, O. Dale

1986-09-02

Rods of magnetrostructive alloys of iron with rare earth elements are formed by flowing a body of rare earth-iron alloy in a crucible enclosed in a chamber maintained under an inert gas atmosphere, forcing such molten rare-earth-iron alloy into a hollow mold tube of refractory material positioned with its lower end portion within the molten body by means of a pressure differential between the chamber and mold tube and maintaining a portion of the molten alloy in the crucible extending to a level above the lower end of the mold tube so that solid particles of higher melting impurities present in the alloy collect at the surface of the molten body and remain within the crucible as the rod is formed in the mold tube.

Mineralogical issues in long-term corrosion of iron and iron-nickel alloys

International Nuclear Information System (INIS)

VanOrden, A.C.; McNeil, M.B.

1988-01-01

Prediction of very long term corrosion behavior of buried objects in general requires taking into account that the corrosion processes themselves after the local conditions. Recent work has analyzed corrosion processes in terms of trajectories on Pourbaix diagrams and appears to offer the prospect for using short-term corrosion tests to project corrosion behavior over very long periods. Two different classes of materials are considered here: essentially pure iron, which is an analogue to the carbon steel design overpacks for the salt and basalt sites (on which work has been suspended at present, and iron-nickel alloys, which are the best analogues available for some of the alloys being considered on the tuff site. There are a number of sources of data on corrosion of iron over archaeological times; the data used in this paper are from the recent National Bureau of Standards work on Roman iron nails for Inchtuthill in Scotland, which can be dated fairly precisely to about 70 A.D. and whose method of production is understood. The only available source of natural-analogue data on Fe-Ni alloys is the corrosion of meteorites

The low-aluminium cast iron of reduced silicon content treated with cerium mischmetal

Directory of Open Access Journals (Sweden)

M. S. Soiński

2008-07-01

Full Text Available The work presents the effect of cerium mischmetal used in quantities of 0.1 and 0.2 wt-% and ferrosilicon used in quantities from 0.5% to 1.5% on the alloy matrix and the shape of graphite precipitates in the low-aluminium cast iron from seven heats, basing on the examination of its structure. The hypereutectic cast iron of the relatively high carbon content (4.0÷4.2% at the prior-to-treatment silicon and manganese content equal to ca. 0.6% and ca. 0.04%, respectively, has been examined.It has been found that the performed treatment leads to the change in the alloy matrix from the nearly almost pearlitic to the ferritic-pearlitic one accompanied by changes in the shape of graphite precipitates. Due to applying both of the mentioned substances in the above stated amounts the graphite precipitates in cast iron have taken the shape of nodular and vermicular ones, and no presence of flake graphite has been revealed. A quantitative analysis of the performed treatment i.e. determining the fractions of graphite precipitates of different shapes has been possible by means of a computer image analyser.

Processing and structure of in situ Fe-Al alloys produced by gas tungsten arc welding

Energy Technology Data Exchange (ETDEWEB)

Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

1997-02-14

Iron aluminide weld overlays are being investigated for corrosion and erosion protection of boiler tubes in low NOx burners. The primary objective of the research is to identify overlay compositions which can be deposited in a crack-free condition and provide corrosion protection in moderately reducing environments. In the current phase of work, Fe-Al alloy weld overlays were produced by depositing commercially pure aluminum wire on to low carbon steel substrates using Gas Tungsten Arc Welding. A systematic variation of the wire feed speed and current, two major factors affecting dilution, resulted in a variation in aluminum contents of the welds ranging from 3--42 wt% aluminum. The aluminum content was observed to increase with wire feed speed and a decrease in the current. The aluminum content was also found to affect the cracking susceptibility of the overlays. At 10wt% aluminum, few to no cracks were observed in the deposits. Above this value, cracking was prevalent throughout the weld. In addition, two types of microstructures were found correlating to different concentrations of aluminum. A homogeneous matrix with second phase particles consisting of coarse columnar grains was found for low aluminum concentrations. With higher aluminum contents, a two-phase constituent was observed to surround primary dendrites growing from the substrate. The transition of the microstructures occurred between 24 and 32 wt% Al.

Aging Optimization of Aluminum-Lithium Alloy L277 for Application to Cryotank Structures

Science.gov (United States)

Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Cho, A.

2003-01-01

Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties and improved damage tolerance. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. A design of experiments aging study was conducted for plate and a limited study on extrusions. To achieve the T8 temper, Alloy L277 is typically aged at 290 F for 40 hours. In the study for plate, a two-step aging treatment was developed through a design of experiments study and the one step aging used as a control. Based on the earlier NASA studies on 2195, the first step aging temperature was varied between 220 F and 260 F. The second step aging temperatures was varied between 290 F and 310 F, which is in the range of the single-step aging temperature. For extrusions, two, single-step, and one two-step aging condition were evaluated. The results of the design of experiments used for the T8 temper as well as a smaller set of experiments for the T6 temper for plate and the results for extrusions will be presented.

A comparison of corrosion inhibition of magnesium aluminum and zinc aluminum vanadate intercalated layered double hydroxides on magnesium alloys

Science.gov (United States)

Guo, Lian; Zhang, Fen; Lu, Jun-Cai; Zeng, Rong-Chang; Li, Shuo-Qi; Song, Liang; Zeng, Jian-Min

2018-04-01

The magnesium aluminum and zinc aluminum layered double hydroxides intercalated with NO3 -(MgAl-NO3-LDH and ZnAl-NO3-LDH) were prepared by the coprecipitation method, and the magnesium aluminum and the zinc aluminum layered double hydroxides intercalated with VO x -(MgAl-VO x -LDH and ZnAl-VO x -LDH) were prepared by the anion-exchange method. Morphologies, microstructures and chemical compositions of LDHs were investigated by SEM, EDS, XRD, FTIR, Raman and TG analyses. The immersion tests were carried to determine the corrosion inhibition properties of MgAl-VO x -LDH and ZnAl-VO x -LDH on AZ31 Mg alloys. The results showed that ZnAl-VO x -LDH possesses the best anion-exchange and inhibition abilities. The influence of treatment parameters on microstructures of LDHs were discussed. Additionally, an inhibition mechanism for ZnAl-VO x -LDH on the AZ31 magnesium alloy was proposed and discussed.

Development of technology of complex aluminum-silicon-chrome alloy with utilization of off grade raw materials

Directory of Open Access Journals (Sweden)

A. Mekhtiev

2015-01-01

Full Text Available Experimental studies on obtaining a complex aluminum-silicon-chrome alloy (FASCh from Karaganda high-ash coals and high-carbon ferrochromefines were carried out. A method for smelting low-carbon ferrochrome using aluminum-silicon-chrome alloy as a reductant is suggested.

Fe-based bulk amorphous alloys with iron contents as high as 82 at%

Energy Technology Data Exchange (ETDEWEB)

Li, Jin-Feng; Liu, Xue; Zhao, Shao-Fan; Ding, Hong-Yu [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yao, Ke-Fu, E-mail: kfyao@tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

2015-07-15

Fe-based bulk amorphous alloys (BAAs) with high Fe contents are advantageous due to their high saturation magnetization and low cost. However, preparing Fe-based BAAs with Fe contents higher than 80 at% is difficult due to their poor glass forming abilities (GFA). In this study, an Fe{sub 81}P{sub 8.5}C{sub 5.5}B{sub 2}Si{sub 3} BAA with a diameter of 1 mm and a saturation magnetization of 1.56 T was successfully prepared using the fluxing and copper mold casting methods. In addition, by introducing a small amount of elemental Mo to the alloy, an Fe{sub 82}Mo{sub 1}P{sub 6.5}C{sub 5.5}B{sub 2}Si{sub 3} BAA rod with a diameter of 1 mm, a high saturation magnetization of 1.59 T, a high yield stress of 3265 MPa, and a clear plasticity of 1.3% was prepared in the same way. The cost effectiveness and good magnetic properties of these newly-developed Fe-based BAAs with Fe contents as high as 82 at% would be advantageous and promising for industrial applications. - Highlights: • Novel Fe-based BAA with no other metallic element except 81 at% Fe was prepared. • Fe-based bulk amorphous alloy (BAA) with the highest Fe content (82%) was prepared. • Very high saturation magnetization of 1.59 T has been achieved. • A new thought for designing Fe-based BAA with high Fe content was provided.

Role of samarium additions on the shape memory behavior of iron based alloys

International Nuclear Information System (INIS)

Shakoor, R.A.; Khalid, F. Ahmad; Kang, Kisuk

2011-01-01

Research highlights: → The effect of samarium contents on shape memory behavior has been studied. → Addition of samarium increases the strength, c/a ratio and ε (hcp martensite). → Addition of samarium retards the nucleation of α (bcc martensite). → Improvement in shape memory effect with the increase in samarium contents. - Abstract: The effect of samarium contents on shape memory behavior of iron based shape memory alloys has been studied. It is found that the strength of the alloys increases with the increase in samarium contents. This effect can be attributed to the solid solution strengthening of austenite by samarium addition. It is also noticed that the shape memory effect increases with the increase in samarium contents. This improvement in shape memory effect presumably can be regarded as the effect of improvement in strength, increase in c/a ratio and obstruction of nucleation of α in the microstructure.

Finite element modelling of aluminum alloy 2024-T3 under transverse impact loading

Science.gov (United States)

Abdullah, Ahmad Sufian; Kuntjoro, Wahyu; Yamin, A. F. M.

2017-12-01

Fiber metal laminate named GLARE is a new aerospace material which has great potential to be widely used in future lightweight aircraft. It consists of aluminum alloy 2024-T3 and glass-fiber reinforced laminate. In order to produce reliable finite element model of impact response or crashworthiness of structure made of GLARE, one can initially model and validate the finite element model of the impact response of its constituents separately. The objective of this study was to develop a reliable finite element model of aluminum alloy 2024-T3 under low velocity transverse impact loading using commercial software ABAQUS. Johnson-Cook plasticity and damage models were used to predict the alloy's material properties and impact behavior. The results of the finite element analysis were compared to the experiment that has similar material and impact conditions. Results showed good correlations in terms of impact forces, deformation and failure progressions which concluded that the finite element model of 2024-T3 aluminum alloy under low velocity transverse impact condition using Johnson-Cook plastic and damage models was reliable.

Formation and stability of aluminum-based metallic glasses in Al-Fe-Gd alloys

International Nuclear Information System (INIS)

He, Y.; Poon, S.J.; Shiflet, G.J.

1988-01-01

Metallic glasses, a class of amorphous alloys made by rapid solidification, have been studied quite extensively for almost thirty years. It has been recognized for a long time that metallic glasses are usually very strong and ductile, and exhibit high corrosion resistance relative to crystalline alloys with the same compositions. Recently, metallic glasses containing as much as 90 atomic percent aluminum have been discovered independently by two groups. This discovery has both scientific and technological implications. The formability of these new glasses have been found to be unusual. Studies of mechanical properties in these new metallic glasses show that many of them have tensile strengths over 800MPa, greatly exceeding the strongest commercial aluminum alloys. The high strengths of aluminum-rich metallic glasses can be of significant importance in obtaining high strength low density materials. Therefore, from both scientific and technological standpoints, it is important to understand the formation and thermal stability of these metallic glasses. Al-Fe-Gd alloys were chosen for a more detailed study since they exhibit high tensile strengths

The influence of the deoxidization on the aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang, Q.; Wu, X.; Wang, W. [Beijing Univ. of Aeronautics and Astronautics (China). Dept. of Mater. Sci. and Eng.

2000-07-01

Though the composition of the 7075 and 7050 aluminum alloys are quite similar, the anodic behaviors of the two alloys were quite different. Unlike the 7075 alloy, a chromic acid anodic film could not be formed on the 7050 alloy surface with a conventional anodizing process, unless a so-called deoxidization was employed. Therefore, the effects of the deoxidization were studied. The results showed that the deoxidization affected the 7050 quite obviously, introducing numerous number of the ''pits'' to the sample surface, and hence the film obtained was relatively thick but rather weak. In addition, the anodizing voltage also brought remarkable effect to the anodic behavior of the 7050 alloy. The test results showed that the deoxidization lowered the corrosion resistance of the 7050 alloys. By contrast, neither oxidization nor the voltage affected the anodic behavior and the corrosion resistance of the 7075 alloy very much. (orig.)

Corrosion and protection of aluminum alloys in seawater

Energy Technology Data Exchange (ETDEWEB)

Nisancioglu Kemal [Department of Materials Technology, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

2004-07-01

The paper deals with pitting and uniform corrosion and effectiveness of cathodic protection in reducing these corrosion forms. In stagnant waters or presence of low flow rates, pitting may occur. However, pitting corrosion, driven by the Fe-rich cathodic intermetallic compounds, is often of superficial nature. The pits tend to passivate as a result of etching or passivation of the intermetallics with time. Cathodic protection is an effective way of preventing pitting. It also requires low current densities since the cathodic area, defined by the Fe-rich intermetallics, is small in contrast to steel, which is uniformly accessible to the cathodic reaction. Although thermodynamic calculations suggest possible instability of the oxide in slightly alkaline solutions, such as seawater, protective nature of the oxide in practice is attributed to the presence of alloying elements such as Mg and Mn. Thus, the passivity of both the aluminum matrix alloy (the anode) and the intermetallics (cathodes) have to be considered in evaluating the corrosion and protection of aluminum alloys. With increasing flow rate, the possibility of pitting corrosion reduces with increase in the rate of uniform corrosion, which is controlled by the flow dependent chemical dissolution of the oxide. Cathodic protection does not stop this phenomenon, and coatings have to be used. (authors)

Differential ion beam sputtering of segregated phases in aluminum casting alloys

International Nuclear Information System (INIS)

Nguyen, Chuong L.; Wirtz, Tom; Fleming, Yves; Metson, James B.

2013-01-01

Highlights: ► Novel combination of SIMS and SPM for accurate 3D chemical mapping. ► Different removal rates of metallurgical phases by ion beam. ► Faster oxidation rate of silicon vs. aluminum at room temperature in vacuum. - Abstract: Differential sputtering of materials is an important phenomenon in materials science with many implications. One of the practical applications of this phenomenon is the modification of the interface between a substrate and coating during sputter coating of materials. Aluminum casting alloys, as common materials in many applications, are suitable candidates to investigate this phenomenon due to their phase separated microstructures. Changes at the sample surface under ion bombardment can be characterized by a range of complimentary techniques. The novel SIMS–SPM instrument used here enables a thorough investigation into the evolution of topography and composition caused by ion beam sputtering. For the alloy examined in this work, the aluminum regions are removed faster than the silicon particles. The faster oxidation rate of silicon compared to aluminum in the exposed surface can also be deduced from this study.

A study of aluminum-lithium alloy solidification using acoustic emission techniques. Ph.D. Thesis, 1991

Science.gov (United States)

Henkel, Daniel P.

1992-01-01

Physical phenomena associated with the solidification of an aluminum lithium alloy was characterized using acoustic emission (AE) techniques. It is shown that repeatable patterns of AE activity may be correlated to microstructural changes that occur during solidification. The influence of the experimental system on generated signals was examined in the time and frequency domains. The analysis was used to show how an AE signal from solidifying aluminum is changed by each component in the detection system to produce a complex waveform. Conventional AE analysis has shown that a period of high AE activity occurs in pure aluminum, an Al-Cu alloy, and the Al-Li alloy, as the last fraction of solid forms. A model attributes this to the internal stresses of grain boundary formation. An additional period of activity occurs as the last fraction of solid forms, but only in the two alloys. A model attributes this to the formation of interdendritic porosity which was not present in the pure aluminum. The AE waveforms were dominated by resonant effects of the waveguide and the transducer.

Moessbauer effect studies of magnetic interactions in iron and dilute iron alloys

International Nuclear Information System (INIS)

Woude, F. van der; Schurer, P.J.; Sawatzky, G.A.

1975-01-01

A temperature-dependent Moessbauer study was conducted in FeX alloys, where X = Al, Si, Ti, V, Cr, Mn, Co, and Ni, aimed at solving the problem of 'what is localized and what is itinerant in iron ferromagnetism'. The experimental results are interpreted using a phenomenological model based on a modified Zener-Vonsovskij theory. Absorption spectra of FeX alloys were measured as a function of temperature. It was found that the 3d magnetic moments in iron were mainly localized while exchange coupling was provided by partly itinerant 3d electrons. (L.D.)

Porosity in fiber laser formation of 5A06 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Yu, Yang Chun; Wang, Chun Ming; Hu, Xi Yuan; Wang, Jun; Yu, Sheng Fu [HUST, Wuhan (China)

2010-05-15

The mechanism of porosity formation and its suppression methods in laser formation of aluminum alloy have been studied using a 4kW fiber laser to weld 5A06 aluminum alloy with SAl-Mg5 filler. It was found that the porosity formation is closely related to the stability of the keyhole and fluctuation of the molten pool in the laser welding aluminum alloy. The filling wire increased the instability of the keyhole and weld pool, thus further increasing the amount of gas cavities in the joint. Prefabrication of a suitable gap for the butt joint can provide a natural passage for the flow of the liquid metal, which can weaken, and even completely eliminate the disturbance of the filling wire on the formation of keyhole. The gap can also provide a passage for the escape of the bubble. Thus, this method can greatly decrease the sheet's susceptibility to porosity. Moreover, for a thin sheet, if the power of the laser is sufficient to form a keyhole with stable penetration through the weld sheet, a weld bead without porosity can also be obtained because closing the keyhole is almost impossible

Porosity in fiber laser formation of 5A06 aluminum alloy

International Nuclear Information System (INIS)

Yu, Yang Chun; Wang, Chun Ming; Hu, Xi Yuan; Wang, Jun; Yu, Sheng Fu

2010-01-01

The mechanism of porosity formation and its suppression methods in laser formation of aluminum alloy have been studied using a 4kW fiber laser to weld 5A06 aluminum alloy with SAl-Mg5 filler. It was found that the porosity formation is closely related to the stability of the keyhole and fluctuation of the molten pool in the laser welding aluminum alloy. The filling wire increased the instability of the keyhole and weld pool, thus further increasing the amount of gas cavities in the joint. Prefabrication of a suitable gap for the butt joint can provide a natural passage for the flow of the liquid metal, which can weaken, and even completely eliminate the disturbance of the filling wire on the formation of keyhole. The gap can also provide a passage for the escape of the bubble. Thus, this method can greatly decrease the sheet's susceptibility to porosity. Moreover, for a thin sheet, if the power of the laser is sufficient to form a keyhole with stable penetration through the weld sheet, a weld bead without porosity can also be obtained because closing the keyhole is almost impossible

Iron-nickel-chromium alloys

International Nuclear Information System (INIS)

Karenko, M.K.

1981-01-01

A specification is given for iron-nickel-chromium age-hardenable alloys suitable for use in fast breeder reactor ducts and cladding, which utilize the gamma-double prime strengthening phase and are characterized in having a delta or eta phase distributed at or near grain boundaries. A range of compositions is given. (author)

Influence of scandium on the microstructure and strength properties of the welded joint at the laser welding of aluminum-lithium alloys

Science.gov (United States)

Malikov, A. G.; Golyshev, A. A.; Ivanova, M. Yu.

2017-10-01

Today, aeronautical equipment manufacture involves up-to-date high-strength aluminum alloys of decreased density resulting from lithium admixture. Various technologies of fusible welding of these alloys are being developed. Serious demands are imposed to the welded joints of aluminum alloys in respect to their strength characteristics. The paper presents experimental investigations of the optimization of the laser welding of aluminum alloys with the scandium-modified welded joint. The effect of scandium on the micro-and macro-structure has been studied as well as the strength characteristics of the welded joint. It has been found that scandium under in the laser welding process increases the welded joint elasticity for the system Al-Mg-Li, aluminum alloy 1420 by 20 %, and almost doubles the same for the system Al-Cu-Li, aluminum alloy 1441.

An Economic Model and Experiments to Understand Aluminum-Cerium Alloy Recycling

Science.gov (United States)

Iyer, Ananth V.; Lim, Heejong; Rios, Orlando; Sims, Zachary; Weiss, David

2018-04-01

We provide an economic model to understand the impact of adoption, sorting and pricing of scrap on the recycling of a new aluminum-cerium (AlCe) alloy for use in engine blocks in the automobile industry. The goal of the laboratory portion of this study is to investigate possible effects of cerium contamination on well-established aluminum recycling streams. Our methodology includes three components: (1) focused data gathering from industry supply chain participants, (2) experimental data through laboratory experiments to understand the impact of cerium on existing alloys and (3) an economic model to understand pricing incentives on a recycler's separation of AlCe engine blocks.

Thermal conductivity prediction of closed-cell aluminum alloy considering micropore effect

Directory of Open Access Journals (Sweden)

Donghui Zhang

2015-02-01

Full Text Available Large quantities of micro-scale pores are observed in the matrix of closed-cell aluminum alloy by scanning electron microscope, which indicates the dual-scale pore characteristics. Corresponding to this kind of special structural morphology, a new kind of dual-scale method is proposed to estimate its effective thermal conductivity. Comparing with the experimental results, the article puts forward the view that the prediction accuracy can be improved by the dual-scale method greatly. Different empirical formulas are also investigated in detail. It provides a new method for thermal properties estimation and makes preparation for more suitable empirical formula for closed-cell aluminum alloy.

Electrochemical Impedance Study of Zinc Yellow Polypropylene-Coated Aluminum Alloy

Directory of Open Access Journals (Sweden)

Zhi-hua Sun

2010-01-01

Full Text Available Performance of zinc yellow polypropylene-coated aluminum alloy 7B04 during accelerated degradation test is studied using electrochemical impedance spectroscopy (EIS. It has been found that the zinc yellow polypropylene paint has few flaw and acts as a pure capacitance before accelerated test. After 336-hour exposure to the test, the impedance spectroscopy shows two time constants, and water has reached to the aluminum alloy/paint interface and forms corrosive microcell. For the scratched samples, the reaction of metal corrosion and the hydrolysis of zinc yellow ion can occur simultaneously. The impedance spectroscopy indicates inductance after 1008-hour exposure to the test, but the inductance disappears after 1344-hour exposure and the passivation film has pitting corrosion.

Study to determine the content of vanadium, aluminum, nickel, sodium, iron and copper in a catalytic cracking catalyst, by using Atomic Absorption Spectrometry

International Nuclear Information System (INIS)

Gomez, J.; Alonso, A.; Tumbarell, O.; Bustanmete, E.

2003-01-01

Atomic Absorption Spectrometry (AAS), has the advantage of its simplicity, speed and low cost. All this, together with its high sensibility and selectivity, makes the AAS one the most widely used analytic techniques. The present work shows, the study to determine the content of vanadium, aluminum, nickel, sodium, iron and copper in a catalytic cracking catalyst of a refinery, by using this technique. The results are compared to those of two laboratories which use the ICP-AES and AAS techniques and shows the processing of the statistics with the use of the t of Student and the F of Snedecor. The results using different methods are also shown as well as the recommended application of this results in the chemical characterization of this type of catalysts

Anodic behaviours, dissolution and passivation of iron-nickel alloys in sulphuric environment. Influence of friction

International Nuclear Information System (INIS)

Ponthiaux, Pierre

1990-01-01

This research thesis reports the study of anodic dissolution and passivation of iron-nickel alloys (10, 20 and 31 pc nickel) in a sulphuric environment, with or without friction, by using anodic polarization curves. Without friction, the three alloys have a similar behaviour as pure iron. The analysis reveals different dissolution and passivation mechanisms with pure iron, and highlights the influence of nickel content on corresponding kinetics. The influence of cyclic plane-on-plane friction has been studied for the 31 pc nickel alloy which has an unsteady austenitic structure. Fretting results in some modifications of polarization curves. These modifications are analysed with respect to fretting parameters (relative speed of antagonist surfaces, contact pressure). They reveal the specific influence of the following phenomena: material strain hardening, martensitic transformation induced by strain hardening, partial destruction of adsorbates and/or of the passive film. Modifications of polarization curves give also information on the evolution of friction characteristics with respect to speed (a phenomenon of lubrication by the electrolyte occurs) [fr

Solid - solid and solid - liquid phase transitions of iron and iron alloys under laser shock compression

Science.gov (United States)

Harmand, M.; Krygier, A.; Appel, K.; Galtier, E.; Hartley, N.; Konopkova, Z.; Lee, H. J.; McBride, E. E.; Miyanishi, K.; Nagler, B.; Nemausat, R.; Vinci, T.; Zhu, D.; Ozaki, N.; Fiquet, G.

2017-12-01

An accurate knowledge of the properties of iron and iron alloys at high pressures and temperatures is crucial for understanding and modelling planetary interiors. While Earth-size and Super-Earth Exoplanets are being discovered in increasingly large numbers, access to detailed information on liquid properties, melting curves and even solid phases of iron and iron at the pressures and temperatures of their interiors is still strongly limited. In this context, XFEL sources coupled with high-energy lasers afford unique opportunities to measure microscopic structural properties at far extreme conditions. Also the achievable time resolution allows the shock history and phase transition mechanisms to be followed during laser compression, improving our understanding of the high pressure and high strain experiments. Here we present recent studies devoted to investigate the solid-solid and solid-liquid transition in laser-shocked iron and iron alloys (Fe-Si, Fe-C and Fe-O alloys) using X-ray diffraction and X-ray diffuse scattering. Experiment were performed at the MEC end-station of the LCLS facility at SLAC (USA). Detection of the diffuse scattering allowed the identification of the first liquid peak position along the Hugoniot, up to 4 Mbar. The time resolution shows ultrafast (between several tens and several hundreds of picoseconds) solid-solid and solid-liquid phase transitions. Future developments at XFEL facilities will enable detailed studies of the solid and liquid structures of iron and iron alloys as well as out-of-Hugoniot studies.

EFFECT OF CONTROLLED QUENCHING ON THE AGING OF 2024 ALUMINUM ALLOY CONTAINING BORON

Directory of Open Access Journals (Sweden)

N. Khatami

2014-03-01

Full Text Available The presence of alloying elements, sometimes in a very small amount, affects mechanical properties one of these elements is Boron. In Aluminum industries, Boron master alloy is widely used as a grain refiner In this research, the production process of Aluminum –Boron master alloy was studied at first then, it was concurrently added to 2024 Aluminum alloy. After rolling and homogenizing the resulting alloy, the optimal temperature and time of aging were determined during the precipitation hardening heat treatment by controlled quenching (T6C. Then, in order to find the effect of controlled quenching, different cycles of heat treatment including precipitation heat treatment by controlled quenching (T6C and conventional quenching (T6 were applied on the alloy at the aging temperature of 110°C. Mechanical properties of the resulting alloy were evaluated after aging at optimum temperature of 110°C by performing mechanical tests including hardness and tensile tests. The results of hardness test showed that applying the controlled quenching instead of conventional quenching in precipitation heat treatment caused reduction in the time of reaching the maximum hardness and also increase in hardness rate due to the generated thermo-elastic stresses rather than hydrostatic stresses and increased atomic diffusion coefficient as well. Tensile test results demonstrated that, due to the presence of boride particles in the microstructure of the present alloy, the ultimate tensile strength in the specimens containing Boron additive increased by 3.40% in comparison with the specimens without such an additive and elongation (percentage of relative length increase which approximately increased by 38.80% due to the role of Boron in the increase of alloy ductility

Achievement report for fiscal 1999 on development of 'technology to promote diversification of secondary aluminum alloys'; 1999 nendo aluminium saisei jigane tayoka sokushin gijutsu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Discussions were given on aluminum scraps anticipated to be generated in a great quantity mainly from automobiles in the future, with an objective to apply secondary aluminum alloys to automotive field. In the study on alloy contents and characteristics of regenerated aluminum lumps, 5182 and 5052 alloys for automobile structure members and 6000 alloy for panel use were selected as the object. Cast lumps were manufactured on a trial basis varying the concentrations of impurity elements assumed to be mixed into the regenerated material, such as Fe, Si, Zn, and Cu, as well as their cooling speeds. Subsequent processes including rolling were proceeded to evaluate the material properties. These activities have resulted in accumulation of the basic data. For the welding technology on regenerated aluminum material, studies were performed on YAG laser welding. Applicability of the regenerated material as the automobile structure members was recognized by optimizing the basic welding conditions and the basic construction conditions according to each part to be structured. In order to clarify the positioning of the regenerated metal as a resource, investigations were performed on demand trends in the aluminum scrap material, and its recycling trends. (NEDO)

Tensile and fracture behavior of AA6061-T6 aluminum alloys: micro-mechanical approach

International Nuclear Information System (INIS)

Shen, Y.

2012-01-01

The AA6061-T6 aluminum alloy was chosen as the material for the core vessel of the future Jules Horowitz testing reactor (JHR). The objective of this thesis is to understand and model the tensile and fracture behavior of the material, as well as the origin of damage anisotropy. A micro-mechanical approach was used to link the microstructure and mechanical behavior. The microstructure of the alloy was characterized on the surface via Scanning Electron Microscopy and in the 3D volume via synchrotron X-ray tomography and laminography. The damage mechanism was identified by in-situ SEM tensile testing, ex-situ X-ray tomography and in-situ laminography on different levels of triaxiality. The observations have shown that damage nucleated at lower strains on Mg 2 Si coarse precipitates than on iron rich intermetallics. The identified scenario and the in-situ measurements were then used to develop a coupled GTN damage model incorporating nucleation, growth and coalescence of cavities formed by coarse precipitates. The relationship between the damage and the microstructure anisotropies was explained and simulated. (author)

Microstructural Characterization of Aluminum-Lithium Alloys 1460 and 2195

Science.gov (United States)

Wang, Z. M.; Shenoy, R. N.

1998-01-01

Transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) techniques were employed to characterize the precipitate distributions in lithium-containing aluminum alloys 1460 and 2195 in the T8 condition. TEM examinations revealed delta prime and T1 as the primary strengthening precipitates in alloys 1460 and 2195 respectively. TEM results showed a close similarity of the Russian alloy 1460 to the U.S. alloy 2090, which has a similar composition and heat treatment schedule. DSC analyses also indicate a comparable delta prime volume fraction. TEM study of a fractured tensile sample of alloy 1460 showed that delta prime precipitates are sheared by dislocations during plastic deformation and that intense stress fields arise at grain boundaries due to planar slip. Differences in fracture toughness of alloys 1460 and 2195 are rationalized on the basis of a literature review and observations from the present study.

Age hardening in rapidly solidified and hot isostatically pressed beryllium-aluminum-silver alloys

International Nuclear Information System (INIS)

Carter, D.H.; McGeorge, A.C.; Jacobson, L.A.; Stanek, P.W.

1995-01-01

Three different alloys of beryllium, aluminum and silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy compositions were, by weight, 50% Be, 47.5% Al, 2.5% Ag, 50% Be, 47% Al, 3% Ag, and 50% Be, 46% Al, 4% Ag. Due to the low solubility of both aluminum and silver in beryllium, the silver was concentrated in the aluminum phase, which appeared to separate from the beryllium in the liquid phase. A fine, continuous composite beryllium-aluminum microstructure was formed, which did not significantly change after hot isostatically pressing at 550 C for one hour at 30,000 psi argon pressure. Samples of HIP material were solution treated at 550 C for one hour, followed by a water quench. Aging temperatures were 150, 175, 200 and 225 C for times ranging from one half hour to 65 hours. Hardness measurements were made using a diamond pyramid indenter with a load of 1 kg. Results indicate that peak hardness was reached in 36--40 hours at 175 C and 12--16 hours at 200 C aging temperature, relatively independent of alloy composition

Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology

Science.gov (United States)

Lang, Lihui; Zhang, Quanda; Sun, Zhiying; Wang, Yao

2017-09-01

In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM). The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

The effect of zinc on the microstructure and phase transformations of casting Al-Cu alloys

OpenAIRE

Manasijević Ivana I.; Štrbac Nada D.; Živković Dragana T.; Balanović Ljubiša T.; Minić Duško M.; Manasijević Dragan M.

2016-01-01

Copper is one of the main alloying elements for aluminum casting alloys. As an alloying element, copper significantly increases the tensile strength and toughness of alloys based on aluminum. The copper content in the industrial casting aluminum alloys ranges from 3,5 to 11 wt.%. However, despite the positive effect on the mechanical properties, copper has a negative influence on the corrosion resistance of aluminum and its alloys. In order to further improve the properties of Al-Cu alloys th...

Field Induced Magnetic Moments in a Metastable Iron-Mercury Alloy

DEFF Research Database (Denmark)

Pedersen, M.S.; Mørup, Steen; Linderoth, Søren

1996-01-01

The magnetic properties of a metastable iron-mercury alloy have been investigated in the temperature range from 5 to 200 K by Mossbauer spectroscopy and magnetization measurements. At low temperature the magnetic moment per iron atom is larger than af alpha-Fe. The effective spontaneous magnetic ....... It was found that the field-induced increase of the magnetic moment in the metastable iron-mecury alloy was about 0.06 Bohr magnetons per iron atom in the temperature range from 5 to 200 K for a field change from 6 to 12 T....

Impact Toughness and Heat Treatment for Cast Aluminum

Science.gov (United States)

Lee, Jonathan A (Inventor)

2016-01-01

A method for transforming a cast component made of modified aluminum alloy by increasing the impact toughness coefficient using minimal heat and energy. The aluminum alloy is modified to contain 0.55%-0.60% magnesium, 0.10%-0.15% titanium or zirconium, less than 0.07% iron, a silicon-tomagnesium product ratio of 4.0, and less than 0.15% total impurities. The shortened heat treatment requires an initial heating at 1,000deg F. for up to I hour followed by a water quench and a second heating at 350deg F. to 390deg F. for up to I hour. An optional short bake paint cycle or powder coating process further increase.

Perforation of Thin Aluminum Alloy Plates by Blunt Projectiles - Experimental and Numerical Investigation

Science.gov (United States)

Wei, Gang; Zhang, Wei

2013-06-01

Reducing the armor weight has become a research focus in terms of armored material with the increasing requirement of the mobility and flexibility of tanks and armored vehicles in modern local wars. Due to high strength-to-density ratio, aluminum alloy has become a potential light armored material. In this study, both lab-scale ballistic test and finite element simulation were adopted to examine the ballistic resistance of aluminum alloy targets. Blunt high strength steel projectiles with 12.7 mm diameter were launched by light gas gun against 3.3 mm thick aluminum alloy plates at velocity of 90 ~ 170 m/s. The ballistic limit velocity was obtained. Plugging failure and obvious structure deformation of targets were observed, and with the impact velocity increasing, the target structure deformation decrease gradually. Corresponding 2D finite element simulations were conducted by ABAQUS/EXPLICIT combined with material performance testing. Good agreement between the numerical simulations and the experimental results was found. National Natural Science Foundation of China (No.: 11072072).

Research on the Treatment of Aluminum Alloy Chemical Milling Wastewater with Fenton Process

Science.gov (United States)

Zong-liang, Huang; Ru, Li; Peng, Luo; Jun-li, Gu

2018-03-01

The aluminum alloy chemical milling wastewater was treated by Fenton method. The effect of pH value, reaction time, rotational speed, H2O2 dosage, Fe2+ dosage and the molar ratio between H2O2 and Fe2+ on the COD removal rate of aluminum alloy chemical milling wastewater were investigated by single factor experiment and orthogonal experiment. The results showed that the optimum operating conditions for Fenton oxidation were as follows: the initial pH value was 3, the rotational speed was 250r/min, the molar ratio of H2O2 and Fe2+ was 8, the reaction time was 90 min. Under the optimum conditions, the removal rate of the wastewater’s COD is about 72.36%. In the reaction kinetics that aluminum alloy chemical milling wastewater was oxidized and degraded by Fenton method under the optimum conditions, the reaction sequence of the initial COD was 0.8204.

Statistical study to determine the effect of carbon, silicon, nickel and other alloying elements on the mechanical properties of as-cast ferritic ductile irons

International Nuclear Information System (INIS)

Lacaze, J.; Sertucha, J.; Larranaga, P.; Suarez, R.

2016-01-01

There is a great interest in fully ferritic ductile irons due to their structural homogeneity, remarkable ductility and good response when machining. On the other hand the wide variety of raw materials available in foundry plants becomes a problem when controlling the chemical composition of the manufactured alloys. The present work shows a statistical study about the effect of different C, Si, Ni contents and other minor elements on structural and mechanical properties of a group of ferritic ductile iron alloys. A set of equations are finally presented to predict room temperature mechanical properties of ferritic ductile irons by means of their chemical composition and pearlite content. (Author)

Statistical study to determine the effect of carbon, silicon, nickel and other alloying elements on the mechanical properties of as-cast ferritic ductile irons

Energy Technology Data Exchange (ETDEWEB)

Lacaze, J.; Sertucha, J.; Larranaga, P.; Suarez, R.

2016-10-01

There is a great interest in fully ferritic ductile irons due to their structural homogeneity, remarkable ductility and good response when machining. On the other hand the wide variety of raw materials available in foundry plants becomes a problem when controlling the chemical composition of the manufactured alloys. The present work shows a statistical study about the effect of different C, Si, Ni contents and other minor elements on structural and mechanical properties of a group of ferritic ductile iron alloys. A set of equations are finally presented to predict room temperature mechanical properties of ferritic ductile irons by means of their chemical composition and pearlite content. (Author)

Dynamic Mechanical Behaviors of 6082-T6 Aluminum Alloy

Directory of Open Access Journals (Sweden)

Peng Yibo

2013-01-01

Full Text Available The structural components of high speed trains are usually made of aluminum alloys, for example, 6082. The dynamic mechanical behavior of the material is one of key factors considered in structural design and safety assessment. In this paper, dynamic mechanical experiments were conducted with strain rate ranging from 0.001 s−1 to 100 s−1 using Instron tensile testing machine. The true stress-strain curves were fitted based on experimental data. Johnson-Cook model of 6082-T6 aluminum alloy was built to investigate the effect of strain and strain rate on flow stress. It has shown that the flow stress was sensitive to the strain rate. Yield strength and tensile strength increased with a high strain rate, which showed strain rate effect to some extent. Fracture analysis was carried out by using Backscattered Electron imaging (BSE. As strain rate increased, more precipitates were generated in fracture.

Joining of dissimilar metals by diffusion bonding. Titanium alloy with aluminum

Energy Technology Data Exchange (ETDEWEB)

Akca, Enes [International Univ. of Sarajevo (Bosnia and Herzegovina). Research and Development Center; International Univ. of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering; Gursel, Ali [International Univ. of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering

2017-05-01

This paper presents a novel diffusion bonding process of commercially pure aluminum to Ti-6Al-4V alloy at 520, 560, 600 and 640 C for 30, 45 and 60 minutes under argon gas shielding without the use of interlayer. The approach is to overcome the difficulties in fusion welding of dissimilar alloys. Diffusion bonding is a dissimilar metal welding process which can be applied to the materials without causing any physical deformations. Processed samples were metallographically prepared, optically examined followed by Vickers microhardness test and subjected to tensile test in order to determine joint strength. Scanning electron microscopy and energy dispersive spectroscopy were used in this work to investigate the compositional changes across the joint region. Elemental composition of the region has been successfully defined between titanium alloy and aluminum. The maximum tensile strength was obtained from the samples bonded at the highest temperatures of 600 and 640 C.

Element segregation behavior of aluminum-copper alloy ZL205A

Directory of Open Access Journals (Sweden)

Fan Li

2014-11-01

Full Text Available In aluminum-copper alloy, the segregation has a severe bad effect on the alloying degree, strength and corrosion resistance. A deeper understanding of element segregation behavior will have a great significance on the prevention of segregation. In the study, the element segregation behavior of ZL205A aluminum-copper alloy was investigated by examining isothermally solidified samples using scanning electron microscopy and energy dispersive spectroscopy. The calculated results of segregation coefficients show that Cu and Mn are negative segregation elements; while Ti, V and Zr are positive segregation elements. The sequence of element segregation degree from the greatest to the least in ZL205A alloy is Cu, Mn, V, Ti, Zr and Al. The density of residual liquid is expected to increase with a decrease in the quenching temperature ranging from 630 ºC to 550 ºC. The calculated results confirm that the quenching temperature has an insignificant effect on the liquid density; and the variation of density is mainly due to element segregation. Consequently, segregations of Al, Cu and Mn lead to an increase in density, but Ti, V and Zr present the opposite effect. The contribution of each element to the variation of the liquid density was analyzed. The sequence of contributions of alloying elements to the variation of total liquid density is Cu﹥Al﹥Mn﹥V﹥Ti﹥Zr.

Study of the controllable reactivity of aluminum alloys and their promising application for hydrogen generation

International Nuclear Information System (INIS)

Fan Meiqiang; Sun Lixian; Xu Fen

2010-01-01

The hydrolysis performances of two aluminum alloys are investigated as their reactivity can be controlled via the different additives. The additive of NaCl has the positive effect to improve the hydrolysis properties of the aluminum alloys with quicker hydrolysis kinetic and lower hydrolysis temperature. For examples, in 6 min of hydrolysis reaction, the Al-5 wt%Hg-5 wt%NaCl can produce 971 mL g -1 hydrogen, higher than 917 mL g -1 hydrogen from Al-10 wt%Hg alloy. The Al-In-NaCl alloy has lower hydrolysis temperature about 10 K than that of Al-In alloy. Meanwhile, the reactivity of Al alloys can be improved or reduced via the additive metals. It can be found that the additive cadmium can reduce the reactivity of Al-Hg alloy. The Al-Hg-Cd alloys can keep good stability at the moist atmosphere below 343 K and have excellent hydrolysis performance around 343-373 K. The debased reactivity of Al-Hg-Cd composite comes from the formation of CdHg 2 compounds in the milling process. But the additive Zn and Ga doped into the Al-In-NaCl alloys can quickly increase the reactivity of the alloy which can quickly react with water at room temperature and have high hydrogen yield up to the theoretic value. Therefore, it is a promising possibility that the controllable reactivity of aluminum alloys can be obtained through the different additive according to the practical request, and the Al alloys can produce pure hydrogen for the fuel cell via the hydrolysis reaction.

Low temperature irradiation effects on iron-boron based amorphous metallic alloys

International Nuclear Information System (INIS)

Audouard, Alain.

1983-01-01

Three iron-boron amorphous alloys and the crystalline Fe 3 B alloy have been irradiated at liquid hydrogen temperature. 2,4 MeV electron irradiation induces the creation of point defects in the amorphous alloys as well as in the crystalline Fe 3 B alloy. These point defects can be assimilated to iron ''Frenkel pairs''. They have been characterized by determining their intrinsic electrical resistivity and their formation volume. The displacement threshold energy of iron atoms has also been determined. 10 B fission fragments induce, in these amorphous alloys, displacement cascades which lead to stable vacancy rich zones. This irradiation also leads to a structural disorder in relation with the presence of defects. 235 U fission fragments irradiation modifies drastically the structure of the amorphous alloys. The results have been interpreted on the basis of the coexistence of two opposite processes which induce local disorder and crystallisation respectively [fr

EVALUATION OF MACHINABILITY OF DUCTILE IRONS ALLOYED WITH Ni AND Cu IN TERMS OF CUTTING FORCES AND SURFACE QUALITY

Directory of Open Access Journals (Sweden)

Yücel AŞKUN

2003-02-01

Full Text Available Due to the enhanced strength, ductility and thoughness of Ductile Iron (DI when compared to the other types cast iron, its machinability is relatively poor. When a steel part is replaced with ductile iron, however, better machinability is considered to be the most important gain. This study presents the results of machining tests of ductile irons alloyed with Ni and Cu at various contents to determine the effect of their microstructure and mechanical properties on cutting forces and surface roughness. Six different specimen groups of ductile iron alloyed with various amounts of nickel and copper were subjected to machining tests and their machinabilities were investigated based on cutting forces and surface roughness criteria. The results were evaluated according to microstructure and mechanical properties of specimens determined before. In terms of both criterion, the best result obtained was specimen added 0.7 % Ni and 0.7 % Cu. When the specimens were evaluated according to their mechanical properties, the specimens alloyed 1 % Ni and 0.65 % Cu seemed promising.

Expanding the Availability of Lightweight Aluminum Alloy Armor Plate Procured from Detailed Military Specifications

Science.gov (United States)

Doherty, Kevin; Squillacioti, Richard; Cheeseman, Bryan; Placzankis, Brian; Gallardy, Denver

For many years, the range of aluminum alloys for armor plate applications obtainable in accordance with detailed military specifications was very limited. However, the development of improved aluminum alloys for aerospace and other applications has provided an opportunity to modernize the Army portfolio for ground vehicle armor applications. While the benefits of offering additional alloy choices to vehicle designers is obvious, the process of creating detailed military specifications for armor plate applications is not trivial. A significant amount of material and testing is required to develop the details required by an armor plate specification. Due to the vast number of material programs that require standardization and with a limited amount of manpower and funds as a result of Standardization Reform in 1995, one typically requires a need statement from a vehicle program office to justify and sponsor the work. This presentation will focus on recent aluminum alloy armor plate specifications that have added capability to vehicle designers' selection of armor materials that offer possible benefits such as lower cost, higher strength, better ballistic and corrosion resistance, improved weldability, etc.

Development of boronated aluminum alloy for basket of cask for nuclear spent fuel

International Nuclear Information System (INIS)

Sakaguchi, Y.; Saida, T.; Matsuoka, T.; Kuri, S.; Ohsono, K.; Hode, S.

2001-01-01

Since 1980's Mitsubishi Heavy Industries, Ltd. (MHI) has been contributing to develop metal cask technologies for utilities and competent authorities in Japan, and have established transport and storage cask design ''MSF series'' which realizes higher payload and reliability for long term storage. MSF series transport and storage cask uses new-developed boronated aluminum as basket material. This boronated aluminum has been developed to improve characteristics of material. To achieve this object, powder metallurgy method has been adopted for manufacturing boronated material. It is well known that this method provides excellent characteristics for the material and this boronated aluminum alloy has obtained excellent both mechanical and neutron absorbing characteristics. In addition, in order to maintain material properties for long-term use this boronated material is not strengthened by aging treatment. This paper summarizes an outline of the boronated aluminum alloy for basket assemblies by powder metallurgy. (author)

Effect of oxide film formation on the fatigue behavior of aluminum alloy

International Nuclear Information System (INIS)

Kim, Jong Cheon; Cheong, Seong Kyun

2012-01-01

In this study, the effects of surface oxide film formation on the fatigue behavior of 7075-T6 aluminum alloy were analyzed in terms of the corrosion time of the alloy. The aluminum material used is known to have high corrosion resistance due to the passivation phenomenon that prevents corrosion. Aluminum alloys have been widely used in various industrial applications such as aircraft component manufacturing because of their lighter weight and higher strength than other materials. Therefore, studies on the fatigue behavior of materials and passivation properties that prevent corrosion are required. The fatigue behavior in terms of the corrosion time was analyzed by using a four pointing bending machine, and the surface corrosion level of the aluminum material in terms of the corrosion time was estimated by measuring the surface were studied by scanning electron microscopy (SEM). The results indicated that corrosion actively progressed for four weeks during the initial corrosion phase, the fatigue life significantly decreased, and the surface roughness increased. However, after four weeks, the corrosion reaction tended to slow down due to the passivation phenomenon of the material. Therefore, on the basis of SEM analysis results, it was concluded that the growth of the surface oxide film was reduced after four weeks and then the oxide film on the material surface served as a protection layer and prevented further corrosion

ANALYSIS OF KINETICS OF CAST IRON ALLOYING THROUGH SLAG PHASE

Directory of Open Access Journals (Sweden)

O. S. Komarov

2012-01-01

Full Text Available The mechanism of cast iron alloying through slag phase due to use of nickel and copper oxides is considered and the analysis of kinetics regularity of alloying in case of absence of fuse in the form of milled cast-iron chips in slag and at their presence in it is carried out.

Influence of Post Weld Heat Treatment on Strength of Three Aluminum Alloys Used in Light Poles

Directory of Open Access Journals (Sweden)

Craig C. Menzemer

2016-03-01

Full Text Available The conjoint influence of welding and artificial aging on mechanical properties were investigated for extrusions of aluminum alloy 6063, 6061, and 6005A. Uniaxial tensile tests were conducted on the aluminum alloys 6063-T4, 6061-T4, and 6005A-T1 in both the as-received (AR and as-welded (AW conditions. Tensile tests were also conducted on the AR and AW alloys, subsequent to artificial aging. The welding process used was gas metal arc (GMAW with spray transfer using 120–220 A of current at 22 V. The artificial aging used was a precipitation heat treatment for 6 h at 182 °C (360 °F. Tensile tests revealed the welded aluminum alloys to have lower strength, both for yield and ultimate tensile strength, when compared to the as-received un-welded counterpart. The beneficial influence of post weld heat treatment (PWHT on strength and ductility is presented and discussed in terms of current design provisions for welded aluminum light pole structures.

Interface and properties of the friction stir welded joints of titanium alloy Ti6Al4V with aluminum alloy 6061

International Nuclear Information System (INIS)

Wu, Aiping; Song, Zhihua; Nakata, Kazuhiro; Liao, Jinsun; Zhou, Li

2015-01-01

Highlights: • Friction stir butt welding of titanium alloy Ti6Al4V and aluminum alloy A6061-T6. • Welding parameters affect interfacial microstructure of the joint. • Welding parameters affect the mechanical property of joint and fracture position. • Joining mechanism of Ti6Al4V/A6061 dissimilar alloys by FSW is investigated. - Abstract: Titanium alloy Ti6Al4V and aluminum alloy 6061 dissimilar material joints were made with friction stir welding (FSW) method. The effects of welding parameters, including the stir pin position, the rotating rate and the travel speed of the tool, on the interface and the properties of the joints were investigated. The macrostructure of the joints and the fracture surfaces of the tensile test were observed with optical microscope and scanning electron microscope (SEM). The interface reaction layer was investigated with transmission electron microscopy (TEM). The factors affecting the mechanical properties of the joints were discussed. The results indicated that the tensile strength of the joints and the fracture location are mainly dependent on the rotating rate, and the interface and intermetallic compound (IMC) layer are the governing factor. There is a continuous 100 nm thick TiAl 3 IMC at the interface when the rotating rate is 750 rpm. When the welding parameters were appropriate, the joints fractured in the thermo-mechanically affected zone (TMAZ) and the heat affected zone (HAZ) of the aluminum alloy and the strength of the joints could reach 215 MPa, 68% of the aluminum base material strength, as well as the joint could endure large plastic deformation

Scientific Background for Processing of Aluminum Waste

Directory of Open Access Journals (Sweden)

Kononchuk Olga

2017-01-01

of the aluminum waste A1- Zn-Cu-Si-Fe shows that depending on the content of the metal the dissolution process of an aluminum alloy should be treated as the result of the chemical interaction of the metal with an alkaline solution. It is necessary to consider the behavior of the main components of alloys in an alkaline solution as applied to the system Na2O - Al2O3 - SiO2 - CO2 - H2O.

Research of Plasma Spraying Process on Aluminum-Magnesium Alloy

Directory of Open Access Journals (Sweden)

Patricija Kavaliauskaitė

2016-04-01

Full Text Available The article examines plasma sprayed 95Ni-5Al coatings on alu-minum-magnesium (Mg ≈ 2,6‒3,6 % alloy substrate. Alumi-num-magnesium samples prior spraying were prepared with mechanical treatment (blasting with Al2O3. 95Ni-5Al coatings on aluminum-magnesium alloys were sprayed with different parameters of process and coating‘s thickness, porosity, micro-hardness and microstructure were evaluated. Also numerical simulations in electric and magnetic phenomena of plasma spray-ing were carried out.

Semi-solid rheocasting of grain refined aluminum alloy 7075

CSIR Research Space (South Africa)

Curle, UA

2010-09-01

Full Text Available mm×6 mm. Fig.1 shows the whole casting including the runner and the biscuit. A batch of the 7075 alloy was melted in a 20 kg tilting furnace and degassed with argon. A sample was poured and cooled to analyze the starting chemical composition... of the liquid metal by optical emission spectroscopy (Thermo Quantris OES). Thermodynamic properties of the starting alloy were then calculated (Scheil solidification model) with an aluminum thermodynamic database (ProCast 2009.1) using the OES composition...

Effect of Aluminum Coating on the Surface Properties of Ti-(~49 at. pct) Ni Alloy

Science.gov (United States)

Sinha, Arijit; Khan, Gobinda Gopal; Mondal, Bholanath; Majumdar, Jyotsna Dutta; Chattopadhyay, Partha Protim

2015-08-01

Stable porous layer of mixed Al2O3 and TiO2 has been formed on the Ti-(~49 at. pct) Ni alloy surface with an aim to suppress leaching of Ni from the alloy surface in contact with bio-fluid and to enhance the process of osseointegration. Aluminum coating on the Ni-Ti alloy surface prior to the anodization treatment has resulted in enhancement of depth and uniformity of pores. Thermal oxidation of the anodized aluminum-coated Ni-Ti samples has exhibited the formation of Al2O3 and TiO2 phases with dense porous structure. The nanoindentation and nanoscratch measurements have indicated a remarkable improvement in the hardness, wear resistance, and adhesiveness of the porous aluminum-coated Ni-Ti sample after thermal oxidation.

Stuy on Fatigue Life of Aluminum Alloy Considering Fretting

Science.gov (United States)

Yang, Maosheng; Zhao, Hongqiang; Wang, Yunxiang; Chen, Xiaofei; Fan, Jiali

2018-01-01

To study the influence of fretting on Aluminum Alloy, a global finite element model considering fretting was performed using the commercial code ABAQUS. With which a new model for predicting fretting fatigue life has been presented based on friction work. The rationality and effectiveness of the model were validated according to the contrast of experiment life and predicting life. At last influence factor on fretting fatigue life of aerial aluminum alloy was investigated with the model. The results revealed that fretting fatigue life decreased monotonously with the increasing of normal load and then became constant at higher pressures. At low normal load, fretting fatigue life was found to increase with increase in the pad radius. At high normal load, however, the fretting fatigue life remained almost unchanged with changes in the fretting pad radius. The bulk stress amplitude had the dominant effect on fretting fatigue life. The fretting fatigue life diminished as the bulk stress amplitude increased.

Inhibitive Action of Ferrous Gluconate on Aluminum Alloy in Saline Environment

Directory of Open Access Journals (Sweden)

Patricia Abimbola Idowu Popoola

2013-01-01

Full Text Available The corrosion of aluminum in saline environment in the presence of ferrous gluconate was studied using weight loss and linear polarization methods. The corrosion rates were studied in different concentrations of ferrous gluconate 0.5, 1.0, 1.5, and 2.0 g/mL at 28°C. Experimental results revealed that ferrous gluconate in saline environment reduced the corrosion rate of aluminum alloy at the different concentrations studied. The minimum inhibition efficiency was obtained at 1.5 g/mL concentration of inhibitor while the optimum inhibition efficiency was achieved with 1.0 g/mL inhibitor concentration. The results showed that adsorption of ferrous gluconate on the aluminium alloy surface fits Langmuir adsorption isotherm. The potentiodynamic polarization results showed that ferrous gluconate is a mixed type inhibitor. Ferrous gluconate acted as an effective inhibitor for aluminium alloy within the temperature and concentration range studied. The data obtained from weight loss and potentiodynamic polarization methods were in good agreement.

Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Liu, X.F. [Xi' an High-technology Institute, Xi' an 710025 (China)], E-mail: xiaofang_liu@263.net; Wu, Q.Y.; Wang, H.G. [Xi' an High-technology Institute, Xi' an 710025 (China)

2008-06-15

This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion.

Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

International Nuclear Information System (INIS)

Liu, X.F.; Wu, Q.Y.; Wang, H.G.

2008-01-01

This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion

Aluminium alloys containing iron and nickel

International Nuclear Information System (INIS)

Coriou, H.; Fournier, R.; Grall, L.; Hure, J.; Herenguel, J.; Lelong, P.

1958-01-01

The first part of this report addresses mechanism, kinetics and structure factors of aluminium alloys containing iron and nickel in water and high temperature steam. The studied alloys contain from 0.3 to 0.7 per cent of iron, and 0.2 to 1.0 per cent of nickel. Corrosion resistance and corrosion structure have been studied. The experimental installation, process and samples are presented. Corrosion structures in water at 350 C are identified and discussed (structure of corrosion products, structure of metal-oxide interface), and then in steam at different temperatures (350-395 C). Corrosion kinetics is experimentally studied (weight variation in time) in water at 350 C and in steam at different temperatures. Reactions occurring at over-heated steam (more than 400 C) are studied, and the case of welded alloys is also addressed. The second part addresses the metallurgical mechanism and processes influencing aluminium alloy resistance to corrosion by high temperature water as it appeared that separated phases protect the solid solution through a neighbourhood action. In order to avoid deep local corrosions, it seems necessary to multiply protective phases in an as uniform as possible way. Some processes enabling this result are described. They belong to conventional metallurgy or to powder metallurgy (with sintering and extrusion)

40 CFR 63.5753 - How do I calculate the combined organic HAP content of aluminum wipedown solvents and aluminum...

Science.gov (United States)

2010-07-01

... HAP content of aluminum wipedown solvents and aluminum recreational boat surface coatings? 63.5753... Standards for Hazardous Air Pollutants for Boat Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5753 How do I calculate the combined organic HAP content of aluminum...

The Cryogenic Properties of Several Aluminum-Beryllium Alloys and a Beryllium Oxide Material

Science.gov (United States)

Gamwell, Wayne R.; McGill, Preston B.

2003-01-01

Performance related mechanical properties for two aluminum-beryllium (Al-Be) alloys and one beryllium-oxide (BeO) material were developed at cryogenic temperatures. Basic mechanical properties (Le., ultimate tensile strength, yield strength, percent elongation, and elastic modulus were obtained for the aluminum-beryllium alloy, AlBeMetl62 at cryogenic [-195.5"C (-320 F) and -252.8"C (-423"F)I temperatures. Basic mechanical properties for the Be0 material were obtained at cyrogenic [- 252.8"C (-423"F)] temperatures. Fracture properties were obtained for the investment cast alloy Beralcast 363 at cryogenic [-252.8"C (-423"F)] temperatures. The AlBeMetl62 material was extruded, the Be0 material was hot isostatic pressing (HIP) consolidated, and the Beralcast 363 material was investment cast.

Recrystallization resistance in aluminum alloys containing zirconium

International Nuclear Information System (INIS)

Ranganathan, K.

1991-01-01

Zirconium forms a fine dispersion of the metastable β' (Al 3 Zr) phase that controls recrystallization by retarding the motion of high-angle boundaries. The primary material chosen for this research was aluminum alloy 7150 containing zinc, magnesium, and copper as the major solute elements and zirconium as the dispersoid-forming element. The size, distribution, and the volume fraction of β' was controlled by varying the alloy composition and preheat practices. Preheated ingots were subjected to a specific sequence of hot-rolling operations to evaluate the resistance to recrystallization of the different microstructures. Optical and transmission electron microscopy (TEM) techniques were used to investigate the influence of dispersoid morphology resulting from the thermal treatments and deformation processing on the recrystallization behavior of the alloy. Studies were conducted to determine the influence of the individual solute elements present in 7150 on the precipitation of β' and consequently on the recrystallization behavior of the material. These studies were done on compositional variants of commercial 7150

Microstructure and Aging of Powder-Metallurgy Al Alloys

Science.gov (United States)

Blackburn, L. B.

1987-01-01

Report describes experimental study of thermal responses and aging behaviors of three new aluminum alloys. Alloys produced from rapidly solidified powders and contain 3.20 to 5.15 percent copper, 0.24 to 1.73 percent magnesium, 0.08 to 0.92 percent iron, and smaller amounts of manganese, nickel, titanium, silicon, and zinc. Peak hardness achieved at lower aging temperatures than with standard ingot-metallurgy alloys. Alloys of interest for automobile, aircraft, and aerospace applications.

Fracture behavior of low-density replicated aluminum alloy foams

NARCIS (Netherlands)

Amsterdam, E.; Goodall, R.; Mortensen, A.; Onck, P. R.; De Hosson, J. Th. M.

2008-01-01

Tensile tests have been performed on replicated aluminum alloy foams of relative density between 4.5% and 8%. During the test the electrical resistance was measured with a four-point set-up and the displacements along the gage section were measured using a digital image correlation (DIC) technique.

Semisolid casting with ultrasonically melt-treated billets of Al-7mass%Si alloys

Directory of Open Access Journals (Sweden)

Yoshiki Tsunekawa

2012-02-01

Full Text Available The demand for high performance cast aluminum alloy components is often disturbed by increasing impurity elements, such as iron accumulated from recycled scraps. It is strongly required that coarse plate-like iron compound of モ-Al5FeSi turns into harmless form without the need for applying refining additives or expensive virgin ingots. The microstructural modification of Al-7mass%Si alloy billets with different iron contents was examined by applying ultrasonic vibration during the solidification. Ultrasonically melt-treated billets were thixocast right after induction heating up to the semisolid temperature of 583 ìC, the microstructure and tensile properties were evaluated in the thixocast components. Globular primary メ-Al is required to fill up a thin cavity in thixocasting, so that the microstructural modification by ultrasonic melt-treatment was firstly confirmed in the billets. With ultrasonic melt-treatment in the temperature range of 630 ìC to 605 ìC, the primary メ-Al transforms itself from dendrite into fine globular in morphology. The coarse plate-like モ-Al5FeSi compound becomes markedly finer compared with those in non-treated billets. Semisolid soaking up to 583 ìC, does not appreciably affect the size of モ-Al5FeSi compounds; however, it affects the solid primary メ-Al morphology to be more globular, which is convenient for thixocasting. After thixocasting with preheated billets, eutectic silicon plates are extremely refined due to the rapid solidification arising from low casting temperature. The tensile strength of thixocast samples with different iron contents does not change much even at 2mass% of iron, when thixocast with ultrasonically melt-treated billets. However, thixocast Al-7mass%Si-2mass%Fe alloy with non-treated billets exhibits an inferior strength of 80 MPa, compared with 180 MPa with ultrasonically melt-treated billets. The elongation is also improved by about a factor of two in thixocastings with

Iron aluminide weld overlay coatings for boiler tube protection in coal-fired low NOx boilers

Energy Technology Data Exchange (ETDEWEB)

Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

1997-12-01

Iron aluminide weld overlay coatings are currently being considered for enhanced sulfidation resistance in coal-fired low NO{sub x} boilers. The use of these materials is currently limited due to hydrogen cracking susceptibility, which generally increases with an increase in aluminum concentration of the deposit. The overall objective of this program is to attain an optimum aluminum content with good weldability and improved sulfidation resistance with respect to conventional materials presently in use. Research has been initiated using Gas Tungsten Arc Welding (GTAW) in order to achieve this end. Under different sets of GTAW parameters (wire feed speed, current), both single and multiple pass overlays were produced. Characterization of all weldments was conducted using light optical microscopy, scanning electron microscopy, and electron probe microanalysis. Resultant deposits exhibited a wide range of aluminum contents (5--43 wt%). It was found that the GTAW overlays with aluminum contents above {approximately}10 wt% resulted in cracked coatings. Preliminary corrosion experiments of 5 to 10 wt% Al cast alloys in relatively simple H{sub 2}/H{sub 2}S gas mixtures exhibited corrosion rates lower than 304 stainless steel.

Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Elevated Temperature Aluminum Metal Matrix Composite (MMC) Alloy and Its Processing Technology

Energy Technology Data Exchange (ETDEWEB)

Weiss, David C. [Eck Industreis, Inc.; Gegal, Gerald A.

2014-04-15

The objective of this project was to provide a production capable cast aluminum metal matrix composite (MMC) alloy with an operating temperature capability of 250-300°C. Important industrial sectors as well as the military now seek lightweight aluminum alloy castings that can operate in temperature ranges of 250-300°C. Current needs in this temperature range are being satisfied by the use of titanium alloy castings. These have the desired strength properties but the end components are heavier and significantly more costly. Also, the energy requirements for production of titanium alloy castings are significantly higher than those required for production of aluminum alloys and aluminum alloy castings.

Effective corrosion protection of AA6061 aluminum alloy by sputtered Al-Ce coatings

International Nuclear Information System (INIS)

Dominguez-Crespo, M.A.; Torres-Huerta, A.M.; Rodil, S.E.; Ramirez-Meneses, E.; Suarez-Velazquez, G.G.; Hernandez-Perez, M.A.

2009-01-01

Al-Ce coatings were deposited on silicon and AA6061 aluminum alloy substrates by DC magnetron sputtering using aluminum in combination with pure cerium targets. The materials were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and electrochemical impedance spectroscopy (EIS) in order to consider their application as high corrosion resistance coatings. The corrosion behavior of the films was studied using a NaCl aqueous solution (3.5 wt%). As for the characterization results, an apparent amorphous phase of aluminum oxide with small cerium compounds embedded in the matrix was detected by the X-ray diffraction patterns and HRTEM on the deposited films at 200 W and 4 Pa. At these conditions, AFM and SEM images evidenced crack-free coatings with low-roughness nanometric structures and columnar growth. EIS and Tafel results converged to indicate an inhibition of the corrosion reactions. The film displayed good stability in the aggressive medium and after 1 day of exposure underwent very little degradation. The variations in the impedance and Tafel characteristics were found to occur as a function of cerium content, which provokes important changes in the film protective properties.

Effective corrosion protection of AA6061 aluminum alloy by sputtered Al-Ce coatings

Energy Technology Data Exchange (ETDEWEB)

Dominguez-Crespo, M.A., E-mail: mdominguezc@ipn.m [Instituto Politecnico Nacional, GIPMAT CICATA-Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Torres-Huerta, A.M. [Instituto Politecnico Nacional, GIPMAT CICATA-Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Rodil, S.E. [Instituto de Investigacion en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, Ciudad Universitaria, Del. Coyoacan, C.P. 04510 Mexico, D.F. (Mexico); Ramirez-Meneses, E. [Instituto Politecnico Nacional, GIPMAT CICATA-Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Suarez-Velazquez, G.G. [Alumna del PTA del CICATA-Altamira IPN, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Hernandez-Perez, M.A. [Instituto Politecnico Nacional, ESIQIE, C.P. 07738 Mexico, D.F. (Mexico)

2009-12-30

Al-Ce coatings were deposited on silicon and AA6061 aluminum alloy substrates by DC magnetron sputtering using aluminum in combination with pure cerium targets. The materials were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and electrochemical impedance spectroscopy (EIS) in order to consider their application as high corrosion resistance coatings. The corrosion behavior of the films was studied using a NaCl aqueous solution (3.5 wt%). As for the characterization results, an apparent amorphous phase of aluminum oxide with small cerium compounds embedded in the matrix was detected by the X-ray diffraction patterns and HRTEM on the deposited films at 200 W and 4 Pa. At these conditions, AFM and SEM images evidenced crack-free coatings with low-roughness nanometric structures and columnar growth. EIS and Tafel results converged to indicate an inhibition of the corrosion reactions. The film displayed good stability in the aggressive medium and after 1 day of exposure underwent very little degradation. The variations in the impedance and Tafel characteristics were found to occur as a function of cerium content, which provokes important changes in the film protective properties.

Corrosion and Corrosion Fatigue of Aluminum Alloys: Chemistry, Micromechanics and Reliability

National Research Council Canada - National Science Library

Wei, Robert

1998-01-01

... No. F49620-98-1-0198, to further develop a basic mechanistic understanding of the damage evolution processes of localized corrosion and corrosion fatigue crack nucleation and growth in aluminum alloys...

On the conjoint influence of heat treatment and lithium content on microstructure and mechanical properties of A380 aluminum alloy

International Nuclear Information System (INIS)

Karamouz, Mostafa; Azarbarmas, Mortaza; Emamy, Masoud

2014-01-01

Highlights: • T4 heat treatment and the addition of Li modify the microstructure of alloy. • Heat treatment improves the tensile properties of non-modified and modified alloys. • Fracture surfaces of modified specimens had more ductile dimples than base alloys. - Abstract: In this study, the effects of a T4 heat treatment on the microstructure and tensile properties of an A380 aluminum alloy with and without lithium (Li) additions have been investigated. Microstructural examination was carried out using optical and scanning electron microscopy, image analysis, and X-ray diffraction (XRD) analysis methods. The results showed that when the T4 heat treatment was applied, spheroidized eutectic Si particles and fragmented β-phase particles were formed. The influence of the heat treatment on the aspect ratio and average length of Si and β phases in a non-modified alloy was more noticeable than in the Li-modified. Significant improvements in tensile properties were also observed in heat-treated samples. Additionally, a fractographical analysis showed that the fracture surfaces of the Li-modified specimens with and without heat treatment had more ductile dimple and fewer brittle cleavage surfaces

Cracking susceptibility of aluminum alloys during laser welding

Directory of Open Access Journals (Sweden)

Lara Abbaschian

2003-06-01

Full Text Available The influence of laser parameters in welding aluminum alloys was studied in order to reduce hot cracking. The extension of cracks at the welding surface was used as a cracking susceptibility (CS index. It has been shown that the CS changes with changing welding velocity for binary Al-Cu alloys. In general, the CS index increased until a maximum velocity and then dropped to zero, generating a typical lambda-curve. This curve is due to two different mechanisms: 1 the refinement of porosities with increasing velocity and 2 the changes in the liquid fraction due to decreasing microsegregation with increasing velocities.

Determination of Impurities in Aluminum Alloy by INAA Single Comparator Method (K0-Standardization Method)

International Nuclear Information System (INIS)

Sarheel, A.; Khamis, I.; Somel, N.

2007-01-01

Multielement determination by the k0 based INAA using k0-IAEA program has been performed at Syrian Atomic Energy Commission using alloys. Concentrations of Cu, Zn, Fe, Ni, Sn and Ti in addition to aluminum element were determined in an aluminum alloy and Ni, Cr, Mo were determined in dental alloys using INAA k0-standardization method. Al-0.1%Au, Ni and Zn certified reference materials were analyzed to assess the suitability and accuracy of the method. Elements were determined in reference materials and samples after short and long irradiations, according to element half-lives.

Microstructural and mechanical properties of pure aluminum, 5083 and 7075 alloys joined by friction stir welding

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, Selim Sarper [Celal Bayar Univ., Manisa, Muradiye (Turkey)

2012-07-01

In this study, microstructural and mechanical properties of pure aluminum, 5083 and 7075 alloys joined by friction stir welding were investigated. Hardness, tensile, bending and impact tests were applied to the welded samples. In addition, optical and SEM tests were carried out. The effects of welding speed on microstructure and mechanical properties were investigated in these materials. Then, the optimal conditions for friction stir welding were determined for pure aluminum, 5083 and 7075 alloys. The maximum hardness was observed for 7075 while the minimum hardness was observed for pure aluminum. (orig.)

DEVELOPMENT OF TREAD ON THE BASIS OF COLOR ALLOYS RECYCLED IRON-CARBON ALLOYS PROTECTION FROM CORROSION

Directory of Open Access Journals (Sweden)

A. A. Pivovarchyk

2016-01-01

Full Text Available The results of development of the compositions of protectors for the corrosion protection low-carbon alloys used in the automotive industry, using as the raw material of the secondary aluminum raw materials. The results of research on the effectiveness of the tread designed to protect the alloy composition.

Investigation of sulphides in iron alloys of high purity

International Nuclear Information System (INIS)

Wyjadlowski, T.

1973-01-01

This research thesis reports the study of the morphology and composition of sulphides in iron alloys with respect to metal composition and to the nature of impurities. In order to understand the specific action of each addition on inclusion morphology, this work has started with high-purity alloys (binary alloys and then ternary alloys). The author studied whether solubility variations would entail either intergranular or intragranular or hybrid iron sulphide precipitation. He examined whether sulphide morphology is depending on thermal treatment, and whether equilibrium precipitates were different in terms of morphology and composition at high and room temperature. He studied the influence of addition elements on sulphide morphology and composition, an important issue as some elements may reduce brittleness. These elements are classified in terms of affinity with sulphur

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.

Carbonate fuel cell anodes

Science.gov (United States)

Donado, Rafael A.; Hrdina, Kenneth E.; Remick, Robert J.

1993-01-01

A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.

Procedure of identification of fullerenes isolated from iron-carbon alloys

International Nuclear Information System (INIS)

Zakirnichnaya, M.M.

2001-01-01

A method of fullerenes isolation from the structure of iron-carbon alloys and their identification using physical methods which provide determination of the different parameters of nanoobjects is developed. Qualitative (mass-spectrometry of positive and negative ions, small angle X-ray scattering) and quantitative (IR-spectrometry, liquid chromatography) evaluation of fullerenes in the samples obtained from iron-carbon alloys and their visual observation using scanning tunnel microscopy are performed. It is found that the method provides isolation and identification of fullerenes present in the structure of steels and irons [ru

Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

Science.gov (United States)

Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M. P.; Hihn, J. Y.

2015-11-01

Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

Liquid oxygen LOX compatibility evaluations of aluminum lithium (Al-Li) alloys: Investigation of the Alcoa 2090 and MMC weldalite 049 alloys

Science.gov (United States)

Diwan, Ravinder M.

1989-01-01

The behavior of liquid oxygen (LOX) compatibility of aluminum lithium (Al-Li) alloys is investigated. Alloy systems of Alcoa 2090, vintages 1 to 3, and of Martin Marietta Corporation (MMC) Weldalite 049 were evaluated for their behavior related to the LOX compatibility employing liquid oxygen impact test conditions under ambient pressures and up to 1000 psi. The developments of these aluminum lithium alloys are of critical and significant interest because of their lower densities and higher specific strengths and improved mechanical properties at cryogenic temperatures. Of the different LOX impact tests carried out at the Marshall Space Flight Center (MSFC), it is seen that in certain test conditions at higher pressures, not all Al-Li alloys are LOX compatible. In case of any reactivity, it appears that lithium makes the material more sensitive at grain boundaries due to microstructural inhomogeneities and associated precipitate free zones (PFZ). The objectives were to identify and rationalize the microstructural mechanisms that could be relaxed to LOX compatibility behavior of the alloy system in consideration. The LOX compatibility behavior of Al-Li 2090 and Weldalite 049 is analyzed in detail using microstructural characterization techniques with light optical metallography, scanning electron microscopy (SEM), electron microprobe analysis, and surface studies using secondary ion mass spectrometry (SIMS), electron spectroscopy in chemical analysis (ESCA) and Auger electron spectroscopy (AES). Differences in the behavior of these aluminum lithium alloys are assessed and related to their chemistry, heat treatment conditions, and microstructural effects.

Demonstration of the Impact of Thermomagnetic Processing on Cast Aluminum Alloys

Energy Technology Data Exchange (ETDEWEB)

Ludtka, Gerard Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Murphy, Bart L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rios, Orlando [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kesler, Michael S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Henderson, Hunter B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-10-01

This project builds on an earlier Manufacturing Demonstration Facility Technical Collaboration phase 1 project to investigate application of high magnetic fields during solution heat treating and aging of three different cast aluminum alloys.

Analysis of iron-base alloys by low-wattage glow discharge emission spectrometry

International Nuclear Information System (INIS)

Wagatsuma, K.; Hirokawa, K.

1984-01-01

Several iron-base alloys were investigated by low-wattage glow discharge emission spectrometry. The emission intensity principally depended on the sputtering parameters of constituent elements in the alloy. However, in the case of chromium, stable and firm oxides formed on the surface influencing the yield of ejected atoms. This paper discusses the relation between the sputtering parameters in Fe-Ni, Fe-Cr, and Fe-Co alloys and their relative emission intensities. Additionally, quantitative analysis was performed for some ternary iron-base alloys and commercial stainless steels with the calibration factors of binary alloy systems

Production of A356 aluminum alloy wheels by thixo-forging combined with a low superheat casting process

Directory of Open Access Journals (Sweden)

Wang Shuncheng

2013-09-01

Full Text Available The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo-forged wheels made from the A356 aluminum alloy were studied. The results show that the A356 aluminum alloy round billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 篊. When the round billet is reheated at 600 篊 for 60 min, the non-dendritic grains are changed into spherical ones and the round billet can be easily thixo-forged into wheels. The tensile strength, yield strength and elongation of the thixo-forged wheels with T6 heat treatment are 327.6 MPa, 228.3 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties.

Fabrication of the micro/nano-structure superhydrophobic surface on aluminum alloy by sulfuric acid anodizing and polypropylene coating.

Science.gov (United States)

Wu, Ruomei; Liang, Shuquan; Liu, Jun; Pan, Anqiang; Yu, Y; Tang, Yan

2013-03-01

The preparation of the superhydrophobic surface on aluminum alloy by anodizing and polypropylene (PP) coating was reported. Both the different anodizing process and different PP coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. By PP coating after anodizing, a good superhydrophobic surface was facilely fabricated. The optimum conditions for anodizing were determined by orthogonal experiments. After the aluminium-alloy was grinded with 600# sandpaper, pretreated by 73 g/L hydrochloric acid solution at 1 min, when the concentration of sulfuric acid was 180 g/L, the concentration of oxalic acid was 5 g/L, the concentration of potassium dichromate was 10 g/L, the concentration of chloride sodium was 50 g/L and 63 g/L of glycerol, anodization time was 20 min, and anodization current was 1.2 A/dm2, anodization temperature was 30-35 degrees C, the best micro-nanostructure aluminum alloy films was obtained. On the other hand, the PP with different concentrations was used to the PP with different concentrations was used to coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was achieved by coating PP, and the duration of the superhydrophobic surface was improved by modifying the coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was surface with high concentration PP. The morphologies of micro/nano-structure superhydrophobic surface were further confirmed by scanning electron microscope (SEM). The material of PP with the low surface free energy combined with the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

Transmission electron microscope study of fusion-environment radiation damage in iron and iron-chromium alloys

International Nuclear Information System (INIS)

Horton, L.L.S.

1982-07-01

A transmission electron microscopy study of radiation damage microstructures in iron and iron-chromium alloys has been performed. This study consisted of both qualitative and quantitative characterization of the dislocation and cavity microstructures, including determination of vacancy/interstitial character and Burgers vectors for dislocation loops and analysis of the cavity morphology. The effects of irradiation temperature, fluence, helium implantation, and chromium content were investigated. Neutron irradiation (iron specimens, 1 dpa, 455 to 1000 K) and triple-beam ion irradiation (Fe-10% Cr specimens, 10 dpa, 725 to 950 K; Fe-10% Cr specimens, 850 K, 0.3 to 100 dpa; and Fe, Fe-5% Cr, Fe-10% Cr specimens, 850 K, 10 dpa) were employed. In the triple-beam ion irradiation procedure, simultaneous bombardment with 4 MeV Fe ++ ions and energetic He + and D 2 + ions was used to simulate the fusion environment (10 at. ppM He/dpa and 41 at. ppM D/dpa). In addition, single-beam 4 MeV Fe ++ ion irradiations of Fe-10% Cr both with and without pre-injection of helium and deuterium were performed

Effects of Alclad Layer and Anodizing Time on Sulfuric Acid Anodizing and Film Properties of 2E12 Aluminum Alloy

Directory of Open Access Journals (Sweden)

CHEN Gao-hong

2017-07-01

Full Text Available Alclad and unclad 2E12 aerospace aluminum alloy were treated by sulfuric acid anodic oxidation. The effects of alclad layer and anodizing time on the anodization behaviour and corrosion resistance of anodic oxide layer on 2E12 aluminum alloy were studied. Surface and cross-section morphology of anodic oxide films were observed by scanning electron microscopy. The electrochemical properties of anodic oxide films were analyzed by potentiodynamic polarization curve and electrochemical impedance spectroscopy. The results show that the protective anodic oxide layers are formed on alclad and unclad 2E12 aluminum alloy. The film thickness increases with anodizing time extending. The copper rich second phase particles lead to more cavity defects and even micro cracks on anodic oxide films of unclad 2E12 aluminum alloy. The anodic oxide films on alclad 2E12 aluminum alloy are thicker and have fewer cavity defects, resulting in better corrosion resistance. The films obtained after 30min and 45min anodic oxidation treatment exhibit lower corrosion current and higher impedance of the porous layer than other anodizing time.

Preparation of bimodal grain size 7075 aviation aluminum alloys and their corrosion properties

Directory of Open Access Journals (Sweden)

Wenming TIAN

2017-10-01

Full Text Available The bimodal grain size metals show improved strength and ductility compared to traditional metals; however, their corrosion properties are unknown. In order to evaluate the corrosion properties of these metals, the bimodal grain size 7075 aviation aluminum alloys containing different ratios of coarse (100 μm in diameter and fine (10 μm in diameter grains were prepared by spark plasma sintering (SPS. The effects of grain size as well as the mixture degree of coarse and fine grains on general corrosion were estimated by immersion tests, electrochemical measurements and complementary techniques such as scanning electron microscope (SEM and transmission electron microscope-energy disperse spectroscopy (TEM-EDS. The results show that, compared to fine grains, the coarse grains have a faster dissolution rate in acidic NaCl solution due to the bigger size, higher alloying elements content and larger area fraction of second phases in them. In coarse grains, the hydrogen ions have a faster reduction rate on cathodic second phases, therefore promoting the corrosion propagation. The mixture of coarse and fine grains also increases the electrochemical heterogeneity of alloys in micro-scale, and thus the increased mixture degree of these grains in metal matrix accelerates the corrosion rate of alloys in acidic NaCl solution.

TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION

International Nuclear Information System (INIS)

Reboul, S.; Hay, Michael; Zeigler, Kristine; Stone, Michael

2009-01-01

A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of ∼7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low (∼20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the H-Canyon plutonium/gadolinium simulant was added to the Tank 12 slurry. Quantification of iron dissolution was less clear, but appeared to be on the order of 1% based on the majority of data (a minor portion of the data suggested iron dissolution could be as high as 10%). The yield stress of the post-dissolution slurry (2.5 Pa) was an order of magnitude lower than the initial slurry, due most likely to the reduced insoluble solids content caused by aluminum dissolution. In contrast, the plastic viscosity remained unchanged (27 cP). The settling rate of the post-dissolution slurry was higher than the initial slurry, but still relatively low compared to settling of typical high iron content/low salt content sludges. Approximately 40% of the

Effects of Alloying Elements on Room and High Temperature Tensile Properties of Al-Si Cu-Mg Base Alloys =

Science.gov (United States)

Alyaldin, Loay

In recent years, aluminum and aluminum alloys have been widely used in automotive and aerospace industries. Among the most commonly used cast aluminum alloys are those belonging to the Al-Si system. Due to their mechanical properties, light weight, excellent castability and corrosion resistance, these alloys are primarily used in engineering and in automotive applications. The more aluminum is used in the production of a vehicle, the less the weight of the vehicle, and the less fuel it consumes, thereby reducing the amount of harmful emissions into the atmosphere. The principal alloying elements in Al-Si alloys, in addition to silicon, are magnesium and copper which, through the formation of Al2Cu and Mg2Si precipitates, improve the alloy strength via precipitation hardening following heat treatment. However, most Al-Si alloys are not suitable for high temperature applications because their tensile and fatigue strengths are not as high as desired in the temperature range 230-350°C, which are the temperatures that are often attained in automotive engine components under actual service conditions. The main challenge lies in the fact that the strength of heat-treatable cast aluminum alloys decreases at temperatures above 200°C. The strength of alloys under high temperature conditions is improved by obtaining a microstructure containing thermally stable and coarsening-resistant intermetallics, which may be achieved with the addition of Ni. Zr and Sc. Nickel leads to the formation of nickel aluminide Al3Ni and Al 9FeNi in the presence of iron, while zirconium forms Al3Zr. These intermetallics improve the high temperature strength of Al-Si alloys. Some interesting improvements have been achieved by modifying the composition of the base alloy with additions of Mn, resulting in an increase in strength and ductility at both room and high temperatures. Al-Si-Cu-Mg alloys such as the 354 (Al-9wt%Si-1.8wt%Cu-0.5wt%Mg) alloys show a greater response to heat treatment as a

Development of new low activation aluminum alloys for fusion devices

International Nuclear Information System (INIS)

Kamada, Kohji; Kakihana, Hidetake.

1985-01-01

As the materials for the R facility (a tokamak nuclear fusion device in the R project intended for D-T burning) in the Institute of Plasma Physics, Nagoya University, Al-4 % Mg-0.2 % Bi (5083 improved type) and Al-4 % Mg-1 % Li, aimed at low radioactivability, high electric resistance and high strength, have been developed. The results of the nuclear properties evaluation with 14 MeV neutrons and of the measurements of electric resistance and mechanical properties were satisfactory. The possibility of producing large Al-4 % Mg-1 % Li plate (1 m x 2 m x 25 mm) in the existing factory was confirmed, with the properties retained. The electric resistances were higher than those in the conventional aluminum alloys, and still with feasibility for the further improvement. General properties of the fusion aluminum alloys and the 26 Al formation in (n, 2n) reaction were studied. (Mori, K.)

Magnesium Removal from an Aluminum A-332 Molten Alloy Using Enriched Zeolite with Nanoparticles of SiO2

Directory of Open Access Journals (Sweden)

R. Muñoz-Arroyo

2014-01-01

Full Text Available In order to improve the Mg removal from an A-380 molten alloy, mixtures of zeolite and SiO2 nanoparticles (SiO2(NPs were tested. Zeolite was enriched with 2.5, 5, 7.5, 10, or 12.5 wt-% of amorphous SiO2(NPs. The SiO2(NPs and zeolite were mixed for 30 min in ethanol for each experiment and then dried in a furnace at 80°C for 12 h. The enriched zeolites were analyzed by scanning electron microscopy, transmission electron microscopy, and N2 gas adsorption analysis. The Mg removal was carried out injecting each mixture into the molten aluminum alloy at 750°C using argon. The Mg content of the molten alloy was measured after different periods of the injection time. Zeolites enriched with 2.5 and 5 wt-% of SiO2(NPs were demonstrated to be the better mixtures, removing Mg from an initial content of 1.6 to a final content of 0.0002 and 0.0101 wt-%, respectively, in 45 min of injection.

The effect of different aluminum alloy surface compositions on barrier anodic film formation

International Nuclear Information System (INIS)

Panitz, J.K.G.; Sharp, D.J.

1984-01-01

The authors have grown barrier anodic coatings on samples of aluminum alloy with different elemental surface compositions. In one series of experiments, they characterized the surface composition present on 6061 aluminum alloy samples after different chemical treatments including a detergent-water and methyl-ethyl ketone solvent clean, a 50% nitric acid-water etch, and a concentrated nitric acid-ammonium bifluoride etch. They anodized samples which were prepared similarly to those analyzed to evaluate the practical effects of the three different surface compositions. The anodization voltage rise time to 950V at constant current was used as a figure of merit. The solvent cleaned and the 50% nitric acid etched samples required, respectively, 113% and 41% more time to reach 950V than the concentrated nitric acidammonium bifloride etched samples. In a second series of experiments, they alternately anodized groups of either 6061 or 1100 (commercially pure) aluminum alloy, observed rise times to 950V, and measured chloride ion concentrations in the electrolyte. Longer rise times and higher chloride ion concentrations were observed for the 1100 samples. It was observed that the chloride ion concentration fell from initially high levels when 6061 samples were anodized. The results of both series of experiments augment the results of other investigators, who report that the surface species initially present on aluminum have a significant effect on anodic film formation

The structure-property relationships of powder processed Fe-Al-Si alloys

Energy Technology Data Exchange (ETDEWEB)

Prichard, Paul D. [Iowa State Univ., Ames, IA (United States)

1998-02-23

Iron-aluminum alloys have been extensively evaluated as semi-continuous product such as sheet and bar, but have not been evaluated by net shape P/M processing techniques such as metal injection molding. The alloy compositions of iron-aluminum alloys have been optimized for room temperature ductility, but have limited high temperature strength. Hot extruded powder alloys in the Fe-Al-Si system have developed impressive mechanical properties, but the effects of sintering on mechanical properties have not been explored. This investigation evaluated three powder processed Fe-Al-Si alloys: Fe-15Al, Fe-15Al-2.8Si, Fe-15Al-5Si (atomic %). The powder alloys were produced with a high pressure gas atomization (HPGA) process to obtain a high fraction of metal injection molding (MIM) quality powder (D₈₄ < 32 μm). The powders were consolidated either by P/M hot extrusion or by vacuum sintering. The extruded materials were near full density with grain sizes ranging from 30 to 50 μm. The vacuum sintering conditions produced samples with density ranging from 87% to 99% of theoretical density, with an average grain size ranging from 26 μm to 104 μm. Mechanical property testing was conducted on both extruded and sintered material using a small punch test. Tensile tests were conducted on extruded bar for comparison with the punch test data. Punch tests were conducted from 25 to 550 C to determine the yield strength, and fracture energy for each alloy as a function of processing condition. The ductile to brittle transition temperature (DBTT) was observed to increase with an increasing silicon content. The Fe-15Al-2.8Si alloy was selected for more extensive testing due to the combination of high temperature strength and low temperature toughness due to the two phase α + DO₃ structure. This investigation provided a framework for understanding the effects of silicon in powder processing and mechanical property behavior of Fe-Al-Si alloys.

Impression creep properties of a semi-solid processed magnesium-aluminum alloy containing calcium and rare earth elements

International Nuclear Information System (INIS)

Nami, B.; Razavi, H.; Miresmaeili, S.M.; Mirdamadi, Sh.; Shabestari, S.G.

2011-01-01

The creep properties of a thixoformed magnesium-aluminum alloy containing calcium and rare earth elements were studied under shear modulus-normalized stresses ranging from 0.0225 to 0.035 at temperatures of 150-212 o C using the impression creep technique. Analysis of the creep mechanism based on a power-law equation indicated that pipe diffusion-controlled dislocation climb is the dominant mechanism during creep. The alloy has a better creep resistance than high-pressure die-cast magnesium-aluminum alloy.

Strengthening Aluminum Alloys for High Temperature Applications Using Nanoparticles of Al203 and Al3-X Compounds (X= Ti, V, Zr)

Science.gov (United States)

Lee, Jonathan A.

2007-01-01

In this paper the effect of nanoparticles A12O3 and A13-X compounds (X= Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their chemical stability and low diffusions rates in aluminum matrix at high temperatures. The strengthening mechanism for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. Samples were prepared from A12O3 nanoparticle preforms, which were produced using ceramic injection molding process and pressure infiltrated by molten aluminum. A12O3 nanoparticles can also be homogeneously mixed with aluminum powder and consolidated into samples through hot pressing and sintering. On the other hand, the Al3-X nanoparticles are produced as precipitates via in situ reactions with molten aluminum alloys using conventional casting techniques. The degree of alloy strengthening using nanoparticles will depend on the materials, particle size, shape, volume fraction, and mean inter-particle spacing.

Antioxidant, Iron-chelating and Anti-glucosidase Activities of Typha ...

African Journals Online (AJOL)

Iron chelating activity was assessed using a ferrozine-based assay. Anti- glucosidase activity was determined using 4-nitrophenyl ... flavonoid (TF) content was determined based an aluminum chloride colorimetric assay [6]. TF content was ..... Dietary iron restriction or iron chelation protects from diabetes and loss of β-cell.

Evaluation of Aluminum Alloy 2050-T84 Microstructure and Mechanical Properties at Ambient and Cryogenic Temperatures

Science.gov (United States)

Hafley, Robert A.; Domack, Marcia S.; Hales, Stephen J.; Shenoy, Ravi N.

2011-01-01

Aluminum alloy 2050 is being considered for the fabrication of cryogenic propellant tanks to reduce the mass of future heavy-lift launch vehicles. The alloy is available in section thicknesses greater than that of the incumbent aluminum alloy, 2195, which will enable designs with greater structural efficiency. While ambient temperature design allowable properties are available for alloy 2050, cryogenic properties are not available. To determine its suitability for use in cryogenic propellant tanks, tensile, compression and fracture tests were conducted on 4 inch thick 2050-T84 plate at ambient temperature and at -320degF. Various metallurgical analyses were also performed in order to provide an understanding of the compositional homogeneity and microstructure of 2050.

Development of high-strength aluminum alloys for basket in transport and storage cask for high burn-up spent fuel

International Nuclear Information System (INIS)

Maeguchi, T.; Sakaguchi, Y.; Kamiwaki, Y.; Ishii, M.; Yamamoto, T.

2004-01-01

Mitsubishi Heavy Industries, Ltd. (MHI) has developed high-strength borated aluminum alloys (high-strength B-Al alloys), suitable for application to baskets in transport and storage casks for high burn-up spent fuels. Aluminum is a suitable base material for the baskets due to its low density and high thermal conductivity. The aluminum basket would reduce weight of the cask, and effectively release heat generated by spent fuels. MHI had already developed borated aluminum alloys (high-toughness B-Al alloy), and registered them as ASME Code Case ''N-673''. However, there has been a strong demand for basket materials with higher strength in the case of MSF (Mitsubishi Spent Fuel) casks for high-burn up spent fuels, since the basket is required to stand up to higher stress at higher temperature. The high-strength basket material enables the design of a compact cask under a limitation of total size and weight. MHI has developed novel high-strength B-Al alloys which meet these requirements, based on a new manufacturing process. The outline of mechanical and metallurgical characteristics of the high-strength B-Al alloys is described in this paper

Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

Science.gov (United States)

Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

2016-08-01

Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

Fiber laser cladding of nickel-based alloy on cast iron

Energy Technology Data Exchange (ETDEWEB)

Arias-González, F., E-mail: felipeag@uvigo.es [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Val, J. del [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Comesaña, R. [Materials Engineering, Applied Mechanics and Construction Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Penide, J.; Lusquiños, F.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pou, J. [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain)

2016-06-30

Highlights: • Fiber laser cladding of Ni-based alloy on cast iron was experimentally studied. • Two different types of cast iron have been analyzed: gray and ductile cast iron. • Suitable processing parameters to generate a Ni-based coating were determined. • Dilution is higher in gray cast iron samples than in ductile cast iron. • Ni-based coating presents higher hardness than cast iron but similar Young's modulus. - Abstract: Gray cast iron is a ferrous alloy characterized by a carbon-rich phase in form of lamellar graphite in an iron matrix while ductile cast iron presents a carbon-rich phase in form of spheroidal graphite. Graphite presents a higher laser beam absorption than iron matrix and its morphology has also a strong influence on thermal conductivity of the material. The laser cladding process of cast iron is complicated by its heterogeneous microstructure which generates non-homogeneous thermal fields. In this research work, a comparison between different types of cast iron substrates (with different graphite morphology) has been carried out to analyze its impact on the process results. A fiber laser was used to generate a NiCrBSi coating over flat substrates of gray cast iron (EN-GJL-250) and nodular cast iron (EN-GJS-400-15). The relationship between processing parameters (laser irradiance and scanning speed) and geometry of a single laser track was examined. Moreover, microstructure and composition were studied by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD). The hardness and elastic modulus were analyzed by means of micro- and nanoindentation. A hardfacing coating was generated by fiber laser cladding. Suitable processing parameters to generate the Ni-based alloy coating were determined. For the same processing parameters, gray cast iron samples present higher dilution than cast iron samples. The elastic modulus is similar for the coating and the substrate, while the Ni

Dependence of an overvoltage of electrochemical properties of aluminum alloys from various additives

International Nuclear Information System (INIS)

Karieva, Z.M.; Sidikov, S.A.

2005-01-01

It is known, that AI and its alloys are electrochemical behavior in electrolytes appreciably differs from many other metals as chrome, nickel, cobalt and iron. The study behavior of aluminum alloys in investigated electrolytes shows about stability of the oxygenic film that during electrode reactions are supplemented and further there is a moderate dissolution even at high temperatures and concentration of a passive film. The greater affinity to oxygen gives advantage, that the passive site of metal is considerably wide. Stage of transportation it is inherent in any heterogeneous processes. In the same a stage transition of the charged particles (electrons and ions) through border an electrode -solution (the stage of the category of ionization) is specifically electrochemical stage. At the slowed down course electrochemical processes the overvoltage develops of two parts -an overvoltage of transition and an overvoltage of reaction. In the present work is investigated behavior of electrochemical properties at addition in electrolyte-electrode of insignificant amounts of organic substances -inhibitors of corrosion. It is revealed, that adsorption of the given substances on surfaces of an electrode appreciably influences size of an overvoltage not changing thus of value of constants coefficient Taffel' s equation. ' The technique of carrying out of experiment and preparation of samples are resulted in works [3-5]. (author)

Analysis of the Chip Geometry in Dry Machining of Aeronautical Aluminum Alloys

Directory of Open Access Journals (Sweden)

Francisco Javier Trujillo Vilches

2017-01-01

Full Text Available Aluminum alloys are widely used in the manufacturing of structural parts for aircraft, frequently in combination with other materials such as CFRP (Carbon Fiber Reinforced Polymer, to form FML (Fiber Metal Laminates structures (CFRP/Al. The dry machining of these structures presents several problems, some of which are related to chip evacuation, either when machining aluminum alloys as an isotropic material, or during hybridization with composites. In this work, a study of the way in which cutting parameters influence the chip morphology in the dry machining of UNS A97075-T6 (Al-Zn and UNS A92024-T3 (Al-Cu alloys, is performed. Thus, different geometric parameters of the chip morphology have been obtained, and their evolution with feed has been analysed. Finally, the different relationships which occur between these geometric parameters and feed, have been obtained. These relationships allow a prediction of the evolution of some of the geometric parameters of the chip, as a function of feed.

Alloyed Aluminum Contacts for Silicon Solar Cells

International Nuclear Information System (INIS)

Tin Tin Aye

2010-12-01

Aluminium is usually deposited and alloyed at the back of p-p silicon solar cell for making a good ohmic contact and establishing a back electric field which avoids carrier recombination of the back surface. It was the deposition of aluminum on multicrystalline silicon (mc-Si) substrate at various annealing temperature. Physical and elemental analysis was carried out by using scanning electron microscopy (SEM) and X-rays diffraction (XRD). The electrical (I-V) characteristic of the photovoltaic cell was also measured.

Determination of trace impurities in iron-based alloy using neutron activation analysis

International Nuclear Information System (INIS)

Zaidi, J.H.; Waheed, S.; Ahmad, S.

2000-01-01

A radiochemical neutron activation analysis procedure has been developed and applied to investigate 40 major, minor, and trace impurities in iron-based alloy. A comparison of RNAA and INAA indicated a significant improvement in the detection limits. The extensive use of these alloys in the heavy mechanical industry, manufacturing of aircraft engines, nuclear applications, medical devices and chemical equipment requires their precise characterization. The concentration of iron in the iron-based alloy was found to be 86.7%, whereas Ca, Cr, K, Mg, Mn, V and W were the other constituents of the alloy, which constituted to around 12.89%. The rest of the elements were present in minor or trace levels. Most of the rare earth elements were also present in trace amounts. (orig.)

Alloying behavior of iron, gold and silver in AlCoCrCuNi-based equimolar high-entropy alloys

International Nuclear Information System (INIS)

Hsu, U.S.; Hung, U.D.; Yeh, J.W.; Chen, S.K.; Huang, Y.S.; Yang, C.C.

2007-01-01

High-entropy alloys are newly developed alloys that are composed, by definition, of at least five principal elements with concentrations in the range of 5-35 at.%. Therefore, the alloying behavior of any given principal element is significantly affected by all the other principal elements present. In order to elucidate this further, the influence of iron, silver and gold addition on the microstructure and hardness of AlCoCrCuNi-based equimolar alloys has been examined. The as-cast AlCoCrCuNi base alloy is found to have a dendritic structure, of which only solid solution FCC and BCC phases can be observed. The BCC dendrite has a chemical composition close to that of the nominal alloy, with a deficiency in copper however, which is found to segregate and form a FCC Cu-rich interdendrite. The microstructure of the iron containing alloys is similar to that of the base alloy. It is found that both of these aforementioned alloys have hardnesses of about 420 HV, which is equated to their similar microstructures. The as-cast ingot forms two layers of distinct composition with the addition of silver. These layers, which are gold and silver in color, are determined to have a hypoeutectic Ag-Cu composition and a multielement mixture of the other principal elements, respectively. This indicates the chemical incompatibility of silver with the other principal elements. The hardnesses of the gold (104 HV) and silver layers (451 HV) are the lowest and highest of the alloy systems studied. This is attributed to the hypoeutectic Ag-Cu composition of the former and the reduced copper content of the latter. Only multielement mixtures, i.e. without copper segregation, form in the gold containing alloy. Thus, it may be said that gold acts as a 'mixing agent' between copper and the other elements. Although several of the atom pairs in the gold containing alloy have positive enthalpies, thermodynamic considerations show that the high entropy contribution is sufficient to counterbalance

Oxidation of zirconium-aluminum alloys

International Nuclear Information System (INIS)

Cox, B.

1967-10-01

Examination of the processes occurring during the oxidation of Zr-1% A1, Zr-3% A1, and Zr-1.5% A1-0.5% Mo alloys has shown that in steam rapid oxidation occurs predominantly around the Zr 3 A1 particles, which at low temperatures appear to be relatively unattacked. The unoxidised particles become incorporated in the oxide, and become fully oxidised as the film thickens. This rapid localised oxidation is preceded by a short period of uniform film growth, during which the oxide film thickness does not exceed ∼200A-o. Thus the high oxidation rates can probably be ascribed to aluminum in solution in the zirconium matrix, although its precise mode of operation has not been determined. Once the solubility limit of aluminum is exceeded, the size, distribution and number of intermetallic particles affects the oxidation rate merely by altering the distribution of regions of metal giving high oxidation rates. The controlling process during the early stages of oxidation is electron transport and not ionic transport. Thus, the aluminum in the oxide film is presumably increasing the ionic conductivity more than the electronic. The oxidation rates in atmospheric pressure steam are very high and their irregular temperature dependence suggests that the oxidation rate will be pressure dependent. This was confirmed, in part, by a comparison with oxidation in moist air. It was found that the rate of development of white oxide around intermetallic particles was considerably reduced by the decrease in the partial pressure of H 2 O; the incubation period was not much different, however. (author)

Modeling of plastic localization in aluminum and Al–Cu alloys under shock loading

International Nuclear Information System (INIS)

Krasnikov, V.S.; Mayer, A.E.

2014-01-01

This paper focuses on the modeling of plastic deformation localization in pure aluminum and aluminum–copper alloys during the propagation of a plane shock wave. Modeling is carried out with the use of continual dislocation plasticity model in 2-D geometry. It is shown that the formation of localization bands occurs at an angle of 45° to the direction of propagation of the shock front. Effective initiators for plastic localization in pure aluminum are the perturbations of the initial dislocation density, in the alloys – perturbations of the dislocation density and the concentration of copper atoms. Perturbations of temperature field in a range of tens of kelvins are not so effective for plastic localization. In the alloy plastic localization intensity decreases with an increase of strain rate due to the thermally activated nature of the dislocation motion

Strength and Ductility of Forged 1200 Aluminum Alloy Reinforced ...

African Journals Online (AJOL)

With 50% reduction and fine-sized steel particles (512μm) in aluminum alloy, tensile strength dropped to 160MPa without significant decrease in ductility (1.7). Microstructure of cast samples show the presence of fine Fe particles at grain boundaries after annealing with most of the particles in solid solution. Al3Fe and AlFeSi ...

Effect of creep-aging on precipitates of 7075 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Lin, Y.C., E-mail: yclin@csu.edu.cn [School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083 (China); State Key Laboratory of Material Processing and Die and Mould Technology, Wuhan 430074 (China); Jiang, Yu-Qiang; Chen, Xiao-Min; Wen, Dong-Xu [School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083 (China); Zhou, Hua-Min [State Key Laboratory of Material Processing and Die and Mould Technology, Wuhan 430074 (China)

2013-12-20

The creep-aging behaviors of 7075 aluminum alloy are studied by uniaxial tensile creep experiments under elevated temperatures. The effects of creep-aging temperature and applied stress on the precipitates of 7075-T651 aluminum alloy are investigated using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Results show that (1) coarse insoluble precipitates (Al{sub 7}Cu{sub 2}Fe and Mg{sub 2}Si) and intermediate precipitates (Al{sub 18}Mg{sub 3}Cr{sub 2} and Al{sub 3}Zr) are found in the aluminum matrix, and the effects of creep-aging treatment on these precipitates are not obvious; (2) the main aging precipitates are η′ and η phases, and the amount of aging precipitates increase with the increase of creep-aging temperature and applied stress; (3) with the increase of creep-aging temperature and applied stress, the precipitates are discontinuously distributed on the grain boundary, and the width of precipitate free zone increases with the increase of creep-aging temperature and applied stress and (4) compared with the microstructure in the traditional stress-free aged sample, the creep-aging process can refine the precipitates and narrow the width of the precipitate free zone.

The Role of Friction Stir Processing (FSP Parameters on TiC Reinforced Surface Al7075-T651 Aluminum Alloy

Directory of Open Access Journals (Sweden)

Felipe García-Vázquez

Full Text Available Abstract: Aluminum alloys are very promising for structural applications in aerospace, military and transportation industries due to their light weight, high strength-to-weight ratio and excellent resistance to corrosion. In comparison to unreinforced aluminum alloys, aluminum/aluminum alloy matrix composites reinforced with ceramic phases exhibit higher strength and hardness, improved tribological characteristics. A novel surface modifying technique, friction stir processing (FSP, has been developed for fabrication of surface composite with an improved performance. The effect of FSP parameters such as number of passes, direction of each pass, sealed or unsealed groove on microstructure was investigated. In this work, nano-particles of TiC (2% in weight were added to aluminum alloy AA7075-T651 to produce a functional surface. Fixed parameters for this AA7075 alloy were used; rotation speed of 1000 rpm, travel speed of 300 mm/min and pin penetration of 2.8 mm. Optical microscopy (OM, scanning electron microscopy (SEM and atomic force microscopy (AFM were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters influenced the area of surface composite, distribution of TiC particles and micro-hardness of the surface composites. Finally, in order to evaluate rate wear the pin on disk test was carried out.

Identification of a cast iron alloy containing nonstrategic elements

Science.gov (United States)

Cooper, C. V.; Anton, D. L.; Lemkey, F. D.; Nowotny, H.; Bailey, R. S.; Favrow, L. H.; Smeggil, J. G.; Snow, D. B.

1989-01-01

A program was performed to address the mechanical and environmental needs of Stirling engine heater head and regenerator housing components, while reducing the dependence on strategic materials. An alloy was developed which contained no strategic elemental additions per se. The base is iron with additions of manganese, molybdenum, carbon, silicon, niobium, and ferro-chromium. Such an alloy should be producible on a large scale at very low cost. The resulting alloy, designated as NASAUT 4G-Al, contained 15 Mn, 15 Cr, 2 Mo, 1.5 C, 1.0 Si, 1.0 Nb (in weight percent) with a balance of Fe. This alloy was optimized for chemistry, based upon tensile strength, creep-rupture strength, fracture behavior, and fatigue resistance up to 800 C. Alloys were also tested for environmental compatibility. The microstructure and mechanic properties (including hardness) were assessed in the as-cast condition and following several heat treatments, including one designed to simulate a required braze cycle. The alloy was fabricated and characterized in the form of both equiaxed and columnar-grained castings. The columnar grains were produced by directional solidification, and the properties were characterized in both the longitudinal and transverse orientations. The NASAUT 4G-Al alloy was found to be good in cyclic-oxidation resistance and excellent in both hydrogen and hot-corrosion resistance, especially in comparison to the baseline XF-818 alloy. The mechanical properties of yield strength, stress-rupture life, high-cycle-fatigue resistance, and low-cycle-fatigue resistance were good to excellent in comparison to the current alloy for this application, HS-31 (X-40), with precise results depending in a complex manner on grain orientation and temperature. If required, the ductility could be improved by lowering the carbon content.

Grain refinement of aluminum and its alloys

International Nuclear Information System (INIS)

Zaid, A.I.O.

2001-01-01

Grain refinement of aluminum and its alloys by the binary Al-Ti and Ternary Al-Ti-B master alloys is reviewed and discussed. The importance of grain refining to the cast industry and the parameters affecting it are presented and discussed. These include parameters related to the cast, parameters related to the grain refining alloy and parameters related to the process. The different mechanisms, suggested in the literature for the process of grain refining are presented and discussed, from which it is found that although the mechanism of refining by the binary Al-Ti is well established the mechanism of grain refining by the ternary Al-Ti-B is still a controversial matter and some research work is still needed in this area. The effect of the addition of other alloying elements in the presence of the grain refiner on the grain refining efficiency is also reviewed and discussed. It is found that some elements e.g. V, Mo, C improves the grain refining efficiency, whereas other elements e.g. Cr, Zr, Ta poisons the grain refinement. Based on the parameters affecting the grain refinement and its mechanism, a criterion for selection of the optimum grain refiner is forwarded and discussed. (author)

Production of NbC reinforced aluminum matrix composites by mechanical alloying

International Nuclear Information System (INIS)

Silva, Marina Judice; Cardoso, Katia Regina; Travessa, Dilermando Nagle

2014-01-01

Aluminum and their alloys are key materials for the automotive and aerospace industries. The dispersion of hard ceramic particles in the Al soft matrix produces lightweight composites with interesting properties, as environmental resistance, high specific strength and stiffness, high thermal and electrical conductivity, and good wear resistance, encouraging their technological use. Powder metallurgy techniques like mechanical alloying (MA) are very attractive to design metal matrix composites, as they are able to achieve a homogeneous distribution of well dispersed particles inside the metal matrix. In this work, pure aluminum has been reinforced with particles of Niobium carbide (NbC), an extremely hard and stable refractory ceramic. NbC is frequently used as a grain growth inhibitor in micro-alloyed steel due to their low solubility in austenite. In the present work, NbC is expected to act as a reinforcing phase by its fine dispersion into the aluminum matrix, produced by MA. Composite powders produced after different milling times (up to 50h), with 10 and 20% (volume) of NbC were characterized by diffraction laser particle size analysis, scanning electron microscopy (SEM) and by X-ray diffraction (DRX), in order to establish a relationship between the milling time and the characteristics of the powder produced, as size and morphology, crystallite size and reinforcement distribution. This characterization is important in defining the MA process for production of composites for further consolidation by hot extrusion process. (author)

Production of NbC reinforced aluminum matrix composites by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Silva, Marina Judice; Cardoso, Katia Regina; Travessa, Dilermando Nagle, E-mail: dilermando.travessa@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Jose dos Campos, SP (Brazil). Instituto de Ciencia e Tecnologia

2014-07-01

Aluminum and their alloys are key materials for the automotive and aerospace industries. The dispersion of hard ceramic particles in the Al soft matrix produces lightweight composites with interesting properties, as environmental resistance, high specific strength and stiffness, high thermal and electrical conductivity, and good wear resistance, encouraging their technological use. Powder metallurgy techniques like mechanical alloying (MA) are very attractive to design metal matrix composites, as they are able to achieve a homogeneous distribution of well dispersed particles inside the metal matrix. In this work, pure aluminum has been reinforced with particles of Niobium carbide (NbC), an extremely hard and stable refractory ceramic. NbC is frequently used as a grain growth inhibitor in micro-alloyed steel due to their low solubility in austenite. In the present work, NbC is expected to act as a reinforcing phase by its fine dispersion into the aluminum matrix, produced by MA. Composite powders produced after different milling times (up to 50h), with 10 and 20% (volume) of NbC were characterized by diffraction laser particle size analysis, scanning electron microscopy (SEM) and by X-ray diffraction (DRX), in order to establish a relationship between the milling time and the characteristics of the powder produced, as size and morphology, crystallite size and reinforcement distribution. This characterization is important in defining the MA process for production of composites for further consolidation by hot extrusion process. (author)

Adsorption of Trametes versicolor laccase to soil iron and aluminum minerals: enzyme activity, kinetics and stability studies.

Science.gov (United States)

Wu, Yue; Jiang, Ying; Jiao, Jiaguo; Liu, Manqiang; Hu, Feng; Griffiths, Bryan S; Li, Huixin

2014-02-01

Laccases play an important role in the degradation of soil phenol or phenol-like substance and can be potentially used in soil remediation through immobilization. Iron and aluminum minerals can adsorb extracellular enzymes in soil environment. In the present study, we investigated the adsorptive interaction of laccase, from the white-rot fungus Trametes versicolor, with soil iron and aluminum minerals and characterized the properties of the enzyme after adsorption to minerals. Results showed that both soil iron and aluminum minerals adsorbed great amount of laccase, independent of the mineral specific surface areas. Adsorbed laccases retained 26-64% of the activity of the free enzyme. Compared to the free laccase, all adsorbed laccases showed higher Km values and lower Vmax values, indicating a reduced enzyme-substrate affinity and a lower rate of substrate conversion in reactions catalyzed by the adsorbed laccase. Adsorbed laccases exhibited increased catalytic activities compared to the free laccase at low pH, implying the suitable application of iron and aluminum mineral-adsorbed T. versicolor laccase in soil bioremediation, especially in acid soils. In terms of the thermal profiles, adsorbed laccases showed decreased thermal stability and higher temperature sensitivity relative to the free laccase. Moreover, adsorption improved the resistance of laccase to proteolysis and extended the lifespan of laccase. Our results implied that adsorbed T. versicolor laccase on soil iron and aluminum minerals had promising potential in soil remediation. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Development of quantitative analysis for cadmium, lead and chromium in aluminum alloys by using x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Yamashita, Satoshi; Kurusu, Kazuhiko; Kudou, Aiko

2009-01-01

A highly reliable quantitative analysis for cadmium, lead and chromium in aluminum alloys was developed. Standard samples were made by doping cadmium, lead and chromium into several aluminum alloys, and the composition of standard samples were determined by inductively coupled plasma optical emission spectrometry and gravimetric method. The calibration curves for these standard samples by using WD-XRF and ED-XRF exhibited linear correlation. Slope of calibration curves for Al-Cu alloy and Al-Zn-Mg alloy were smaller than other alloy's one, because of the effect by coexistent elements. Then, all calibration curves agreed with each other by performing correction with α-coefficient method. (author)

Influence of Filler Alloy Composition and Process Parameters on the Intermetallic Layer Thickness in Single-Sided Cold Metal Transfer Welding of Aluminum-Steel Blanks

Science.gov (United States)

Silvayeh, Zahra; Vallant, Rudolf; Sommitsch, Christof; Götzinger, Bruno; Karner, Werner; Hartmann, Matthias

2017-11-01

Hybrid components made of aluminum alloys and high-strength steels are typically used in automotive lightweight applications. Dissimilar joining of these materials is quite challenging; however, it is mandatory in order to produce multimaterial car body structures. Since especially welding of tailored blanks is of utmost interest, single-sided Cold Metal Transfer butt welding of thin sheets of aluminum alloy EN AW 6014 T4 and galvanized dual-phase steel HCT 450 X + ZE 75/75 was experimentally investigated in this study. The influence of different filler alloy compositions and welding process parameters on the thickness of the intermetallic layer, which forms between the weld seam and the steel sheet, was studied. The microstructures of the weld seam and of the intermetallic layer were characterized using conventional optical light microscopy and scanning electron microscopy. The results reveal that increasing the heat input and decreasing the cooling intensity tend to increase the layer thickness. The silicon content of the filler alloy has the strongest influence on the thickness of the intermetallic layer, whereas the magnesium and scandium contents of the filler alloy influence the cracking tendency. The layer thickness is not uniform and shows spatial variations along the bonding interface. The thinnest intermetallic layer (mean thickness < 4 µm) is obtained using the silicon-rich filler Al-3Si-1Mn, but the layer is more than twice as thick when different low-silicon fillers are used.

Research progress on microstructure evolution of semi-solid aluminum alloys in ultrasonic field and their rheocasting

Directory of Open Access Journals (Sweden)

Wu Shusen

2014-07-01

Full Text Available The effects of ultrasonic vibration (UV treatment on microstructure of semi-solid aluminum alloys and the application of UV in rheocasting process are reviewed. Good semi-solid slurry can be produced by high-intensity UV process for aluminum alloys. The microstructures of Al-Si, Al-Mg and Al-Cu alloys produced by rheocasting assisted with UV are compact and with fine grains. The mechanical properties of the UV treated alloys are increased by about 20%-30%. Grain refinement of the alloys is generally considered because of cavitation and acoustic streaming caused by UV. Apart from these mechanisms, a hypothesis of the fuse of dendrite root caused by capillary infiltration in the ultrasonic field, as well as a mechanism of crystallites falling off from the mould-wall and crystal multiplication by mechanical vibration effect in indirect ultrasonic vibration are proposed to explain the microstructure evolution of the alloys.

Influence of Alloy and Solidification Parameters on Grain Refinement in Aluminum Weld Metal due to Inoculation

Energy Technology Data Exchange (ETDEWEB)

Schempp, Philipp [BAM, Germany; Tang, Z. [BIAS, Germany; Cross, Carl E. [Los Alamos National Laboratory; Seefeld, T. [BIAS, Germany; Pittner, A. [BAM, Germany; Rethmeier, M. [BAM, Germany

2012-06-28

The goals are: (1) Establish how much Ti/B grain refiner is need to completely refine aluminum weld metal for different alloys and different welding conditions; (2) Characterize how alloy composition and solidification parameters affect weld metal grain refinement; and (3) Apply relevant theory to understand observed behavior. Conclusions are: (1) additions of Ti/B grain refiner to weld metal in Alloys 1050, 5083, and 6082 resulted in significant grain refinement; (2) grain refinement was more effective in GTAW than LBW, resulting in finer grains at lower Ti content - reason is limited time available for equiaxed grain growth in LBW (inability to occlude columnar grain growth); (3) welding travel speed did not markedly affect grain size within GTAW and LBW clusters; and (4) application of Hunt CET analysis showed experimental G to be on the order of the critical G{sub CET}; G{sub CET} was consistently higher for GTAW than for LBW.

Fish scale deformation analysis using scanning electron microscope: New potential biomarker in aquatic environmental monitoring of aluminum and iron contamination

Energy Technology Data Exchange (ETDEWEB)

Hidayati, Dewi; Sulaiman, Norela; Othman, Shuhaimi; Ismail, B. S. [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2013-11-27

Fish scale has the potential to be a rapid biomarker due to its structure and high possibility to come into contact with any pollutant in the aquatic environment. The scale structure consists of osteoblastic cells and other bone materials such as collagen where it is possible to form a molecular complex with heavy metals such as aluminum and iron. Hence, aluminum and iron in water could possibly destroy the scale material and marked as a scale deformation that quantitatively could be analyzed by comparing it to the normal scale structure. Water sampling and fish cage experiment were performed between June and July 2011 in Porong river which represented the water body that has high aluminum and iron contamination. The filtered water samples were preserved and extracted using the acid-mixture procedure prior to measurement of the aluminum and iron concentrations using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), while samples for total suspended solid (TSS) analysis were kept at 4 °C in cool-boxes. The scales were cleaned with sterile water, then dehydrated in 30, 50, 70, and 90% ethanol and dried on filter papers. They were then mounted on an aluminum stub and coated with gold in a sputter coater prior to Scanning Electron Microscope (SEM) observation. According to the SEM analysis, it was found that there were several deformations on the scale samples taken from sites that have high concentrations of aluminum and iron i.e. the increasing number of pits, deformation and decreasing number of spherules and ridges while the control scale exhibited the normal features. However, the site with higher TSS and pH indicated lower aluminum effect. A moderate correlation was found between the number of pits with aluminum (r=0.43) and iron (r=0.41) concentrations. Fish scale deformation using SEM analysis can potentially be a rapid biomarker in aquatic monitoring of aluminum and iron contamination. However, the measurement must be accompanied by pH and

Fish scale deformation analysis using scanning electron microscope: New potential biomarker in aquatic environmental monitoring of aluminum and iron contamination

Science.gov (United States)

Hidayati, Dewi; Sulaiman, Norela; Othman, Shuhaimi; Ismail, B. S.

2013-11-01

Fish scale has the potential to be a rapid biomarker due to its structure and high possibility to come into contact with any pollutant in the aquatic environment. The scale structure consists of osteoblastic cells and other bone materials such as collagen where it is possible to form a molecular complex with heavy metals such as aluminum and iron. Hence, aluminum and iron in water could possibly destroy the scale material and marked as a scale deformation that quantitatively could be analyzed by comparing it to the normal scale structure. Water sampling and fish cage experiment were performed between June and July 2011 in Porong river which represented the water body that has high aluminum and iron contamination. The filtered water samples were preserved and extracted using the acid-mixture procedure prior to measurement of the aluminum and iron concentrations using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), while samples for total suspended solid (TSS) analysis were kept at 4 °C in cool-boxes. The scales were cleaned with sterile water, then dehydrated in 30, 50, 70, and 90% ethanol and dried on filter papers. They were then mounted on an aluminum stub and coated with gold in a sputter coater prior to Scanning Electron Microscope (SEM) observation. According to the SEM analysis, it was found that there were several deformations on the scale samples taken from sites that have high concentrations of aluminum and iron i.e. the increasing number of pits, deformation and decreasing number of spherules and ridges while the control scale exhibited the normal features. However, the site with higher TSS and pH indicated lower aluminum effect. A moderate correlation was found between the number of pits with aluminum (r=0.43) and iron (r=0.41) concentrations. Fish scale deformation using SEM analysis can potentially be a rapid biomarker in aquatic monitoring of aluminum and iron contamination. However, the measurement must be accompanied by pH and