Rotary Friction Welding of Weight Heavy Alloy with Wrought AlMg3 Alloy for Subcaliber Ammunition

OpenAIRE

Olgierd Janusz Goroch; Zbigniew Gulbinowicz

2017-01-01

The results of studies concerning friction welding of Weight Heavy Alloy (WHA) with AlMg3 alloy are presented. The friction welding of density 17,5 Mg/m3 with aluminum alloy showed that it is possible to reach the joints with the strength exceeding the yield strength of wrought AlMg3 alloy. This strength looks to be promising from point of view of condition which have to be fulfilled in case of armor subcaliber ammunition, where WHA rods play the role Kinetic Energy Penetrators and aluminum i...

Susceptibility testing for welding of AlMg alloys intended for extrusion

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J. Borowski

2016-07-01

Full Text Available The objective of research was to determine the weldability, using Tungsten Inert Gas (TIG of extruded sections made of hard-deformable 5xxx series aluminum alloys with differing magnesium content, i.e. AlMg3, AlMg4,5, AlMg5, AlMg7. Welded joints were obtained as a result of a welding process consisting of several steps. Only welds characterized by very good appearance and quality were selected for tests. As a result of conducted research, TIG welding parameters were determined for sections with a thickness of 8 mm. It was observed that alloys of differing Mg content are characterized by high weldability and do not exhibit a significant reduction of the yield point. Moreover, joints exhibit uniform hardness distribution in the welded joint and heat-affected zone. Tensile strength is reduced.

The Influence of Aluminum on the Microstructure and Hardness of Mg-5Si-7Sn Alloy

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Rzychoń T.

2016-03-01

Full Text Available Magnesium alloys due the low density and good mechanical properties are mainly used in the automotive and aerospace industry. In recent years, magnesium alloys are extensively developed for use in high temperatures (above 120°C. Among these alloys, magnesium alloys containing tin and silicon have large possibilities of application due to the formation of thermally stable intermetallic Mg2Sn and Mg2Si. In this paper the influence of aluminum and heat treatment on the on the microstructure and hardness of Mg-7Sn-5Si alloy is reported. It was found that the microstructure of Mg-7Sn-5Si alloy consist of α-Mg solid solution, Mg2Sn and Mg2Si compounds. Addition of 2 wt% of Al to Mg-7Sn-5Si alloy causes the formation of Al2Sn phase. Moreover, Al dissolves in the α-Mg solid solution. The solution heat-treatment of tested alloys at 500°C for 24 h causes the dissolve the Mg2Sn phase in the α-Mg matrix and spheroidization of Mg2Si compound. The Mg2Si primary crystals are stable at solution temperature. After ageing treatment the precipitation process of equilibrium Mg2Sn phase was found in both alloys. The addition of aluminum has a positive effect on the hardness of Mg-7Sn-5Si alloy. In case of Mg-5Si-7Sn-2Al alloy the highest hardness was obtained for sample aged for 148 h at 250°C (88 HV2, while in case of Al-free alloy the highest hardness is 70 HV for material aged for 148 h at 250°C.

The Age-Precipitations Structure Of Al-Mg-Ge Alloy Aged At 473K

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Kawai A.

2015-06-01

Full Text Available The Al-Mg-Ge alloy is one of the age-hardening aluminum alloy after solution heat treatment. It has been proposed that the age-precipitation behavior of Al-Mg-Ge alloy is different from that of Al-Mg-Si alloy according to our previous works about the microstructure on Al-Mg-Ge alloy over-aged at 523K. For example, The hardness of peak aged Al-1.0mass%Mg2Ge alloy is higher than that of Al-1.0mass%Mg2Si alloy. The precipitates in the over-aged samples have been classified as some metastable phases, such as the β’-phase and Type-A precipitates and equilibrium phase of β-Mg2Ge by TEM observation. There a few reports about microstructure on Al-Mg-Ge alloys observed by TEM for different aging times. The age-precipitations structure of Al-Mg-Ge alloy has not been became clear. In this work, TEM observation was investigated the microstructure on Al-1.0mass%Mg2Ge alloy for difference aging times aged at 473K.

Rotary Friction Welding of Weight Heavy Alloy with Wrought AlMg3 Alloy for Subcaliber Ammunition

Directory of Open Access Journals (Sweden)

Olgierd Janusz Goroch

2017-12-01

Full Text Available The results of studies concerning friction welding of Weight Heavy Alloy (WHA with AlMg3 alloy are presented. The friction welding of density 17,5 Mg/m3 with aluminum alloy showed that it is possible to reach the joints with the strength exceeding the yield strength of wrought AlMg3 alloy. This strength looks to be promising from point of view of condition which have to be fulfilled in case of armor subcaliber ammunition, where WHA rods play the role Kinetic Energy Penetrators and aluminum is used for projectile ballistic cup.

MgCoAl and NiCoAl LDHs synthesized by the hydrothermal urea hydrolysis method: Structural characterization and thermal decomposition

International Nuclear Information System (INIS)

Chagas, L.H.; De Carvalho, G.S.G.; Do Carmo, W.R.; San Gil, R.A.S.; Chiaro, S.S.X.; Leitão, A.A.; Diniz, R.; De Sena, L.A.; Achete, C.A.

2015-01-01

Highlights: • We synthesized MgCoAl and NiCoAl LDHs by the urea hydrolysis method. • Aluminum rich and crystalline materials have been formed. • The calcination of the LDHs generated mixed oxides with high surface areas. - Abstract: Layered double hydroxides (LDHs) with Mg/Co/Al and Ni/Co/Al were synthesized for the first time by the urea hydrolysis method. The experimental conditions promoted aluminum rich and crystalline materials. The formation of LDHs was investigated by powder X-ray diffraction (XRD), chemical analysis, solid state nuclear magnetic resonance with magic angle spinning ( 27 Al-MAS-NMR), simultaneous thermogravimetric/differential thermal analysis (TGA/DTA), FTIR spectroscopy, scanning electron microscopy (SEM), and N 2 adsorption–desorption experiments. A single phase corresponding to LDH could be obtained in all the investigated compositions. Thermal calcination of these LDHs at 500 °C resulted in the formation of solid solutions in which Al 3+ was dissolved. All the calcined materials have rock-salt like structures and high surface areas

ALUMINUM CHLORIDE EFFECT ON Ca2+,Mg(2+)-ATPase ACTIVITY AND DYNAMIC PARAMETERS OF SKELETAL MUSCLE CONTRACTION.

Science.gov (United States)

Nozdrenko, D M; Abramchuk, O M; Soroca, V M; Miroshnichenko, N S

2015-01-01

We studied enzymatic activity and measured strain-gauge contraction properties of the frog Rana temporaria m. tibialis anterior muscle fascicles during the action of aluminum chloride solution. It was shown that AlCl3 solutions did not affect the dynamic properties of skeletal muscle preparation in concentrations less than 10(-4) M Increasing the concentration of AlCl3 to 10(-2) M induce complete inhibition of muscle contraction. A linear correlation between decrease in Ca2+,Mg(2+)-ATPase activity of sarcoplasmic reticulum and the investigated concentrations range of aluminum chloride was observed. The reduction in the dynamic contraction performance and the decrease Ca2+,Mg(2+)-ATPase activity of the sarcoplasmic reticulum under the effect of the investigated AlCl3 solution were minimal in pre-tetanus period of contraction.

Aluminum chloride effect on Ca(2+,Mg(2+-ATPase activity and dynamic parameters of skeletal muscle contraction

Directory of Open Access Journals (Sweden)

D. M. Nozdrenko

2015-10-01

Full Text Available We studied enzymatic activity and measured strain-gauge contraction properties of the frog Rana temporaria m. tibialis anterior muscle fascicles during the action of aluminum chloride solution. It was shown that AlCl3 solutions did not affect the dynamic properties of skeletal muscle preparation in concentrations less than 10-4 M. Increasing the concentration of AlCl3 to 10-2 M induce complete inhibition of muscle contraction. A linear correlation between decrease in Ca2+,Mg2+-ATPase activity of sarcoplasmic reticulum and the investigated concentrations range of aluminum chloride was observed. The reduction in the dynamic contraction performance and the decrease Ca2+,Mg2+-ATPase activity of the sarcoplasmic reticulum under the effect of the investigated AlCl3 solution were minimal in pre-tetanus period of contraction.

Influence of Mg O and B2O3 addition on reaction sintering, properties and microstructure of Aluminum titanate

International Nuclear Information System (INIS)

Ajami, R.; Sarpoolaki, H.; Akbari, G. H.

2007-01-01

The effect of Mg O and B 2 O 3 on the formation, physical properties, phase analysis and microstructure of aluminum titanate was investigated. Density results showed the sample containing of 1 wt percent B 2 O 3 and 2 wt percent Mg O leads to the highest density while the lowest density was seen in samples containing 1 wt percent B 2 O 3 compared to pure aluminum titanate. Regarding the phase analysis of samples, Mg O was found most effective additive on reaction sintering of aluminum titanate through the intermediate phases. Furthermore at the temperatures above 1350 d eg C , B 2 O 3 promote the formation reaction of aluminum titanate. Microstructural analysis showed the samples containing Mg O are fine grain and homogeneous. Thermal expansion coefficient of samples with additives is greater than pure aluminum titanate. Pure aluminum titanate samples and one containing B 2 O 3 additive decompose to Al 2 O 3 and TiO 2 after 5 hours heat treatment at 1150 d eg C while the samples containing 2 wt percent Mg O was stable even after 25 hours

The Effectiveness of Al-Si Coatings for Preventing Interfacial Reaction in Al-Mg Dissimilar Metal Welding

Science.gov (United States)

Wang, Yin; Al-Zubaidy, Basem; Prangnell, Philip B.

2018-01-01

The dissimilar welding of aluminum to magnesium is challenging because of the rapid formation of brittle intermetallic compounds (IMC) at the weld interface. An Al-Si coating interlayer was selected to address this problem, based on thermodynamic calculations which predicted that silicon would change the reaction path to avoid formation of the normally observed binary Al-Mg IMC phases ( β-Al3Mg2 and γ-Al12Mg17). Long-term static heat treatments confirmed that a Si-rich coating will preferentially produce the Mg2Si phase in competition with the less stable, β-Al3Mg2 and γ-Al12Mg17 binary IMC phases, and this reduced the overall reaction layer thickness. However, when an Al-Si clad sheet was tested in a real welding scenario, using the Refill™ friction stir spot welding (FSSW) technique, Mg2Si was only produced in very small amounts owing to the much shorter reaction time. Surprisingly, the coating still led to a significant reduction in the IMC reaction layer thickness and the welds exhibited enhanced mechanical performance, with improved strength and fracture energy. This beneficial behavior has been attributed to the softer coating material both reducing the welding temperature and giving rise to the incorporation of Si particles into the reaction layer, which toughened the brittle interfacial IMC phases during crack propagation.

MgCoAl and NiCoAl LDHs synthesized by the hydrothermal urea hydrolysis method: Structural characterization and thermal decomposition

Energy Technology Data Exchange (ETDEWEB)

Chagas, L.H., E-mail: lhchagas-prometro@inmetro.gov.br [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); Instituto Nacional de Metrologia Qualidade e Tecnologia, Divisão de Metrologia de Materiais, 25250-020 Duque de Caxias, RJ (Brazil); De Carvalho, G.S.G.; Do Carmo, W.R. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); San Gil, R.A.S. [Universidade Federal do Rio de Janeiro, Instituto de Química, 21949-900 Rio de Janeiro, RJ (Brazil); Chiaro, S.S.X. [PETROBRAS-CENPES, 21941-915 Rio de Janeiro, RJ (Brazil); Leitão, A.A.; Diniz, R. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); De Sena, L.A.; Achete, C.A. [Instituto Nacional de Metrologia Qualidade e Tecnologia, Divisão de Metrologia de Materiais, 25250-020 Duque de Caxias, RJ (Brazil)

2015-04-15

Highlights: • We synthesized MgCoAl and NiCoAl LDHs by the urea hydrolysis method. • Aluminum rich and crystalline materials have been formed. • The calcination of the LDHs generated mixed oxides with high surface areas. - Abstract: Layered double hydroxides (LDHs) with Mg/Co/Al and Ni/Co/Al were synthesized for the first time by the urea hydrolysis method. The experimental conditions promoted aluminum rich and crystalline materials. The formation of LDHs was investigated by powder X-ray diffraction (XRD), chemical analysis, solid state nuclear magnetic resonance with magic angle spinning ({sup 27}Al-MAS-NMR), simultaneous thermogravimetric/differential thermal analysis (TGA/DTA), FTIR spectroscopy, scanning electron microscopy (SEM), and N{sub 2} adsorption–desorption experiments. A single phase corresponding to LDH could be obtained in all the investigated compositions. Thermal calcination of these LDHs at 500 °C resulted in the formation of solid solutions in which Al{sup 3+} was dissolved. All the calcined materials have rock-salt like structures and high surface areas.

Study on effects of powder and flake chemistry and morphology on the properties of Al-Cu-Mg-X-X-X powder metallurgy advanced aluminum alloys

Science.gov (United States)

Meschter, P. J.; Lederich, R. J.; Oneal, J. E.

1986-01-01

A study was conducted: (1) to develop rapid solidification processed (RSP) dispersoid-containing Al-3Cu-2Li-1Mg-0.2Zr alloys as substitutes for titanium alloys and commercial 2XXX aluminum alloys for service to at least 150 C; and (2) to develop RSP Al-4Li-Cu-Mg-Zr alloys as substitutes for high-strength commercial 7XXX alloys in ambient-temperature applications. RSP Al-3Cu-2Li-1Mg-0.2Zr alloys have density-normalized yield stresses at 150 C up to 52% larger than that of 2124-T851 and up to 30% larger than that of Ti-6Al-4V. Strength at 150 C in these alloys is provided by thermally stable delta' (Al3Li), T1 (Al2LiCu), and S' (Al2CuMg) precipitates. Density-normalized yield stresses of RSP Al-3Cu-2Li-1Mg-0.2Zr alloys are up to 100% larger than that of 2124-T851 and equivalent to that of Al-8Fe-4Ce at 260 C. Strength in the RSP alloys at 260 C is provided by incoherent dispersoids and subboundary constituent particles such as T1 and S. The RSP alloys are attractive substitutes in less than or = 100-h exposures for 2xxx and Al-4Fe-Ce alloys up to 260 C and for titanium alloys up to 150 C. RSP Al-4Li-Cu-Mg-Zr alloys have ambient-temperature yield and ultimate tensile stresses similar to that of 7050-T7651, and are 14% less dense. RSP Al-4Li-0.5Cu-1.5Mg-0.2Zr has a 20% higher specific yield stress, 40% higher specific elastic modulus, and superior corrosion resistance compared to the properties of 7050-T7651. Strength in the Al-4Li-Cu-Mg-Zr alloy class is primarily provided by the substructure and delta' precipitates and is independent of Cu:Mg ratio. Improvements in fracture toughness and transverse-orientation properties in both alloy classes depend on improved melt practices to eliminate oxide inclusions which are incorporated into the consolidated forms.

26Al-containing acidic and basic sodium aluminum phosphate preparation and use in studies of oral aluminum bioavailability from foods utilizing 26Al as an aluminum tracer

Science.gov (United States)

Yokel, Robert A.; Urbas, Aaron A.; Lodder, Robert A.; Selegue, John P.; Florence, Rebecca L.

2005-04-01

We synthesized 26Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down (∼3000- and 850-fold) to prepare ∼300-400 mg of each SALP. The 26Al was incorporated at the beginning of the syntheses to maximize 26Al and 27Al equilibration and incorporate the 26Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used to characterize the two SALP samples and some intermediate samples. Multi-elemental analysis (MEA) was used to determine Na, Al and P content. Commercial products were included for comparison. Satisfactory XRD analyses, near infrared spectra and MEA results confirmed that we synthesized acidic and basic SALP, as well as some of the syntheses intermediates. The 26Al-containing acidic and basic SALPs were incorporated into a biscuit material and a processed cheese, respectively. These were used in oral bioavailability studies conducted in rats in which the 26Al present in blood after its oral absorption was quantified by accelerator mass spectrometry. The results showed oral Al bioavailability from acidic SALP in biscuit was ∼0.02% and from basic SALP in cheese ∼0.05%, lower than our previous determination of Al bioavailability from drinking water, ∼0.3%. Both food and water can appreciably contribute to the Al absorbed from typical human Al intake.

26Al-containing acidic and basic sodium aluminum phosphate preparation and use in studies of oral aluminum bioavailability from foods utilizing 26Al as an aluminum tracer

International Nuclear Information System (INIS)

Yokel, Robert A.; Urbas, Aaron A.; Lodder, Robert A.; Selegue, John P.; Florence, Rebecca L.

2005-01-01

We synthesized 26 Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down (∼3000- and 850-fold) to prepare ∼300-400 mg of each SALP. The 26 Al was incorporated at the beginning of the syntheses to maximize 26 Al and 27 Al equilibration and incorporate the 26 Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used to characterize the two SALP samples and some intermediate samples. Multi-elemental analysis (MEA) was used to determine Na, Al and P content. Commercial products were included for comparison. Satisfactory XRD analyses, near infrared spectra and MEA results confirmed that we synthesized acidic and basic SALP, as well as some of the syntheses intermediates. The 26 Al-containing acidic and basic SALPs were incorporated into a biscuit material and a processed cheese, respectively. These were used in oral bioavailability studies conducted in rats in which the 26 Al present in blood after its oral absorption was quantified by accelerator mass spectrometry. The results showed oral Al bioavailability from acidic SALP in biscuit was ∼0.02% and from basic SALP in cheese ∼0.05%, lower than our previous determination of Al bioavailability from drinking water, ∼0.3%. Both food and water can appreciably contribute to the Al absorbed from typical human Al intake

Thermal and microstructural analysis of alloys of Al-Mg-Li system

International Nuclear Information System (INIS)

Ovsyannikov, B.V.; Zamaytin, V.M.; Smirnov, V.L.; Mushnikov, V.S.

2008-01-01

By means of the thermal analysis one investigated into melting and solidification of Al-Mg-Li system 1420, 1421 and 1424 aluminum-lithium alloys. One determined the temperature values of the nonequilibrium and the equilibrium solidus, the initiation of the liquidus linear shrinkage of the listed alloys. Making use of a scanning electron microscope with a microanalyser unit one studied the microstructure of the alloys and determined the local chemical composition of the phases unsoluble under homogenization of ingots along the aluminum matrix grain boundaries [ru

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.

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.

{sup 26}Al-containing acidic and basic sodium aluminum phosphate preparation and use in studies of oral aluminum bioavailability from foods utilizing {sup 26}Al as an aluminum tracer

Energy Technology Data Exchange (ETDEWEB)

Yokel, Robert A. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States) and Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536-0305 (United States)]. E-mail: ryokel@email.uky.edu; Urbas, Aaron A. [Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Lodder, Robert A. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States); Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Selegue, John P. [Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Florence, Rebecca L. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States)

2005-04-01

We synthesized {sup 26}Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down ({approx}3000- and 850-fold) to prepare {approx}300-400 mg of each SALP. The {sup 26}Al was incorporated at the beginning of the syntheses to maximize {sup 26}Al and {sup 27}Al equilibration and incorporate the {sup 26}Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used to characterize the two SALP samples and some intermediate samples. Multi-elemental analysis (MEA) was used to determine Na, Al and P content. Commercial products were included for comparison. Satisfactory XRD analyses, near infrared spectra and MEA results confirmed that we synthesized acidic and basic SALP, as well as some of the syntheses intermediates. The {sup 26}Al-containing acidic and basic SALPs were incorporated into a biscuit material and a processed cheese, respectively. These were used in oral bioavailability studies conducted in rats in which the {sup 26}Al present in blood after its oral absorption was quantified by accelerator mass spectrometry. The results showed oral Al bioavailability from acidic SALP in biscuit was {approx}0.02% and from basic SALP in cheese {approx}0.05%, lower than our previous determination of Al bioavailability from drinking water, {approx}0.3%. Both food and water can appreciably contribute to the Al absorbed from typical human Al intake.

Characterization of Al-Cu-Mg-Ag Alloy RX226-T8 Plate

Science.gov (United States)

Lach, Cynthia L.; Domack, Marcia S.

2003-01-01

Aluminum-copper-magnesium-silver (Al-Cu-Mg-Ag) alloys that were developed for thermal stability also offer attractive ambient temperature strength-toughness combinations, and therefore, can be considered for a broad range of airframe structural applications. The current study evaluated Al-Cu-Mg-Ag alloy RX226-T8 in plate gages and compared performance with sheet gage alloys of similar composition. Uniaxial tensile properties, plane strain initiation fracture toughness, and plane stress tearing resistance of RX226-T8 were examined at ambient temperature as a function of orientation and thickness location in the plate. Properties were measured near the surface and at the mid-plane of the plate. Tensile strengths were essentially isotropic, with variations in yield and ultimate tensile strengths of less than 2% as a function of orientation and through-thickness location. However, ductility varied by more than 15% with orientation. Fracture toughness was generally higher at the mid-plane and greater for the L-T orientation, although the differences were small near the surface of the plate. Metallurgical analysis indicated that the microstructure was primarily recrystallized with weak texture and was uniform through the plate with the exception of a fine-grained layer near the surface of the plate. Scanning electron microscope analysis revealed Al-Cu-Mg second phase particles which varied in composition and were primarily located on grain boundaries parallel to the rolling direction. Fractography of toughness specimens for both plate locations and orientations revealed that fracture occurred predominantly by transgranular microvoid coalescence. Introduction High-strength, low-density Al-Cu-Mg-Ag alloys were initially developed to replace conventional 2000 (Al-Cu-Mg) and 7000 (Al-Zn-Cu-Mg) series aluminum alloys for aircraft structural applications [1]. During the High Speed Civil Transport (HSCT) program, improvements in thermal stability were demonstrated for candidate

Preparation of a high strength Al-Cu-Mg alloy by mechanical alloying and press-forming

Energy Technology Data Exchange (ETDEWEB)

Tang Huaguo [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Cheng Zhiqiang [College of Resources and Environment, Jilin Agricultural University, Changchun 130118 (China); Liu Jianwei [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Ma Xianfeng, E-mail: xfma@ciac.jl.cn [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2012-07-30

Highlights: Black-Right-Pointing-Pointer A high strength aluminum alloy of Al-2 wt.%Mg-2 wt.%Cu has been prepared by mechanical alloying and press-forming. Black-Right-Pointing-Pointer The alloy only consists of solid solution {alpha}-Al. Black-Right-Pointing-Pointer The grains size of {alpha}-Al was about 300 nm-5 {mu}m. Black-Right-Pointing-Pointer The solid solution strengthening and the grain refinement strengthening are the main reasons for such a high strength. - Abstract: A high strength aluminum alloy, with the ratio of 96 wt.%Al-2 wt.%Mg-2 wt.%Cu, has been prepared by mechanical alloying and press-forming. The alloy exhibited a high tensile strength of 780 MPa and a high microhardness of 180 HV. X-ray diffraction characterizations confirmed that the alloy only consists of a solid solution {alpha}-Al. Microstructure characterizations revealed that the grain size of {alpha}-Al was about 300 nm-5 {mu}m. The solid solution strengthening and the grain refinement strengthening were considered to be the reason for such a high strength.

Discharge behaviour of Mg-Al-Pb and Mg-Al-Pb-In alloys as anodes for Mg-air battery

International Nuclear Information System (INIS)

Wang, Naiguang; Wang, Richu; Peng, Chaoqun; Peng, Bing; Feng, Yan; Hu, Chengwang

2014-01-01

Highlights: • We investigate the effect of indium on the discharge behaviour of Mg-Al-Pb alloy. • We evaluate the performance of Mg-air batteries with Mg-Al-Pb and Mg-Al-Pb-In anodes. • We analyze the activation mechanism of Mg-Al-Pb-In alloy in the discharge process. - Abstract: The discharge behaviour of Mg-Al-Pb and Mg-Al-Pb-In alloys in 3.5 wt.% NaCl solution is investigated by electrochemical techniques, and compared with that of pure magnesium. The results show that Mg-Al-Pb-In alloy provides a more negative potential and exhibits a higher utilization efficiency in contrast with Mg-Al-Pb alloy and pure magnesium during the half-cell test at a large current density, and gives desirable discharge performance when used as anode for Mg- air battery. The peak power density of the Mg-air battery with Mg-Al-Pb-In anode is 94.5 mW cm −2 , which is comparable with those of Mg-H 2 O 2 semi-fuel batteries. Moreover, the activation mechanism of Mg-Al-Pb-In alloy during the discharge process is also analyzed

Effect of thermal tempering on microstructure and mechanical properties of Mg-AZ31/Al-6061 diffusion bonding

Energy Technology Data Exchange (ETDEWEB)

Jafarian, Mojtaba [Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Rizi, Mohsen Saboktakin, E-mail: M.saboktakin@Pa.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Department of Industrial Engineering, Lenjan Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Jafarian, Morteza [Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Honarmand, Mehrdad [Department of Mechanical Engineering, Tiran Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Javadinejad, Hamid Reza; Ghaheri, Ali [Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Department of Industrial Engineering, Lenjan Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Bahramipour, Mohammad Taghi [Materials Engineering Department, Hakim Sabzevari University, Sabzevar, 397 (Iran, Islamic Republic of); Ebrahimian, Marzieh [Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Department of Industrial Engineering, Lenjan Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

2016-06-01

The objective of this study is to investigate the effect of the types thermal tempering of aluminum alloy on microstructure and mechanical properties of AZ31-O Mg and Al 6061-T6 diffusion bonding. Using Optical Microscope (OM) and Scanning Electron Microscopes (SEM) equipped with EDS analysis and line scan the interfaces of joints were evaluated. The XRD analysis was carried out to characterize phase constitution near the interface zone. The mechanical properties of joints were measured using Vickers micro-hardness and shear strength. According to the results in bonding of AZ31-Mg/Al-6061-O, in less plastic deformation in magnesium alloy, diffusion rate of most magnesium atoms occurred to aluminum alloy and formation of diffusion zone with minimum micro-hardness (140 HV) and maximum shear strength (32 MPa) compared to Al 6061-T6/Mg-AZ31 bonding. Evaluation of fracture surfaces indicates an occurrence of failure from the brittle intermetallic phases. - Highlights: • Diffusion bonding AZ31 to Al-6061withoutany interlayer was successful. • Thermal tempered aluminum alloy plays a vital role in the mechanical properties of joint. • Less thickness of reaction layers and micro-hardness in bonding annealed Al- 6061 layers to AZ31 was achieved. • Fracture surfaces indicated that the onset of fracture from intermetallic compounds resulted in fracture of the cleavage.

Effect of thermal tempering on microstructure and mechanical properties of Mg-AZ31/Al-6061 diffusion bonding

International Nuclear Information System (INIS)

Jafarian, Mojtaba; Rizi, Mohsen Saboktakin; Jafarian, Morteza; Honarmand, Mehrdad; Javadinejad, Hamid Reza; Ghaheri, Ali; Bahramipour, Mohammad Taghi; Ebrahimian, Marzieh

2016-01-01

The objective of this study is to investigate the effect of the types thermal tempering of aluminum alloy on microstructure and mechanical properties of AZ31-O Mg and Al 6061-T6 diffusion bonding. Using Optical Microscope (OM) and Scanning Electron Microscopes (SEM) equipped with EDS analysis and line scan the interfaces of joints were evaluated. The XRD analysis was carried out to characterize phase constitution near the interface zone. The mechanical properties of joints were measured using Vickers micro-hardness and shear strength. According to the results in bonding of AZ31-Mg/Al-6061-O, in less plastic deformation in magnesium alloy, diffusion rate of most magnesium atoms occurred to aluminum alloy and formation of diffusion zone with minimum micro-hardness (140 HV) and maximum shear strength (32 MPa) compared to Al 6061-T6/Mg-AZ31 bonding. Evaluation of fracture surfaces indicates an occurrence of failure from the brittle intermetallic phases. - Highlights: • Diffusion bonding AZ31 to Al-6061withoutany interlayer was successful. • Thermal tempered aluminum alloy plays a vital role in the mechanical properties of joint. • Less thickness of reaction layers and micro-hardness in bonding annealed Al- 6061 layers to AZ31 was achieved. • Fracture surfaces indicated that the onset of fracture from intermetallic compounds resulted in fracture of the cleavage.

Superplastic properties of an Al-2.4Mg-1.8Li-0.5Sc alloy

International Nuclear Information System (INIS)

Bradley, E.L. III; Morris, J.W. Jr.

1991-01-01

This paper reports that there is a need in the aerospace industry for structural, superplastic aluminum alloys that are formable at strain-rates greater than 10 -3 s -1 in order for the economic benefits of superplastic forming to be realized. The standard, structural, superplastic aluminum alloy in the aerospace industry is 7475, which has an optimum forming strain-rate near 10 -4 s -1 . Thus, research has been focused on modifying the microstructures of wrought Al-Li alloys such as 2090 and 8090 into superplastically formable (SPF) microstructures with improved properties, but the results have not been completely successful. Superplastic alloys with high strengths have been produced from the Al-Mg-Sc system. These alloys are strengthened by thermomechanical processing which precipitates small, coherent Al 3 Sc particles and increases the dislocation density of the material. The Mg is in solid solution and improves the work hardening capability of these alloys. Because superplastic forming is carried out at relatively high temperatures, recovery processes eliminate the dislocation strengthening resulting from the rolling and overage the precipitates. Lithium provides the most promising choice since it forms the ordered coherent precipitate δ (Al 3 Li), lowers the density, and increases the stiffness of aluminum alloys

Crystallinity and superconductivity of as-grown MgB2 thin films with AlN buffer layers

International Nuclear Information System (INIS)

Tsujimoto, K.; Shimakage, H.; Wang, Z.; Kaya, N.

2005-01-01

The effects of aluminum nitride (AlN) buffer layers on the superconducting properties of MgB 2 thin film were investigated. The AlN buffer layers and as-grown MgB 2 thin films were deposited in situ using the multiple-target sputtering system. The best depositing condition for the AlN/MgB 2 bi-layer occurred when the AlN was deposited on c-cut sapphire substrates at 290 deg. C. The crystallinity of the AlN/MgB 2 bi-layer was studied using the XRD φ-scan and it showed that AlN and MgB 2 had the same in-plane alignment rotated at an angle of 30 deg. as compared to c-cut sapphire. The critical temperature of the MgB 2 film was 29.8 K and the resistivity was 50.0 μΩ cm at 40 K

Effect of Ce on Casting Structure of Near-rapidly Solidified Al-Zn-Mg-Cu Alloy

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HUANG Gao-ren

2017-11-01

Full Text Available Through using XRD,DSC,SEM,EDS and other modern analysis methods, the effects of rare earth element Ce on microstructure and solidification temperature of Al-Zn-Mg-Cu under different cooling rates were studied, the principle of Ce on grain refining and melt cleaning of alloys was analyzed and discussed. The results show that MgZn2 phase and α-Al matrix are the main precipitations, Al,Cu,Mg and other elements dissolve in MgZn2 phase, a new phase Mg(Zn, Cu, Al2 is formed, solute elements in the grain boundary have higher concentration, eutectic reaction takes place between MgZn2 and α-Al, lamellar eutectic structure is generated. The addition of Ce decreases the dendritic arm spacing,reduces the layer spacing between eutectic phases and refines the eutectic structure and the grain significantly, and inhibits the appearance of the impurity phase Al7Cu2Fe in aluminum alloys. The addition of Ce also reduces the precipitation temperature of α-Al matrix and eutectic phase by 6.4℃ and 5.6℃ respectively.

Nano-ZnO Particles’ Effect in Improving the Mechanical Response of Mg-3Al-0.4Ce Alloy

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Sravya Tekumalla

2016-11-01

Full Text Available Magnesium based nanocomposites, due to their excellent dimensional stability and mechanical integrity, have a lot of potential to replace the existing commercial Al alloys and steels used in aerospace and automotive applications. Mg-Al alloys are commercially used in the form of AZ (magnesium-aluminum-zinc and AM (magnesium-aluminum-manganese series in automobile components. However, the Mg17Al12 phase in Mg-Al alloys is a low melting phase which results in a poor creep and high temperature performance of the alloys. Rare earth additions modify the phase and hence improve the properties of the materials. In this paper, Ce and nano ZnO particles were added to Mg-Al alloys to attain a favorable effect on their properties. The developed materials exhibited promising properties in terms of thermal expansion coefficient (CTE, hardness, and tensile strength. Further, the ZnO addition refined the microstructure and helped in obtaining a uniform distribution, however without grain size refinement. The increased addition of ZnO and the improvement in the distribution led to an enhancement in the properties, rendering the materials suitable for a wide spectrum of engineering applications.

Preparation of Al-Mg Alloy Electrodes by Using Powder Metallurgy and Their Application for Hydrogen Production

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Wen-Nong Hsu

2014-01-01

Full Text Available The choice of an electrode is the most critical parameter for water electrolysis. In this study, powder metallurgy is used to prepare aluminum-magnesium (Al-Mg alloy electrodes. In addition to pure Mg and Al electrodes, five Al-Mg alloy electrodes composed of Al-Mg (10 wt%, Al-Mg (25 wt%, Al-Mg (50 wt%, and Al-Mg (75 wt% were prepared. In water electrolysis experiments, the pure Al electrode exhibited optimal electrolytic efficiency. However, the Al-Mg (25 wt% alloy was the most efficient when the anticorrosion effect and materials costs were considered. In this study, an ultrasonic field was applied to the electrolysis cell to improve its efficiency. The results revealed that the current increased by approximately 23.1% when placed in a 30 wt% KOH solution under the ultrasonic field. Electrochemical polarization impedance spectroscopy (EIS was employed to evaluate the effect of the ultrasonic field on the reduction of polarization resistance. The results showed that the concentration impedance in the 30 wt% KOH electrolyte decreased markedly by 44%–51% Ω.

Synthesis and characterization of hard ternary AlMgB composite films prepared by sputter deposition

Energy Technology Data Exchange (ETDEWEB)

Yan Ce [Department of Physics and Materials Science and Center of Super-Diamond and Advanced Films, City University of Hong Kong (Hong Kong); Zhou, Z.F. [Department of Manufacturing Engineering and Engineering Management and Advanced Coatings Applied Research Laboratory, City University of Hong Kong (Hong Kong); Chong, Y.M.; Liu, C.P.; Liu, Z.T. [Department of Physics and Materials Science and Center of Super-Diamond and Advanced Films, City University of Hong Kong (Hong Kong); Li, K.Y., E-mail: mekyli@cityu.edu.h [Department of Manufacturing Engineering and Engineering Management and Advanced Coatings Applied Research Laboratory, City University of Hong Kong (Hong Kong); Bello, I., E-mail: apibello@cityu.edu.h [Department of Physics and Materials Science and Center of Super-Diamond and Advanced Films, City University of Hong Kong (Hong Kong); Kutsay, O.; Zapien, J.A.; Zhang, W.J. [Department of Physics and Materials Science and Center of Super-Diamond and Advanced Films, City University of Hong Kong (Hong Kong)

2010-07-30

Hard and superlight thin films laminated with boron carbide have been proposed as candidates for strategic use such as armor materials in military and space applications. Aluminum magnesium boride (AlMgB) films are excellent candidates for these purposes. We prepared AlMgB films by sputter deposition using multiple unbalanced planar magnetrons equipped with two boron and one AlMg targets. The film morphology changed and the film's root mean square (rms) roughness varied from 1.0 to 18 nm as the power density of the AlMg target increased from 0.2 to 1.0 W/cm{sup 2} while the power density of each boron target was maintained at 2 W/cm{sup 2}. Chemical analyses show dominating Al, Mg, B and trace elements of oxygen, carbon and argon. The film composition also varies with altering the power density supplied to the AlMg target. The film with an atomic ratio of Al:Mg:B = 1.38:0.64:1 exhibits the highest hardness ({approx} 30 GPa). This value surpasses the hardness of hydrogenated diamond-like carbon films (24-28 GPa) prepared by plasma enhanced chemical vapor deposition.

Synthesis and characterization of hard ternary AlMgB composite films prepared by sputter deposition

International Nuclear Information System (INIS)

Yan Ce; Zhou, Z.F.; Chong, Y.M.; Liu, C.P.; Liu, Z.T.; Li, K.Y.; Bello, I.; Kutsay, O.; Zapien, J.A.; Zhang, W.J.

2010-01-01

Hard and superlight thin films laminated with boron carbide have been proposed as candidates for strategic use such as armor materials in military and space applications. Aluminum magnesium boride (AlMgB) films are excellent candidates for these purposes. We prepared AlMgB films by sputter deposition using multiple unbalanced planar magnetrons equipped with two boron and one AlMg targets. The film morphology changed and the film's root mean square (rms) roughness varied from 1.0 to 18 nm as the power density of the AlMg target increased from 0.2 to 1.0 W/cm 2 while the power density of each boron target was maintained at 2 W/cm 2 . Chemical analyses show dominating Al, Mg, B and trace elements of oxygen, carbon and argon. The film composition also varies with altering the power density supplied to the AlMg target. The film with an atomic ratio of Al:Mg:B = 1.38:0.64:1 exhibits the highest hardness (∼ 30 GPa). This value surpasses the hardness of hydrogenated diamond-like carbon films (24-28 GPa) prepared by plasma enhanced chemical vapor deposition.

The influence of chemical composition on the properties and structure Al-Si-Cu(Mg) alloys

OpenAIRE

M. Kaczorowski; A. Krzyńska

2007-01-01

The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg) type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening ...

Effect of Copper on Corrosion of Forged AlSi1MgMn Automotive Suspension Components

Science.gov (United States)

Koktas, Serhan; Gokcil, Emre; Akdi, Seracettin; Birol, Yucel

2017-09-01

Recently, modifications in the alloy composition and the manufacturing process cycle were proposed to achieve a more uniform structure with no evidence of coarse grains across the section of the AlSi1MgMn alloys. Cu was added to the AlSi1MgMn alloy to improve its age hardening capacity without a separate solution heat treatment. However, Cu addition degrades the corrosion resistance of this alloy due to the formation of Al-Cu precipitates along the grain boundaries that are cathodic with respect to the aluminum matrix and thus encourage intergranular corrosion. The present work was undertaken to identify the impact of Cu addition on the corrosion properties of AlSi1MgMn alloys with different Cu contents. A series of AlSi1MgMn alloys with 0.06-0.89 wt.% Cu were tested in order to identify an optimum level of Cu addition.

Tem Observation Of Precipitate Structures In Al-Zn-Mg Alloys With Additions Of Cu/Ag

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Watanabe K.

2015-06-01

Full Text Available Al-Zn-Mg alloy has been known as one of the aluminum alloys with the good age-hardening ability and the high strength among commercial aluminum alloys. The mechanical property of the limited ductility, however, is required to further improvement. In this work, three alloys, which were added Cu or Ag into the Al-Zn-Mg alloy, were prepared to compare the effect of the additional elements on the aging behavior. The content of Ag and Cu were 0.2at.% and the same as, respectively. Ag or Cu added alloy showed higher maximum hardness than base alloy. The particle shape and rod shape precipitates were observed in all alloys peak-aged at 423K. According to addition of Ag or Cu, the number density of the precipitates increased higher than that of base alloy.

Influence of Ni content on physico-chemical characteristics of Ni, Mg, Al-Hydrotalcite like compounds

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Alexandre Carlos Camacho Rodrigues

2003-12-01

Full Text Available The physico-chemical properties of a series of Ni,Mg,Al-HTLC with Al/(Al+Mg+Ni = 0.25 and low Ni/Mg ratios were studied by means of X-ray diffraction (XRD, thermogravimetric (TGA and thermodifferential (DTA analysis, N2 physissorption and temperature programmed reduction (TPR. The as-synthesized materials were well-crystallized, with XRD patterns typical of the HTLCs in carbonate form. Upon calcination and dehydration the dehydroxilation of the layers with concurrent decomposition of carbonate anions produced mixed oxides with high surface area. XRD analysis indicated that the different nickel and aluminum oxides species are well-dispersed in a poor-crystallized MgO periclase-type phase. As observed by TPR, the different Ni species showed distinct interactions with Mg(AlO phase, which were influenced by both nickel content and calcination temperature. Regardless of the the nickel content, the reduction of nickel species was not complete as indicated by the presence of metallic dispersions.

Anti-scratch AlMgB14 Gorilla® Glass coating

Science.gov (United States)

Putrolaynen, V. V.; Grishin, A. M.; Rigoev, I. V.

2017-10-01

Hard aluminum-magnesium boride (BAM) films were fabricated onto Corning® Gorilla® Glass by radio-frequency magnetron sputtering of a single stoichiometric AlMgB14 target. BAM films exhibit a Vickers hardness from 10 to 30 GPa and a Young's modulus from 80 to 160 GPa depending on applied loading forces. Deposited hard coating increases the critical load at which glass substrate cracks. The adhesion energy of BAM films on Gorilla® Glass is 6.4 J/m2.

Kinetic energy distributions of sputtered neutral aluminum clusters: Al--Al6

International Nuclear Information System (INIS)

Coon, S.R.; Calaway, W.F.; Pellin, M.J.; Curlee, G.A.; White, J.M.

1992-01-01

Neutral aluminum clusters sputtered from polycrystalline aluminum were analyzed by laser postionization time-of-flight (TOF) mass spectrometry. The kinetic energy distributions of Al through Al 6 were measured by a neutrals time-of-flight technique. The interpretation of laser postionization TOF data to extract velocity and energy distributions is presented. The aluminum cluster distributions are qualitatively similar to previous copper cluster distribution measurements from our laboratory. In contrast to the steep high energy tails predicted by the single- or multiple- collision models, the measured cluster distributions have high energy power law dependences in the range of E -3 to E -4.5 . Correlated collision models may explain the substantial abundance of energetic clusters that are observed in these experiments. Possible influences of cluster fragmentation on the distributions are discussed

Corrosion analysis of AlMg2 and AlMgSi using electrochemical method

International Nuclear Information System (INIS)

Dian A; Maman Kartaman; Rosika K; Yanlinastuti

2014-01-01

Corrosion test of cladding materials and structures of research reactor fuel, AlMgSi and AlMg2 have been performed in demineralized water of pH 2 and 6.7 using an electrochemical method. Corrosion phenomenon is affected by several factor such as composition and condition of solution. The purpose of this activity is to investigate the corrosion phenomena through the determination of the parameters of corrosion and polarization curve. The materials used are AlMg2 and AlMgSi alloy in circular dish shape with an area of 1 Cm"2. Preparation of the test sample is performed through several stages polishing, cleaning and drying procedures followed ASTM G3. The electrochemical method is done by measuring the open circuit potential (OCP), polarization resistance and potentiodynamic in demineralized water of pH 2 and pH 6.7 at temperature of 25°C. The results of the OCP is the corrosion potential (Ecorr) of AlMg2 and AlMgSi each of -906.1 mV and -619.8 mV at pH 2 and -868.6 and -756.7 mV at pH 6.7 mV. The results of measurements by polarization resistance technique showed that the corrosion rate of AlMg2 and AlMgSi in safe category (<2 mpy) at pH 6.7 and at pH 2 corrosion rate increased significantly, but still in the lightweight category (<20 mpy). Potentiodynamic curves showed that the passivation at pH 6.7 is very low while the passivation at pH 2 occurs within a relatively short range potential and followed events corroded. (author)

Superconducting properties of MgB2 particle impregnated with Mg-based alloys

International Nuclear Information System (INIS)

Shimizu, Yusuke; Matsuda, Kenji; Mizutani, Manabu; Nishimura, Katsuhiko; Kawabata, Tokimasa; Ikeno, Susumu; Hishinuma, Yoshimitsu; Aoyama, Shigeki

2011-01-01

The three-dimensional penetration method combined with semi-solid casting (SS-3DPC) was utilized to prepare magnesium diboride (MgB 2 ) powder composite materials with various host materials of Mg, Mg-3%Al, Mg-3%Al-1%Zn, Mg-9%Al, and Mg-9%Al-1%Zn. X-ray diffraction measurements indicated predominant peak patterns of MgB 2 and a host alloy, implying that the host material tightly bonded MgB 2 grains without melting the MgB 2 powder. This was confirmed by SEM images. Measured electrical resistivity and magnetization versus temperature showed clear signals of superconducting transition temperature of 27-38 K for all the samples cut out from the billets. Magnetic hysteresis loop observed at 5 K enabled us to estimate a critical current density (J c ) based on the extended Bean model. Additions of aluminum and zinc elements to magnesium host-matrix were found to enhance J c and increase residual resistivity (ρ 0 ) suggesting that aluminum and zinc have an effect on pinning magnetic flux flow for J c enhancement, and scattering conduction electrons for increase of ρ 0 . (author)

A new class of ultra-hard materials based on AlMgB14

International Nuclear Information System (INIS)

Cook, B.A.; Harringa, J.L.; Lewis, T.L.; Russell, A.M.

2000-01-01

In this study, aluminum magnesium boride combined with 5 to 30 mol.% additives (AlMgB 14 :X where X = Si, P, C, AlN, TiB 2 , or BN), were prepared by mechanical alloying and consolidated by vacuum hot pressing. Matkovich and Economy first reported the orthorhombic AlMgB 14 intermetallic compound (oI64, space group Imam, a - 0.5848 nm, b = 0.8112 nm, c = 1.0312 nm), and the structure determination was later refined by Higashi and Ito. The unit cell is based on four B 12 icosahedral units centered at (0, 0, 0), (0, 0.5, 0.5), (0.5, 0, 0), and (0.5, 0.5, 0.5) within the unit cell. The remaining eight B atoms lie outside the icosahedra, bonding to the icosahedral B atoms and to the Al and Mg atoms. The Al atoms occupy a four-fold position at (0.250, 0.750, 0.250), and the Mg atoms occupy a four-fold position at (0.250, 0.359, 0). The icosahedra are arranged in distorted, close-packed layers. The unique electronic, optical, and mechanical properties of this material are due to a complex icosahedra (intericosahedral bonding). The highest hardness was observed in the AlMgB 14 + 30%TiB 2 material, which possesses a multi-phase microstructure. Here again, an increase in hardness accompanying the introduction of additional phases is somewhat surprising and difficult to explain. The possible compounds that may form at the AlMgB 14 -TiB 2 interface during hot pressing are numerous

A study on preparation and hydriding of β-Mg2Al3 and γ-Mg17Al12

International Nuclear Information System (INIS)

Hadi Suwarno

2009-01-01

The mechanism of the synthetic formation of β-Mg 2 Al 3 and γ-Mg 17 Al 12 has been studied. Mechanical alloying of Mg and Al powders with the atomic ratio of Mg:Al = 2:3 in toluene solution yields β-Mg 2 Al 3 compound after milling for 30 h. The γ-Mg 17 Al 12 can be formed by heating the β-Mg 2 Al 3 at 430°C under high vacuum. The measured hydrogen capacities of β-Mg 2 Al 3 and γ-Mg 17 Al 12 as hydride at 300°C are 3.2 and 4.9 wt%, respectively. Microstructure of the Mg-Al specimen shows that on hydriding at 300°C the polygonal shape of the γ-Mg 17 Al 12 changes into irregular shapes which are composed of γ-MgH 2 and Al. (author)

Fabrication and Analysis of the Wear Properties of Hot-Pressed Al-Si/SiCp + Al-Si-Cu-Mg Metal Matrix Composite

Science.gov (United States)

Bang, Jeongil; Oak, Jeong-Jung; Park, Yong Ho

2016-01-01

The aim of this study was to characterize microstructures and mechanical properties of aluminum metal matrix composites (MMC's) prepared by powder metallurgy method. Consolidation of mixed powder with gas atomized Al-Si/SiCp powder and Al-14Si-2.5Cu-0.5Mg powder by hot pressing was classified according to sintering temperature and sintering time. Sintering condition was optimized using tensile properties of sintered specimens. Ultimate tensile strength of the optimized sintered specimen was 228 MPa with an elongation of 5.3% in longitudinal direction. In addition, wear properties and behaviors of the sintered aluminum-based MMC's were analyzed in accordance with vertical load and linear speed. As the linear speed and vertical load of the wear increased, change of the wear behavior occurred in order of oxidation of Al-Si matrix, formation of C-rich layer, Fe-alloying to matrix, and melting of the specimen

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.

Phase diagrams of aluminium alloys of Al-Cu-Mg, Al-Mg-Si-Cu, and Al-Mg-Li system

International Nuclear Information System (INIS)

Ber, L.B.; Kaputkin, E.Ya.

2001-01-01

Isothermal diagrams of phase transformations (DPT) and temperature-time charts (TTC) of variation of electric conductivity and of mechanical features at tension were plotted following thermal treatment according to the pattern of direct hardening and ageing and according to the pattern of normal aging for D16 commercial alloy, Al-Cu-Mg model alloy of the same system, AD37 commercial alloys of Al-Mg-Si-Cu and 1424 one of Al-Li-Mg system. Phase transformations were studied by means of fluorescence electron microscopy, micro-X-ray spectral analysis, X-ray phase analysis of single crystals and polycrystals and differential scanning calorimetry. For every alloy comparison of TTC and DPT enables to clarity the mechanism of phase composition effect on features and to optimize conditions of hardening cooling and ageing [ru

Heavy Mg-doping of (Al,Ga)N films for potential applications in deep ultraviolet light-emitting structures

Science.gov (United States)

Liang, Y. H.; Towe, E.

2018-03-01

Doping of high aluminum-containing (Al,Ga)N thin films has remained a challenging problem that has hindered progress in the development of deep ultraviolet light-emitters. This paper reports on the synthesis and use of heavily doped (Al,Ga)N films in deep ultraviolet (˜274 nm) light-emitting structures; these structures were synthesized by molecular beam epitaxy under liquid-metal growth conditions that facilitate the incorporation of extremely high density of Mg dopant impurities (up to 5 × 1019 cm-3) into aluminum-rich (Al,Ga)N thin films. Prototypical light-emitting diode structures incorporating Al0.7Ga0.3N films doped with Mg impurities that ionize to give free hole carrier concentrations of up to 6 × 1017 cm-3 exhibit external quantum efficiencies of up 0.56%; this is an improvement from previous devices made from molecular beam epitaxy-grown materials. This improvement is believed to be due to the high hole carrier concentration enabled by the relatively low activation energy of 220 meV compared to the expected values of 408-507 meV for Al0.7Ga0.3N films.

Aluminum metabolism studied by [sup 26]Al tracer using AMS technique

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Koichi (Tokyo Univ. (Japan). Research Center for Nuclear Science and Technology); Yumoto, Sakae; Nagai, Hisao; Hosoyama, Yoshiyuki; Imamura, Mineo; Hotta, Masayoshi; Ohashi, Hideo

1992-01-01

By accelerator mass spectrometry (AMS), we studied aluminum metabolism using [sup 26]Al as a tracer. To investigate the role of aluminum toxicity in the etiology of amyotrophic lateral sclerosis (ALS) and Alzheimer's disease, aluminum incorporation into the rat cerebrum was studied. When healthy rats were injected intraperitoneally with [sup 26]Al, a considerable amount of the tracer was incorporated into the brain within only 5 days after the injection. This [sup 26]Al accumulation was apparently irreversible, since it persisted even after 75 days. (author).

Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

International Nuclear Information System (INIS)

Li, Shuo; Bhushan, Bharat

2016-01-01

Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

Energy Technology Data Exchange (ETDEWEB)

Li, Shuo [School of Materials Science and Technology, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian Distract, Beijing 100083 (China); Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States); Bhushan, Bharat, E-mail: bhushan.2@osu.edu [Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States)

2016-08-15

Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

Formation of Al3Ti/Mg composite by powder metallurgy of Mg-Al-Ti system.

Science.gov (United States)

Yang, Zi R; Qi Wang, Shu; Cui, Xiang H; Zhao, Yu T; Gao, Ming J; Wei, Min X

2008-07-01

An in situ titanium trialuminide (Al 3 Ti)-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg-Al-Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC), x-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Al 3 Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg-Al-Ti system, Al 3 Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg-Al-Ti system is almost the same as that of the Al-Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

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.

Drosophila melanogaster as a model system of aluminum toxicity and aging.

Science.gov (United States)

Kijak, Ewelina; Rosato, Ezio; Knapczyk, Katarzyna; Pyza, Elżbieta

2014-04-01

The aim of this study was to investigate the toxic effects of aluminum (Al) on the model organism-Drosophila melanogaster. The study is especially concerned with the effects of aluminum on the fruit fly's development, life span, and circadian rhythm in rest and activity. Flies were exposed to aluminum in concentrations from 40 to 280 mg/kg in rearing media or the flies were raised on control medium. Moreover, the life span of insects exposed to aluminum containing 40, 120, or 240 mg/kg of Al in the medium, only during their larval development, during the whole life cycle and only in their adult life was tested. To check if aluminum and aging cause changes in D. melanogaster behavior, the locomotor activity of flies at different ages was recorded. Results showed that aluminum is toxic in concentrations above 160 mg/kg in the rearing medium. Depending on Al concentration and time of exposure, the life span of the flies was shortened. At intermediate concentrations (120 mg/kg), however, Al had a stimulating effect on males increasing their life span and level of locomotor activity. At higher concentration the aluminum exposure increased or decreased the level of locomotor activity of D. melanogaster depending on age of flies. In addition, in the oldest insects reared on aluminum supplemented media and in mid-aged flies reared on the highest concentration of Al the daily rhythm of activity was disrupted. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Microstructure and Mechanical Properties of Dissimilar Joints of Al-Mg2Si and 5052 Aluminum Alloy by Friction Stir Welding

Science.gov (United States)

Huang, B. W.; Qin, Q. D.; Zhang, D. H.; Wu, Y. J.; Su, X. D.

2018-03-01

Al-Mg2Si alloy and 5052 Al alloy were welded successfully by friction stir welding (FSW) in this study. The results show that the alloy consists of three distinct zones after FSW: the base material zone (BMZ), the transitional zone, and the weld nugget (WN). The morphologies of the primary Mg2Si phases are identified as coarse equiaxed crystals for Al-Mg2Si alloys in the BMZ. The WN is a mixture of rich Al-Mg2Si and rich 5052 alloy, and a banded structure is formed in the zone. Interestingly, in the WN, the equiaxed crystals changed to polygonal particles with substantially reduced sizes in the rich Al-Mg2Si zone. However, in addition to the white rich Mg phase appearing in the rich 5052 zone near the interface, the 5052 alloy does not show obvious changes. The hardness gradually increases from the BMZ of the 5052 to the welded joint to the Al-Mg2Si BMZ. In addition, the ultimate tensile strength (UTS) of the welded joint is higher than that of the base material of the Al-Mg2Si, whereas it is lower than that of the 5052 base alloy. The results of the elongation are similar to the UTS results. The fracture mechanism is also investigated.

Assessment of retrogression and re-aging treatment on microstructural and mechanical properties of Al-Zn-Mg-Cu P/M alloy

Energy Technology Data Exchange (ETDEWEB)

Naeem, Haider T. [School of Materials Engineering, Universiti Malaysia Perlis, Taman Muhibbah, 02600 Jejawi, Perlis (Malaysia); College of Engineering, Al-Muthanna University, South Baghdad (Iraq); Mohammad, Kahtan S.; Hussin, Kamarudin; Tan, T. Qing; Idris, M. Sobri [School of Materials Engineering, Universiti Malaysia Perlis, Taman Muhibbah, 02600 Jejawi, Perlis (Malaysia)

2015-05-15

In order to understand the importance of the retrogression and re-aging as a heat treatment for improving microstructural and mechanical properties of the Al-Zn-Mg-Cu powder metallurgy alloys, Al-Zn-Mg-Cu-Fe-Cr alloys were fabricated from the elemental powders. Green compacts are compressed under compaction pressure about 370 MPa. The sintering process carried out for the samples of aluminum alloys at temperature was 650°C under argon atmosphere for two hours. The sintered compacts were subjected into homogenizing condition at 470°C for 1.5 hours and then aged at 120°C for 24 hours (T6 temper) after that it carried out the retrogressed at 180°C for 30 min., and then re-aged at 120°C for 24 hours (RRA). Observations microstructures were examined using optical, scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction. Density and porosity content was conducted for the samples of alloys. The result showing that the highest Vickers hardness exhibited for an Al-Zn-Mg-Cu alloy after underwent the retrogression and reaging treatment. Increasing in hardness was because of the precipitation hardening through precipitate the (Mg Zn) and (Mg{sub 2}Zn{sub 11}) phases during matrix of aluminum-alloy.

Assessment of retrogression and re-aging treatment on microstructural and mechanical properties of Al-Zn-Mg-Cu P/M alloy

International Nuclear Information System (INIS)

Naeem, Haider T.; Mohammad, Kahtan S.; Hussin, Kamarudin; Tan, T. Qing; Idris, M. Sobri

2015-01-01

In order to understand the importance of the retrogression and re-aging as a heat treatment for improving microstructural and mechanical properties of the Al-Zn-Mg-Cu powder metallurgy alloys, Al-Zn-Mg-Cu-Fe-Cr alloys were fabricated from the elemental powders. Green compacts are compressed under compaction pressure about 370 MPa. The sintering process carried out for the samples of aluminum alloys at temperature was 650°C under argon atmosphere for two hours. The sintered compacts were subjected into homogenizing condition at 470°C for 1.5 hours and then aged at 120°C for 24 hours (T6 temper) after that it carried out the retrogressed at 180°C for 30 min., and then re-aged at 120°C for 24 hours (RRA). Observations microstructures were examined using optical, scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction. Density and porosity content was conducted for the samples of alloys. The result showing that the highest Vickers hardness exhibited for an Al-Zn-Mg-Cu alloy after underwent the retrogression and reaging treatment. Increasing in hardness was because of the precipitation hardening through precipitate the (Mg Zn) and (Mg 2 Zn 11 ) phases during matrix of aluminum-alloy

A Study of Phase Composition and Structure of Alloys of the Al - Mg - Si - Fe System

Science.gov (United States)

Mailybaeva, A. D.; Zolotorevskii, V. S.; Smagulov, D. U.; Islamkulov, K. M.

2017-03-01

The Thermo-Calc software is used to compute the phase transformations occurring during cooling of alloys. Polythermal and isothermal sections of the phase diagram of the Al - Mg - Si - Fe system are plotted. The phase composition and the structure of aluminum alloys in cast condition and after a heat treatment are studied experimentally.

Effect of substituting cerium-rich mischmetal with lanthanum on high temperature properties of die-cast Mg-Zn-Al-Ca-RE alloys

International Nuclear Information System (INIS)

Anyanwu, Ifeanyi A.; Gokan, Yasuhiro; Suzuki, Atsuya; Kamado, Shigeharu; Kojima, Yo; Takeda, Suguru; Ishida, Taketoshi

2004-01-01

Mg-Zn-Al-Ca-RE alloys have been found to be promising materials for substituting aluminum alloys used for automatic transmission case applications in the automobile industry. Particularly, Mg-0.5%Zn-6%Al-1%Ca-3%RE (ZAXE05613) alloy exhibits comparable creep resistance as ADC12 die-casting aluminum alloy that is currently used for automatic transmission case applications. Changing the rare earth (RE) content of the alloy from mischmetal to lanthanum gives a further improvement in the creep properties of the alloy. Lanthanum addition results in the crystallization of a large amount of acicular Al 11 RE 3 (Al 11 La 3 ) compound along the grain boundaries as well as across the grain boundaries and this effectively controls grain boundary sliding and dislocation motion in the vicinity of the grain boundaries. As a result, die-cast ZAXLa05613 alloy exhibits a higher creep resistance than that of ZAXE05613 alloy

Solid-state 27Al nuclear magnetic resonance investigation of three aluminum-centered dyes

KAUST Repository

Mroué, Kamal H.

2010-02-01

We report the first solid-state 27Al NMR study of three aluminum phthalocyanine dyes: aluminum phthalocyanine chloride, AlPcCl (1); aluminum-1,8,15,22-tetrakis(phenylthio)-29H,31H-phthalocyanine chloride, AlPc(SPh)4Cl (2); and aluminum-2,3-naphthalocyanine chloride, AlNcCl (3). Each of these compounds contains Al3+ ions coordinating to four nitrogen atoms and a chlorine atom. Solid-state 27Al NMR spectra, including multiple-quantum magic-angle spinning (MQMAS) spectra and quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) spectra of stationary powdered samples have been acquired at multiple high magnetic field strengths (11.7, 14.1, and 21.1 T) to determine their composition and number of aluminum sites, which were analyzed to extract detailed information on the aluminum electric field gradient (EFG) and nuclear magnetic shielding tensors. The quadrupolar parameters for each 27Al site were determined from spectral simulations, with quadrupolar coupling constants (CQ) ranging from 5.40 to 10.0 MHz and asymmetry parameters (η) ranging from 0.10 to 0.50, and compared well with the results of quantum chemical calculations of these tensors. We also report the largest 27Al chemical shielding anisotropy (CSA), with a span of 120 ± 10 ppm, observed directly in a solid material. The combination of MQMAS and computational predictions are used to interpret the presence of multiple aluminum sites in two of the three samples.

The electrochemical properties and mechanism of formation of anodic oxide films on Mg-Al alloys

International Nuclear Information System (INIS)

Kim, Seong Jong; Okido, Masazumi

2003-01-01

The electronchemical properties and the mechanism of formation of anodic oxide films on Mg alloys containing 0-15 mass% Al, when anodized in NaOH solution, were investigated by focusing on the effects of anodizing potential, Al content, and anodizing time. The intensity ratio of Mg(OH) 2 in the XRD analysis decreased with increasing applied potential, while that of MgO increased. Mg(OH) 2 was barely detected at 80 V, while MgO was readily detected. The anti-corrosion properties of anodized specimens at each constant potential were better than those of non-anodized specimens. The specimen anodized at an applied potential of 3 V had the best anti-corrosion property. The intensity ratio of the β phase increased with aluminum content in Mg-Al alloys. During anodizing, the active dissolution reaction occurred preferentially in β phase until about 4 min, and then the current density increased gradually until 7 min. The dissolution reaction progressed in α phase, which had a lower Al content. In the anodic polarization test in 0.017 mol·dm -3 NaCl and 0.1 mol·dm -3 Na 2 SO 4 at 298 K, the current density of Mg-15 mass% Al alloy anodized for 10 min increased, since the anodic film that forms on the α phase is a non-compacted film. The anodic film on the α phase at 30 min was a compact film as compared with that at 10 min

Microstructure features and mechanical properties of a UFG Al-Mg-Si alloy produced via SPD

International Nuclear Information System (INIS)

Bobruk, E; Kazykhanov, V; Valiev, R; Murashkin, M; Sabirov, I

2014-01-01

The effect of equal channel angular pressing in parallel channels (ECAP-PC) and subsequient artificial ageing on the microstructure and room temperature mechanical properties of the commercial aluminum alloys 6063 (Al-0.6Mg-0.5Si, wt.%) and 6010 (Al-0.8Mg-1.0Si-0.15Cu-0.25Mn, wt.%) was investigated. It was shown that mechanical strength of the ECAP-PC processed Al alloys is higher compared to that achieved in these alloys after conventional thermo-mechanical processing. Prior ECAP- PC solution treatment and post-ECAP-PC artificial aging can additionally increase the mechanical strength of both Al alloys. Under optimal artificial ageing conditions, the yield strength (YS) of 299 MPa and ultimate tensile strength (UTS) of 308 MPa was achieved in the 6063 alloy, whereas YS of 423 MPa and UTS of 436 MPa was achieved in the 6010 alloy

Pore structure and mechanical properties of directionally solidified porous aluminum alloys

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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.

Microstructure and mechanical properties of friction stir lap welded Mg/Al joint assisted by stationary shoulder

Science.gov (United States)

Ji, Shude; Li, Zhengwei

2017-11-01

Using magnesium alloy as upper sheet, 3 mm-thick AZ31 magnesium alloy and 6061 aluminum alloy were joined using friction stir lap welding assisted by stationary shoulder. The effects of tool rotating speed on cross-sections, microstructure and mechanical properties of Mg/Al lap joints were mainly discussed. Results showed that stationary shoulder contributed to joint formation, by which stir zones (SZ) were characterized by big onion rings after welding. Because of the big forging force exerted by stationary shoulder, the upper region of hook was well bonded. SZ showed much higher hardness because of intermetallic compounds (IMCs). The bonding conditions at the base material (BM)/SZ interface at advancing side and the hook region played important roles on joint lap shear properties. The X-ray diffraction pattern analysis revealed that the main IMCs were Al3Mg2 and Al12Mg17.

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

Synthesizing (ZrAl3 + AlN)/Mg-Al composites by a 'matrix exchange' method

Science.gov (United States)

Gao, Tong; Li, Zengqiang; Hu, Kaiqi; Han, Mengxia; Liu, Xiangfa

2018-06-01

A method named 'matrix exchange' to synthesize ZrAl3 and AlN reinforced Mg-Al composite was developed in this paper. By inserting Al-10ZrN master alloy into Mg matrix and reheating the cooled ingot to 550 °C, Al and Mg atoms diffuse to the opposite side. As a result, liquid melt occurs once the interface areas reach to proper compositions. Then dissolved Al atoms react with ZrN, leading to the in-situ formation of ZrAl3 and AlN particles, while the Al matrix is finally replaced by Mg. This study provides a new insight for preparing Mg composites.

Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

Science.gov (United States)

Lee, Jonathan A.

2009-01-01

In this paper, the effect of nanoparticles Al2O3 and Al3-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 low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment

Directory of Open Access Journals (Sweden)

He Kezhun

2011-08-01

Full Text Available Heat treatment has important influence on the microstructure and mechanical properties of Al-Si alloys. The most common used heat treatment method for these alloys is solution treatment followed by age-hardening. This paper investigates the microstructural evolution of a direct chill (DC cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy after solution treated at 500, 510, 520 and 530℃, respectively for different times. The major phases observed in the as-cast alloy are α-aluminum dendrite, primary Si particle, eutectic Si, Al7Cu4Ni, Al5Cu2Mg8Si6, Al15(Cr, Fe, Ni, Cu4Si2 and Al2Cu. The Al2Cu phase dissolves completely after being solution treated for 2 h at 500℃, while the eutectic Si, Al5Cu2Mg8Si6 and Al15(Cr, Fe, Ni, Cu4Si2 phases are insoluble. In addition, the Al7Cu4Ni phase is substituted by the Al3CuNi phase. The α-aluminum dendrite network disappears when the solution temperature is increased to 530℃. Incipient melting of the Al2Cu-rich eutectic mixture occurrs at 520℃, and melting of the Al5Cu2Mg8Si6 and Al3CuNi phases is observed at a solution temperature of 530℃. The void formation of the structure and deterioration of the mechanical properties are found in samples solution treated at 530℃.

Improved Interfacial Bonding in Magnesium/Aluminum Overcasting Systems by Aluminum Surface Treatments

Science.gov (United States)

Zhang, Hui; Chen, Yiqing; Luo, Alan A.

2014-12-01

"Overcasting" technique is used to produce bimetallic magnesium/aluminum (Mg/Al) structures where lightweight Mg can be cast onto solid Al substrates. An inherent difficulty in creating strong Mg/Al interfacial bonding is the natural oxide film on the solid Al surfaces, which reduces the wettability between molten Mg and Al substrates during the casting process. In the paper, an "electropolishing + anodizing" surface treatment has been developed to disrupt the oxide film on a dilute Al-0.08 wt pct Ga alloy, improving the metallurgical bonding between molten Mg and Al substrates in the bimetallic experiments carried out in a high-vacuum test apparatus. The test results provided valuable information of the interfacial phenomena of the Mg/Al bimetallic samples. The results show significantly improved metallurgical bonding in the bimetallic samples with "electropolishing + anodizing" surface treatment and Ga alloying. It is recommended to adjust the pre-heating temperature and time of the Al substrates and the Mg melt temperature to control the interfacial reactions for optimum interfacial properties in the actual overcasting processes.

Sorption of selenium on Mg-Al and Mg-Al-Eu layered double hydroxides

International Nuclear Information System (INIS)

Curtius, H.; Paparigas, Z.; Kaiser, G.

2008-01-01

Salt domes represent deep geological formations which are under consideration as final repositories for irradiated research reactor fuel elements. For long-term safety aspects the mobilisation of the radionuclides due to a water ingress is intensively investigated. At the Institute of Energy Research (IEF-6), leaching experiments were performed in a hot cell facility with UAl x -Al and U 3 Si 2 -Al dispersed research reactor fuel elements in repository-relevant MgCl 2 -rich salt brines under anaerobic conditions. The fuel plates corroded completely within one year and a Mg-Al-layered double hydroxide (LDH) with chloride as interlayer anion was identified as one crystalline phase component of the corrosion products (secondary phases). This Mg-Al-LDH was synthesized, characterized, and the ability to retard europium by an incorporation process was investigated. Europium, as a representative for lanthanides, was identified to be one of the radionuclides which were found in the corrosion products. We could show that europium was incorporated in the lattice structure. LDHs have high anion exchange capacities that enhance their potential to remove anionic contaminants from aqueous systems. In this work the sorption behaviour of selenium in the chemical form as selenite (SeO 3 2- ) on Mg-Al-LDH and on Mg-Al-Eu-LDH was investigated. Especially the influence of the larger europium-III ion was of interest. It represents in the Mg-Al-Eu-LDH about 10% of the molar aluminium amount. The sorption has been experimentally studied in a wide range of pH, ionic strength, radionuclide and sorbent concentration. Both LDHs with chloride as interlayer anion were synthesized by a coprecipitation method under controlled conditions, and their main physico-chemical properties were analyzed prior to the sorption experiments. The sorption kinetics of selenite on the LDHs in water and in MgCl 2 -rich brine were rapid using a LDH concentration of 10 g/L. Equilibrium, indicated by stable p

Corrosion and Discharge Behaviors of Mg-Al-Zn and Mg-Al-Zn-In Alloys as Anode Materials

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Jiarun Li

2016-03-01

Full Text Available The Mg-6%Al-3%Zn and Mg-6%Al-3%Zn-(1%, 1.5%, 2%In alloys were prepared by melting and casting. Their microstructures were investigated via metallographic and energy-dispersive X-ray spectroscopy (EDS analysis. Moreover, hydrogen evolution and electrochemical tests were carried out in 3.5 wt% NaCl solution aiming at identifying their corrosion mechanisms and discharge behaviors. The results suggested that indium exerts an improvement on both the corrosion rate and the discharge activity of Mg-Al-Zn alloy via the effects of grain refining, β-Mg17Al12 precipitation, dissolving-reprecipitation, and self-peeling. The Mg-6%Al-3%Zn-1.5%In alloy with the highest corrosion rate at free corrosion potential did not perform desirable discharge activity indicating that the barrier effect caused by the β-Mg17Al12 phase would have been enhanced under the conditions of anodic polarization. The Mg-6%Al-3%Zn-1.0%In alloy with a relative low corrosion rate and a high discharge activity is a promising anode material for both cathodic protection and chemical power source applications.

The electrochemical properties and mechanism of formation of anodic oxide films on Mg-Al alloys

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Jong; Okido, Masazumi [Nagoya Univ., Nagoya (Japan)

2003-07-01

The electronchemical properties and the mechanism of formation of anodic oxide films on Mg alloys containing 0-15 mass% Al, when anodized in NaOH solution, were investigated by focusing on the effects of anodizing potential, Al content, and anodizing time. The intensity ratio of Mg(OH){sub 2} in the XRD analysis decreased with increasing applied potential, while that of MgO increased. Mg(OH){sub 2} was barely detected at 80 V, while MgO was readily detected. The anti-corrosion properties of anodized specimens at each constant potential were better than those of non-anodized specimens. The specimen anodized at an applied potential of 3 V had the best anti-corrosion property. The intensity ratio of the {beta} phase increased with aluminum content in Mg-Al alloys. During anodizing, the active dissolution reaction occurred preferentially in {beta} phase until about 4 min, and then the current density increased gradually until 7 min. The dissolution reaction progressed in {alpha} phase, which had a lower Al content. In the anodic polarization test in 0.017 mol{center_dot}dm{sup -3} NaCl and 0.1 mol{center_dot}dm{sup -3} Na{sub 2}SO{sub 4} at 298 K, the current density of Mg-15 mass% Al alloy anodized for 10 min increased, since the anodic film that forms on the {alpha} phase is a non-compacted film. The anodic film on the {alpha} phase at 30 min was a compact film as compared with that at 10 min.

Microstructure and Mechanical Properties of Al-10Zn-4.5Mg-xCu Turbine Impeller Produced by Investment Casting

Directory of Open Access Journals (Sweden)

Muhammad Syahid

2017-03-01

Full Text Available Aluminium alloy can be applied for a turbine impeller of Organic Rankine Cycle power plant that operates at temperatures below 150 oC. Aluminum turbine impeller can enhance efficiency of turbine due to light weight material. Al alloys was used for impeller due to good mechanical properties. Turbine impeller commonly produced by machining but which is time-consuming and less efficient because of material removal. . It can be replace by Investment casting to produce impeller turbine due to their complex geometry and precision. This study identifies effect Cu content of Al-9Zn-4Mg-xCu on the microstructure and mechanical properties of turbine impeller produce by investment casting. The study also identifies casting defect of turbine impeller. The structures consisted of α-Al, MgZn2, CuMgAl2 and CuAl2. Higher Cu content is the higher hardness value due to CuAl2 phase. Visual examination showed that the turbine impeller was free of macro defects and misruns

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

Microstructural evolution during friction stir welding of AlSi1MgMn alloy

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M. Janjić

2012-01-01

Full Text Available This paper provides the research of the infl uence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6 obtained through the Friction Stir Welding (FSW process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out.

Manufacturing of Aluminum Composite Material Using Stir Casting Process

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Muhammad Hayat Jokhio

2011-01-01

Full Text Available Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is available on reinforcement of \\"Al2O3\\" particles in 7xxx aluminum matrix. The 7xxx series aluminum matrix usually contains Cu-Zn-Mg. Therefore, the present research was conducted to investigate the effect of elemental metal such as Cu-Zn-Mg in aluminum matrix on mechanical properties of stir casting of aluminum composite materials reinforced with alpha \\"Al2O3\\" particles using simple foundry melting alloying and casting route. The age hardening treatments were also applied to study the aging response of the aluminum matrix on strength, ductility and hardness. The experimental results indicate that aluminum matrix cast composite can be manufactured via conventional foundry method giving very good responses to the strength and ductility up to 10% \\"Al2O3\\" particles reinforced in aluminum matrix.

Microstructure and Mechanical Properties of an Al-Li-Mg-Sc-Zr Alloy Subjected to ECAP

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Anna Mogucheva

2016-10-01

Full Text Available The effect of post-deformation solution treatment followed by water quenching and artificial aging on microstructure and mechanical properties of an Al-Li-Mg-Sc-Zr alloy subjected to equal-channel angular pressing (ECAP was examined. It was shown that the deformed microstructure produced by ECAP remains essentially unchanged under solution treatment. However, extensive grain refinement owing to ECAP processing significantly affects the precipitation sequence during aging. In the aluminum-lithium alloy with ultrafine-grained (UFG microstructure, the coarse particles of the S1-phase (Al2LiMg precipitate on high-angle boundaries; no formation of nanoscale coherent dispersoids of the δ′-phase (Al3Li occurs within grain interiors. Increasing the number of high-angle boundaries leads to an increasing portion of the S1-phase. As a result, no significant increase in strength occurs despite extensive grain refinement by ECAP.

Influence of spray forming process parameters on the microstructure and porosity of Mg{sub 2}Si rich aluminum alloys

Energy Technology Data Exchange (ETDEWEB)

Stelling, O.; Hehl, A. von [Foundation Institute for Material Science, Bremen (Germany); Uhlenwinkel, V. [University of Bremen, FB4 FG01 Department Process and Chemcial Engineering, Bremen (Germany); Krug, P. [PEAK Werkstoff GmbH, Velbert (Germany); Ellendt, N.

2010-07-15

Due to high cooling rates spray forming is an appropriate process to produce aluminum alloys with a high content of Mg{sub 2}Si. Compared to common casting processes, a fine microstructure can be achieved yielding in improved mechanical properties. In this work, billets were spray formed from the two alloys AlMg15Si8Cu2 (22 mass-% Mg{sub 2}Si) and AlMg20.5Si11Cu2 (30 mass-% Mg{sub 2}Si) under different spraying conditions. The analysis of the microstructure showed that the size of Mg{sub 2}Si dispersoids is very sensitive to process parameters. Besides the well known thermal effects of melt superheat (carried out from -40 K to +170 K) and GMR (varied from 2.0 to 6.3) a strong influence of the scanning frequency of the atomizer nozzle (7 Hz and 15 Hz) could be observed. Similar effects could be found for the occurrence of porosity. A new parameter, the enthalpy flow to gas flow ratio (EGR), was defined from these two parameters of which correlations of Mg{sub 2}Si dispersoid size and amount of porosity were found. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

The in vitro biocompatibility and macrophage phagocytosis of Mg17Al12 phase in Mg-Al-Zn alloys.

Science.gov (United States)

Liu, Chen; He, Peng; Wan, Peng; Li, Mei; Wang, Kehong; Tan, Lili; Zhang, Yu; Yang, Ke

2015-07-01

Mg alloys are gaining interest for applications as biodegradable medical implant, including Mg-Al-Zn series alloys with good combination of mechanical properties and reasonable corrosion resistance. However, whether the existence of second phase particles in the alloys exerts influence on the biocompatibility is still not clear. A deeper understanding of how the particles regulate specific biological responses is becoming a crucial requirement for their subsequent biomedical application. In this work, the in vitro biocompatibility of Mg17Al12 as a common second phase in biodegradable Mg-Al-Zn alloys was investigated via hemolysis, cytotoxicity, cell proliferation, and cell adhesion tests. Moreover, osteogenic differentiation was evaluated by the extracellular matrix mineralization assay. The Mg17Al12 particles were also prepared to simulate the real situation of second phase in the in vivo environment in order to estimate the cellular response in macrophages to the Mg17Al12 particles. The experimental results indicated that no hemolysis was found and an excellent cytocompatibility was also proved for the Mg17Al12 second phase when co-cultured with L929 cells, MC3T3-E1 cells and BMSCs. Macrophage phagocytosis co-culture test revealed that Mg17Al12 particles exerted no harmful effect on RAW264.7 macrophages and could be phagocytized by the RAW264.7 cells. Furthermore, the possible inflammatory reaction and metabolic way for Mg17Al12 phase were also discussed in detail. © 2014 Wiley Periodicals, Inc.

Microstructure and mechanical properties of Al-Mg-Si-Cu matrix composites reinforced with AINp. processed by extrusion of powders

International Nuclear Information System (INIS)

Ortiz, J. L.; Amigo, V.; Salvador, M. D.; Perz, C. R.

2000-01-01

This article presents an experimental investigation on the structure and mechanical properties of an Al-Mg-Si-Cu P/M alloy reinforced with 5%, 10% and 15% aluminum nitride, produced by extrusion of cold compacted powders mixtures. Mechanical properties in as extruded and T6 conditions are compared. Differential Scanning Calorimetry and Dilatometric analysis were conducted to gain further insight into the precipitation process of these materials. Low cost 6061 Al/AINp composites can be produced with rate and small porosity by extrusion of cold compacted shapes without canning. The mechanical properties of the MMCs obtained by this process have limitations for high particles fractions because of clustering effects. All materials are always harder than the matrix and shows a similar behavior during aging processes but kinetics is changed. Potential applications of dilatometric techniques in the aging investigations of aluminum alloys and aluminum matrix composites have been established. (Author) 23 refs

Catalytic activity of Co-Mg-Al, Cu-Mg-Al and Cu-Co-Mg-Al mixed oxides derived from hydrotalcites in SCR of NO with ammonia

Energy Technology Data Exchange (ETDEWEB)

Chmielarz, Lucjan; Kustrowski, Piotr; Rafalska-Lasocha, Alicja [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Majda, Dorota; Dziembaj, Roman [Regional Laboratory for Physicochemical Analyses and Structural Research, Ingardena 3, 30-060 Krakow (Poland)

2002-01-10

M-Mg-Al hydrotalcites (where M=Cu{sup 2+}, Co{sup 2+} and Cu{sup 2+}+Co{sup 2+}) with M ranging from 5 to 20% (as atomic ratio) were prepared by co-precipitation method. Obtained samples were characterised by XRD and TGA techniques. The influence of transition metal content on thermal decomposition of hydrotalcites was observed. Calcination of the hydrotalcites at 600C resulted in the formation of mixed oxides with surface areas in the range 71-154m{sup 2}/g. Calcined hydrotalcites were tested as catalysts in the selective reduction of NO with ammonia (NO-SCR). The catalytic activity depends on the kind of transition metal, as well as its content. For the NO-SCR the following reactivity order was found: Cu-Mg-Al>Cu-Co-Mg-Al>Co-Mg-Al. Temperature-programmed methods (TPD, TPSR, stop flow-TPD), as well as FT-IR spectroscopy have been applied to determine interaction of NO and NH{sub 3} molecules with the catalyst surface.

Effect of Si addition to Al-8Mg alloy on the microstructure and thermo-physical properties of SiCp/Al composites prepared by pressureless infiltration

International Nuclear Information System (INIS)

Ren Shubin; He Xinbo; Qu Xuanhui; Humail, Islam S.; Li Yan

2007-01-01

Fifty-five volume percentage of SiCp/Al composites were prepared by pressureless infiltration to investigate the effect of Si addition to Al-8Mg alloy from 0 wt% to 18 wt% on the interfacial reaction between Al and SiC and the thermo-physical properties of the prepared composites. TEM and X-ray analysis showed that the degree of interfacial reaction decreased as the Si content increased, and that it ceased at 1273 K when the Si addition to the aluminum was greater than 12 wt%. The Si addition to Al-8Mg alloy reduced the CTE of the composites and increased their thermal conductivity (TC), but Si beyond 12 wt% led to the reduction of TC, though the CTE was lower. This is attributable to the combined action of the Si on the wettability, interfacial reaction and the TC and CTE of the matrix itself

Ball-milling and AlB2 addition effects on the hydrogen sorption properties of the CaH2 + MgB2 system

International Nuclear Information System (INIS)

Schiavo, B.; Girella, A.; Agresti, F.; Capurso, G.; Milanese, C.

2011-01-01

Research highlights: → Calcium hydride + magnesium-aluminum borides as candidates for hydrogen storage. → Long time ball milling improves hydrogen sorption kinetics of the CaH 2 +MgB 2 system. → Coexistence of MgB 2 and AlB 2 does not improve hydrogen sorption performances. → Total substitution of MgB 2 with AlB 2 improves the system kinetics and reversibility. → Below 400 deg. C almost the full hydrogen capacity of the CaH 2 + AlB 2 system is reached. - Abstract: Among the borohydrides proposed for solid state hydrogen storage, Ca(BH 4 ) 2 is particularly interesting because of its favourable thermodynamics and relatively cheap price. Composite systems, where other species are present in addition to the borohydride, show some advantages in hydrogen sorption properties with respect to the borohydrides alone, despite a reduction of the theoretical storage capacity. We have investigated the milling time influence on the sorption properties of the CaH 2 + MgB 2 system from which Ca(BH 4 ) 2 and MgH 2 can be synthesized by hydrogen absorption process. Manometric and calorimetric measurements showed better kinetics for long time milled samples. We found that the total substitution of MgB 2 with AlB 2 in the starting material can improve the sorption properties significantly, while the co-existence of both magnesium and aluminum borides in the starting mixture did not cause any improvement. Rietveld refinements of the X-ray powder diffraction spectra were used to confirm the hypothesized reactions.

The Influence of Nickel and Tin Additives on the Microstructural and Mechanical Properties of Al-Zn-Mg-Cu Alloys

Directory of Open Access Journals (Sweden)

Haider T. Naeem

2014-01-01

Full Text Available The effects of nickel and nickel combined tin additions on mechanical properties and microstructural evolutions of aluminum-zinc-magnesium-copper alloys were investigated. Aluminum alloys containing Ni and Sn additives were homogenized at different temperatures conditions and then aged at 120°C for 24 h (T6 and retrogressed at 180°C for 30 min and then reaged at 120°C for 24 h (RRA. Comparison of the ultimate tensile strength (UTS of as-quenched Al-Zn-Mg-Cu-Ni and Al-Zn-Mg-Cu-Ni-Sn alloys with that of similar alloys which underwent aging treatment at T6 temper showed that gains in tensile strengths by 385 MPa and 370 MPa were attained, respectively. These improvements are attributed to the precipitation hardening effects of the alloying element within the base alloy and the formation of nickel/tin-rich dispersoid compounds. These intermetallic compounds retard the grain growth, lead to grain refinement, and result in further strengthening effects. The outcomes of the retrogression and reaging processes which were carried on aluminum alloys indicate that the mechanical strength and Vickers hardness have been enhanced much better than under the aging at T6 temper.

Fabrication and heat treatment of high strength Al-Cu-Mg alloy processed using selective laser melting

Science.gov (United States)

Zhang, Hu; Zhu, Haihong; Nie, Xiaojia; Qi, Ting; Hu, Zhiheng; Zeng, Xiaoyan

2016-04-01

The proposed paper illustrates the fabrication and heat treatment of high strength Al-Cu-Mg alloy produced by selective laser melting (SLM) process. Al-Cu-Mg alloy is one of the heat treatable aluminum alloys regarded as difficult to fusion weld. SLM is an additive manufacturing technique through which components are built by selectively melting powder layers with a focused laser beam. The process is characterized by short laser-powder interaction times and localized high heat input, which leads to steep thermal gradients, rapid solidification and fast cooling. In this research, 3D Al-Cu-Mg parts with relative high density of 99.8% are produced by SLM from gas atomized powders. Room temperature tensile tests reveal a remarkable mechanical behavior: the samples show yield and tensile strengths of about 276 MPa and 402 MPa, respectively, along with fracture strain of 6%. The effect of solution treatment on microstructure and related tensile properties is examined and the results demonstrate that the mechanical behavior of the SLMed Al-Cu-Mg samples can be greatly enhanced through proper heat treatment. After T4 solution treatment at 540°C, under the effect of precipitation strengthening, the tensile strength and the yield strength increase to 532 MPa and 338 MPa, respectively, and the elongation increases to 13%.

Structural, magnetic and Moessbauer spectral studies of aluminum substituted Mg-Mn-Ni ferrites (Mg{sub 0.2}Mn{sub 0.5}Ni{sub 0.3}Al{sub y}Fe{sub 2-y}O{sub 4})

Energy Technology Data Exchange (ETDEWEB)

Verma, Satish, E-mail: satishapurva@gmail.com [Department of Physics, Govt. P.G. College, Solan-173212 (India); Chand, Jagdish [Department of Physics, Govt. P.G. College, Solan-173212 (India); Batoo, Khalid Mujasam [King Abdullah Institute of Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia); Singh, M. [Department of Physics, Himachal Pradesh University, Summer-Hill, Shimla-171005 (India)

2013-02-25

Highlights: Black-Right-Pointing-Pointer Single phase nanocrystalline Al{sup 3+} ions doped Mg-Mn-Ni ferrite have been synthesized by citrate precursor method. Black-Right-Pointing-Pointer Particle size decreases as non-magnetic Al content increases. Black-Right-Pointing-Pointer The presence of doublets in the Moessbauer spectra can be attributed to superparamagnetic relaxation. - Abstract: Nanocrystalline Al{sup 3+} ions doped Mg{sub 0.2}Mn{sub 0.5}Ni{sub 0.3}Al{sub y}Fe{sub 2-y}O{sub 4} compositions, where y = 0.0, 0.05 and 0.10 have been synthesized by citrate precursor method. Crystal structure and magnetic properties have been investigated at 300 K by means of X-ray diffraction, transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and Moessbauer spectra measurements. XRD study reveals that particle size decreases from 102.25 nm to 41.65 nm. A decrease in lattice constant and saturation magnetization was attributed to smaller ionic radius of Al{sup 3+} ions and weakening of super exchange interaction. Experimental and X-ray density decrease with increasing aluminum concentration. Though Moessbauer spectra of y = 0.0 exhibit normal Zeeman split sextets, spectra of samples for y = 0.05 and 0.10 are characterized by simultaneous presence of a central paramagnetic doublet. Dependence of Moessbauer parameters such as isomer shift, quadrupole splitting, linewidth and hyperfine magnetic field on Al{sup 3+} ions concentration have been discussed. Initial permeability '{mu}{sub i}', saturation magnetization (4 {pi}M{sub S}), retentivity (M{sub R}), Bohr magneton number (n{sub B}{sup N}), magneto crystalline anisotropy constant (K{sub 1}) and magnetic loss decreases while coercivity (H{sub C}) increases with increasing substitution of Al{sup 3+} ions. Magnetic loss has very low value in the range of 10{sup -3} which is two orders of magnitude less than samples prepared by conventional method.

Understanding AlN Obtaining Through Computational Thermodynamics Combined with Experimental Investigation

Science.gov (United States)

Florea, R. M.

2017-06-01

Basic material concept, technology and some results of studies on aluminum matrix composite with dispersive aluminum nitride reinforcement was shown. Studied composites were manufactured by „in situ” technique. Aluminum nitride (AlN) has attracted large interest recently, because of its high thermal conductivity, good dielectric properties, high flexural strength, thermal expansion coefficient matches that of Si and its non-toxic nature, as a suitable material for hybrid integrated circuit substrates. AlMg alloys are the best matrix for AlN obtaining. Al2O3-AlMg, AlN-Al2O3, and AlN-AlMg binary diagrams were thermodynamically modelled. The obtained Gibbs free energies of components, solution parameters and stoichiometric phases were used to build a thermodynamic database of AlN- Al2O3-AlMg system. Obtaining of AlN with Liquid-phase of AlMg as matrix has been studied and compared with the thermodynamic results. The secondary phase microstructure has a significant effect on the final thermal conductivity of the obtained AlN. Thermodynamic modelling of AlN-Al2O3-AlMg system provided an important basis for understanding the obtaining behavior and interpreting the experimental results.

Microstructure and properties of Mg-Al binary alloys

Directory of Open Access Journals (Sweden)

ZHENG Wei-chao

2006-11-01

Full Text Available The effects of different amounts of added Al, ranging from 1 % to 9 %, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

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.

Mechanical property, biocorrosion and in vitro biocompatibility evaluations of Mg-Li-(Al)-(RE) alloys for future cardiovascular stent application.

Science.gov (United States)

Zhou, W R; Zheng, Y F; Leeflang, M A; Zhou, J

2013-11-01

Mg-Li-based alloys were investigated for future cardiovascular stent application as they possess excellent ductility. However, Mg-Li binary alloys exhibited reduced mechanical strengths due to the presence of lithium. To improve the mechanical strengths of Mg-Li binary alloys, aluminum and rare earth (RE) elements were added to form Mg-Li-Al ternary and Mg-Li-Al-RE quarternary alloys. In the present study, six Mg-Li-(Al)-(RE) alloys were fabricated. Their microstructures, mechanical properties and biocorrosion behavior were evaluated by using optical microscopy, X-ray diffraction, scanning electronic microscopy, tensile tests, immersion tests and electrochemical measurements. Microstructure characterization indicated that grain sizes were moderately refined by the addition of rare earth elements. Tensile testing showed that enhanced mechanical strengths were obtained, while electrochemical and immersion tests showed reduced corrosion resistance caused by intermetallic compounds distributed throughout the magnesium matrix in the rare-earth-containing Mg-Li alloys. Cytotoxicity assays, hemolysis tests as well as platelet adhesion tests were performed to evaluate in vitro biocompatibilities of the Mg-Li-based alloys. The results of cytotoxicity assays clearly showed that the Mg-3.5Li-2Al-2RE, Mg-3.5Li-4Al-2RE and Mg-8.5Li-2Al-2RE alloys suppressed vascular smooth muscle cell proliferation after 5day incubation, while the Mg-3.5Li, Mg-8.5Li and Mg-8.5Li-1Al alloys were proven to be tolerated. In the case of human umbilical vein endothelial cells, the Mg-Li-based alloys showed no significantly reduced cell viabilities except for the Mg-8.5Li-2Al-2RE alloy, with no obvious differences in cell viability between different culture periods. With the exception of Mg-8.5Li-2Al-2RE, all of the other Mg-Li-(Al)-(RE) alloys exhibited acceptable hemolysis ratios, and no sign of thrombogenicity was found. These in vitro experimental results indicate the potential of Mg-Li-(Al

Shielding gas effect to diffusion activities of magnesium and copper on aluminum clad

Science.gov (United States)

Manurung, Charles SP; Napitupulu, Richard AM

2017-09-01

Aluminum is the second most metal used in many application, because of its corrosion resistance. The Aluminum will be damaged in over time if it’s not maintained in good condition. That is important to give protection to the Aluminums surface. Cladding process is one of surface protection methodes, especially for metals. Aluminum clad copper (Al/Cu) or copper clad aluminum (Cu/Al) composite metals have been widely used for many years. These mature protection method and well tested clad metal systems are used industrially in a variety application. The inherent properties and behavior of both copper and aluminum combine to provide unique performance advantages. In this paper Aluminum 2024 series will be covered with Aluminum 1100 series by hot rolling process. Observations will focus on diffusion activities of Mg and Cu that not present on Aluminum 1100 series. The differences of clad material samples is the use of shielding gas during heating before hot rolling process. The metallurgical characteristics will be examined by using optical microscopy. Transition zone from the interface cannot be observed but from Energy Dispersive Spectrometry it’s found that Mg and Cu are diffused from base metal (Al 2024) to the clad metal (Al 1100). Hardness test proved that base metals hardness to interface was decrease.

Effect of Aluminum Addition on the Evolution of Microstructure, Crystallographic Texture and Mechanical Properties of Single Phase Hexagonal Close Packed Mg-Li Alloys

Science.gov (United States)

Bhagat Singh, P.; Sabat, R. K.; Kumaran, S.; Suwas, S.

2018-02-01

In the present investigation, an effort has been made to understand the effect of aluminum addition to α Mg-Li alloys. The corresponding composition Mg-4Li- xAl ( x = 0, 2, 4 and 6 wt.%) alloys have been prepared by stir casting route under an argon environment. Extrusion was carried out at 300 °C with the extrusion ratio of 15:1. Significant grain refinement was observed after extrusion. X-ray diffraction-based investigation of the cast and extruded alloys showed the presence of intermetallic compounds such as Mg17Al12 and AlLi in the Al-rich alloys namely, Mg-4Li- xAl ( x = 4 and 6 wt.%). These precipitates were also present in the extruded plus annealed samples, indicating the stability of the precipitates at high temperature. The bulk x-ray texture measurement revealed a crystallographic texture where the c-axis of the h.c.p crystals was perpendicular to the extrusion direction (ED) for extruded sample. A texture transition was observed on annealing. The c-axis was oriented parallel to the ED. Mechanical properties of the cast, extruded and extruded plus annealed material illustrate that the addition of Al led to enhancement in hardness, yield strength and ultimate tensile strength.

The metal-organic framework MIL-53(Al) constructed from multiple metal sources: alumina, aluminum hydroxide, and boehmite.

Science.gov (United States)

Li, Zehua; Wu, Yi-nan; Li, Jie; Zhang, Yiming; Zou, Xin; Li, Fengting

2015-04-27

Three aluminum compounds, namely alumina, aluminum hydroxide, and boehmite, are probed as the metal sources for the hydrothermal synthesis of a typical metal-organic framework MIL-53(Al). The process exhibits enhanced synthetic efficiency without the generation of strongly acidic byproducts. The time-course monitoring of conversion from different aluminum sources into MIL-53(Al) is achieved by multiple characterization that reveals a similar but differentiated crystallinity, porosity, and morphology relative to typical MIL-53(Al) prepared from water-soluble aluminum salts. Moreover, the prepared MIL-53(Al) constructed with the three insoluble aluminum sources exhibit an improved thermal stability of up to nearly 600 °C and enhanced yields. Alumina and boehmite are more preferable than aluminum hydroxide in terms of product porosity, yield, and reaction time. The adsorption performances of a typical environmental endocrine disruptor, dimethyl phthalate, on the prepared MIL-53(Al) samples are also investigated. The improved structural stability of MIL-53(Al) prepared from these alternative aluminum sources enables double-enhanced adsorption performance (up to 206 mg g(-1)) relative to the conventionally obtained MIL-53(Al). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of Spirulina in mitigating hemato-toxicity in Swiss albino mice exposed to aluminum and aluminum fluoride.

Science.gov (United States)

Sharma, Shweta; Sharma, K P; Sharma, Subhasini

2016-12-01

Aluminum is ingested through foods, water, air, and even drugs. Its intake is potentiated further through foods and tea prepared in aluminum utensils and Al salt added in the drinking water for removal of suspended impurities and also fluoride in the affected areas. The ameliorating role of a blue green alga Spirulina is well documented to various pollutants in the animal models. We, therefore, examined its protective role (230 mg/kg body weight) on the hematology of male Swiss albino mice treated with aluminum (sub-acute = 78.4 mg/kg body weight for 7 days, sub-chronic = 7.8 mg/kg body weight for 90 days) and aluminum fluoride (sub-acute = 103 mg/kg body weight, sub-chronic = 21 mg/kg body weight), along with their recovery after 90 days of sub-chronic exposure. This study revealed significant reduction in the values of RBC (5-18 %), Hb (15-17 %), PCV (8-14 %), and platelets (26-36 %), and increase in WBC (54-124 %) in the treated mice, particularly after sub-acute exposure. Aluminum fluoride was comparatively more toxic than aluminum. Further, Spirulina supplement not only alleviated toxicity of test chemicals in Swiss albino mice but also led to their better recovery after withdrawal.

Ultrasonic spot welding of Al/Mg/Al tri-layered clad sheets

International Nuclear Information System (INIS)

Macwan, A.; Patel, V.K.; Jiang, X.Q.; Li, C.; Bhole, S.D.; Chen, D.L.

2014-01-01

Highlights: • The optimal welding condition is achieved at 100 J and 0.1 s. • Failure load first increases and then decreases with increasing welding energy. • The highest failure load after welding is close to that of the clad sheets. • At low energy levels failure occurs in the mode of interfacial failure. • At high energy levels failure takes place at the edge of nugget region. - Abstract: Solid-state ultrasonic spot welding (USW) was used to join Al/Mg/Al tri-layered clad sheets, aiming at exploring weldability and identifying failure mode in relation to the welding energy. It was observed that the application of a low welding energy of 100 J was able to achieve the optimal welding condition during USW at a very short welding time of 0.1 s for the tri-layered clad sheets. The optimal lap shear failure load obtained was equivalent to that of the as-received Al/Mg/Al tri-layered clad sheets. With increasing welding energy, the lap shear failure load initially increased and then decreased after reaching a maximum value. At a welding energy of 25 J, failure occurred in the mode of interfacial failure along the center Al/Al weld interface due to insufficient bonding. At a welding energy of 50 J, 75 J and 100 J, failure was also characterized by the interfacial failure mode, but it occurred along the Al/Mg clad interface rather than the center Al/Al weld interface, suggesting stronger bonding of the Al/Al weld interface than that of the Al/Mg clad interface. The overall weld strength of the Al/Mg/Al tri-layered clad sheets was thus governed by the Al/Mg clad interface strength. At a welding energy of 125 J and 150 J, thinning of weld nugget and extensive deformation at the edge of welding tip caused failure at the edge of nugget region, leading to a lower lap shear failure load

Effect Of SiC Particles On Sinterability Of Al-Zn-Mg-Cu P/M Alloy

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Rudianto H.

2015-06-01

Full Text Available Premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder was analyzed as matrix in this research. Gas atomized powder Al-9Si with 20% volume fraction of SiC particles was used as reinforcement and added into the alloy with varied concentration. Mix powders were compacted by dual action press with compaction pressure of 700 MPa. High volume fraction of SiC particles gave lower green density due to resistance of SiC particles to plastic deformation during compaction process and resulted voids between particles and this might reduce sinterability of this mix powder. Sintering was carried out under ultra high purity nitrogen gas from 565°-580°C for 1 hour. High content of premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder gave better sintering density and reached up to 98% relative. Void between particles, oxide layer on aluminum powder and lower wettability between matrix and reinforcement particles lead to uncompleted liquid phase sintering, and resulted on lower sintering density and mechanical properties on powder with high content of SiC particles. Mix powder with wt90% of Alumix 431D and wt10% of Al-9Si-vf20SiC powder gave higher tensile strength compare to another mix powder for 270 MPa. From chemical compositions, sintering precipitates might form after sintering such as MgZn2, CuAl2 and Mg2Si. X-ray diffraction, DSC-TGA, and SEM were used to characterize these materials.

Stimulatory effects of aluminum on growth of sugar maple seedlings

Science.gov (United States)

George A. Schier; Carolyn J. McQuattie

2002-01-01

To determine the effect of aluminum (Al) on sugar maple (Acer saccharum Marsh.), seedlings were grown in sand irrigated with nutrient solution (pH 3.8) containing 0, 2.5, 5, 10, 20, or 40 mg L-1 Al. Seedling growth was enhanced at 2.5 and 5mgL-1 Al. Although higher levels of Al reduced calcium (Ca) and...

Borax counteracts genotoxicity of aluminum in rat liver.

Science.gov (United States)

Turkez, Hasan; Geyikoğlu, Fatime; Tatar, Abdulgani

2013-10-01

This study was carried out to evaluate the protective role of borax (BX) on genotoxicity induced by aluminum (Al) in rat liver, using liver micronucleus assay as an indicator of genotoxicity. Sprague-Dawley rats were randomly separated into six groups and each group had four animals. Aluminum chloride (AlCl₃; 5 mg/kg b.w.) and BX (3.25 and 13 mg/kg b.w.) were injected intraperitoneally to rats. Besides, animals were also treated with Al for 4 consecutive days followed by BX for 10 days. Rats were anesthetized after Al and BX injections and the hepatocytes were isolated for counting the number of micronucleated hepatocytes (MNHEPs). AlCl₃ was found to significantly (p < 0.05) increase the number of MNHEPs. Rats treated with BX, however, showed no increase in MNHEPs. Moreover, simultaneous treatments with BX significantly modulated the genotoxic effects of AlCl₃ in rats. It can be concluded that BX has beneficial influences and has the ability to antagonize Al toxicity.

Electrochemical Deposition of Aluminum from NaCl-AlCl3 Melts

DEFF Research Database (Denmark)

Li, Qingfeng; Hjuler, H. A.; Berg, Rolf W.

1990-01-01

Electrochemical deposition of aluminum from NaAlCl4 melts saturated with NaCl onto a glassy carbon electrode at175°C has been studied by voltammetry, chronoamperometry, and constant current deposition. The deposition of aluminumwas found to proceed via a nucleation/growth mechanism, and the nucle......Electrochemical deposition of aluminum from NaAlCl4 melts saturated with NaCl onto a glassy carbon electrode at175°C has been studied by voltammetry, chronoamperometry, and constant current deposition. The deposition of aluminumwas found to proceed via a nucleation/growth mechanism......, and the nucleation process was found to be progressive.The morphology of aluminum deposits was examined with photomicroscopy. It was shown that depending on the currentdensities (c.d.) applied, three types of aluminum deposits could be obtained, namely, spongy deposits formed at lower c.d.(below 0.7 mA/cm2), smooth...... layers deposited at intermediate c.d. (between 2 and 10 mA/cm2), and dendritic or porous depositsobtained at high c.d. (above 15 mA/cm2). However, the smooth aluminum deposits were about five times more voluminousthan the theoretical value. The spongy deposits were formed due to difficulties...

Performance of Mg-14Li-1Al-0.1Ce as anode for Mg-air battery

Energy Technology Data Exchange (ETDEWEB)

Ma, Yibin; Li, Deyu [School of Chemical Engineering and Technology, Harbin Institute of Technology, West Street No. 92, Harbin 150001 (China); Li, Ning [School of Chemical Engineering and Technology, Harbin Institute of Technology, West Street No. 92, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China); Zhang, Milin; Huang, Xiaomei [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China)

2011-02-15

In this research, a new Mg-air battery based on Mg-14Li-1Al-0.1Ce was prepared and the battery performance was investigated by constant current discharge test. The corrosion behavior of Mg, AZ31 and Mg-Li-Al-Ce were studied by self-corrosion rate measurement and potentiodynamic polarization measurement. The characteristics of Mg-Li-Al-Ce after discharge were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that Mg-Li-Al-Ce is more active than Mg and AZ31. The self-corrosion rate is found to be in the order: Mg-Li-Al-Ce < Mg < AZ31. It has been observed that the Mg-air battery based on Mg-Li-Al-Ce offers higher operating voltage, anodic efficiency and capacity than those with Mg and AZ31. SEM and EIS results show that the discharge product of Mg-Li-Al-Ce is loosely adhered to the alloy surface, and thus Mg-Li-Al-Ce could keep high discharge activity during discharge. (author)

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

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

Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

Science.gov (United States)

Wang, Xiao; Wang, Wei; Wang, Jingli; Wu, Hao; Liu, Chang

2017-03-01

P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as MgGa δ doped AlGaN SLs. Mg acceptor activation energy was significantly reduced from 0.378 to 0.331 eV by using MgGa δ doping in SLs instead of traditional doping in alloys. This new process was confirmed to be able to realize high p-type doping in high Al-content AlGaN.

Aluminum drinking water treatment residuals (Al-WTRs) as sorbent for mercury: Implications for soil remediation.

Science.gov (United States)

Hovsepyan, Anna; Bonzongo, Jean-Claude J

2009-05-15

The potential of readily available and non-hazardous waste material, aluminum drinking water treatment residuals (Al-WTRs), to efficiently sorb and immobilize mercury (Hg) from aqueous solutions was evaluated. Al-WTR samples with average specific surface area of 48m(2)/g and internal micropore surface area of 120m(2)/g were used in a series of batch sorption experiments. Obtained sorption isotherms indicated a strong affinity of Hg for Al-WTRs. Using the Langmuir adsorption model, a relatively high maximum sorption capacity of 79mg Hg/g Al-WTRs was determined. Sorption kinetic data was best fit to a pseudo-first-order model, while the use of the Weber-Morris and Bangham models suggested that the intraparticle diffusion could be the rate-limiting step. Also, Al-WTRs effectively immoblized Hg in the pH range of 3-8. The results from these short-term experiments demonstrate that Al-WTRs can be effectively used to remove Hg from aqueous solutions. This ability points to the potential of Al-WTRs as a sorbent in soil remediation techniques based on Hg-immobilization.

Alloy development for the enhanced stability of Ω precipitates in Al-Cu-Mg-Ag alloys

Science.gov (United States)

Gable, B. M.; Shiflet, G. J.; Starke, E. A.

2006-04-01

The coarsening resistance and thermal stability of several Ω plate-dominated microstructures were controlled through altering the chemistry and thermomechanical processing of various Al-Cu-Mg-Ag alloys. Quantitative comparisons of Ω nucleation density, particle size, and thermal stability were used to illustrate the effects of alloy composition and processing conditions. The long-term stability of Ω plates was found to coincide with relatively high levels of silver and moderate magnesium additions, with the latter limiting the competition for solute with S-phase precipitation. This analysis revealed that certain microstructures initially dominated by Ω precipitation were found to remain stable through long-term isothermal and double-aging heat treatments, which represents significant improvement over the previous generation of Al-Cu-Mg-Ag alloys, in which Ω plates dissolved sacrificially after long aging times. The quantitative precipitate data, in conjunction with a thermodynamic database for the aluminum-rich corner of the Al-Cu-Mg-Ag quaternary system, were used to estimate the chemistry of the α/Ω-interphase boundary. These calculations suggest that silver is the limiting species at the α/Ω interfacial layer and that Ω plates form with varying interfacial chemistries during the early stages of artificial aging, which is directly related to the overall stability of certain plates.

Effect of Mg and Cu on mechanical properties of high-strength welded joints of aluminum alloys obtained by laser welding

Science.gov (United States)

Annin, B. D.; Fomin, V. M.; Karpov, E. V.; Malikov, A. G.; Orishich, A. M.

2017-09-01

Results of experimental investigations of welded joints of high-strength aluminum-lithium alloys of the Al-Cu-Li and Al-Mg-Li systems are reported. The welded joints are obtained by means of laser welding and are subjected to various types of processing for obtaining high-strength welded joints. A microstructural analysis is performed. The phase composition and mechanical properties of the welded joints before and after heat treatment are studied. It is found that combined heat treatment of the welded joint (annealing, quenching, and artificial ageing) increases the joint strength, but appreciably decreases the alloy strength outside the region thermally affected by the welding process.

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.

Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

OpenAIRE

Xiao Wang; Wei Wang; Jingli Wang; Hao Wu; Chang Liu

2017-01-01

P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as MgG...

Preliminary study of the electrolysis of aluminum sulfide in molten salts

Energy Technology Data Exchange (ETDEWEB)

Minh, N.Q.; Loutfy, R.O.; Yao, N.P.

1983-02-01

A preliminary laboratory-scale study of the electrolysis of aluminum sulfide in molten salts investigated the (1) solubility of Al/sub 2/S/sub 3/ in molten salts, (2) electrochemical behavior of Al/sub 2/S/sub 3/, and (3) electrolysis of Al/sub 2/S/sub 3/ with the determination of current efficiency as a function of current density. The solubility measurements show that MgCl/sub 2/-NaCl-KCl eutectic electrolyte at 1023 K can dissolve up to 3.3 mol % sulfide. The molar ratio of sulfur to aluminum in the eutectic is about one, which suggests that some sulfur remains undissolved, probably in the form of MgS. The experimental data and thermodynamic calculations suggest that Al/sub 2/S/sub 3/ dissolves in the eutectic to form AlS/sup +/ species in solution. Addition of AlCl/sub 3/ to the eutectic enhances the solubility of Al/sub 2/S/sub 3/; the solubility increases with increasing AlCl/sub 3/ concentration. The electrode reaction mechanism for the electrolysis of Al/sub 2/S/sub 3/ was elucidated by using linear sweep voltammetry. The cathodic reduction of aluminum-ion-containing species to aluminum proceeds by a reversible, diffusion-controlled, three-electron reaction. The anodic reaction involves the two-electron discharge of sulfide-ion-containing species, followed by the fast dimerization of sulfur atoms to S/sub 2/. Electrolysis experiments show that Al/sub 2/S/sub 3/ dissolved in molten MgCl/sub 2/-NaCl-KCl eutectic or in eutectic containing AlCl/sub 3/ can be electrolyzed to produce aluminum and sulfur. In the eutectic at 1023 K, the electrolysis can be conducted up to about 300 mA/cm/sup 2/ for the saturation solubility of Al/sub 2/S/sub 3/. Although these preliminary results are promising, additional studies are needed to elucidate many critical operating parameters before the technical potential of the electrolysis can be accurately assessed. 20 figures, 18 tables.

Co-current Doping Effect of Nanoscale Carbon and Aluminum Nitride on Critical Current Density and Flux Pinning Properties of Bulk MgB2 Superconductors

Science.gov (United States)

Tripathi, D.; Dey, T. K.

2018-05-01

The effect of nanoscale aluminum nitride (n-AlN) and carbon (n-C) co-doping on superconducting properties of polycrystalline bulk MgB2 superconductor has been investigated. Polycrystalline pellets of MgB2, MgB2 + 0.5 wt% AlN (nano), MgB_{1.99}C_{0.01} and MgB_{1.99}C_{0.01} + 0.5 wt% AlN (nano) have been synthesized by a solid reaction process under inert atmosphere. The transition temperature (TC) estimated from resistivity measurement indicates only a small decrease for C (nano) and co-doped MgB2 samples. The magnetic field response of investigated samples has been measured at 4, 10, and 20 K in the field range ± 6 T. MgB2 pellets co-doped with 0.5 wt% n-AlN and 1 wt% n-C display appreciable enhancement in critical current density (J_C) of MgB2 in both low (≥ 3 times), as well as, high-field region (≥ 15 times). J_C versus H behavior of both pristine and doped MgB2 pellets is well explained in the light of the collective pinning model. Further, the normalized pinning force density f_p(= F_p/F_{pmax}) displays a fair correspondence with the scaling procedure proposed by Eisterer et al. Moreover, the scaled data of the pinning force density (i.e., f_p{-}h data) of the investigated pellets at different temperature are well interpreted by a modified Dew-Hughes expression reported by Sandu and Chee.

Influence of Temperature on Mechanical Behavior During Static Restore Processes of Al-Zn-Mg-Cu High Strength Aluminum Alloy

Directory of Open Access Journals (Sweden)

ZHANG Kun

2017-06-01

Full Text Available Flow stress behaviors of as-cast Al-Zn-Mg-Cu high strength aluminum alloy during static restore processes were investigated by: Isothermal double-pass compression tests at temperatures of 300-400℃, strain rates of 0.01-1 s-1, strains of 33% +20% with the holding times of 0~900 s after the first pass compression. The results indicate that the deformation temperature has a dramatical effect on mechanical behaviors during static restore processes of the alloy. (1 At 300 ℃ and 330 ℃ lower temperatures, the recovery during the deformation is slow, and deformation energy stored in matrix is higher, flow stresses at the second pass deformation decreased during the recovery and recrystallization, and the stress softening phenomena is observed. Stress softening is increased with the increasing holding time; Precipitation during the holding time inhibites the stress softening. (2 At 360 ℃ and 400 ℃ higher temperatures, the recovery during deformation is rapid, and deformation energy stored in matrix is lower. Solid solubility is higher after holding, so that flow stress at the second pass deformation is increased, stress hardening phenomena is observed. Stress hardening decreased with the increasing holding time duo to the recovery and recrystallization during holding period at 360 ℃; Precipitation during holding also inhibited the stress softening. However, Stress hardening remains constant with the increasing holding time duo to the reasanenal there are no recovery and recrystallization during holding period at 400 ℃.

Sensitization of Naturally Aged Aluminum 5083 Armor Plate

Science.gov (United States)

2015-07-29

5 - 1 - SENSITIZATION OF NATURALLY AGED ALUMINUM 5083 ARMOR PLATE INTRODUCTION Aluminum -magnesium alloys are important for both ship...boundaries [3,4]. The magnesium-rich phase (normally β-Al3Mg2) is highly anodic with respect to the surrounding aluminum phase, thus is susceptible... alloys , and with varying amounts of debris scattered about the surface consistent with corrosion product, Figure 2b, that often forms over time within

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.)

AlN powder synthesis via nitriding reaction of aluminum sub-chloride

Energy Technology Data Exchange (ETDEWEB)

Ohashi, T.; Nishida, T.; Sugiura, M. (Waseda Univ., Tokyo (Japan). Graduate School); Fuwa, A. (Waseda Univ., Tokyo (Japan))

1993-06-01

In order to obtain the pertinent properties of aluminium nitride in its sintered form, it is desirable to have powders of finer sizes with narrower size distribution and higher purity, thereby making the sintering processing easier and the final body denser. Instead of using sublimated aluminum tri-chloride vapor (AlCl3) as an aluminum source in the vapor phase nitriding reaction, the mixed aluminum chloride vapor consisted of aluminum tri-chloride, bi-chloride and mono-chloride are used in the reaction with ammonia at temperatures of 1000 and 1200K. The mixed chloride vapors are produced by reacting chlorine with molten aluminum at 1000 or 1200K under atmospheric pressure. The reaction of this mixed chloride vapor with ammonia is then experimentally investigated to study the aluminum nitride powder morphology. The aluminum nitride powders synthesized under various ammonia concentrations are characterized for size distribution, mean particle size and particle morphology. 24 refs., 8 figs., 2 tabs.

Ultra-hard AlMgB14 coatings fabricated by RF magnetron sputtering from a stoichiometric target

Science.gov (United States)

Grishin, A. M.; Khartsev, S. I.; Böhlmark, J.; Ahlgren, M.

2015-01-01

For the first time hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric ceramic AlMgB14 target. Optimized processing conditions (substrate temperature, target sputtering power and target-to-substrate distance) enable fabrication of stoichiometric in-depth compositionally homogeneous films with the peak values of nanohardness 88 GPa and Young's modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 and 275 GPa at 200 nm depth in 2 μm thick film.

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.

Microstructure and Mechanical Behaviour of Stir-Cast Al-Mg-Sl Alloy Matrix Hybrid Composite Reinforced with Corn Cob Ash and Silicon Carbide

Directory of Open Access Journals (Sweden)

Oluwagbenga Babajide Fatile

2014-10-01

Full Text Available In this present study, the microstructural and mechanical behaviour of Al-Mg-Si alloy matrix composites reinforced with silicon carbide (SiC and Corn cob ash (An agro‑waste was investigated. This research work was aimed at assessing the suitability of developing low cost- high performance Al-Mg-Si hybrid composite. Silicon carbide (SiC particulates added with 0,1,2,3 and 4 wt% Corn cob ash (CCA were utilized to prepare 10 wt% of the reinforcing phase with Al-Mg-Si alloy as matrix using two-step stir casting method. Microstructural characterization, density measurement, estimated percent porosity, tensile testing, and micro‑hardness measurement were used to characterize the composites produced. From the results obtained, CCA has great potential to serve as a complementing reinforcement for the development of low cost‑high performance aluminum hybrid composites.

Microstructure And Mechanical Properties Of An Al-Zn-Mg-Cu Alloy Produced By Gravity Casting Process

Directory of Open Access Journals (Sweden)

Saikawa S.

2015-06-01

Full Text Available High-strength aluminum alloy are widely used for structural components in aerospace, transportation and racing car applications. The objective of this study is to enhance the strength of the Al-Zn-Mg-Cu alloy used for gravity casting process. All alloys cast into stepped-form sand mold (Sand-mold Casting; SC and Y-block shaped metal mold(Permanent mold Casting; PC C and then two –step aged at 398-423 K after solution treated at 743 K for 36 ks. The tensile strength and total elongation of the two-step aged SC alloys were 353-387 MPa and about 0.4% respectively. This low tensile properties of the SC alloys might be caused by remaining of undissolved crystallized phase such as Al2CuM, MgZn2 and Al-Fe-Cu system compounds. However, good tensile properties were obtained from PC alloys, tensile strength and 0.2% proof stress and elongation were 503-537 MPa, 474-519 MPa and 1.3-3.3%.

Abrasion resistant low friction and ultra-hard magnetron sputtered AlMgB14 coatings

Science.gov (United States)

Grishin, A. M.

2016-04-01

Hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric AlMgB14 ceramic target. X-ray amorphous AlMgB14 films are very smooth. Their roughness does not exceed the roughness of Si wafer and Corning glass used as the substrates. Dispersion of refractive index and extinction coefficient were determined within 300 to 2500 nm range for the film deposited onto Corning glass. Stoichiometric in-depth compositionally homogeneous 2 μm thick films on the Si(100) wafer possess the peak values of nanohardness 88 GPa and Young’s modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 GPa and 275 GPa at 200 nm depth. Friction coefficient was found to be 0.06. The coating scratch adhesion strength of 14 N was obtained as the first chipping of the coating whereas its spallation failure happened at 21 N. These critical loads and the work of adhesion, estimated as high as 18.4 J m-2, surpass characteristics of diamond like carbon films deposited onto tungsten carbide-cobalt (WC-Co) substrates.

IMPACT OF A REVISED {sup 25}Mg(p, {gamma}){sup 26}Al REACTION RATE ON THE OPERATION OF THE Mg-Al CYCLE

Energy Technology Data Exchange (ETDEWEB)

Straniero, O.; Cristallo, S. [INAF-Osservatorio Astronomico di Collurania, Teramo (Italy); Imbriani, G.; DiLeva, A.; Limata, B. [INFN Sezione di Napoli, Napoli (Italy); Strieder, F. [Institut fuer Experimentalphysik, Ruhr-Universitaet Bochum, Bochum (Germany); Bemmerer, D. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400 (Germany); Broggini, C.; Caciolli, A. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Padova, via Marzolo 8, I-35131 Padova (Italy); Corvisiero, P.; Costantini, H.; Lemut, A. [Universita di Genova and INFN Sezione di Genova, Genova (Italy); Formicola, A.; Gustavino, C.; Junker, M. [INFN, Laboratori Nazionali del Gran Sasso (LNGS), Assergi (AQ) (Italy); Elekes, Z.; Fueloep, Zs.; Gyuerky, Gy. [Institute of Nuclear Research (ATOMKI), Debrecen (Hungary); Gervino, G. [Dipartimento di Fisica Universita di Torino and INFN Sezione di Torino, Torino (Italy); Guglielmetti, A., E-mail: straniero@oa-teramo.inaf.it [Universita degli Studi di Milano and INFN, Sezione di Milano (Italy); and others

2013-02-15

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H-burning regions. In particular, low-energy nuclear resonances in the {sup 25}Mg(p, {gamma}){sup 26}Al reaction affect the production of radioactive {sup 26}Al{sup gs} as well as the resulting Mg/Al abundance ratio. Reliable estimations of these quantities require precise measurements of the strengths of low-energy resonances. Based on a new experimental study performed at the Laboratory for Underground Nuclear Astrophysics, we provide revised rates of the {sup 25}Mg(p, {gamma}){sup 26}Al{sup gs} and the {sup 25}Mg(p, {gamma}){sup 26}Al {sup m} reactions with corresponding uncertainties. In the temperature range 50-150 MK, the new recommended rate of {sup 26}Al {sup m} production is up to five times higher than previously assumed. In addition, at T = 100 MK, the revised total reaction rate is a factor of two higher. Note that this is the range of temperature at which the Mg-Al cycle operates in a H-burning zone. The effects of this revision are discussed. Due to the significantly larger {sup 25}Mg(p, {gamma}){sup 26}Al {sup m} rate, the estimated production of {sup 26}Al{sup gs} in H-burning regions is less efficient than previously obtained. As a result, the new rates should imply a smaller contribution from Wolf-Rayet stars to the galactic {sup 26}Al budget. Similarly, we show that the asymptotic giant branch (AGB) extra-mixing scenario does not appear able to explain the most extreme values of {sup 26}Al/{sup 27}Al, i.e., >10{sup -2}, found in some O-rich presolar grains. Finally, the substantial increase of the total reaction rate makes the hypothesis of self-pollution by massive AGBs a more robust explanation for the Mg-Al anticorrelation observed in globular-cluster stars.

The influence of chemical composition on the properties and structure Al-Si-Cu(Mg alloys

Directory of Open Access Journals (Sweden)

M. Kaczorowski

2007-04-01

Full Text Available The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening heat treatment. The age hardened specimens were evaluated using tensile test, hardness measurements and impact test. Moreover, the structure investigation were carried out using either conventional light Metallography and scanning (SEM and transmission (TEM electron microscopy. The two last methods were used for fractography observations and precipitation process observations respectively. It was concluded that the changes in chemical composition which can reach even 2,5wt.% cause essential differences of the structure and mechanical properties of the alloys. As followed from quantitative evaluation and as could be predicted theoretically, copper and silicon mostly influenced the mechanical properties of AlSi5Cu3(Mg type cast alloys. Moreover it was showed that the total concentration of alloying elements accelerated and intensifies the process of decomposition of supersaturated solid solution. The increase of Cu and Mg concentration increased the density of precipitates. It increases of strength properties of the alloys which are accompanied with decreasing in ductility.

Predictive calculation of phase formation in Al-rich Al-Zn-Mg-Cu-Sc-Zr alloys using a thermodynamic Mg-alloy database

International Nuclear Information System (INIS)

Groebner, J.; Rokhlin, L.L.; Dobatkina, T.V.; Schmid-Fetzer, R.

2007-01-01

Three series of Al-rich alloys in the system Al-Zn-Mg-Cu-Sc-Zr and the subsystems Al-Zn-Mg-Cu-Sc and Al-Zn-Mg-Sc were studied by thermodynamic calculations. Phase formation was compared with experimental data obtained by DTA and microstructural analysis. Calculated phase diagrams, phase amount charts and enthalpy charts together with non-equilibrium calculations under Scheil conditions reveal significant details of the complex phase formation. This enables consistent and correct interpretation of thermal analysis data. Especially the interpretation of liquidus temperature and primary phase is prone to be wrong without using this tool of computational thermodynamics. All data are predictions from a thermodynamic database developed for Mg-alloys and not a specialized Al-alloy database. That provides support for a reasonable application of this database for advanced Mg-alloys beyond the conventional composition ranges

Predictive calculation of phase formation in Al-rich Al-Zn-Mg-Cu-Sc-Zr alloys using a thermodynamic Mg-alloy database

Energy Technology Data Exchange (ETDEWEB)

Groebner, J. [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch Strasse 42, D-38678 Clausthal-Zellerfeld (Germany); Rokhlin, L.L. [Baikov Institute of Metallurgy and Materials Science, Leninsky prosp. 49, 119991 GSP-1, Moscow (Russian Federation); Dobatkina, T.V. [Baikov Institute of Metallurgy and Materials Science, Leninsky prosp. 49, 119991 GSP-1, Moscow (Russian Federation); Schmid-Fetzer, R. [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch Strasse 42, D-38678 Clausthal-Zellerfeld (Germany)]. E-mail: schmid-fetzer@tu-clausthal.de

2007-05-16

Three series of Al-rich alloys in the system Al-Zn-Mg-Cu-Sc-Zr and the subsystems Al-Zn-Mg-Cu-Sc and Al-Zn-Mg-Sc were studied by thermodynamic calculations. Phase formation was compared with experimental data obtained by DTA and microstructural analysis. Calculated phase diagrams, phase amount charts and enthalpy charts together with non-equilibrium calculations under Scheil conditions reveal significant details of the complex phase formation. This enables consistent and correct interpretation of thermal analysis data. Especially the interpretation of liquidus temperature and primary phase is prone to be wrong without using this tool of computational thermodynamics. All data are predictions from a thermodynamic database developed for Mg-alloys and not a specialized Al-alloy database. That provides support for a reasonable application of this database for advanced Mg-alloys beyond the conventional composition ranges.

Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

Science.gov (United States)

Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.

2017-06-01

An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

The Mechanism of Solid State Joining THA with AlMg3Mn Alloy

Directory of Open Access Journals (Sweden)

Kaczorowski M.

2014-06-01

Full Text Available The results of experimental study of solid state joining of tungsten heavy alloy (THA with AlMg3Mn alloy are presented. The aim of these investigations was to study the mechanism of joining two extremely different materials used for military applications. The continuous rotary friction welding method was used in the experiment. The parameters of friction welding process i.e. friction load and friction time in whole studies were changed in the range 10 to 30kN and 0,5 to 10s respectively while forging load and time were constant and equals 50kN and 5s. The results presented here concerns only a small part whole studies which were described elsewhere. These are focused on the mechanism of joining which can be adhesive or diffusion controlled. The experiment included macro- and microstructure observations which were supplemented with SEM investigations. The goal of the last one was to reveal the character of fracture surface after tensile test and to looking for anticipated diffusion of aluminum into THA matrix. The results showed that joining of THA with AlMg2Mn alloy has mainly adhesive character, although the diffusion cannot be excluded.

Influence of secondary ageing temperature on hardening and residual elastic stresses in AlMgSi and AlMgSiCu alloys

International Nuclear Information System (INIS)

Milosavlevich, A.Ya.; Shiyachki-Zheravchich; Rogulin, M.Ya.; Milenkovich, V.M.; Prokich-Tsvetkovich, R.M.

1993-01-01

The investigations were conducted on samples of AlMgSi and AlMgSiCu alloys quenched, aged and cold worked with 20, 40, 60 and 85 % reduction in area. Secondary ageing was carried out at 200 and 250 deg C. Residual stresses wee determined by X-ray diffraction method. It was shown that cold deformation effect on hardness and residual stresses is dependent on alloy composition. The hardening due to secondary ageing is more pronounced for AlMgSi alloy at 200 deg C and for AlMgSiCu alloy at 250 deg C. Positive residual stresses increase with secondary ageing temperature

Strengthening of Aluminum Wires Treated with A206/Alumina Nanocomposites

Directory of Open Access Journals (Sweden)

David Florián-Algarín

2018-03-01

Full Text Available This study sought to characterize aluminum nanocomposite wires that were fabricated through a cold-rolling process, having potential applications in TIG (tungsten inert gas welding of aluminum. A206 (Al-4.5Cu-0.25Mg master nanocomposites with 5 wt % γAl2O3 nanoparticles were first manufactured through a hybrid process combining semi-solid mixing and ultrasonic processing. A206/1 wt % γAl2O3 nanocomposites were fabricated by diluting the prepared master nanocomposites with a monolithic A206 alloy, which was then added to a pure aluminum melt. The fabricated Al–γAl2O3 nanocomposite billet was cold-rolled to produce an Al nanocomposite wire with a 1 mm diameter and a transverse area reduction of 96%. Containing different levels of nanocomposites, the fabricated samples were mechanically and electrically characterized. The results demonstrate a significantly higher strength of the aluminum wires with the nanocomposite addition. Further, the addition of alumina nanoparticles affected the wires’ electrical conductivity compared with that of pure aluminum and aluminum–copper alloys. The overall properties of the new material demonstrate that these wires could be an appealing alternative for fillers intended for aluminum welding.

Microstructure and Mechanical Properties of Ultrasonic Spot Welded Mg/Al Alloy Dissimilar Joints

Directory of Open Access Journals (Sweden)

He Peng

2018-04-01

Full Text Available Lightweight structural applications of magnesium and aluminum alloys inevitably necessitate welding and joining, especially dissimilar welding between these alloys. The objective of this study was to examine the feasibility of joining ZEK100 Mg alloy to Al6022 alloy via ultrasonic spot welding, focusing on effects of welding energy. An interface diffusion layer consisting of α-Mg and Al12Mg17 eutectic structure was observed to form, with its thickness increased from ~0.5 µm to ~30 µm with increasing welding energy from 500 J to 2000 J. The tensile lap shear peak load or strength and critical stress intensity of the welded joints first increased and then decreased with increasing welding energy, with their peak values achieved at 750 J. Fatigue life of the joints made at 750 J and 2000 J was equivalent at the lower cyclic loading levels, while it was longer for the joints made at 750 J at the higher cyclic loading levels. Fatigue fracture mode changed from interfacial failure to mainly transverse-through-thickness crack growth with decreasing cyclic loading level, which corresponded well to the bi-linear characteristic of S-N curves. Crack initiation basically occurred at the weld nugget border and at the interface between the two sheets, which can be understood via a theoretical stress analysis.

Sintering of (Ni,Mg)(Al,Fe)2O4 Materials and their Corrosion Process in Na3AlF6-AlF3-K3AlF6 Electrolyte

Science.gov (United States)

Xu, Yibiao; Li, Yawei; Yang, Jianhong; Sang, Shaobai; Wang, Qinghu

2017-06-01

The application of ledge-free sidewalls in the Hall-Héroult cells can potentially reduce the energy requirement of aluminum production by about 30 pct (Nightingale et al. in J Eur Ceram, 33:2761-2765, 2013). However, this approach poses great material challenges since such sidewalls are in direct contact with corrosive electrolyte. In the present paper, (Ni,Mg)(Al,Fe)2O4 materials were prepared using fused magnesia, reactive alumina, nickel oxide, and iron oxide powders as the starting materials. The sintering behaviors of specimens as well as their corrosion resistance to molten electrolyte have been investigated by means of X-ray diffraction and scanning electron microscope. The results show that after firing at temperature ranging from 1673 K (1400 °C) up to 1873 K (1600 °C), all the specimens prepared are composed of single-phase (Ni,Mg)(Al,Fe)2O4 composite spinel, the lattice parameter of which increases with increasing Fe3+ ion concentration. Increasing the iron oxide content enhances densification of the specimens, which is accompanied by the formation of homogeneously distributed smaller pores in the matrix. The corrosion tests show that corrosion layers consist of fluoride and Ni(Al,Fe)2O4 composite spinel grains are produced in specimens with Fe/Al mole ratio no more than 1, whereas dense Ni(Al,Fe)2O4 composite spinel layers are formed on the surface of the specimens with Fe/Al mole ratio more than 1. The dense Ni(Al,Fe)2O4 composite spinel layers formed improve the corrosion resistance of the specimens by inhibiting the infiltration of electrolyte and hindering the chemical reaction between the specimen and electrolyte.

Preliminary study of the characteristics of a high Mg containing Al-Mg-Si alloy

International Nuclear Information System (INIS)

Yan, F; McKay, B J; Fan, Z; Chen, M F

2012-01-01

An Al-20Mg-4Si high Mg containing alloy has been produced and its characteristics investigated. The as-cast alloy revealed primary Mg 2 Si particles evenly distributed throughout an α-Al matrix with a β-Al 3 Mg 2 fully divorced eutectic phase observed in interdendritic regions. The Mg 2 Si particles displayed octahedral, truncated octahedral, and hopper morphologies. Additions of Sb, Ti and Zr had a refining influence reducing the size of the Mg 2 Si from 52 ± 4 μm to 25 ± 0.1 μm, 35 ± 1 μm and 34 ± 1 μm respectively. HPDC tensile test samples could be produced with a 0.6 wt.% Mn addition which prevented die soldering. Solution heating for 1 hr was found to dissolve the majority of the Al 3 Mg 2 eutectic phase with no evidence of any effect on the primary Mg 2 Si. Preliminary results indicate that the heat treatment has a beneficial effect on the elongation and the UTS.

Effect of tool offsetting on microstructure and mechanical properties dissimilar friction stir welded Mg-Al alloys

Science.gov (United States)

Baghdadi, Amir Hossein; Fazilah Mohamad Selamat, Nor; Sajuri, Zainuddin

2017-09-01

Automotive and aerospace industries are attempting to produce lightweight structure by using materials with low density such as aluminum and magnesium alloys to increase the fuel efficiency and consequently reduce the environmental pollution. It can be beneficial to join Mg to Al to acquire ideal performance in special applications. Friction stir welding (FSW) is solid state welding processes and relatively lower temperature of the process compared to fusion welding processes. This makes FSW a potential joining technique for joining of the dissimilar materials. In this study, Mg-Al butt joints were performed by FSW under different tool offset conditions, rotation rates (500-600 rpm) and traverse speeds (20 mm/min) with tool axis offset 1 mm shifted into AZ31B or Al6061 (T6), and without offset. During the welding process AZ31B was positioned at the advancing side (AS) and Al6061 (T6) was located at the retreating side (RS). Defect free AZ31B-Al6061 (T6) dissimilar metal FSW joints with good mechanical properties were obtained with the combination of intermediate rotation rate and low traverse speed pin is in the middle. When tool positioned in -1 mm or +1 mm offsetting, some defects were found in SZ of dissimilar FSWed joints such as cavity, tunnel, and crack. Furthermore, a thin layer of intermetallic compounds was observed in the stir zone at the interface between Mg-Al plates. The strength of the joint was influenced by FSW parameters. Good mechanical properties obtained with the combination of intermediate rotational speed of 600 rpm and low travelling speed of 20 mm/min by locating Mg on advancing side when pin is in the middle. Also, Joint efficiency of the welds prepared in the present study was between 29% and 68% for the different welding parameters.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Electroless Growth of Aluminum Dendrites in NaCl-AlCl3 Melts

DEFF Research Database (Denmark)

Li, Qingfeng; Hjuler, H.A.; Berg, Rolf W.

1989-01-01

The spontaneous growth of aluminum dendrites after deposition was observed and examined in sodium chloride-aluminumchloride melts. The concentration gradient of AlCl3 in the vicinity of the cathode surface resulting from electrolysisconstitutes a type of concentration cell with aluminum dendrites...... as electrodes. The short-circuit discharge of thecell is found to be the driving force for the growth of aluminum dendrites. Such a concentration gradient is proposed to beone of the causes for dendrite formation in the case of metal deposition....

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.

Microestructura y propiedades mecánicas de materiales compuestos de matriz Al-Mg-Si-Cu reforzada con AlNp, procesados por extrusión de polvos

Directory of Open Access Journals (Sweden)

Ortiz, José Luis

2000-10-01

Full Text Available This article presents an experimental investigation on the structure and mechanical properties of an Al-Mg-Si-Cu P/M alloy reinforced with 5 %, 10 % and 15 % aluminum nitride, produced by extrusión of cold compacted powders mixtures. Mechanical properties in "as extruded" and T6 conditions are compared. Differential Scanning Calorimetry and Dilatometric analysis were conducted to gain further insight into the precipitation process of these materials. Low cost 6061Al/AlNp composites can be produced with rare and small porosity by extrusión of cold compacted shapes without canning. The mechanical properties of the MMCs obtained by this process have limitations for high particles fractions because of clustering effects. All materials are always harder than the matrix and shows a similar behavior during aging processes but kinetics is changed. Potential applications of dilatometric techniques in the aging investigations of aluminum alloys and aluminum matrix composites have been established.

Se presenta una investigación experimental sobre la relación entre la estructura y las propiedades mecánicas de materiales obtenidos mediante la extrusión en caliente de preformas de polvos compactados en frío y cuya matriz es una aleación Al-Mg-Si-Cu con composición cercana a la AA6061, reforzada con tres proporciones diferentes (5, 10 y 15 % en volumen de partículas de AlN. Se utilizó Calorimetría Diferencial de Barrido y Dilatometría sobre las muestras solubilizadas y templadas para complementar el estudio del efecto de las partículas sobre el envejecimiento de la aleación base. Se establece que es posible producir, a bajo costo, materiales compuestos de matriz metálica, MMCs, de matriz de aleación AA6061 reforzada con partículas de AlN con baja porosidad y buenas propiedades mecánicas, mediante la extrusión de mezclas de polvos compactados en frío, sin necesidad de enlatado. Sin embargo, las aglomeraciones de partículas, para

Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

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Liming Liu

2014-02-01

Full Text Available Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated.

Effect of Iron Impurity on the Phase Composition, Structure and Properties of Magnesium Alloys Containing Manganese and Aluminum

Science.gov (United States)

Volkova, E. F.

2017-07-01

Results of a study of the interaction between iron impurity and manganese and aluminum alloying elements during formation of phase composition in alloys of the Mg - Mn, Mg - Al, Mg - Al - Mn, and Mg - Al - Zn - Mn systems are presented. It is proved that this interaction results in introduction of Fe into the intermetallic phase. The phase compositions of model magnesium alloys and commercial alloys MA2-1 and MA5 are studied. It is shown that both manganese and aluminum may bind the iron impurity into phases. Composite Fe-containing intermetallic phases of different compositions influence differently the corrosion resistance of magnesium alloys.

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

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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.

FT-Raman and FT-IR spectroscopy of synthetic Mg/Zn/Al-hydrotalcites

International Nuclear Information System (INIS)

Leishman, N.; Kloprogge, J.T.; Fry, R.; Frost, R.L.

1998-01-01

Full text: Hydrotalcites, also known as layered double hydroxides, are less well known and more diffuse in nature than cationic clays. They can be visualised as positively charged hydroxide layers comparable to brucite in which a part of the Mg 2+ is substituted by a trivalent metal like Al 3+ or Fe 3+ separated by charge compensating mostly hydrated interlayer anions. In synthetic hydrotalcites a broad range of compositions are possible of the type [M 2+ 1-x M 3+ x (OH) 2 ][A n- ] x/n -yH 2 O, where M 2+ and M 3+ are the di- and trivalent cations in the octahedral positions within the hydroxide layers with x between 0.17 and 0.33. A n- is an exchangeable interlayer anion. The hydrotalcites with Mg/Zn/Al atomic ratios of 6/0/2, 4/2/2, 2/4/2 and 0/6/2 were synthesised by the slow simultaneous addition of a mixed aluminum-magnesium-zinc nitrate solution and a NaOH solution under vigorous stirring buffering the pH at ± 10. The products were washed to eliminate excess salt and dried at 60 deg C. The nature of the resulting material was checked by XRD and TEM. Both proved the materials to exist of only crystalline hydrotalcite except for the Zn 6 Al 2 (OH) 16 CO 3 .nH 2 O, which contained some unidentified products. The infrared and Raman spectra of synthetic hydrotalcites with different Mg/Zn ratios reveal complicated spectra. Based on the differences in the spectra between the various hydrotalcites and comparison to the comparable hydroxides and hydroxycarbonates a much more detailed band assignment can be made than has been published before

A study of stability of MgH{sub 2} in Mg-8at%Al alloy powder

Energy Technology Data Exchange (ETDEWEB)

Tanniru, Mahesh; Ebrahimi, Fereshteh [Materials Science and Engineering Department, University of Florida, Gainesville, FL 32611 (United States); Slattery, Darlene K. [Florida Solar Energy Center (FSEC), Cocoa, FL (United States)

2010-04-15

To investigate the effect of Al addition on the stability of magnesium hydride, the hydrogenation characteristics of a Mg-8at%Al alloy powder synthesized using the electrodeposition technique were evaluated. The characterization of the hydrogenation behavior within the 180 C-280 C temperature range and the subsequent microstructural analysis elucidated that the amount of Al present in the hydride decreased with increasing temperature. This observation suggests that Al has very low solubility in magnesium hydride but Al can be accommodated in MgH{sub 2} by processing under non-equilibrium conditions. Pressure-composition isotherms were developed at different temperatures for the Mg-Al powder as well as pure Mg powder. The results indicate that the enthalpy of formation was slightly lower for the Mg-8at%Al powder while the enthalpy of dissociation did not change. The absence of noticeable influence of Al addition on the stability of magnesium hydride is attributed to its lack of solubility. (author)

Leonardsenite, MgAlF₅(H₂O)₂, a new mineral species from Eldfell Volcano, Heimaey Island, Iceland

DEFF Research Database (Denmark)

Mitolo, Donatella; Garavelli, Anna; Balic Zunic, Tonci

2013-01-01

microscope produced a mean elemental composition as follows (wt.: Mg 14.66, Al 16.16, F 52.98, 0 15.88, H 1.78, total 101.46. The corresponding empirical formula, calculated on the basis of 2 cations pfu, is Mgi.00Ali 004.64(011)0.361E5.00(1420)1 29. On the basis of chemical analyses and X-ray diffraction...... data, leonardsenite corresponds to the synthetic compound MgAlF5(H2O)(2). The crystal structure of leonardsenite contains infinite chains of [A(1)F(6)] octahedra along the c-axis which are connected via common fluorine atoms to isolated [MgF4(H2O)(2)] octahedra. Leonardsenite is the first aluminum...

Aluminum anode for aluminum-air battery - Part I: Influence of aluminum purity

Science.gov (United States)

Cho, Young-Joo; Park, In-Jun; Lee, Hyeok-Jae; Kim, Jung-Gu

2015-03-01

2N5 commercial grade aluminum (99.5% purity) leads to the lower aluminum-air battery performances than 4N high pure grade aluminum (99.99% purity) due to impurities itself and formed impurity complex layer which contained Fe, Si, Cu and others. The impurity complex layer of 2N5 grade Al declines the battery voltage on standby status. It also depletes discharge current and battery efficiency at 1.0 V which is general operating voltage of aluminum-air battery. However, the impurity complex layer of 2N5 grade Al is dissolved with decreasing discharge voltage to 0.8 V. This phenomenon leads to improvement of discharge current density and battery efficiency by reducing self-corrosion reaction. This study demonstrates the possibility of use of 2N5 grade Al which is cheaper than 4N grade Al as the anode for aluminum-air battery.

Interaction of hydrogen with an Mg-Al alloy

International Nuclear Information System (INIS)

Andreasen, A.; Sorensen, M.B.; Burkarl, R.; Moller, B.; Molenbroek, A.M.; Pedersen, A.S.; Andreasen, J.W.; Nielsen, M.M.; Jensen, T.R.

2005-01-01

The interaction of hydrogen with an Mg-Al alloy pre-exposed to air have been studied with in situ time resolved X-ray powder diffraction. Phase fractions as a function of time are derived from series of consecutive diffraction patterns allowing kinetic analysis. The apparent activation energy for dehydrogenation of the Mg-Al alloy is found to be 160 kJ/mol. This is not significantly higher than for pure and fully activated Mg. It is suggested that the addition of Al improves the resistance towards oxygen contamination

First-principles calculations on Mg/Al2CO interfaces

International Nuclear Information System (INIS)

Wang, F.; Li, K.; Zhou, N.G.

2013-01-01

The electronic structure, work of adhesion, and interfacial energy of the Mg(0 0 0 2)/Al 2 CO(0 0 0 1) interface were studied with the first-principles calculations to clarify the heterogeneous nucleation potential of Al 2 CO particles in Mg melt. AlO-terminated Al 2 CO(0 0 0 1) slabs with seven atomic layers were adopted for interfacial model geometries. Results show that the “Over O” stacking interface is more stable than the “Over Al” stacking interface due to the larger interfacial adhesion and stronger mixed ionic/metallic bond formed across the interface. The calculated interfacial energies of Mg/Al 2 CO depend on the value of Δμ Al + Δμ C , proving Al 2 CO particles can exist stably in Mg–Al alloys melt and become effective nucleation substrate for α-Mg grain under certain conditions. The above calculation and corresponding analysis provide strong theoretical support to the Al 2 CO nucleus hypothesis from interfacial atomic structure and atomic bonding energy considerations.

Electrochemical Deposition and Dissolution of Aluminum in NaAlCl4 Melts

DEFF Research Database (Denmark)

Li, Qingfeng; Hjuler, H.A.; Berg, Rolf W.

1990-01-01

Effects of the additives MnCl2, sulfide, and their combined influence on aluminum deposition and dissolution inNaAlCl4 saturated with NaCl have been studied by polarization measurements, galvanostatic deposition, and current reversalchronopotentiometry (CRC). The solubility of MnCl2 was found...... to be 0.086 ± 0.006 m/o in the melt at 175°C. Aluminum-manganesealloys can be deposited in NaAlCl4 saturated with both NaCl and MnCl2, resulting in a slight increase incathodic overpotentials. The codeposition of the binary alloys at current densities below 4 mA/cm2 gave rise to formationof deposits so...

Study of polarization curves from AlSi12, AlSi5Mg and AlMg5 alloys due to corrosion problems in telecomunication equipment

International Nuclear Information System (INIS)

Silva, J.R.A. da

1984-01-01

The corrosion behaviour of three aluminium based alloys (AlSi 12, AlMg5 and AlSi 5Mg) when exposed to aqueous media containing chloride is investigated; these alloys are used in the manufacturing of telecomunication equipment. Accelerated corrosion testing and salt spray tests were carried out. The results include polarization curves obtained with three kinds of aqueous solutions (the first containing only 3% NaCl and the others, 3% NaCl and small amounts of Fe 3+ and Cu 2+ ions). (C.L.B.) [pt

Strengthening of Aluminum Wires Treated with A206/Alumina Nanocomposites.

Science.gov (United States)

Florián-Algarín, David; Marrero, Raúl; Li, Xiaochun; Choi, Hongseok; Suárez, Oscar Marcelo

2018-03-10

This study sought to characterize aluminum nanocomposite wires that were fabricated through a cold-rolling process, having potential applications in TIG (tungsten inert gas) welding of aluminum. A206 (Al-4.5Cu-0.25Mg) master nanocomposites with 5 wt % γAl₂O₃ nanoparticles were first manufactured through a hybrid process combining semi-solid mixing and ultrasonic processing. A206/1 wt % γAl₂O₃ nanocomposites were fabricated by diluting the prepared master nanocomposites with a monolithic A206 alloy, which was then added to a pure aluminum melt. The fabricated Al-γAl₂O₃ nanocomposite billet was cold-rolled to produce an Al nanocomposite wire with a 1 mm diameter and a transverse area reduction of 96%. Containing different levels of nanocomposites, the fabricated samples were mechanically and electrically characterized. The results demonstrate a significantly higher strength of the aluminum wires with the nanocomposite addition. Further, the addition of alumina nanoparticles affected the wires' electrical conductivity compared with that of pure aluminum and aluminum-copper alloys. The overall properties of the new material demonstrate that these wires could be an appealing alternative for fillers intended for aluminum welding.

Effect of AlB2-Mg interaction on the mechanical properties of Al-based composites

International Nuclear Information System (INIS)

Calderon, Hermes E.; Hidalgo, Ruth G.I.; Melgarejo, Z. Humberto; Suarez, O. Marcelo

2010-01-01

A series of Al-based composites with a matrix containing 2.5 wt.%Cu and 1 wt.%Mg, and reinforced with Al diborides was manufactured and characterized via microscopy and mechanical testing. The impact resistance of the composites revealed interaction between AlB 2 dispersoids and Mg originally present in the Al matrix. An unexpected increase in the absorbed impact energy of composites with diborides prompted complementary experiments leading to this finding. Hardness tests were correlated to those results and provided further evidence of the interaction between Mg and the dispersoids. Additional energy dispersive spectroscopy (EDS) analysis and X-ray diffraction tests supported with crystal modeling demonstrated that Mg effectively diffused into the AlB 2 crystal producing a doped structure with an Al 1-x Mg x B 2 formula where x lies between 0.08 and 0.15.

BoALMT1, an Al-Induced Malate Transporter in Cabbage, Enhances Aluminum Tolerance in Arabidopsis thaliana

OpenAIRE

Zhang, Lei; Wu, Xin-Xin; Wang, Jinfang; Qi, Chuandong; Wang, Xiaoyun; Wang, Gongle; Li, Mingyue; Li, Xingsheng; Guo, Yang-Dong

2018-01-01

Aluminum (Al) is present in approximately 50% of the arable land worldwide and is regarded as the main limiting factor of crop yield on acidic soil. Al-induced root malate efflux plays an important role in the Al tolerance of plants. Here, the aluminum induced malate transporter BoALMT1 (KF322104) was cloned from cabbage (Brassica oleracea). BoALMT1 showed higher expression in roots than in shoots. The expression of BoALMT1 was specifically induced by Al treatment, but not the trivalent catio...

Development and Characterisation of Aluminium Matrix Nanocomposites AlSi10Mg/MgAl2O4 by Laser Powder Bed Fusion

Directory of Open Access Journals (Sweden)

Giulio Marchese

2018-03-01

Full Text Available Recently, additive manufacturing techniques have been gaining attention for the fabrication of parts from aluminium alloys to composites. In this work, the processing of an AlSi10Mg based composite reinforced with 0.5% in weight of MgAl2O4 nanoparticles through laser powder bed fusion (LPBF process is presented. After an initial investigation about the effect of process parameters on the densification levels, the LPBF materials were analysed in terms of microstructure, thermo-mechanical and mechanical properties. The presence of MgAl2O4 nanoparticles involves an increment of the volumetric energy density delivered to the materials, in order to fabricate samples with high densification levels similar to the AlSi10Mg samples. However, the application of different building parameters results in modifying the size of the cellular structures influencing the mechanical properties and therefore, limiting the strengthening effect of the reinforcement.

Quasi-superplasticity of a banded-grained Al-Mg-Y alloy processed by continuous casting-extrusion

Energy Technology Data Exchange (ETDEWEB)

Cao, Furong, E-mail: cfr-lff@163.com [School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Zhu, Xiaotong [School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Huaian Dekema Semiconductor Co., Ltd., Huaian 223300 (China); Wang, Shuncheng [Institute of Materials Processing and Forming Technology, Guangdong General Research Institute of Industrial Technology, Guangzhou 510650 (China); Shi, Lu [School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Xu, Guangming [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Wen, Jinglin [School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China)

2017-04-06

The continuous casting-extrusion (CTE) process is a short-route technology for fabricating aluminum and aluminum alloy wires. A novel Al-1.44Mg-1.09Y alloy was prepared by CTE, and its mechanical properties and microstructure evolution were investigated at elevated temperatures to explore the hot tensile ductility of aluminum alloy wire. A true strain to failure of 1.159 was obtained at 773 K and 1.67×10{sup −2} s{sup −1}, and the present alloy exhibits high strain rate quasi-superplasticity. Microstructure observations reveal that it is difficult to realize the equiaxedness of elongated or textured grains through hot tensile deformation. A new deformation mechanism map (DMM) was constructed which predicts that dislocation climb at high stress dominates the high-temperature deformation process. This theoretical prediction using the DMM is in good agreement with experimental transmission-electron-microscopy results and with the estimated true stress exponent of 5 and the activation energy for deformation in the range 127.378―141.536 kJ mol{sup −1}. A new three-dimensional histogram containing a dynamic recovery (DRV) or dynamic recrystallization factor was constructed to demonstrate that the DRV mechanism dominates the deformation. Most experimental results are consistent with prediction using this histogram.

Quasi-superplasticity of a banded-grained Al-Mg-Y alloy processed by continuous casting-extrusion

International Nuclear Information System (INIS)

Cao, Furong; Zhu, Xiaotong; Wang, Shuncheng; Shi, Lu; Xu, Guangming; Wen, Jinglin

2017-01-01

The continuous casting-extrusion (CTE) process is a short-route technology for fabricating aluminum and aluminum alloy wires. A novel Al-1.44Mg-1.09Y alloy was prepared by CTE, and its mechanical properties and microstructure evolution were investigated at elevated temperatures to explore the hot tensile ductility of aluminum alloy wire. A true strain to failure of 1.159 was obtained at 773 K and 1.67×10 −2 s −1 , and the present alloy exhibits high strain rate quasi-superplasticity. Microstructure observations reveal that it is difficult to realize the equiaxedness of elongated or textured grains through hot tensile deformation. A new deformation mechanism map (DMM) was constructed which predicts that dislocation climb at high stress dominates the high-temperature deformation process. This theoretical prediction using the DMM is in good agreement with experimental transmission-electron-microscopy results and with the estimated true stress exponent of 5 and the activation energy for deformation in the range 127.378―141.536 kJ mol −1 . A new three-dimensional histogram containing a dynamic recovery (DRV) or dynamic recrystallization factor was constructed to demonstrate that the DRV mechanism dominates the deformation. Most experimental results are consistent with prediction using this histogram.

Influence of the heat treatment condition of alloy AlCu4Mg1 on the microstructure and properties of anodic oxide layers

Science.gov (United States)

Morgenstern, R.; Dietrich, D.; Sieber, M.; Lampke, T.

2017-03-01

Due to their outstanding specific mechanical properties, high-strength, age-hardenable aluminum alloys offer a high potential for lightweight security-related applications. However, the use of copper-alloyed aluminum is limited because of their susceptibility to selective corrosion and their low wear resistance. These restrictions can be overcome and new applications can be opened up by the generation of protective anodic aluminum oxide layers. In contrast to the anodic oxidation of unalloyed aluminum, oxide layers produced on copper-rich alloys exhibit a significantly more complex pore structure. It is the aim of the investigation to identify the influence of microstructural parameters such as size and distribution of the strengthening precipitations on the coating microstructure. The aluminum alloy EN AW-2024 (AlCu4Mg1) in different heat treatment conditions serves as substrate material. The influence of the strengthening precipitations’ size and distribution on the development of the pore structure is investigated by the use of high-resolution scanning electron microscopy. Integral coating properties are characterized by non-destructive and light-microscopic thickness measurements and instrumented indentation tests.

Studies on the sedimentation and agglomeration behavior of Al-Ti-B and Al-Ti-C grain refiners

Energy Technology Data Exchange (ETDEWEB)

Gazanion, F.; Chen, X.G.; Dupuis, C. [Alcan International Ltd., Jonquiere, PQ (Canada). Arvida Research and Development Centre

2002-07-01

The sedimentation and agglomeration behavior of Al-Ti-B and Al-Ti-C grain refiners in liquid aluminum has been investigated using the LiMCA and PoDFA analysis techniques in combination with metallographic examination. The widely used Al-5%Ti-1%B and Al-3%Ti-0.15%C master alloys were chosen. Two aluminum alloys, an AAlxxx (commercially pure metal) and an AA5182 (Al-4.5%Mg) alloy, were prepared with different additions of grain refiners. The difference in particle behavior in liquid aluminum for both refiners is described and briefly analyzed in terms of sensitivity to agglomeration and grain refiner performance. Experimental results indicate that, in comparison with the Al-Ti-B refiner, the Al-Ti-C refiner is detrimentally affected by long holding periods due to the decomposition of TiC particles within the melt. (orig.)

Strength of Al and Al-Mg/alumina bonds prepared using ultrahigh vacuum diffusion bonding

International Nuclear Information System (INIS)

King, W.E.; Campbell, G.H.; Wien, W.L.; Stoner, S.L.

1994-01-01

The authors have measured the cross-breaking strength of Al and Al-Mg alloys bonded with alumina. Diffusion bonding of Al and Al-Mg alloys requires significantly more bonding time than previously thought to obtain complete bonding. In contrast to previous diffusion bonding studies, fracture morphologies are similar to those obtained in bonds formed by liquid phase reaction; i.e., bonds are as strong or stronger than the ceramic; and fracture tends to propagate in the metal for pure Al and near the interface in the ceramic for the alloys. There are indications that the fracture morphology depends on Mg content and therefore on plasticity in the metal

Microstructural and mechanical properties of Al-Mg/Al{sub 2}O{sub 3} nanocomposite prepared by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Safari, J., E-mail: safari.jam@gmail.com [Department of Material Science and Engineering, Shahid Bahonar University of Kerman, P.O. Box No. 76135-133, Kerman (Iran, Islamic Republic of); Akbari, G.H. [Department of Material Science and Engineering, Shahid Bahonar University of Kerman, P.O. Box No. 76135-133, Kerman (Iran, Islamic Republic of); Research Center for Mineral Industries, Shahid Bahonar University of Kerman, P.O. Box No. 76135-133, Kerman (Iran, Islamic Republic of); Shahbazkhan, A. [Islamic Azad University, Saveh Branch, Saveh (Iran, Islamic Republic of); Delshad Chermahini, M. [Materials and Energy Research Center, Karaj (Iran, Islamic Republic of)

2011-09-29

Highlights: > The presence of Mg has remarkable effects on crystallite size and lattice strain. > The solution of Mg in the Al matrix accelerates the mechanical milling stages. > The microhardness increased in the presence of Mg. > The presence of Mg has significant effect on lattice parameter. > Steady-state situation was occurred in presence of Mg. - Abstract: The effect of milling time on the microstructure and mechanical properties of Al and Al-10 wt.% Mg matrix nanocomposites reinforced with 5 wt.% Al{sub 2}O{sub 3} during mechanical alloying was investigated. Steady-state situation was occurred in Al-10Mg/5Al{sub 2}O{sub 3} nanocomposite after 20 h, due to solution of Mg into Al matrix, while the situation was not observed in Al/5Al{sub 2}O{sub 3} nanocomposite at the same time. For the binary Al-Mg matrix, after 10 h, the predominant phase was an Al-Mg solid solution with an average crystallite size 34 nm. Up to 10 h, the lattice strain increased to about 0.4 and 0.66% for Al and Al-Mg matrix, respectively. The increasing of lattice parameter due to dissolution of Mg atom into Al lattice during milling was significant. By milling for 10 h the dramatic increase in microhardness (155 HV) for Al-Mg matrix nanocomposite was caused by grain refinement and solid solution formation. From 10 to 20 h, slower rate of increasing in microhardness may be attributed to the completion of alloying process, and dynamic and static recovery of powders.

Cu-segregation at the Q'/α-Al interface in Al-Mg-Si-Cu alloy

International Nuclear Information System (INIS)

Matsuda, Kenji; Teguri, Daisuke; Uetani, Yasuhiro; Sato, Tatsuo; Ikeno, Susumu

2002-01-01

Cu segregation was detected at the Q ' /α-Al interface in an Al-Mg-Si-Cu alloy by energy-filtered transmission electron microscopy. By contrast, in a Cu-free Al-Mg-Si alloy no segregation was observed at the interface between the matrix and Type-C precipitate

Melt quality induced failure of electrical conductor (EC grade aluminum wires

Directory of Open Access Journals (Sweden)

Khaliq A.

2017-01-01

Full Text Available The failure of electrical conductor grade (EC aluminum during wire drawing process was investigated. The fractured aluminum wires were subjected to Scanning Electron Microscopy (SEM and Energy Dispersive X-ray (EDX analyses for an initial examination. Thermodynamic analyses of molten aluminum interaction with refractories was also carried out using FactSage at 710°C to predict the stable phases. The SEM/EDX analyses has revealed the inclusions in aluminum matrix. The typical inclusions observed were Al2O3, Al3C4 (Al-Carbide and oxides of refractories elements (Al, Mg, Si and O that have particle size ranging up to 5 μm. The transition metal boride particles were not identified during SEM/EDX analyses these might be too fine to be detected with this microscope. The overall investigation suggested that the possible cause of this failure is second phase particles presence as inclusions in the aluminum matrix, and this was associated with the poor quality of melt. During wire drawing process, these inclusions were pulled out of the aluminum matrix by the wiredrawing forces to produce micro-voids which led to ductile tearing and final fracture of wires. It was recommended to use ceramic foam filters to segregate inclusions from molten aluminum.

A background subtraction routine for enhancing energy-filtered plasmon images of MgAl2O4 implanted with Al+ and Mg+ ions

International Nuclear Information System (INIS)

Evans, N.D.; Kenik, E.A.; Bentley, J.; Zinkle, S.J.

1995-01-01

MgAl 2 O 4 , a candidate fusion reactor material, was irradiated with Al + or Mg + ions; electron energy-loss spectra and energy-filtered plasmon images showed that metallic Al colloids are present in the ion-irradiated regions. This paper shows the subtraction of the spinel plasmon component in images using 15-eV-loss electrons in some detail

The determination of aluminum, copper, iron, and lead in glycol formulations by atomic absorption spectroscopy

Science.gov (United States)

1977-01-01

Initial screening tests and the results obtained in developing procedures to determine Al, Cu, Fe, and Pb in glycol formulations are described. Atomic absorption completion was selected for Cu, Fe and Pb, and after comparison with emission spectroscopy, was selected for Al also. Before completion, carbon, iron, and lead are extracted with diethyl dithio carbamate (DDC) into methyl isobutyl ketone (MIBK). Aluminum was also extracted into MIBK using 8-hydroxyquinoline as a chelating agent. As little as 0.02 mg/l carbon and 0.06 mg/l lead or iron may be determined in glycol formulations. As little as 0.3 mg/l aluminum may be determined.

Low-energy resonances in sup 25 Mg(p,. gamma. ) sup 26 Al, sup 26 Mg(p,. gamma. ) sup 27 Al and sup 27 Al(p,. gamma. ) sup 28 Si

Energy Technology Data Exchange (ETDEWEB)

Iliadis, C; Schange, T; Rolfs, C; Schroeder, U; Somorjai, E; Trautvetter, H P; Wolke, K [Muenster Univ. (Germany, F.R.). Inst. fuer Kernphysik; Endt, P M; Kikstra, S W [Rijksuniversiteit Utrecht (Netherlands). Robert van de Graaff Lab.; Champagne, A E [Princeton Univ., NJ (USA). Dept. of Physics; Arnould, M; Paulus, G [Universite Libre de Bruxelles (Belgium). Inst. d' Astronomie et d' Astrophysique

1990-06-11

Gamma-ray decay schemes have been measured with bare and Compton-suppressed Ge detectors at low-energy resonances (E{sub p}<340 keV) in the (p, {gamma}) reactions on {sup 25}Mg, {sup 26}Mg and {sup 27}Al. Althogether 58 new decay branches have been observed and a new {sup 26}Mg(p, {gamma}){sup 27}Al resonance has been found at E{sub p}=154.5{plus minus}1.0 keV. The new branchings lead to J{sup {pi}}; T determinations (or limitations) for two states in {sup 26}Al and four states in {sup 28}Si. The absolute strengths of the {sup 25}Mg(p, {gamma}){sup 26}Al and {sup 26}Mg(p, {gamma}){sup 27}Al resonances have also been obtained, and the uncertainties of the stellar rates, deduced from the available data for both reactions, are significantly reduced. Some astrophysical consequences are discussed. (orig.).

Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

International Nuclear Information System (INIS)

Qin, Gaowu W.; Ren Yuping; Huang Wei; Li Song; Pei Wenli

2010-01-01

Graphical abstract: Display Omitted Research highlights: The ε-AlMn phase acts as the heterogeneous nucleus of α-Mg phase during the solidification of the AZ31 Mg alloy, not the γ-Al 8 Mn 5 phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure ε-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 o C. - Abstract: The effect of manganese on grain refinement of Al-containing AZ31 Mg alloy has been investigated by designing a series of Mn-Al alloys composed of either pure ε-AlMn, γ 2 -Al 8 Mn 5 or both of them using optical microscopy and X-ray diffraction. It is experimentally clarified that the grain refinement of the AZ31 Mg alloy is due to the existence of the ε-AlMn phase in the Mn-Al alloys, not the γ 2 -Al 8 Mn 5 phase. The grain size of AZ31 Mg alloy is about 91 μm without any addition of Mn-Al alloys, but remarkably decreases to ∼55 μm with the addition of either Mn-34 wt% Al or Mn-28 wt% Al. With a minor addition of 0.5 wt% Mn-28Al alloy, the grain size of AZ31 alloy decreases to ∼53 μm, and the Mn-28Al alloy can be active as grain refiner for holding time up to 60 min for the melt AZ31 alloy at 750 o C.

Multinuclear solid-state high-resolution and C-13 -{Al-27} double-resonance magic-angle spinning NMR studies on aluminum alkoxides

NARCIS (Netherlands)

Abraham, A.; Prins, R.; Bokhoven, J.A. van; Eck, E.R.H. van; Kentgens, A.P.M.

2006-01-01

A combination of Al-27 magic-angle spinning (MAS)/multiple quantum (MQ)-MAS, C-13-H-1 CPMAS, and C-13-{Al-27} transfer of population in double-resonance (TRAPDOR) nuclear magnetic resonance (NMR) were used for the structural elucidation of the aluminum alkoxides aluminum ethoxide, aluminum

Efficient KF loaded on MgCaAl hydrotalcite-like compounds in the transesterification of Jatropha curcas oil

International Nuclear Information System (INIS)

Guzmán-Vargas, Ariel; Santos-Gutiérrez, Teresa; Lima, Enrique; Flores-Moreno, Jorge L.; Oliver-Tolentino, Miguel A.; Martínez-Ortiz, María de J.

2015-01-01

Highlights: • MgCaAl hydrotalcite-like compounds were synthetized. • After KF impregnation and calcination fluorinated species were detected. • Fluorinated species were stables and actives. • LDH composition and KF load effect were evaluated in biodiesel production. - Abstract: In this work a series of MgCaAl hydrotalcite-like compounds were synthetized by coprecipitation method at constant pH. In order to obtain the catalysts, the samples were modified with KF by incipient wetness impregnation at different wt%, after that, they were dried and calcined to obtain the mixed oxides. The effect of divalent cations ratio and KF load were studied in the transesterification reaction of Jatropha curcas oil to obtain biodiesel employing an inedible oil. XRD analysis showed typical diffraction patterns of LDH, by nitrogen physisorption the LDH mesoporous structure was also confirmed, 27 Al NMR spectra showed bands at 10 and 88 ppm attributed to the Al coordination before and after thermal treatment. While for the impregnated samples after calcination the profiles exhibited the mixed oxide formation, in addition, another peaks appeared associated to the formation of various fluorinated species as shown by XRD, additionally, 19 F NMR showed a main signal at −180 ppm indicating the presence of active tetrahedral aluminum fluoride species. The reaction evolution was monitoring calculating the oil conversion to biodiesel by integration of the signal spectra using 1 H NMR spectroscopy. The results of catalytic tests in transesterification reaction showed a direct correlation between Mg/Ca ratio and KF content in the oil conversion to biodiesel, the higher conversion was achieved (90%) when Mg/Ca = 1 and KF load was 30 wt%

Efficient KF loaded on MgCaAl hydrotalcite-like compounds in the transesterification of Jatropha curcas oil

Energy Technology Data Exchange (ETDEWEB)

Guzmán-Vargas, Ariel, E-mail: aguzmanv@ipn.mx [ESIQIE-IPN, Departamento de Ingeniería Química, Laboratorio de Investigación en Materiales Porosos, Catálisis Ambiental y Química Fina, UPALM Edif.7 P.B. Zacatenco, México D.F. 07738 (Mexico); Santos-Gutiérrez, Teresa [ESIQIE-IPN, Departamento de Ingeniería Química, Laboratorio de Investigación en Materiales Porosos, Catálisis Ambiental y Química Fina, UPALM Edif.7 P.B. Zacatenco, México D.F. 07738 (Mexico); Lima, Enrique [IIM-Universidad Nacional Autónoma de México, Circuito exterior s/n, Cd. Universitaria, 04510 México DF (Mexico); Flores-Moreno, Jorge L. [UAM-Azcapotzalco, Área de Química de Materiales, Av. San Pablo 180, Col. Reynosa Tamaulipas, 02200 México DF (Mexico); Oliver-Tolentino, Miguel A.; Martínez-Ortiz, María de J. [ESIQIE-IPN, Departamento de Ingeniería Química, Laboratorio de Investigación en Materiales Porosos, Catálisis Ambiental y Química Fina, UPALM Edif.7 P.B. Zacatenco, México D.F. 07738 (Mexico)

2015-09-15

Highlights: • MgCaAl hydrotalcite-like compounds were synthetized. • After KF impregnation and calcination fluorinated species were detected. • Fluorinated species were stables and actives. • LDH composition and KF load effect were evaluated in biodiesel production. - Abstract: In this work a series of MgCaAl hydrotalcite-like compounds were synthetized by coprecipitation method at constant pH. In order to obtain the catalysts, the samples were modified with KF by incipient wetness impregnation at different wt%, after that, they were dried and calcined to obtain the mixed oxides. The effect of divalent cations ratio and KF load were studied in the transesterification reaction of Jatropha curcas oil to obtain biodiesel employing an inedible oil. XRD analysis showed typical diffraction patterns of LDH, by nitrogen physisorption the LDH mesoporous structure was also confirmed, {sup 27}Al NMR spectra showed bands at 10 and 88 ppm attributed to the Al coordination before and after thermal treatment. While for the impregnated samples after calcination the profiles exhibited the mixed oxide formation, in addition, another peaks appeared associated to the formation of various fluorinated species as shown by XRD, additionally, {sup 19}F NMR showed a main signal at −180 ppm indicating the presence of active tetrahedral aluminum fluoride species. The reaction evolution was monitoring calculating the oil conversion to biodiesel by integration of the signal spectra using {sup 1}H NMR spectroscopy. The results of catalytic tests in transesterification reaction showed a direct correlation between Mg/Ca ratio and KF content in the oil conversion to biodiesel, the higher conversion was achieved (90%) when Mg/Ca = 1 and KF load was 30 wt%.

Single-crystalline MgAl2O4 spinel nanotubes using a reactive and removable MgO nanowire template

International Nuclear Information System (INIS)

Fan Hongjin; Knez, Mato; Scholz, Roland; Nielsch, Kornelius; Pippel, Eckhard; Hesse, Dietrich; Goesele, Ulrich; Zacharias, Margit

2006-01-01

Using MgO nanowires as a reactive template, we fabricated for the first time single-crystal MgAl 2 O 4 spinel nanotubes through an interfacial solid-state reaction of MgO-Al 2 O 3 core-shell nanowires. Single-crystal MgO nanowires are coated with a conformal thin layer of amorphous Al 2 O 3 via atomic layer deposition. Subsequent annealing at 700 deg. C activates the interfacial reaction between MgO and Al 2 O 3 , transforming the alumina shell into a spinel shell. Finally, after etching away the remaining MgO core in ammonia sulfuric solution, MgAl 2 O 4 spinel nanotubes are obtained. As a transition from conventional planar spinel layers via thin-film interface reactions, our result might open a window for the fabrication of a wide variety of MgO-based spinel one-dimensional nanostructures

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. ...

Investigation of the Precipitation Behavior in Aluminum Based Alloys

KAUST Repository

Khushaim, Muna S.

2015-11-30

ternary Al-Li-Cu alloys. Atom probe tomography and statistical testing are combined to investigate the fine scale segregation effects of dilute solutes in aluminum alloys. The optimum application of atom probe tomography in a wide range of materials is enabled by the integration of a laser pulse mode in the atom probe analysis. However, the nature of the laser mechanism used during atom probe tomography analyses is still debated. Systematic investigation of the microstructural change of δ′(Al3Li) precipitates influenced by different pulsed laser energies are used to describe the important phenome associated with the laser pulse mode. In this study, atom probe tomography presented a series of snapshots during in-situ reversion of ′(Al3Li) precipitates, initiated by laser irradiation, using different laser energies for the first time. An estimation method to investigate real sample temperatures during laser-APT analyses using an interface reaction itself as a probe has been proposed. Finally, the considerable potential of aluminum liquid is demonstrated as a powerful synthesis solvent of important intermetallic phases such as: Mg2Si, Al2Mg and CaMgSi .The atom probe tomography technique is utilized to characterize the intermediate reaction steps of the flux-grown intermetallic phases. The study proposed a direct approach to investigate the involved reactions during the formation of the synthesized intermetallic phase.

Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

Energy Technology Data Exchange (ETDEWEB)

Qin, Gaowu W., E-mail: qingw@smm.neu.edu.c [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Wenhu Road 3-11, Heping District, Shenyang 110004, Liaoning Province (China); Ren Yuping; Huang Wei; Li Song; Pei Wenli [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Wenhu Road 3-11, Heping District, Shenyang 110004, Liaoning Province (China)

2010-10-08

Graphical abstract: Display Omitted Research highlights: The {epsilon}-AlMn phase acts as the heterogeneous nucleus of {alpha}-Mg phase during the solidification of the AZ31 Mg alloy, not the {gamma}-Al{sub 8}Mn{sub 5} phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure {epsilon}-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 {sup o}C. - Abstract: The effect of manganese on grain refinement of Al-containing AZ31 Mg alloy has been investigated by designing a series of Mn-Al alloys composed of either pure {epsilon}-AlMn, {gamma}{sub 2}-Al{sub 8}Mn{sub 5} or both of them using optical microscopy and X-ray diffraction. It is experimentally clarified that the grain refinement of the AZ31 Mg alloy is due to the existence of the {epsilon}-AlMn phase in the Mn-Al alloys, not the {gamma}{sub 2}-Al{sub 8}Mn{sub 5} phase. The grain size of AZ31 Mg alloy is about 91 {mu}m without any addition of Mn-Al alloys, but remarkably decreases to {approx}55 {mu}m with the addition of either Mn-34 wt% Al or Mn-28 wt% Al. With a minor addition of 0.5 wt% Mn-28Al alloy, the grain size of AZ31 alloy decreases to {approx}53 {mu}m, and the Mn-28Al alloy can be active as grain refiner for holding time up to 60 min for the melt AZ31 alloy at 750 {sup o}C.

Dynamic behavior of reactive aluminum nanoparticle-fluorinated acrylic (AlFA) polymer composites

Science.gov (United States)

Crouse, Christopher A.; White, Brad; Spowart, Jonathan E.

2011-06-01

The dynamic behavior of aluminum nanoparticle-fluorinated acrylic (AlFA) composite materials has been explored under high strain rates. Cylindrical pellets of the AlFA composite materials were mounted onto copper sabots and impacted against a rigid anvil at velocities between 100 and 400 m/s utilizing a Taylor gas gun apparatus to achieve strain rates on the order of 104 /s. A framing camera was used to record the compaction and reaction events that occurred upon contact of the pellet with the anvil. Under both open air and vacuum environments the AlFA composites demonstrated high reactivity suggesting that the particles are primarily reacting with the fluorinated matrix. We hypothesize, based upon the compaction history of these materials, that reaction is initiated when the oxide shells on the aluminum nanoparticles are broken due an interparticle contact deformation process. We have investigated this hypothesis through altering the particle loading in the AlFA composites as well as impact velocities. This data and the corresponding trends will be presented in detail.

Determining casting defects in near-net shape casting aluminum parts by computed tomography

Science.gov (United States)

Li, Jiehua; Oberdorfer, Bernd; Habe, Daniel; Schumacher, Peter

2018-03-01

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.

Influence of Substrates on the Electrochemical Deposition and Dissolution of Aluminum in NaAlCl4 Melts

DEFF Research Database (Denmark)

Li, Qingfeng; Hjuler, Hans Aage; Berg, Rolf W.

1991-01-01

The deposition and dissolution of aluminum in NaAlCl4 melts saturated with NaCl have been investigated by voltammetryand potentiometry for different electrode materials at 175°C. The tungsten and glassy carbon electrodes are shownto be electrochemically inert in the melts, whereas copper is elect......The deposition and dissolution of aluminum in NaAlCl4 melts saturated with NaCl have been investigated by voltammetryand potentiometry for different electrode materials at 175°C. The tungsten and glassy carbon electrodes are shownto be electrochemically inert in the melts, whereas copper...... is electrochemically active; it dissolves into the melts at a lowanodic potential. On a nickel substrate, nickel dichloride will be formed at a potential of ca. 1.0 V vs. an aluminum referenceelectrode. The reversibility (of deposition and dissolution of aluminum) is found to be strongly affected by currentdensity...... investigated. Nickel and, to some extent,tungsten electrodes proved to be appropriate as working anodes in the Al/NaCl-AlCl3/Ni battery system....

Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment

OpenAIRE

He Kezhun; Yu Fuxiao; Zhao Dazhi

2011-01-01

Heat treatment has important influence on the microstructure and mechanical properties of Al-Si alloys. The most common used heat treatment method for these alloys is solution treatment followed by age-hardening. This paper investigates the microstructural evolution of a direct chill (DC) cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy after solution treated at 500, 510, 520 and 530℃, respectively for different times. The major phases observed in the as-cast alloy are α-aluminum dendrite, primary Si p...

Investigation of blue luminescence in Mg doped AlN films

Energy Technology Data Exchange (ETDEWEB)

Sun, Xiliang; Xiong, Juan, E-mail: xiongjuana@163.com; Zhang, Weihai; Liu, Lei; Gu, Haoshuang, E-mail: guhsh@hubu.edu.cn

2015-02-05

Highlights: • AlN films doped with 0.8–4.4 at.% Mg were deposited by magnetron sputtering. • Structural and photoluminescence properties of Mg-doped AlN films were synthesized in detailed. • A broad blue band centered at 420 nm and 440 nm was observed in Mg-doped AlN films. • An enhancement of A1 (TO) mod and a slightly blue-shift of E2 (high) mode were observed. - Abstract: The Al{sub 1−x}Mg{sub x}N thin films were deposited on (1 0 0) silicon substrates by magnetron sputtering. The structural and photoluminescence properties of the films with varying Mg concentrations were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectra and photoluminescence (PL), respectively. The results clearly showed that the Mg atoms successfully incorporated into AlN, while the crystal structure of the films was maintained. The Raman spectra of Al{sub 1−x}Mg{sub x}N films reveals the enhancement of A{sub 1} (TO) mode, a slightly blue-shift and an augment in FWHM for E{sub 2} (high) phonon mode with increasing Mg content, which can be associated with the deterioration of (0 0 2) orientation and the appearance of (1 0 0) orientation. A broad blue band centered at 420 nm and 440 nm was observed in Mg-doped AlN films. It was suggested that the transitions from the shallow donor level not only to the ground state but also to the excited states of the deep level was responsible for the broad blue emission band. This work indicates the AlN film for the application in lighting emission devices.

Kinetic studies of oxidation of MgAlON and a comparison of the oxidation behaviour of AlON, MgAlON, O'SiAlON-ZrO{sub 2}, and BN-ZCM ceramics

Energy Technology Data Exchange (ETDEWEB)

Wang Xidong; Seetharaman, S. [Div. of Metallurgy, Royal Inst. of Tech., Stockholm (Sweden); Li Wenchao [Dept. of Physical Chemistry, Univ. of Science and Technology Beijing (USTB), Beijing, BJ (China)

2002-06-01

The kinetics and morphology of the oxidation process of magnesium-aluminium oxynitride (MgAlON), aluminium oxynitride (AlON), O'SiAlON-ZrO{sub 2}, and BN-ZCM have been studied in the temperature range 1373-1773 K (ZCM=30 wt% ZrO{sub 2}, 52 wt% Al{sub 2}O{sub 3} and 18 wt% 3 Al{sub 2}O{sub 3}.2 SiO{sub 2}). Oxidation experiments with powder and plate samples of the above materials have been carried out in air. MgAlON shows the best resistance to oxidation at lower temperatures (< 1473 K), whereas at higher temperatures ({proportional_to} 773 K), AlON shows the best resistance. O'SiAlON-ZrO{sub 2} shows very good oxidation resistance up to 1673 K. But its oxidation rate increases strongly above 1673 K, presumably due to the formation of liquid phase. BN-ZCM has the poorest oxidation resistance due to the evaporation of B{sub 2}O{sub 3}. The activation energies for the chemical oxidation reaction of AlON, MgAlON, and O'SiAlON-ZrO{sub 2} are 214, 330 and 260 kJ/mol, respectively. The overall diffusion activation energies for AlON, MgAlON, O'SiAlON-ZrO{sub 2} and BN-ZCM are 227, 573, 367 and 289 kJ/mol, respectively. (orig.)

First-principles investigation of the structure and synergistic chemical bonding of Ag and Mg at the Al | Ω interface in a Al-Cu-Mg-Ag alloy

International Nuclear Information System (INIS)

Sun Lipeng; Irving, Douglas L.; Zikry, Mohammed A.; Brenner, D.W.

2009-01-01

Density functional theory was used to characterize the atomic structure and bonding of the Al | Ω interface in a Al-Cu-Mg-Ag alloy. The most stable interfacial structure was found to be connected by Al-Al bonds with a hexagonal Al lattice on the surface of the Ω phase sitting on the vacant hollow sites of the Al {1 1 1} matrix plane. The calculations predict that when substituted separately for Al at this interface, Ag and Mg do not enhance the interface stability through chemical bonding. Combining Ag and Mg, however, was found to chemically stabilize this interface, with the lowest-energy structure examined being a bi-layer with Ag atoms adjacent to the Al matrix and Mg adjacent to the Ω phase. This study provides an atomic arrangement for the interfacial bi-layer observed experimentally in this alloy.

Reducing Mg acceptor activation-energy in Al(0.83)Ga(0.17)N disorder alloy substituted by nanoscale (AlN)₅/(GaN)₁ superlattice using Mg(Ga) δ-doping: Mg local-structure effect.

Science.gov (United States)

Zhong, Hong-xia; Shi, Jun-jie; Zhang, Min; Jiang, Xin-he; Huang, Pu; Ding, Yi-min

2014-10-23

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al(0.83)Ga(0.17)N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al(0.83)Ga(0.17)N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 10(19) cm(-3) can be obtained in (AlN)5/(GaN)1 SL by Mg(Ga) δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

Reducing Mg Acceptor Activation-Energy in Al0.83Ga0.17N Disorder Alloy Substituted by Nanoscale (AlN)5/(GaN)1 Superlattice Using MgGa δ-Doping: Mg Local-Structure Effect

Science.gov (United States)

Zhong, Hong-Xia; Shi, Jun-Jie; Zhang, Min; Jiang, Xin-He; Huang, Pu; Ding, Yi-Min

2014-10-01

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al0.83Ga0.17N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al0.83Ga0.17N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 1019 cm-3 can be obtained in (AlN)5/(GaN)1 SL by MgGa δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

Bioinspired, Graphene/Al2O3 Doubly Reinforced Aluminum Composites with High Strength and Toughness.

Science.gov (United States)

Zhang, Yunya; Li, Xiaodong

2017-11-08

Nacre, commonly referred to as nature's armor, has served as a blueprint for engineering stronger and tougher bioinspired materials. Nature organizes a brick-and-mortar-like architecture in nacre, with hard bricks of aragonite sandwiched with soft biopolymer layers. However, cloning nacre's entire reinforcing mechanisms in engineered materials remains a challenge. In this study, we employed hybrid graphene/Al 2 O 3 platelets with surface nanointerlocks as hard bricks for primary load bearer and mechanical interlocking, along with aluminum laminates as soft mortar for load distribution and energy dissipation, to replicate nacre's architecture and reinforcing effects in aluminum composites. Compared with aluminum, the bioinspired, graphene/Al 2 O 3 doubly reinforced aluminum composite demonstrated an exceptional, joint improvement in hardness (210%), strength (223%), stiffness (78%), and toughness (30%), which are even superior over nacre. This design strategy and model material system should guide the synthesis of bioinspired materials to achieve exceptionally high strength and toughness.

Characterization of microstructure and mechanical properties of friction stir welded AlMg5- Al_2O_3 nanocomposites

International Nuclear Information System (INIS)

Babu, N. Kishore; Kallip, Kaspar; Leparoux, Marc; AlOgab, Khaled A.; Reddy, G.M.; Talari, M.K.

2016-01-01

In the present study, powder metallurgy processed unmilled AlMg5, milled AlMg5 and milled AlMg5-0.5 vol% Al_2O_3 nanocomposite have been successfully friction stir welded (FSW). The effect of friction stir welding on the evolution of weld microstructures; hardness and tensile properties were studied and discussed in detail. FSW of unmilled AlMg5 resulted in significant grain refinement and strain hardening in the nugget zone induced by the thermo-mechanical processing, thereby increasing the stir zone hardness and tensile strengths to 100 HV and 324 MPa when compared to 80 HV and 300 MPa of base metal, respectively. In contrast, the FSW of milled AlMg5 and milled AlMg5-0.5 vol% Al_2O_3 samples showed a reduction in UTS values to 375 MPa and 401 MPa in the stir zone compared to 401 MPa and 483 MPa of respective base metal values. Transmission electron microscopic (TEM) investigation of weld stir zones revealed the homogenous distribution of Al_4C_3 nanophases in milled AlMg5 and Al_2O_3 nanoparticles in milled AlMg5-0.5 vol% Al_2O_3 samples throughout the aluminium matrix. It was revealed that the pre-stored energy from the prior ball milling and hot pressing processes, higher deformation energy and grain boundary pinning effect due to the presence of reinforcement particles has resulted in a higher recrystallization tendency and retarded grain growth during FSW of milled samples. The welds prepared with milled AlMg5-0.5 vol% Al_2O_3 exhibited higher hardness and tensile strength in the stir zone when compared to all other conditions which was attributed to Hall Petch effect due to fine grain size and Orowan strengthening effect due to Al_2O_3 reinforcements.

Friction stir processing of an aluminum-magnesium alloy with pre-placing elemental titanium powder: In-situ formation of an Al{sub 3}Ti-reinforced nanocomposite and materials characterization

Energy Technology Data Exchange (ETDEWEB)

Khodabakhshi, F., E-mail: farzadkhodabakhshi83@gmail.com [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Boulevard, Shiraz (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Kokabi, A.H. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Gerlich, A.P. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON (Canada)

2015-10-15

A fine-grained Al–Mg/Al{sub 3}Ti nanocomposite was fabricated by friction stir processing (FSP) of an aluminum-magnesium (AA5052) alloy with pre-placed titanium powder in the stirred zone. Microstructural evolutions and formation of intermetallic phases were analyzed by optical and electron microscopic techniques across the thickness section of the processed sheets. The microstructure of the nanocomposite consisted of a fine-grained aluminum matrix (1.5 µm), un-reacted titanium particles (<40 µm) and reinforcement particles of Al{sub 3}Ti (<100 nm) and Mg{sub 2}Si (<100 nm). Detailed microstructural analysis indicated solid-state interfacial reactions between the aluminum matrix and micro-sized titanium particles to form Al{sub 3}Ti intermetallic phase. The hard inclusions were then fractured and re-distributed in the metal matrix by the severe thermo-mechanical conditions imposed by FSP. Evaluation of mechanical properties by hardness measurement and uniaxial tensile test determined significant enhancement in the mechanical strength (by 2.5 order of magnetite) with a high ductility (~22%). Based on a dislocation-based model analysis, it was suggested that the strength enhancement was governed by grain refinement and the presence of hard inclusions (4 vol%) in the metal matrix. Fractographic studies also showed a ductile-brittle fracture mode for the nanocomposite compared with fully ductile rupture of the annealed alloy as well as the FSPed specimen without pre-placing titanium particles. - Highlights: • FSP was employed to fabricate in situ nanocomposite. • The AA5052 Al alloy with pre-placed micro-sized Ti particles were utilized. • The structural analysis was revealed that the in situ formation of Al{sub 3}Ti nanophase. • The SZ grain structure was refined by PSN and ZHP mechanisms during DRX. • Hardness and tensile strength were improved up to ~2.5 times with a good ductility.

Interface reactions in the Al-Si-SiC and Mg-Al-Al{sub 2}O{sub 3} composite systems

Energy Technology Data Exchange (ETDEWEB)

Johnson, P.K. [Commission of the European Communities, Petten (Netherlands). Inst. for Advanced Materials; Fazal-Ur-Rehman [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials; Fox, S. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials; Flower, H.M. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials; West, D.R.F.

1995-12-31

Structural and compositional observations are reported on the influence of the interfaces on the mechanisms and kinetics of liquid metal-ceramic reactions in Al-SiC, Al-Si-SiC, Mg-Al{sub 2}O{sub 3} and Mg-Al-Al{sub 2}O{sub 3} composites. The aluminium based materials contained up to 20 vol% SiC in particulate form, and were produced by a spray casting process; subsequently the interface reactions were studied in samples heated to temperatures up to 1100 C. The reaction product was Al{sub 4}C{sub 3} in both Al-SiC and Al-Si-SiC composites. The influence of the crystallography and topology of the SiC particle surfaces on the nucleation of the Al{sub 4}C{sub 3} has been demonstrated; surface asperities play an important role. Growth of nuclei proceeds to form continuous reaction product layers which control the subsequent kinetics. The magnesium based composites contained 5 vol% Al{sub 2}O{sub 3} fibres (3 {mu}m in diameter), and were produced by a liquid infiltration process. SD Safimax fibres with relatively low and high porosity, and also RF Saffil fibres, with a silica binder, were investigated. Fibre porosity plays a major role in accelerating the penetration of Mg into the fibres with reaction to form MgO. Silica binder on the fibre surface transforms to MgO. The reaction rate was reduced by the presence of aluminium in the matrix. The factors controlling the reactions in the aluminium and magnesium based composites are compared. (orig.)

Protective effect of ashwagandha (Withania somnifera against neurotoxicity induced by aluminum chloride in rats

Directory of Open Access Journals (Sweden)

Mohamed E Elhadidy

2018-01-01

Full Text Available Objective: To evaluate the neuroprotective effect of ashwagandha extract against aluminum chloride-induced neurotoxicity in rats. Methods: Rats were divided into control, aluminum-intoxicated rats treated daily with aluminum trichloride (AlCl3 (100 mg/kg, orally for 30 d and aluminum-intoxicated animals protected by receiving daily ashwagandha extract (200 mg/kg, orally one hour before AlCl3 administration for 30 d. Levels of lipid peroxidation, nitric oxide, reduced glutathione and tumor necrosis factor-α were measured in the cortex, hippocampus and striatum. In addition, the activities of Na+, K+, ATPase and acetylcholinesterase were determined in the three studied brain regions. Results: Aluminum increased the levels of lipid peroxidation and nitric oxide in the cortex, hippocampus and striatum and decreased the reduced glutathione level in the hippocampus and striatum. In rats protected with ashwagandha extract, non significant changes were observed in lipid peroxidation, nitric oxide and reduced glutathione. In addition, ashwagandha extracts prevented the increased activity of acetylcholinesterase and Na+, K+, ATPase induced by AlCl3 in the cortex, hippocampus and striatum. The present findings also showed that the significant increase in tumor necrosis factor-α induced by AlCl3 in the cortex and hippocampus was prevented by ashwagandha extract. Conclusions: The present results suggest that ashwagandha extract possesses antioxidant and anti-inflammatory effects against aluminum neurotoxicity. In addition, ashwagandha extract could prevent the decline in cholinergic activity by maintaining normal acetylcholinesterase activity. The later effect could recommend the use of ashwagandha as a memory enhancer.

Effect of TiAl_3 on distribution of TiC particles in aluminum matrix and nucleation of α(Al) grain%TiAl_3对TiC粒子在铝基体中分布及α(Al)晶粒形核的影响

Institute of Scientific and Technical Information of China (English)

夏天东; 丁万武; 赵文军; 王晓军; 徐仰涛

2009-01-01

研究TiC和TiAl_3细化工业纯铝时TiAl_3的存在对TiC在铝基体中分布及α(Al)晶粒形核的影响,分析Al-Ti-C晶粒细化机制.结果表明:TiC单独作为工业纯铝的晶粒细化剂时,大量TiC被α(Al)晶粒推向树枝晶的晶界处,从而限制了TiC的异质形核作用;当TiC和TiAl_3共同作为晶粒细化剂时,在α(Al)晶粒内部出现了大量TiC粒子,大量的TiC粒子成为了α(Al)的结晶核心,并且在TiC颗粒和铝基体的界面处存在"富Ti过渡区";TiAl_3在铝熔体中分解释放出Ti原子并向TiC粒子周围偏聚,形成的"TiC/铝熔体界面富Ti过渡区" 改善了TiC与α(Al)的结构适应性,降低了TiC粒子的表面张力,促进了TiC粒子在铝熔体中的均匀分布,提高了其形核能力.%The effect of TiAl_3 on the distribution of TiC particles in aluminum matrix and nucleation of α(Al) grain was studied when the TiC and TiAl_3 refining industry aluminum, and the nucleation mechanism of Al-Ti-C grain refiner were discussed. The results show that when TiC alone is used as the nucleation phase, most of the TiC is pushed into the grain boundaries by the α(Al) dendrites and the nucleation of TiC is restricted. On the other hand, when TiC and TiAl_3 refine the industry aluminum together, most of the TiC particles are found within the α(Al) grains and nucleation occurs on TiC particles, and there is a Ti transition zone between TiC and aluminum interface. TiAl_3 releases Ti atoms in aluminum melt, Ti atoms congregate to the TiC surface, and ultimately forming TiC/aluminum interface Ti transition zone, which not only improves the structure of adaptability and wettability between TiC and Al , but also reduces the surface tension of TiC particles, which making a lot of TiC particles can be uniformly distributed in the aluminum melt, which advance α(Al) core and heterogeneous nucleation in the aluminum melt solidification.

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 %.

Effects of aluminum on root growth and absorption of nutrients by ...

African Journals Online (AJOL)

Aluminum (Al) is a biotoxic which often influences the absorption of nutrients by plants in strongly acidic soils. In this experiment, the effect of Al on root growth, absorption of macronutrients; phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and micronutrients; iron (Fe), manganese (Mn), copper (Cu) and zinc ...

Effect of Al and Mg Contents on Wettability and Reactivity of Molten Zn-Al-Mg Alloys on Steel Sheets Covered with MnO and SiO2 Layers

Science.gov (United States)

Huh, Joo-Youl; Hwang, Min-Je; Shim, Seung-Woo; Kim, Tae-Chul; Kim, Jong-Sang

2018-05-01

The reactive wetting behaviors of molten Zn-Al-Mg alloys on MnO- and amorphous (a-) SiO2-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at 460 °C and the variation in the contact angles (θc) of alloys containing 0.2-2.5 wt% Al and 0-3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the a-SiO2-covered steel exhibited nonreactive, nonwetting (θc > 90°) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the a-SiO2 layer were found to be sluggish, the wettability of Zn-Al-Mg alloys on the a-SiO2 layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and SiO2, with Zn-Al-Mg alloys could be most effectively improved by increasing the Mg content of the alloys.

The effect of metallic oxide deposition on the electrochemical behaviour of Al-Zn-Mg-Sn alloy in natural tropical seawater

Science.gov (United States)

Din Yati, M. S.; Nazree Derman, Mohd; Isa, M. C.; Y Ahmad, M.; Yusoff, N. H. N.; Muhammad, M. M.; Nain, H.

2014-06-01

The potential of aluminium alloys as anode materials in cathodic protection system has been explored and a significant improvement has been achieved. However, for marine application, it is quite difficult to maintain continuous activation process due to passivation behavior of aluminum alloys. Therefore, to choose the best activation mechanism for aluminium alloy in marine environment, it has to be considered from various points such as alloy composition and surface treatment. This paper report the effect of metallic ruthenium oxide (RuO2) deposition on the surface of as-cast Al-Zn-Mg-Sn alloy and to study the effect of its presence on the electrochemical behavior using direct current (DC) electrochemical polarization and current capacity measurement. The morphology and topography of corroded surface were studied by the aid of scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM) respectively. Results from this study showed that the presence of intermetallic compound (Mg2Sn) and also mixed metal oxide compound (Al2O3 and RuO2) on the alloy surface has been very useful in improving electrochemical reaction and charge transfer activities in chloride containing solution. This study also showed that RuO2 catalytic coating applied on the surface of Al-Zn-Mg-Sn alloy has slightly increased the corrosion current density compared to Al-Zn-Mg-Sn without RuO2. The corrosion morphology and topography of corroded surface of Al-Zn-Mg-Sn alloy deposited with RuO2 was found more uniform corrosion attack with the formation of porous and fibrous mud-like crack on outer layer. Based on surface morphology and 3D topographic studies, these features were believed to facilitate ionic species adsorption and diffusion through corrosion product layer at solution-alloy interface. Deposited RuO2 films also was found to increase of current efficiency by more than 10%.

Neural network potential for Al-Mg-Si alloys

Science.gov (United States)

Kobayashi, Ryo; Giofré, Daniele; Junge, Till; Ceriotti, Michele; Curtin, William A.

2017-10-01

The 6000 series Al alloys, which include a few percent of Mg and Si, are important in automotive and aviation industries because of their low weight, as compared to steels, and the fact their strength can be greatly improved through engineered precipitation. To enable atomistic-level simulations of both the processing and performance of this important alloy system, a neural network (NN) potential for the ternary Al-Mg-Si has been created. Training of the NN uses an extensive database of properties computed using first-principles density functional theory, including complex precipitate phases in this alloy. The NN potential accurately reproduces most of the pure Al properties relevant to the mechanical behavior as well as heat of solution, solute-solute, and solute-vacancy interaction energies, and formation energies of small solute clusters and precipitates that are required for modeling the early stage of precipitation and mechanical strengthening. This success not only enables future detailed studies of Al-Mg-Si but also highlights the ability of NN methods to generate useful potentials in complex alloy systems.

Sorption of phosphates and thiocyanates on isomorphic substituted Mg/Zn–Al-type hydrotalcites

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RODICA PODE

2008-08-01

Full Text Available The sorption equilibriums of phosphate and thiocyanate anions on isomorphic substituted Mg/Zn–Al-type hydrotalcites were investigated in this study. Langmuir and Freundlich isotherms were used to interpret the equilibrium data for phosphate. The sorption equilibriums of phosphate on Mg3Al, Mg2ZnAl and Mg1.5Zn1.5Al hydrotalcites were well described by the Langmuir isotherm. The highest maximum sorption capacities for these adsorbents were as follows: 111, 101 and 95 mg g-1. The equilibrium constant and standard Gibbs energy changes were also calculated from the sorption data. Standard Gibbs energy changes of about –20 kJ mol-1 indicated that the process might be considered as physical adsorption. The sorption equilibriums of phosphate on isomorphic substituted samples of MgZn2Al and Zn3Al were well described by the Freundlich isotherm. Thiocyanate showed a relative low affinity for the studied materials, as indicated by both the “S”-shaped isotherms and low sorption capacities. The sorption of phosphate and thiocyanate on the investigated hydrotalcites showed a continuous decrease of the sorption capacity in the following order: Mg3Al > Mg2ZnAl > Mg1.5Zn1.5Al > MgZn2Al > Zn3Al.

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.

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.

Thermomechanical Treatments on High Strength Al-Zn-Mg(-Cu) Alloys

National Research Council Canada - National Science Library

Di Russo, E; Conserva, M; Gatto, F

1974-01-01

An investigation was carried out to determine the metallurgical properties of Al-Zn-Mg and Al-Zn-Mg-Cu alloy products processed according to newly developed Final Thermomechanical Treatments (FTMT) of T-AHA type...

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.

Low oxidation state aluminum-containing cluster anions: Cp{sup ∗}Al{sub n}H{sup −}, n = 1–3

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xinxing; Ganteför, Gerd; Bowen, Kit, E-mail: AKandalam@wcupa.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Eichhorn, Bryan [Department of Chemistry, University of Maryland, College Park, Maryland 20742 (United States); Mayo, Dennis [EOD Technology Division, Naval Surface Warfare Center, Indian Head, Maryland 20640 (United States); Sawyer, William H.; Gill, Ann F.; Kandalam, Anil K., E-mail: AKandalam@wcupa.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University of PA, West Chester, Pennsylvania 19383 (United States); Schnöckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe (Germany)

2016-08-21

Three new, low oxidation state, aluminum-containing cluster anions, Cp*Al{sub n}H{sup −}, n = 1–3, were prepared via reactions between aluminum hydride cluster anions, Al{sub n}H{sub m}{sup −}, and Cp*H ligands. These were characterized by mass spectrometry, anion photoelectron spectroscopy, and density functional theory based calculations. Agreement between the experimentally and theoretically determined vertical detachment energies and adiabatic detachment energies validated the computed geometrical structures. Reactions between aluminum hydride cluster anions and ligands provide a new avenue for discovering low oxidation state, ligated aluminum clusters.

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.

Differentiation and magmatic activity in Vesta evidenced by 26Al-26Mg dating in eucrites and diogenites

Science.gov (United States)

Hublet, G.; Debaille, V.; Wimpenny, J.; Yin, Q.-Z.

2017-12-01

The 26Al-26Mg short-lived chronometer has been widely used for dating ancient objects in studying the early Solar System. Here, we use this chronometer to investigate and refine the geological history of the asteroid 4-Vesta. Ten meteorites widely believed to come from Vesta (4 basaltic eucrites, 3 cumulate eucrites and 3 diogenites) and the unique achondrite Asuka 881394 were selected for this study. All samples were analyzed for their δ26Mg∗ and 27Al/24Mg ratios, in order to construct both whole rock and model whole rock isochrons. Mineral separation was performed on 8 of the HED's in order to obtain internal isochrons. While whole rock Al-Mg analyses of HED's plot on a regression that could be interpreted as a vestan planetary isochron, internal mineral isochrons indicate a more complex history. Crystallization ages obtained from internal 26Al-26Mg systematic in basaltic eucrites show that Vesta's upper crust was formed during a short period of magmatic activity at 2.66-0.58+1.39 million years (Ma) after Calcium-Aluminum inclusions (after CAI). We also suggest that impact metamorphism and subsequent age resetting could have taken place at the surface of Vesta while 26Al was still extant. Cumulate eucrites crystallized progressively from 5.48-0.60+1.56 to >7.25 Ma after CAI. Model ages obtained for both basaltic and cumulate eucrites are similar and suggest that the timing of differentiation of a common eucrite source from a chondritic body can be modeled at 2.88-0.12+0.14 Ma after CAI, i.e. contemporaneously from the onset of the basaltic eucritic crust. Based on their cumulate texture, we suggest cumulate eucrites were likely formed deeper in the crust of Vesta. Diogenites have a more complicated history and their 26Al-26Mg systematics show that they likely formed after the complete decay of 26Al and thus are younger than eucrites. This refined chronology for eucrites and diogenites is consistent with a short magma ocean stage on 4-Vesta from which the

Improving the Elevated-Temperature Properties by Two-Step Heat Treatments in Al-Mn-Mg 3004 Alloys

Science.gov (United States)

Liu, K.; Ma, H.; Chen, X. Grant

2018-05-01

In the present work, two-step heat treatments with preheating at different temperatures (175 °C, 250 °C, and 330 °C) as the first step followed by the peak precipitation treatment (375 °C/48 h) as the second step were performed in Al-Mn-Mg 3004 alloys to study their effects on the formation of dispersoids and the evolution of the elevated-temperature strength and creep resistance. During the two-step heat treatments, the microhardness is gradually increased with increasing time to a plateau after 24 hours when first treated at 250 °C and 330 °C, while there is a minor decrease with time when first treated at 175 °C. Results show that both the yield strength (YS) and creep resistance at 300 °C reach the peak values after the two-step treatment of 250 °C/24 h + 375 °C/48 h. The formation of dispersoids is greatly related to the type and size of pre-existing Mg2Si precipitated during the preheating treatments. It was found that coarse rodlike β ' -Mg2Si strongly promotes the nucleation of dispersoids, while fine needle like β ″-Mg2Si has less influence. Under optimized two-step heat treatment and modified alloying elements, the YS at 300 °C can reach as high as 97 MPa with the minimum creep rate of 2.2 × 10-9 s-1 at 300 °C in Al-Mn-Mg 3004 alloys, enabling them as one of the most promising candidates in lightweight aluminum alloys for elevated-temperature applications.

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.)

Bioleaching of copper, aluminum, magnesium and manganese from ...

African Journals Online (AJOL)

The present study was done to check the bioleaching feasibility of brown shale for the recovery of copper (Cu), aluminum (Al), magnesium (Mg) and manganese (Mn) ions using Ganoderma lucidum. Different experimental parameters were optimized for the enhanced recovery of metals ions. Effect of different substrates like ...

Thermodynamic calculation of Al-Gd and Al-Gd-Mg phase equilibria checked by key experiments

International Nuclear Information System (INIS)

Groebner, J.; Kevorkov, D.; Schmid-Fetzer, R.

2001-01-01

The binary Al-Gd and the ternary Al-Gd-Mg systems were calculated using the Calphad method. It is demonstrated that previous interpretation of ternary liquidus temperatures below 700 C must be related to other phase equilibria. The actual ternary liquidus temperatures are much higher, up to some 600 C above the previous interpretation in literature. They are widely governed by the high-melting compounds Al 2 Gd and Al 3 Gd with liquidus surfaces stretching far into the ternary system. A small number of key experiments in this work confirmed the calculated liquidus temperature and the phase relations. The available experimental data in literature fit excellently with the calculation in the binary Al-Gd system. In the ternary Al-Gd-Mg system, which is shown in several sections of the phase diagram, a good agreement can be observed too, considering the necessary reinterpretation of the liquidus temperatures suggested by Rokhlin et al. Ternary solubilities were not found experimentally. The ternary compound Al 4 GdMg (τ) forms in a ternary peritectic reaction at 761 C. (orig.)

From Powders to Dense Metal Parts: Characterization of a Commercial AlSiMg Alloy Processed through Direct Metal Laser Sintering.

Science.gov (United States)

Manfredi, Diego; Calignano, Flaviana; Krishnan, Manickavasagam; Canali, Riccardo; Ambrosio, Elisa Paola; Atzeni, Eleonora

2013-03-06

In this paper, a characterization of an AlSiMg alloy processed by direct metal laser sintering (DMLS) is presented, from the analysis of the starting powders, in terms of size, morphology and chemical composition, through to the evaluation of mechanical and microstructural properties of specimens built along different orientations parallel and perpendicular to the powder deposition plane. With respect to a similar aluminum alloy as-fabricated, a higher yield strength of about 40% due to the very fine microstructure, closely related to the mechanisms involved in this additive process is observed.

From Powders to Dense Metal Parts: Characterization of a Commercial AlSiMg Alloy Processed through Direct Metal Laser Sintering

Directory of Open Access Journals (Sweden)

Eleonora Atzeni

2013-03-01

Full Text Available In this paper, a characterization of an AlSiMg alloy processed by direct metal laser sintering (DMLS is presented, from the analysis of the starting powders, in terms of size, morphology and chemical composition, through to the evaluation of mechanical and microstructural properties of specimens built along different orientations parallel and perpendicular to the powder deposition plane. With respect to a similar aluminum alloy as-fabricated, a higher yield strength of about 40% due to the very fine microstructure, closely related to the mechanisms involved in this additive process is observed.

Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

The performance of Al-Ti-C master alloy in refining Al-10Mg and A1-5Cu alloys was studied by using electron probe micro-analyzer (EPMA) and X-ray diffractometer (XRD) analysis.The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds.Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading.However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti(Al, Cu)2, which is responsible for the refinement fading in Al-5Cu alloy.These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.

Influence of Microstructure on Corrosion Property of Mg-Al-Zn Alloy

International Nuclear Information System (INIS)

Lee, Jeong Ja; Na, Seung Chan; Yang, Won Seong; Hwang, WoonSuk; Jang, Si Sung; Yoo, Hwang Ryong

2006-01-01

Influence of microstructure on the corrosion property of Mg-Al-Zn Alloy was investigated using potentiodynamic polarization experiments, galvanic coupling experiments, and scanning electron microscopy in sodium chloride solutions. Pitting was the mot common form of attack in chloride solution, and filiform corrosion was also occurred in AZ91D-T4 alloy. On the contrary, filiform attack in the bulk matrix was predominant corrosion form in AZ91D-T6 alloy, and the number and size of pit were decreased than those of AZ91D-T4 alloy. Galvanic coupling effect between Mg 17 Al 12 and matrix was existed, but the propagation of galvanic corrosion was localized only near the Mg 17 Al 12 phase in AZ91D-6T alloy. The corrosion resistance of Mg-Al matrix increased with decreasing Al content in the matrix. And, it could be regarded that Al content in the matrix is decreased by precipitation of Mg 17 Al 12 curing the aging treatment and it decreases the anodic reaction rate of the matrix and galvanic effect in AZ91D-T6 alloy. It could be considered that the composition and macrostructure of surface protective layer would be varied by precipitation of Mg 17 Al 12 and subsequent decreasing of Al content in the matrix. And it would contribute the corrosion resistance of AZ91D-T6 aging alloy

Hydrodeoxygenation of furfuryl alcohol over Cu/MgAl and Cu/ZnAl catalysts derived from hydrotalcite-like precursors

Directory of Open Access Journals (Sweden)

Natalia Andrea Pino

2017-01-01

Full Text Available The aqueous phase hydrodeoxygenation (HDO of furfuryl alcohol over Cu/MgAl and Cu/ZnAl catalysts with different Mg/Al and Zn/Al molar ratios, were investigated. Mg-Al and Zn-Al mixed oxides derived from hydrotalcites precursors were used as supports, which were impregnated with an aqueous solution of copper nitrate by incipient wetness impregnation. The HDO reaction was carried out in a typical batch reactor at 5 MPa of H2 and 200 °C for 4 h. Among the catalysts studied, the Cu/MgAl-0.5 catalyst exhibited the higher furfuryl alcohol conversion (86% and yield of cyclopentanol (35%, which is the reaction product with the highest hydrogen-carbon (H/C ratio. With the Cu/MgAl-3 catalyst a high cyclopentanone yield (67% was achieved. The results obtained, showed that copper supported on mixed oxides catalysts derived from hydrotalcite precursors are a promising alternative to improve the bio-oil quality.

The Influence of the Asymmetric Arb Process on the Properties of Al-Mg-Al Multi-Layer Sheets / Wpływ Asymetrii W Procesie Arb Na Właściwości Wielowarstwowych Blach Al-Mg-Al

Directory of Open Access Journals (Sweden)

Wierzba A.

2015-12-01

Full Text Available The paper presents the results of the experimental study of the three-layer Al-Mg-Al sheets rolling process by the ARB method. The tests carried out were limited to single-pass symmetric and asymmetric rolling processes. An Al-Mg-Al package with an initial thickness of 4 mm (1-2-1 mm was subjected to the process of rolling with a relative reduction of 50%. To activate the shear band in the strip being deformed, an asymmetry factor of av=2 was applied. From the test results, an increase in the tensile strength of the multi-layer Al-Mg-Al sheets obtained from the asymmetric process was observed. Microhardness tests did not show any significant differences in aluminium layer between respective layers of sheets obtained from the symmetric and the asymmetric process. By contrast, for the magnesium layer, an increase in microhardness from 72 HV to 79 HV could be observed for the asymmetric rolling. The analysis of the produced Al-Mg-Al sheets shows that the good bond between individual layers and grain refinement in the magnesium layer contributed to the obtaining of higher mechanical properties in the multi-layer sheets produced in the asymmetric process compared to the sheets obtained from the symmetric process.

Corrosion of aluminum alloys as a function of alloy composition

International Nuclear Information System (INIS)

Johnson, A.B. Jr.

1969-10-01

A study was initiated which included nineteen aluminum alloys. Tests were conducted in high purity water at 360 0 C and flow tests (approx. 20 ft/sec) in reactor process water at 130 0 C (TF-18 loop tests). High-silicon alloys and AlSi failed completely in the 360 0 C tests. However, coupling of AlSi to 8001 aluminum suppressed the failure. The alloy compositions containing iron and nickel survived tht 360 0 C autoclave exposures. Corrosion rates varied widely as a function of alloy composition, but in directions which were predictable from previous high-temperature autoclave experience. In the TF-18 loop flow tests, corrosion penetrations were similar on all of the alloys and on high-purity aluminum after 105 days. However, certain alloys established relatively low linear corrosion rates: Al-0.9 Ni-0.5 Fe-0.1 Zr, Al-1.0 Ni-0.15 Fe-11.5 Si-0.8 Mg, Al-1.2 Ni-1.8 Fe, and Al-7.0 Ni-4.8 Fe. Electrical polarity measurements between AlSi and 8001 alloys in reactor process water at temperatures up to 150 0 C indicated that AlSi was anodic to 8001 in the static autoclave system above approx. 50 0 C

Metallic Glasses as Potential Reinforcements in Al and Mg Matrices: A Review

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S. Jayalakshmi

2018-04-01

Full Text Available Development of metal matrix composites (MMCs with metallic glass/amorphous alloy reinforcements is an emerging research field. As reinforcements, metallic glasses with their high strength (up to ~2 GPa and high elastic strain limit (~2% can provide superior mechanical properties. Being metallic in nature, the glassy alloys can ensure better interfacial properties when compared to conventional ceramic reinforcements. Given the metastable nature of metallic glasses, lightweight materials such as aluminum (Al and magnesium (Mg with relatively lower melting points are suitable matrix materials. Synthesis of these advanced composites is a challenge as selection of processing method and appropriate reinforcement type (which does not allow devitrification of the metallic glass during processing is important. Non-conventional techniques such as high frequency induction sintering, bidirectional microwave sintering, friction stir processing, accumulative roll-bonding, and spark plasma sintering are being explored to produce these novel materials. In this paper, an overview on the synthesis and properties of aluminum and magnesium based composites with glassy reinforcement produced by various unconventional methods is presented. Evaluation of properties of the produced composites indicate: (i retention of amorphous state of the reinforcement after processing; (ii significant improvement in hardness and strength; (iii improvement/retention of ductility; and (iv high wear resistance and low coefficient of friction. Further, a comparative understanding of the properties highlights that the selection of the processing method is important in producing high performance composites.

Direct observations of grain boundary phenomena during indentation of Al and Al-Mg thin films

NARCIS (Netherlands)

Soer, WA; De Hosson, JTM; Minor, AM; Stach, EA; Morris, Joan K.; Corcoran, SG; Joo, YC; Moody, NR; Suo, Z

2004-01-01

The deformation behaviour of Al and Al-Mg thin films has been studied with the unique experimental approach of in-situ nanoindentation in a transmission electron microscope. This paper concentrates on the role of solute Mg additions in the transfer of plasticity across grain boundaries. The

Evaluation of aluminum drill-pipe material and design

Energy Technology Data Exchange (ETDEWEB)

Placido, Joao C. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Lourenco, Marcelo I.; Netto, Theodoro Antoun [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)

2008-07-01

Experimental program and numerical analyses were carried out to investigate the fatigue mechanisms of aluminum drill pipes designed and manufactured in compliance with ISO 15546. The main objective is to improve the fatigue performance of these components by selecting the appropriate aluminum alloy and by enhancing the mechanical design of the threaded steel connector. This paper presents the experimental test program and numerical analyses conducted on a drill-pipe of different materials (Al-Cu-Mg and Al-Zn-Mg system aluminum alloys) and geometry. Material mechanical properties, including S-N curve, were determined through small-scale tests on specimens cut from actual drill pipes. Full-scale experiments were also performed in laboratory. A finite element model of the drill pipe, including the tool-joint region, was developed. The model simulates, through different load steps, the tool-joint hot assembly, and then reproduces the physical experiments numerically in order to obtain the actual stress distribution. Good correlation between full-scale and small-scale fatigue tests was obtained by adjusting the strain/stress levels monitored in the full-scale tests in light of the numerical simulations and performing fatigue life calculations via multiaxial fatigue models. The weak points of the current practice design are highlighted for further development. (author)

Hydrothermal synthesis and characterization of polycrystalline gadolinium aluminum perovskite (GdAlO3, GAP

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N. Girish H.

2015-06-01

Full Text Available Gadolinium aluminum perovskite (GdAlO3, GAP is a promising high temperature ceramic material, known for its wide applications in phosphors. Polycrystalline gadolinium aluminum perovskites were synthesized using a precursor of co-precipitate gel of GdAlO3 by employing hydrothermal supercritical fluid technique under pressure and temperature ranging from 150 to 200 MPa and 600 to 700 °C, respectively. The resulted products of GAP were studied using the characterization techniques, such as powder X-ray diffraction analysis (XRD, infrared spectroscopy (IR, scanning electron microscopy (SEM and energy dispersive analysis of X-ray (EDX. The X-ray diffraction pattern matched well with the reported orthorhombic GAP pattern (JCPDS-46-0395.

Deposition behavior of residual aluminum in drinking water distribution system: Effect of aluminum speciation.

Science.gov (United States)

Zhang, Yue; Shi, Baoyou; Zhao, Yuanyuan; Yan, Mingquan; Lytle, Darren A; Wang, Dongsheng

2016-04-01

Finished drinking water usually contains some residual aluminum. The deposition of residual aluminum in distribution systems and potential release back to the drinking water could significantly influence the water quality at consumer taps. A preliminary analysis of aluminum content in cast iron pipe corrosion scales and loose deposits demonstrated that aluminum deposition on distribution pipe surfaces could be excessive for water treated by aluminum coagulants including polyaluminum chloride (PACl). In this work, the deposition features of different aluminum species in PACl were investigated by simulated coil-pipe test, batch reactor test and quartz crystal microbalance with dissipation monitoring. The deposition amount of non-polymeric aluminum species was the least, and its deposition layer was soft and hydrated, which indicated the possible formation of amorphous Al(OH)3. Al13 had the highest deposition tendency, and the deposition layer was rigid and much less hydrated, which indicated that the deposited aluminum might possess regular structure and self-aggregation of Al13 could be the main deposition mechanism. While for Al30, its deposition was relatively slower and deposited aluminum amount was relatively less compared with Al13. However, the total deposited mass of Al30 was much higher than that of Al13, which was attributed to the deposition of particulate aluminum matters with much higher hydration state. Compared with stationary condition, stirring could significantly enhance the deposition process, while the effect of pH on deposition was relatively weak in the near neutral range of 6.7 to 8.7. Copyright © 2015. Published by Elsevier B.V.

Age hardening in mechanically alloyed Al-Mg-Li-C-O

Energy Technology Data Exchange (ETDEWEB)

Papazian, J.M. (Corporate Research Center, Grumman Corporation, Bethpage, NY (USA)); Gilman, P. (Allied-Signal Inc., Morristown, NJ (USA))

1990-05-01

The age-hardening behavior of a series of mechanically alloyed Al-Mg-Li-C-O alloys containing 3.0-4.0 wt.% Mg and 1.3-1.75 wt.% Li was studied using hardness tests, differential scanning calorimetry (DSC) and transmission electron microscopy. The hardness tests showed an increased hardness after 100degC aging in all the alloys containing at least 1.5 at.% Li. Likewise, the calorimetry results showed the presence of pronounced precipitate dissolution peaks in these same alloys after 100degC aging. The volume fraction of precipitates formed (as measured by the dissolution enthalpies of the DSC peaks) increased systematically with increasing solute content. Transmission electron microscopy after 100 and 190degC aging showed images and diffraction spots similar to those of {delta}' (Al{sub 3}Li). Comparison of the DSC results with results from binary Al-Li and Al-Mg alloys indicated that the precipitates formed in the Al-Mg-Li-C-O alloys were similar to those formed in binary Al-Li alloys, and that the primary role of the magnesium was to lower the solid solubility of lithium. (orig.).

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

Institute of Scientific and Technical Information of China (English)

高英俊; 班冬梅; 韩永剑; 钟夏平; 刘慧

2004-01-01

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

Effect of solution concentration on sealing treatment of Mg-Al hydrotalcite film on AZ91D Mg alloy

Directory of Open Access Journals (Sweden)

Qiangsheng Dong

2017-09-01

Full Text Available Cerium-based sealing treatment was developed for Mg-Al hydrotalcite film on AZ91D Mg alloy, and the influence of cerium salt solution was investigated to modify the surface integrity and corrosion resistance. Scanning electron microscope (SEM and X-ray diffraction (XRD measurements were carried out to analyze the surface morphology and phase composition. The corrosion resistance of Mg-Al hydrotalcite film after sealing treatment was evaluated by the polarization curve and electrochemical impedance spectroscopy (EIS tests. The results showed that lower concentration of Ce-containing solution was beneficial to seal the micro-cracks on Mg-Al hydrotalcite film, and improve the surface integrity and corrosion resistance; higher concentration of Ce-containing solution could seal fewer micro-cracks, and the corrosion resistance was decreased owing to the disintegration of Mg-Al hydrotalcite film.

Hydrogenation of carbon monoxide on Co/MgAl2O4 and Ce-Co/MgAl2O4 catalysts

International Nuclear Information System (INIS)

Kondoh, S.; Muraki, H.; Fujitani

1986-01-01

It is well known that various hydrocarbons are obtained by hydrogenation of CO on Fischer-Tropsch catalysts, the products depending on the catalyst components such as Co, Ni, Fe and Ru: and the reaction conditions, particularly, temperature, pressure, space velocity and H 2 /CO ratio. Further, both reactivity and selectivity of catalysts may be improved by suitable selection of support and an additive. The main program of the present work is to develop a catalyst for producing C 5 + liquid hydrocarbons, as an automobile fuel, by the Fischer-Tropsch synthesis. The authors have studied unique CO catalyst systems consisting of various supports - such as Al 2 O 3 (γ, β, α), MgAl 2 O 4 (alumina magnesia spinel), MgO and additives selected from the lanthanoid elements (LE). The composition of spinel-based supports was altered in a range from 28 mol % excess Al 2 O 3 to 28 mol % excess MgO. Particularly, they found that a MgAl 2 O 4 support with 15-18 mol % excess Al 2 O 3 is the most preferable for our purpose and CeO 2 as the additive for Co/spinel catalyst remarkably improves C 5 + yield. Further, it was confirmed that the catalytic activity of Co-base catalysts agree with the oxidation state of Co-oxides on Co and Co-Ce/spinel catalysts. The performance of Co-based catalysts for the production of higher hydrocarbons from syn-gas were described elsewhere. The items described in this report include (a) selection of supports, (b) selection of optimum reaction conditions for Co-Ce/spinel catalyst, (c) redox characteristics of Co-oxides on a spinel surface, and (d) experimental observation of TPD profiles, adsorption capacities and IR spectra relating to adsorbed CO

Friction Stir Welding-assisted Diffusion Bond of Al/Zn/Mg Lap Joint

Directory of Open Access Journals (Sweden)

JIN Yu-hua

2018-03-01

Full Text Available Dissimilar materials welding between 2mm-thick AZ31B Mg alloy and 6061 Al alloy plates in overlap form was performed using the friction stir-induced diffusion bond with zinc foil as the interlayer. The microstructure and mechanical properties of the Al/Zn/Mg lap joints were analyzed by means of SEM, EPMA, XRD, tensile experiment and Vickers hardness test. The results show that diffusion layer consists of Al enrichment zone, Al5Mg11Zn4 layer and Mg-Zn eutectic zone at proper rotation speed; however, when rotation speed is low, the residual zinc interlayer remains in the diffusion layer; when rotation speed is high, the Al-Mg intermetallic compounds are present again. Due to the existence of intermetallic compounds in diffusion layer, its microhardness is significantly higher than that of base metal. The addition of zinc foil can improve the mechanical properties of Al/Mg lap joints. According to analysis on the fracture, joint failure occurs in the diffusion layer near to Al side.

Elevated temperature wear of Al6061 and Al6061-20%Al{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Singh, J.; Alpas, A.T. [Univ. of Windsor, Ontario (Canada)

1995-04-01

Both current and potential applications of particulate reinforced aluminum alloys involve components which are required to operate under sliding contact conditions at elevated temperatures. Examples include brake rotors, piston and cylinder liners in automotive engines where operating temperatures can reach 0.5--0.8 of the melting temperature of the matrix alloy. For this reason, study of the high temperature wear resistance of aluminum alloys reinforced by Al{sub 2}O{sub 3} or SiC particles is important. These studies are also of interest for the problem of die wear during hot extrusion of aluminum matrix composites and to rationalize the process of frictional welding involved in joining of the composites. Although the room temperature tribological and mechanical behaviors of aluminum matrix composites have received considerable attention, their high temperature properties have only recently started being considered. It has been shown that Al-Si-Mg (A356) alloys with or without SiC particles show a transition from mild to severe wear when a critical temperature (at about 0.4 T{sub m}, where T{sub m} is the melting temperature of aluminum) is reached as a result of frictional heating under dry sliding conditions. In this work, high temperature wear of A16061 and A16061-20%Al{sub 2}O{sub 3} was studied at temperatures between 25--500 C. The microstructural changes that occurred during wear have been delineated in order to understand the wear mechanisms that operate at high temperatures.

Direct visualization of β phase causing intergranular forms of corrosion in Al–Mg alloys

Energy Technology Data Exchange (ETDEWEB)

Yang, Young-Ki, E-mail: deltag@naver.com; Allen, Todd

2013-06-15

For a more effective examination of microstructure in Al–Mg alloys, a new etching solution has been developed; dissolved ammonium persulfate in water. It is demonstrated how β phase (Al{sub 3}Mg{sub 2}) in Al–Mg alloys respond to this solution using samples of a binary Al–Mg alloy and a commercial 5083 aluminum alloy. Nanometer sized β phase is clearly visualized for the first time using scanning electron microscopy (SEM) instead of transmission electron microscopy (TEM). It is anticipated that direct and unambiguous visualization of β phase will greatly augment intergranular corrosion research in 5xxx series aluminum alloys. - Highlights: • Nanometer sized β phase in Al-10% Mg is first clearly visualized with SEM. • Nanometer sized β phase in wrought alloy 5083 is first clearly visualized with SEM. • Grain boundary decorating β phase and isolated sponge-like β phase are shown. • This phase is confirmed to be β phase using composition analysis.

Synthesis and structural transformations of hydrotalcite-like materials Mg-Al and Zn-Al

NARCIS (Netherlands)

Prihod'ko, R.V.; Sychev, M.V.; Astrelin, I.M.; Erdmann, K.; Mangel, A.; Santen, van R.A.

2001-01-01

Mg-Al and Zn-Al hydrotalcite-like layered double hydroxides of various compositions were synthesized and characterized. A detailed comparative analysis of the structure and composition of starting and reconstructed layered double hydroxides was made

Theory and X-ray Absorption Spectroscopy for Aluminum Coordination Complexes – Al K-Edge Studies of Charge and Bonding in (BDI)Al, (BDI)AlR2, and (BDI)AlX2 Complexes.

Science.gov (United States)

Altman, Alison B; Pemmaraju, C D; Camp, Clément; Arnold, John; Minasian, Stefan G; Prendergast, David; Shuh, David K; Tyliszczak, Tolek

2015-08-19

Polarized aluminum K-edge X-ray absorption near edge structure (XANES) spectroscopy and first-principles calculations were used to probe electronic structure in a series of (BDI)Al, (BDI)AlX2, and (BDI)AlR2 coordination compounds (X = F, Cl, I; R = H, Me; BDI = 2,6-diisopropylphenyl-β-diketiminate). Spectral interpretations were guided by examination of the calculated transition energies and polarization-dependent oscillator strengths, which agreed well with the XANES spectroscopy measurements. Pre-edge features were assigned to transitions associated with the Al 3p orbitals involved in metal-ligand bonding. Qualitative trends in Al 1s core energy and valence orbital occupation were established through a systematic comparison of excited states derived from Al 3p orbitals with similar symmetries in a molecular orbital framework. These trends suggested that the higher transition energies observed for (BDI)AlX2 systems with more electronegative X(1-) ligands could be ascribed to a decrease in electron density around the aluminum atom, which causes an increase in the attractive potential of the Al nucleus and concomitant increase in the binding energy of the Al 1s core orbitals. For (BDI)Al and (BDI)AlH2 the experimental Al K-edge XANES spectra and spectra calculated using the eXcited electron and Core-Hole (XCH) approach had nearly identical energies for transitions to final state orbitals of similar composition and symmetry. These results implied that the charge distributions about the aluminum atoms in (BDI)Al and (BDI)AlH2 are similar relative to the (BDI)AlX2 and (BDI)AlMe2 compounds, despite having different formal oxidation states of +1 and +3, respectively. However, (BDI)Al was unique in that it exhibited a low-energy feature that was attributed to transitions into a low-lying p-orbital of b1 symmetry that is localized on Al and orthogonal to the (BDI)Al plane. The presence of this low-energy unoccupied molecular orbital on electron-rich (BDI)Al distinguishes

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

Band alignment of atomic layer deposited MgO/Zn0.8Al0.2O heterointerface determined by charge corrected X-ray photoelectron spectroscopy

Science.gov (United States)

Yan, Baojun; Liu, Shulin; Yang, Yuzhen; Heng, Yuekun

2016-05-01

Pure magnesium (MgO) and zinc oxide doped with aluminum oxide (Zn0.8Al0.2O) were prepared via atomic layer deposition. We have studied the structure and band gap of bulk Zn0.8Al0.2O material by X-ray diffractometer (XRD) and Tauc method, and the band offsets and alignment of atomic layer deposited MgO/Zn0.8Al0.2O heterointerface were investigated systematically using X-ray photoelectron spectroscopy (XPS) in this study. Different methodologies, such as neutralizing electron gun, the use of C 1s peak recalibration and zero charging method, were applied to recover the actual position of the core levels in insulator materials which were easily influenced by differential charging phenomena. Schematic band alignment diagram, valence band offset (ΔEV) and conduction band offset (ΔEC) for the interface of the MgO/Zn0.8Al0.2O heterostructure have been constructed. An accurate value of ΔEV = 0.72 ± 0.11 eV was obtained from various combinations of core levels of heterojunction with varied MgO thickness. Given the experimental band gaps of 7.83 eV for MgO and 5.29 eV for Zn0.8Al0.2O, a type-II heterojunction with a ΔEC of 3.26 ± 0.11 eV was found. Band offsets and alignment studies of these heterojunctions are important for gaining deep consideration to the design of various optoelectronic devices based on such heterointerface.

Aluminum-doped Zn O polycrystalline films prepared by co-sputtering of a Zn O-Al target

Energy Technology Data Exchange (ETDEWEB)

Becerril, M.; Silva L, H.; Guillen C, A.; Zelaya A, O. [Instituto Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Departamento de Fisica, Apdo. Postal 14-740, 07000 Mexico D. F. (Mexico)

2014-07-01

Aluminum-doped Zinc oxide polycrystalline thin films (Azo) were grown on 7059 Corning glass substrates at room temperature by co-sputtering from a Zn O-Al target. The target was designed as follows, high purity elemental Aluminum was evaporated onto a Zn O target covering small areas. The structural, optical and electrical properties were analyzed as a function of Al content. The Al doped Zn O polycrystalline films showed an n-type conductivity. It was found that the electrical resistivity drops and the carrier concentration increases as a consequence of Al incorporation within the Zn O lattice. In both cases, the changes are of several orders of magnitude. From the results, we conclude that, using these Zn O-Al targets, n-type Al doped Zn O polycrystalline films with high transmittance and low resistivity can be obtained. The crystalline structure of the films was determined by X-ray diffraction. Atomic Force Microscopy images were obtained with an Auto probe C P (Veeco Metrology Group) Microscope. (Author)

Mg/Al HYDROTALCITE-LIKE SYNTHESIZED FROM BRINE WATER FOR EOSIN YELLOW REMOVAL

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Eddy Heraldy

2011-11-01

Full Text Available Attempts to synthesis of Mg/Al HTlc using magnesium from several raw material resources are widely investigated. One of raw material would purpose as source of magnesium to synthesis of Mg/Al HTlc is brine water which is well known as the desalination process wastewater. Mg/Al HTlc are widely investigated for their potential applications in research and industrial processes as adsorbents, anionic exchange, catalysts and /or catalyst precursors for the preparation of inorganic materials and pharmaceutical industry excipients. As adsorbents, Mg/Al HTlc are receiving greater interests in the environmental community due to their high adsorption capacity. However, there is no literature available on the synthesis of Mg/Al HTlc from brine water except from artificial seawater. The objective of this research is to synthesis of Mg/Al HTlc from brine water and its ability tested for eosin yellow (EY removal. Characterization of the Mg/Al HTlc synthesized was confirmed through X-ray Diffraction and FT-IR Spectroscopy. The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, the adsorption isotherms, adsorption kinetics, and pH effects upon EY adsorption on Mg/Al HTlc were examined. The result showed that EY data fit well with the pseudo-second order kinetic model. The isothermal data could be well described by the Freundlich equation. The adsorption capacity was 2.41 × 10-1 mol g-1, and adsorption energy of EY was 24.89 kJ mol-1.

Corrosion behavior of die-cast Mg-4Al-2Sn-xCa alloy

Energy Technology Data Exchange (ETDEWEB)

Park, Kyung Chul; Kim, Byeong Ho; Kim, Kyung Ro [Defence Agency for Technology and Quality, Jinju (Korea, Republic of); Cho, Dae Hyun; Park, Ik Min [Pusan National University, Busan (Korea, Republic of)

2016-05-15

In the present work, the effect of Ca additions on microstructure and corrosion characteristics of high pressure die-cast Mg-4Al-2Sn alloy has been investigated. Mg-4Al-2Sn-xCa (x= 0, 0.3 and 0.7wt.%) alloy was prepared by using a high pressure die-casting method. Results indicated that the microstructure of Mg-4Al-2Sn alloy consisted of α-Mg, Mg{sub 17}Al{sub 12} and Mg{sub 2}Sn phase. With increase of Ca additions, CaMgSn phase was newly formed and grain size was sharply decreased. From the test results, the corrosion resistance of die-cast Mg-4Al-2Sn alloy was significantly improved by Ca addition. It is considered that stabilization of Mg(OH){sub 2} layer and refinements of microstructure with increase of Ca additions.

Gas Metal Arc Weld (GMAW) Qualification of 7020-T651 Aluminum

Science.gov (United States)

2015-11-01

strength Al, with tough, ductile , weld joints may provide improved protection and crash safety by means of a rigid vehicle structure. This...characteristics and ballistic protection, with V50 statistics of 5083 and 7039 aluminum and RHA steel . Aberdeen Proving Ground (MD): Army Research...633. 9. McQueen H, Leo P, Cerri E. Al-Zn-Mg for extrusion– hot workability. In TMS 2009, Al Alloys: Fabrication, Characterization and Applications II

Application of Al-2La-1B Grain Refiner to Al-10Si-0.3Mg Casting Alloy

Science.gov (United States)

Jing, Lijun; Pan, Ye; Lu, Tao; Li, Chenlin; Pi, Jinhong; Sheng, Ningyue

2018-05-01

This paper reports the application and microstructure refining effect of an Al-2La-1B grain refiner in Al-10Si-0.3Mg casting alloy. Compared with the traditional Al-5Ti-1B refiner, Al-2La-1B refiner shows better performances on the grain refinement of Al-10Si-0.3Mg alloy. Transmission electron microscopy analysis suggests that the crystallite structure features of LaB6 are beneficial to the heterogeneous nucleation of α-Al grains. Regarding the mechanical performances, tensile properties of Al-10Si-0.3Mg casting alloy are prominently improved, due to the refined microstructures.

Aluminum coordination chemistry and the inhibition of phosphoryl-transferring enzymes

International Nuclear Information System (INIS)

Furumo, N.C.; Viola, R.E.

1986-01-01

Aluminium ion is a potent inhibitor of the enzymes hexokinase (K/sub i/ = 0.16 μM) and glycerokinase (K/sub i/ = 4.0 μM). It has been shown that aluminum forms a complex with ATP that is 80 times more stable than the magnesium complex with ATP which is the normal substrate for phosphoryl-transferring enzymes. Kinetic studies performed on several kinases at pH 7.0 have shown that Al-ATP is a competitive inhibitor vs. Mg-ATP with moderate K/sub i/ values (0.1-0.5 mM) for creatine kinase(CK) and myokinase(MK), and weakly competitive (K/sub i/ > 0.5 mM) with acetate, galactose, arginine and gluconate kinases. Equilibrium dialysis binding studies indicate no significant binding of aluminum ion by the enzymes, while the interaction of aluminum ion with ADP and ATP has been characterized by 13 C, 27 Al, and 31 P NMR spectroscopy. It appears that the inhibition by aluminum is as the Al-nucleotide complex rather than direct binding of free aluminum ion by the enzyme. Kinetic studies indicate that Al 3+ inhibition of CK and MK is pH dependent with decreased values of K/sub i/ at lower pH. At pH 6.1 K/sub i/ = 25 μM for MK (160 μM at pH 7.0) and 53 μM for CK (240 μM at pH 7.0). This may be due to an increased effective concentration of aluminum ion at lower pH

26Mg(p,n)26Al and 23Na(α,n)26Al reactions

International Nuclear Information System (INIS)

Skelton, R.T.

1985-01-01

Cross sections for the 26 Mg(p,n) 26 Al reaction were measured from threshold at 4.988 MeV to 5.820 MeV. Cross sections for the 23 Na(α,n) 26 Al reaction were measured from threshold at 3.483 MeV to 4.597 MeV. In each case, separate measurements were to the ground state and to the first and second excited states of 26 Al. Cross sections for the inverse reactions were calculated and reaction rate factors relating to the destruction of 26 Al in a supernova environment were determined. Astrophysical implications relating to the observation of live and extinct 26 Al are discussed. Excitation functions for several additional exit channels for the 26 Mg + rho and 23 Na + α reactions are reported

Hot deformation of particulate reinforced Al-4Li-1Mg-0.5Ge-0.2Zr

International Nuclear Information System (INIS)

Chanda, T.; Lavernia, E.J.; Wolfenstine, J.

1991-01-01

Lithium additions to aluminum give the greatest reduction in density and increase in elastic modulus per wt.% of any known alloying element. The potential for aluminum alloy density reduction through lithium additions is evident by comparing its atomic weight (6.94) to that of aluminum (26.98). Over the past decade, considerable research efforts have been directed towards developing aluminum-lithium alloys, with lithium contents of up to 2.5 wt.%, for aircraft applications, where their low density and increased stiffness can lead to significant improvements in payload capacity. A recent notable example has been the development of a quarternary aluminum-lithium alloy containing silver, (A1-(4.5-6.3) Cu-1.3Li-0.4Ag-0.4Mg-0.14Zr, in wt.%). In an effort to further decrease the density and increase the modulus of aluminum-lithium alloys, research efforts have progressively shifted towards alloys containing higher concentrations of lithium (>3.0 wt.%). Furthermore, aluminum-lithium alloys are being studied as potential candidate matrix materials in metal matrix composites (MMCs), as a result of the observation that lithium effectively enhances the ability of the aluminum matrix to wet the ceramic reinforcement. The extreme reactivity associated with high additions of lithium, and the difficulties associated with processing MMCs, have prompted the development of alternate synthesis approaches. One such approach, spray atomization and co-deposition, is actively being studied as a result of its ability to rapidly quench, reinforce, and consolidate in a single step, thus avoiding the difficulties associated with the handling of fine reactive particulates. The object of the paper is to provide insight into the elevated temperature deformation behavior of high lithium (4 wt.%) aluminum alloys reinforced with SiC particles prepared by spray atomization and co-deposition. The selection of the A1-4Li-1Mg-0.5Ge-0.2Zr wt

Soldering of Mg Joints Using Zn-Al Solders

Science.gov (United States)

Gancarz, Tomasz; Berent, Katarzyna; Skuza, Wojciech; Janik, Katarzyna

2018-04-01

Magnesium has applications in the automotive and aerospace industries that can significantly contribute to greater fuel economy and environmental conservation. The Mg alloys used in the automotive industry could reduce mass by up to 70 pct, providing energy savings. However, alongside the advantages there are limitations and technological barriers to use Mg alloys. One of the advantages concerns phenomena occurring at the interface when joining materials investigated in this study, in regard to the effect of temperature and soldering time for pure Mg joints. Eutectic Zn-Al and Zn-Al alloys with 0.05 (wt pct) Li and 0.2 (wt pct) Na were used in the soldering process. The process was performed for 3, 5, and 8 minutes of contact, at temperatures of 425 °C, 450 °C, 475 °C, and 500 °C. Selected, solidified solder-substrate couples were cross-sectioned, and their interfacial microstructures were investigated by scanning electron microscopy. The experiment was designed to demonstrate the effect of time, temperature, and the addition of Li and Na on the kinetics of the dissolving Mg substrate. The addition of Li and Na to eutectic Zn-Al caused to improve mechanical properties. Higher temperatures led to reduced joint strength, which is caused by increased interfacial reaction.

On the Selective Laser Melting (SLM of the AlSi10Mg Alloy: Process, Microstructure, and Mechanical Properties

Directory of Open Access Journals (Sweden)

Francesco Trevisan

2017-01-01

Full Text Available The aim of this review is to analyze and to summarize the state of the art of the processing of aluminum alloys, and in particular of the AlSi10Mg alloy, obtained by means of the Additive Manufacturing (AM technique known as Selective Laser Melting (SLM. This process is gaining interest worldwide, thanks to the possibility of obtaining a freeform fabrication coupled with high mechanical properties related to a very fine microstructure. However, SLM is very complex, from a physical point of view, due to the interaction between a concentrated laser source and metallic powders, and to the extremely rapid melting and the subsequent fast solidification. The effects of the main process variables on the properties of the final parts are analyzed in this review: from the starting powder properties, such as shape and powder size distribution, to the main process parameters, such as laser power and speed, layer thickness, and scanning strategy. Furthermore, a detailed overview on the microstructure of the AlSi10Mg material, with the related tensile and fatigue properties of the final SLM parts, in some cases after different heat treatments, is presented.

On the Selective Laser Melting (SLM) of the AlSi10Mg Alloy: Process, Microstructure, and Mechanical Properties.

Science.gov (United States)

Trevisan, Francesco; Calignano, Flaviana; Lorusso, Massimo; Pakkanen, Jukka; Aversa, Alberta; Ambrosio, Elisa Paola; Lombardi, Mariangela; Fino, Paolo; Manfredi, Diego

2017-01-18

The aim of this review is to analyze and to summarize the state of the art of the processing of aluminum alloys, and in particular of the AlSi10Mg alloy, obtained by means of the Additive Manufacturing (AM) technique known as Selective Laser Melting (SLM). This process is gaining interest worldwide, thanks to the possibility of obtaining a freeform fabrication coupled with high mechanical properties related to a very fine microstructure. However, SLM is very complex, from a physical point of view, due to the interaction between a concentrated laser source and metallic powders, and to the extremely rapid melting and the subsequent fast solidification. The effects of the main process variables on the properties of the final parts are analyzed in this review: from the starting powder properties, such as shape and powder size distribution, to the main process parameters, such as laser power and speed, layer thickness, and scanning strategy. Furthermore, a detailed overview on the microstructure of the AlSi10Mg material, with the related tensile and fatigue properties of the final SLM parts, in some cases after different heat treatments, is presented.

Effect of polymorphism of Al2O3 on the sintering and microstructure of transparent MgAl2O4 ceramics

Science.gov (United States)

Han, Dan; Zhang, Jian; Liu, Peng; Wang, Shiwei

2017-09-01

Transparent MgAl2O4 ceramics were fabricated by reactive sintering in air followed by hot isostatic press treatment using commercial Al2O3 powder (γ-Al2O3 or α-Al2O3) and MgO powder as raw materials. The densification rate, microstructure and optical properties of the ceramics were investigated. Densification temperature of the sample from γ-Al2O3/MgO was lower than that from α-Al2O3/MgO. However, in-line transmission (2 mm thick) of the sample from α-Al2O3/MgO at the wavelength of 600 nm and 1100 nm were respectively 77.7% and 84.3%, higher than those (66.7%, 81.4%) of the sample from γ-Al2O3/MgO. SEM observation revealed that the sample from α-Al2O3/MgO exhibited a homogeneous and pore-free microstructure, while, the sample from γ-Al2O3/MgO showed an apparent bimodal microstructure containing pores.

TiB2/Al2O3 ceramic particle reinforced aluminum fabricated by spray deposition

International Nuclear Information System (INIS)

Chen Xing; Yang Chengxiao; Guan Leding; Yan Biao

2008-01-01

Aluminum matrix ceramic particle reinforced composites (AMCs) is a kind of composite with great importance. Aluminum matrix composite reinforced with TiB 2 /Al 2 O 3 ceramic particles was successfully in situ synthesized in Al-TiO 2 -B 2 O 3 system in this paper, using spray deposition with hot-press treatment technique. Five groups of composites with different reinforcement volume contents were prepared and the comparisons of porosity, ultimate tensile strength (UTS), elongation and Brinell hardness (BH) between the composites with and without hot-press treating were carried out. The composite with 21.0% reinforcement volume content was analyzed by X-ray diffraction (XRD), Environmental Scanning Electron Microscope (ESEM), Transmission Electron Microscope (TEM) and Energy Disperse Spectroscopy (EDS). The results revealed the formation and uniform distribution of fine reinforcements in the matrix after hot-press treating, while a new intermetallic phase Al 3 Ti was found besides TiB 2 /Al 2 O 3 ceramic phase

Determination of trace aluminum concentration and homogeneity in biological material TORT-1 by instrumental neutron activation and graphite furnace atomic absorption spectrometry

International Nuclear Information System (INIS)

Kratochvil, B.; Motkosky, N.; Duke, M.J.M.; Ng, D.

1987-01-01

The biological reference material TORT-1, lobster hepatopancreas, was analyzed for aluminum by instrumental neutron activation analysis (INAA) and graphite furnace atomic absorption spectroscopy (GFAAS). After correction of the INAA results for interferences from 28 Al produced by 31 P(n,α) 28 Al and 28 (n,p) 28 Al reactions, and use of HNO 3 plus HF for sample dissolution for the GFAAS analyses, the methods gave similar results of 43 ± 3 and 42 ± 2 μg/g respectively for 200 to 300-mg test portions. Analysis of six portions from each of six bottles of TORT-1 showed no statistical difference at the 95% confidence level for the between and within bottle variances. Therefore, The material can be considered homogeneous for aluminum if 200- to 300-mg test portions are taken. The variance was greater and the average lower when 30-mg test portions were analyzed for aluminum by GFAAS. The pattern of the results, together with the need for HF in the dissolution procedure, suggests the presence of aluminum-containing microparticulate mineral matter, perhaps silicate material, in the material

Determination of trace aluminum concentration and homogeneity in biological material TORT-1 by instrumental neutron activation and graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Kratochvil, B; Motkosky, N; Duke, M J.M.; Ng, D

1987-05-01

The biological reference material TORT-1, lobster hepatopancreas, was analyzed for aluminum by instrumental neutron activation analysis (INAA) and graphite furnace atomic absorption spectroscopy (GFAAS). After correction of the INAA results for interferences from /sup 28/Al produced by /sup 31/P(n,..cap alpha..)/sup 28/Al and /sup 28/(n,p)/sup 28/Al reactions, and use of HNO/sub 3/ plus HF for sample dissolution for the GFAAS analyses, the methods gave similar results of 43 +- 3 and 42 +- 2 ..mu..g/g respectively for 200 to 300-mg test portions. Analysis of six portions from each of six bottles of TORT-1 showed no statistical difference at the 95% confidence level for the between and within bottle variances. Therefore, The material can be considered homogeneous for aluminum if 200- to 300-mg test portions are taken. The variance was greater and the average lower when 30-mg test portions were analyzed for aluminum by GFAAS. The pattern of the results, together with the need for HF in the dissolution procedure, suggests the presence of aluminum-containing microparticulate mineral matter, perhaps silicate material, in the material.

Helium trapping in aluminum and sintered aluminum powders

International Nuclear Information System (INIS)

Das, S.K.; Kaminsky, M.; Rossing, T.

1975-01-01

The surface erosion of annealed aluminum and of sintered aluminum powder (SAP) due to blistering from implantation of 100-keV 4 He + ions at room temperature has been investigated. A substantial reduction in the blistering erosion rate in SAP was observed from that in pure annealed aluminum. In order to determine whether the observed reduction in blistering is due to enhanced helium trapping or due to helium released, the implanted helium profiles in annealed aluminum and in SAP have been studied by Rutherford backscattering. The results show that more helium is trapped in SAP than in aluminum for identical irradiation conditions. The observed reduction in erosion from helium blistering in SAP is more likely due to the dispersion of trapped helium at the large Al-Al 2 O 3 interfaces and at the large grain boundaries in SAP than to helium release

Microstructural and mechanical property characterization of Er modified Al-Mg-Mn alloy Tungsten Inert Gas welds

International Nuclear Information System (INIS)

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

2012-01-01

Highlights: → The microstructural characterization of TIG welded Al-Mg-Mn-Zr-Er alloy is studied. → A typical equaixed zone (EQZ) with finer grains is observed in the weld metal at the fusion boundary. → The dissolution of non-primary Al 3 Er particles in Al matrix is one reason of the weakness of TIG welded joint. →The relationship between mechanical properties and microstructure of welded joints is evaluated. →Reasons for joint softening are given from work-hardening, precipitation strengthening and solution strengthening. -- Abstract: Samples of Al-Mg-Mn-Zr-Er alloys have been welded using the method of TIG welding. Microstructures characterization was performed by optical microscopy (OM), energy dispersive X-ray (EDX) and transmission electron microscopy (TEM), respectively. In addition, tensile and hardness test was conducted. The relationship between mechanical properties and microstructure of welded joints is evaluated. Results indicate that the ultimate tensile strength of the joints is 72% of that of the base metal. The base metal consists of a typical rolled structure, and the fusion zone (FZ) is mainly made up of dendrite grains. A characteristic equiaxed zone (EQZ) is obtained at the fusion boundary between the base metal and fusion zone. Fine dispersion of coherent Al 3 Er precipitates was found in the base metal, however, the quantity of these particles dropped significantly in the fusion zone. The hardness test results indicate that the microhardness in the fusion zone is lower than that of the base metal, due to the as-cast structure in this region. Based on the present work, it is concluded that TIG welding is the suitable welding procedure for joining this new type Er-containing aluminum alloy.

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.

Fabrication of biodegradable Zn-Al-Mg alloy: Mechanical properties, corrosion behavior, cytotoxicity and antibacterial activities.

Science.gov (United States)

Bakhsheshi-Rad, H R; Hamzah, E; Low, H T; Kasiri-Asgarani, M; Farahany, S; Akbari, E; Cho, M H

2017-04-01

In this work, binary Zn-0.5Al and ternary Zn-0.5Al-xMg alloys with various Mg contents were investigated as biodegradable materials for implant applications. Compared with Zn-0.5Al (single phase), Zn-0.5Al-xMg alloys consisted of the α-Zn and Mg 2 (Zn, Al) 11 with a fine lamellar structure. The results also revealed that ternary Zn-Al-Mg alloys presented higher micro-hardness value, tensile strength and corrosion resistance compared to the binary Zn-Al alloy. In addition, the tensile strength and corrosion resistance increased with increasing the Mg content in ternary alloys. The immersion tests also indicated that the corrosion rates in the following order Zn-0.5Al-0.5MgAl-0.3MgAl-0.1MgAl. The cytotoxicity tests exhibited that the Zn-0.5Al-0.5Mg alloy presents higher viability of MC3T3-E1 cell compared to the Zn-0.5Al alloy, which suggested good biocompatibility. The antibacterial activity result of both Zn-0.5Al and Zn-0.5Al-Mg alloys against Escherichia coli presented some antibacterial activity, while the Zn-0.5Al-0.5Mg significantly prohibited the growth of Escherichia coli. Thus, Zn-0.5Al-0.5Mg alloy with appropriate mechanical properties, low corrosion rate, good biocompatibility and antibacterial activities was believed to be a good candidate as a biodegradable implant material. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid-state 27Al nuclear magnetic resonance investigation of three aluminum-centered dyes

KAUST Repository

Mroué , Kamal H.; Emwas, Abdul-Hamid M.; Power, William P.

2010-01-01

on the aluminum electric field gradient (EFG) and nuclear magnetic shielding tensors. The quadrupolar parameters for each 27Al site were determined from spectral simulations, with quadrupolar coupling constants (CQ) ranging from 5.40 to 10.0 MHz and asymmetry

Evolution of Mg-5Al-0.4Mn microstructure after rare earth elements addition

Directory of Open Access Journals (Sweden)

A. Żydek

2011-04-01

Full Text Available Mg-5Al-0.4Mn-xRE (x = 0, 1, 2, 3 wt.% magnesium alloys were prepared successfully by casting method. The microstructure wasinvestigated by light microscopy. The influence of rare earth (RE elements on the area fraction of eutectic was analysed. The obtainedresults revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. However, whilerare earth elements were added to the Mg-Al type alloy, Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitatesincreased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased.

Revisiting 26Al-26Mg systematics of plagioclase in H4 chondrites

Science.gov (United States)

Telus, M.; Huss, G. R.; Nagashima, K.; Ogliore, R. C.

2014-06-01

Zinner and Göpel found clear evidence for the former presence of 26Al in the H4 chondrites Ste. Marguerite and Forest Vale. They assumed that the 26Al-26Mg systematics of these chondrites date "metamorphic cooling of the H4 parent body." Plagioclase in these chondrites can have very high Al/Mg ratios and low Mg concentrations, making these ion probe analyses susceptible to ratio bias, which is inversely proportional to the number of counts of the denominator isotope (Ogliore et al.). Zinner and Göpel used the mean of the ratios to calculate the isotope ratios, which exacerbates this problem. We analyzed the Al/Mg ratios and Mg isotopic compositions of plagioclase grains in thin sections of Ste. Marguerite, Forest Vale, Beaver Creek, and Sena to evaluate the possible influence of ratio bias on the published initial 26Al/27Al ratios for these meteorites. We calculated the isotope ratios using total counts, a less biased method of calculating isotope ratios. The results from our analyses are consistent with those from Zinner and Göpel, indicating that ratio bias does not significantly affect 26Al-26Mg results for plagioclase in these chondrites. Ste. Marguerite has a clear isochron with an initial 26Al/27Al ratio indicating that it cooled to below 450 °C 5.2 ± 0.2 Myr after CAIs. The isochrons for Forest Vale and Beaver Creek also show clear evidence that 26Al was alive when they cooled, but the initial 26Al/27Al ratios are not well constrained. Sena does not show evidence that 26Al was alive when it cooled to below the Al-Mg closure temperature. Given that metallographic cooling rates for Ste. Marguerite, Forest Vale, and Beaver Creek are atypical (>5000 °C/Myr at 500 °C) compared with most H4s, including Sena, which have cooling rates of 10-50 °C/Myr at 500 °C (Scott et al.), we conclude that the Al-Mg systematics for Ste. Marguerite, Forest Vale, and Beaver Creek are the result of impact excavation of these chondrites and cooling at the surface of the

Air permeability of the artificially synthesized Zn-Al-Mg alloy rusts

International Nuclear Information System (INIS)

Ishikawa, Tatsuo; Ueda, Masato; Kandori, Kazuhiko; Nakayama, Takenori

2007-01-01

The rust particles of Zn-Al-Mg alloys were synthesized from aqueous solutions dissolving ZnCl 2 , AlCl 3 , and MgCl 2 at different atomic ratios of the metal ions. The crystal phase and particle morphology of the products depended on the composition of the starting solutions. The compactness of the layers of the products was estimated by measuring their air permeability. The layer of mixed metal hydroxide chloride formed at Zn:Al:Mg = 1:1:1 showed a highest compactness, that was ascribed to the preferred orientation of the fine plate particles. The addition of Mg(II) made plate particles smaller to give more compact layers

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

Microstructure and wear properties of laser cladding Ti-Al-Fe-B coatings on AA2024 aluminum alloy

International Nuclear Information System (INIS)

Xu Jiang; Liu Wenjin; Kan Yide; Zhong Minlin

2006-01-01

In order to improve wear resistance of aluminum alloy, the in situ synthesized TiB 2 and Ti 3 B 4 peritectic composite particulate reinforced metal matrix composite formed on the 2024 aluminum alloy by laser cladding with a powder mixture of Fe coated Boron, Ti and Al was successfully achieved using 3 kW CW CO 2 laser. The laser cladding coating present excellent bonding with aluminum alloy substrate. The chemical composition, microstructure and phase structure of the composite clad coating were analyzed by energy dispersive X-ray spectroscopy (EDX), SEM and XRD. The typical microstructure of composite coating is composed of TiB 2 , Ti 3 B 4 , Al 3 Ti, Al 3 Fe and α-Al. The surface hardness of cladding coating is increased with the amount of added Fe coated B and Ti powder which determines the amount of TiB 2 and Ti 3 B 4 peritectic composite particulate, and obviously higher than that of substrate. The wear tests were carried out using a FALEX-6 type pin-on-disc machine. The test results show that the composite coatings with the in situ synthesized TiB 2 and Ti 3 B 4 peritectic improve wear resistance when compared with the as-received Al substrate

Role of 3d-ions for radiation defect production in MgO and MgAl2O4

International Nuclear Information System (INIS)

Mironova, N.A.; Grinvald, G.A.; Skvortsova, V.N.

1985-01-01

Optical properties of MgO and MgAl 2 O 4 crystals containing chromium and manganese impurity ions were studied by exposure to but all types of radiation. Complicated defects of the ''impurity-intrinsic matrix defect'' type were preferably considered. It has been shown that different symmetry center forming chromium ions in MgO:Crsup(3+) change their valency with various efficiency being exposed to external action. Besides, the compensating vacancy does not participate in the hole center formation. For MgOxAl 2 O 3 single crystals the presence of octahedrally coordinated manganese ions suppresses the hole center creation by gamma-irradiation. Studying luminescence spectra of Crsup(3+) ions in MgAl 2 O 4 it has been states that neutron irradiation increases the degree of inversion for the magnesium-aluminium spinel

Adsorption of procion red using layer double hydroxide Mg/Al

Directory of Open Access Journals (Sweden)

Muhammad Imron

2017-07-01

Full Text Available Layer double hydroxide Mg/Al was synthesized by inorganic synthetic method. Material was characterized using FTIR and XRD analyses and used as adsorbent of procion red dye in aqueous medium.  Factors that affect the adsorption process are adsorption time as the kinetic parameter; and the temperature and concentration of procion red as the thermodynamic parameter. FTIR spectra of layer double hydroxides showed unique vibration at wavenumber 1300 cm-1 and 1600 cm-1. Characterization using XRD shows diffraction angles at 29o, 27o, and 28o, which are typical of Mg/Al double layer hydroxides. Adsorption of procion red using layer double hydroxide Mg/Al resulted adsorption rate 7.1 minutes-1, maximum adsorption capacity 111.1 mg/g at 60 oC with increasing energy by increasing adsorption temperature.   Keywords: Layered double hydroxides, adsorption, procion red.

Mechanical, dynamical and thermodynamic properties of Al-3wt%Mg from first principles

Energy Technology Data Exchange (ETDEWEB)

Yang, Rong [Chongqing Jiaotong Univ., Chongqing (China). College of Materials Science and Engineering; Tang, Bin [Chongqing City Management College, Chongqing (China). Inst. of Finance and Trade; Gao, Tao [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics

2017-09-01

The mechanical, dynamical and thermodynamic properties of Al-3wt%Mg have been investigated using the first-principles method. The calculated structural parameter is in good agreement with previous works. Results for the elastic modulus, stress-strain relationships, ideal tensile and shear strengths are presented. Al-3wt%Mg is found to have larger moduli and higher strengths than Al, which is consistent with its exploitation in Al precipitate-hardening mechanisms. The partial density of states (PDOS) show that the partly covalent-like bonding through Al p-Mg s hybridization is the origin of excellent mechanical properties of Al-3wt%Mg. The phonon dispersion curves indicate that Al-3wt%Mg is dynamically stable at ambient pressure and 0 K. Furthermore, the Helmholtz free energy ΔF, the entropy S, the constant-volume specific heat C{sub V} and the phonon contribution to the internal energy ΔE are predicted using the phonon density of states. We expect that our work can provide useful guidance to help with the performance of Al-3wt%Mg.

Mechanical, dynamical and thermodynamic properties of Al-3wt%Mg from first principles

International Nuclear Information System (INIS)

Yang, Rong; Tang, Bin; Gao, Tao

2017-01-01

The mechanical, dynamical and thermodynamic properties of Al-3wt%Mg have been investigated using the first-principles method. The calculated structural parameter is in good agreement with previous works. Results for the elastic modulus, stress-strain relationships, ideal tensile and shear strengths are presented. Al-3wt%Mg is found to have larger moduli and higher strengths than Al, which is consistent with its exploitation in Al precipitate-hardening mechanisms. The partial density of states (PDOS) show that the partly covalent-like bonding through Al p-Mg s hybridization is the origin of excellent mechanical properties of Al-3wt%Mg. The phonon dispersion curves indicate that Al-3wt%Mg is dynamically stable at ambient pressure and 0 K. Furthermore, the Helmholtz free energy ΔF, the entropy S, the constant-volume specific heat C_V and the phonon contribution to the internal energy ΔE are predicted using the phonon density of states. We expect that our work can provide useful guidance to help with the performance of Al-3wt%Mg.

Inclusions, Porosity, and Fatigue of AlSi10Mg Parts Produced by Selective Laser Melting

Science.gov (United States)

Tang, Ming

Additive manufacturing (AM) has experienced remarkable growth in the past decade with applications in both rapid prototyping and rapid manufacturing for functional end-usable parts. As one of the most promising AM processes, selective laser melting (SLM) can be used to fabricate metal products line by line and layer upon layer within a powder bed system. Such process allows the building of parts with customized shapes, which brings higher design flexibility than traditional casting and wrought manufacturing. In this work, AlSi10Mg powder is chosen as the raw material for producing parts by SLM, since aluminum alloys are widely used in automotive and aerospace industries thanks to an excellent combination of low density and competitive mechanical properties. However, there remain multiple drawbacks which limit further applications of aluminum parts produced by SLM: lack of prediction of solidification microstructure, few studies on fatigue properties, and cost and time caused by the limited production rate. All these issues were studied in this work and summarized as follows: Rapid movement of the melt pool (at a speed around 1 m/s) in SLM of metal powder directly implies rapid solidification. In this research, the length scale of the as-built microstructure of parts built with the alloy AlSi10Mg was measured and compared with the well-known relationship between cell size and cooling rate. Cooling rates during solidification were estimated using the Rosenthal equation. It was found that the solidification structure is the expected cellular combination of silicon with alpha-aluminum. The dependence of the measured cell spacing on the calculated cooling rate follows the well-established relationship for aluminum alloys. The implication is that cell spacing can be manipulated by changing the heat input. Microscopy of polished sections through particles of the metal powder used to build the parts showed that the particles have a dendritic-eutectic structure; the

Dual-scale phase-field simulation of Mg-Al alloy solidification

International Nuclear Information System (INIS)

Monas, A; Shchyglo, O; Tegeler, M; Steinbach, I; Höche, D

2015-01-01

Phase-field simulations of the nucleation and growth of primary α-Mg phase as well as secondary, β-phase of a Mg-Al alloy are presented. The nucleation model for α- and β-Mg phases is based on the “free growth model” by Greer et al.. After the α-Mg phase solidification we study a divorced eutectic growth of α- and β-Mg phases in a zoomed in melt channel between α-phase dendrites. The simulated cooling curves and final microstructures of α-grains are compared with experiments. In order to further enhance the resolution of the interdendritic region a high-performance computing approach has been used allowing significant simulation speed gain when using supercomputing facilities. (paper)

Oxaliplatin-Induced Peripheral Neuropathy via TRPA1 Stimulation in Mice Dorsal Root Ganglion Is Correlated with Aluminum Accumulation.

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Jin-Hee Park

Full Text Available Oxaliplatin is a platinum-based anticancer drug used to treat metastatic colorectal, breast, and lung cancers. While oxaliplatin kills cancer cells effectively, it exhibits several side effects of varying severity. Neuropathic pain is commonly experienced during treatment with oxaliplatin. Patients describe symptoms of paresthesias or dysesthesias that are triggered by cold (acute neuropathy, or as abnormal sensory or motor function (chronic neuropathy. In particular, we found that aluminum levels were relatively high in some cancer patients suffering from neuropathic pain based on clinical observations. Based on these findings, we hypothesized that aluminum accumulation in the dorsal root ganglion (DRG in the course of oxaliplatin treatment exacerbates neuropathic pain. In mice injected with oxaliplatin (three cycles of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest, we detected cold allodynia using the acetone test, but not heat hyperalgesia using a hot plate. However, co-treatment with aluminum chloride (AlCl3∙6H2O; 7 mg/kg i.p. for 14 days: equivalent 0.78 mg/kg of elemental Al and oxaliplatin (1 cycle of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest synergistically induced cold allodynia as well as increased TRPAl mRNA and protein expression. Inductively Coupled Plasma Mass Spectrometry (ICP-MS analysis showed a significant increase in aluminum concentrations in the DRG of mice treated with aluminum chloride and oxaliplatin compared to aluminum chloride alone. Similarly, in a mouse induced-tumor model, aluminum concentrations were increased in DRG tissue and tumor cells after oxaliplatin treatment. Taken together, these findings suggest that aluminum accumulation in the DRG may exacerbate neuropathic pain in oxaliplatin-treated mice.

A melt refining method for uranium-contaminated aluminum

International Nuclear Information System (INIS)

Uda, T.; Iba, H.; Hanawa, K.

1986-01-01

Melt refining of uranium-contaminated aluminum which has been difficult to decontaminate because of the high reactivity of aluminum, was experimentally studied. Samples of contaminated aluminum and its alloys were melted after adding various halide fluxes at various melting temperatures and various melting times. Uranium concentration in the resulting ingots was determined. Effective flux compositions were mixtures of chlorides and fluorides, such as LiF, KCl, and BaCl 2 , at a fluoride/chloride mole ratio of 1 to 1.5. The removal of uranium from aluminum (the ''decontamination effect'') increased with decreasing melting temperature, but the time allowed for reaction had little influence. Pure aluminum was difficult to decontaminate from uranium; however, uranium could be removed from alloys containing magnesium. This was because the activity of the aluminum was decreased by formation of the intermetallic compound Al-Mg. With a flux of LiF-KCl-BaCl 2 and a temperature of 800 0 C, uranium added to give an initial concentration of 500 ppm was removed from a commercial alloy of aluminum, A5056, which contains 5% magnesium, to a final concentration of 0.6 ppm, which is near that in the initial aluminum alloy

Characterization of microstructure and mechanical properties of friction stir welded AlMg5- Al{sub 2}O{sub 3} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Babu, N. Kishore, E-mail: kishorebabu.nagumothu@empa.ch [Empa, Swiss Federal Laboratories for Material Science and Technology, Laboratory for Advanced Materials Processing, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Kallip, Kaspar; Leparoux, Marc [Empa, Swiss Federal Laboratories for Material Science and Technology, Laboratory for Advanced Materials Processing, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); AlOgab, Khaled A. [King Abdulaziz City for Science and Technology (KACST), National Centers for Advanced Materials, P O Box 6086, Riyadh, 11442 (Saudi Arabia); Reddy, G.M. [Defence Metallurical Research Laboratory, Hyderabad-500 058 (India); Talari, M.K. [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia)

2016-03-21

In the present study, powder metallurgy processed unmilled AlMg5, milled AlMg5 and milled AlMg5-0.5 vol% Al{sub 2}O{sub 3} nanocomposite have been successfully friction stir welded (FSW). The effect of friction stir welding on the evolution of weld microstructures; hardness and tensile properties were studied and discussed in detail. FSW of unmilled AlMg5 resulted in significant grain refinement and strain hardening in the nugget zone induced by the thermo-mechanical processing, thereby increasing the stir zone hardness and tensile strengths to 100 HV and 324 MPa when compared to 80 HV and 300 MPa of base metal, respectively. In contrast, the FSW of milled AlMg5 and milled AlMg5-0.5 vol% Al{sub 2}O{sub 3} samples showed a reduction in UTS values to 375 MPa and 401 MPa in the stir zone compared to 401 MPa and 483 MPa of respective base metal values. Transmission electron microscopic (TEM) investigation of weld stir zones revealed the homogenous distribution of Al{sub 4}C{sub 3} nanophases in milled AlMg5 and Al{sub 2}O{sub 3} nanoparticles in milled AlMg5-0.5 vol% Al{sub 2}O{sub 3} samples throughout the aluminium matrix. It was revealed that the pre-stored energy from the prior ball milling and hot pressing processes, higher deformation energy and grain boundary pinning effect due to the presence of reinforcement particles has resulted in a higher recrystallization tendency and retarded grain growth during FSW of milled samples. The welds prepared with milled AlMg5-0.5 vol% Al{sub 2}O{sub 3} exhibited higher hardness and tensile strength in the stir zone when compared to all other conditions which was attributed to Hall Petch effect due to fine grain size and Orowan strengthening effect due to Al{sub 2}O{sub 3} reinforcements.

Solubility and release of fenbufen intercalated in Mg, Al and Mg, Al, Fe layered double hydroxides (LDH): The effect of Eudragit S 100 covering

International Nuclear Information System (INIS)

Arco, M. del; Fernandez, A.; Martin, C.; Rives, V.

2010-01-01

Following different preparation routes, fenbufen has been intercalated in the interlayer space of layered double hydroxides with Mg 2+ and Al 3+ or Mg 2+ , Al 3+ and Fe 3+ in the layers. Well crystallized samples were obtained in most of the cases (intercalation was not observed by reconstruction of the MgAlFe matrix), with layer heights ranging between 16.1 and 18.8 A. The presence of the LDH increases the solubility of fenbufen, especially when used as a matrix. The dissolution rate of the drug decreases when the drug is intercalated, and is even lower in those systems containing iron; release takes place through ionic exchange with phosphate anions from the solution. Preparation of microspheres with Eudragit S 100 leads to solids with an homogeneous, smooth surface with efficient covering of the LDH surface, as drug release was not observed at pH lower than 7. - Graphical abstract: LDHs containing Mg, Al, Fe increase fenbufen solubility, release takes place through ionic exchange with phosphate anions from the medium. Spherical solids with homogeneous, smooth surface are formed when using Eudragit S 100, efficiently covering the LDH surface. Display Omitted

Research of Plasma Spraying Process on Aluminum-Magnesium Alloy

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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.

Alizarin red S dye removal from contaminated water on calcined [Mg/Al, Zn/Al and MgZn/Al]-LDH

Science.gov (United States)

Aissat, Miloud; Hamouda, Sara; Benhadria, Naceur; Chellali, Rachid; Bettahar, Noureddine

2018-05-01

The waste water rejected by the textile industries is loaded with organic dyes, responsible for the high color present in the effluents. Some dyes and / or their degradation products could be carcinogenic and may have mutagenic properties. The rapid growth of the global economy has caused many environmental problems with a huge pollution problem. The abuse use of chemicals product is an environmental toxicological problem. The consequences can be serious for water resources. In this perspective, our study comes to participate with new means of depollution using new materials with interesting properties in the treatment of pollution. Among these materials, LDHs whose synthesis is easy and inexpensive can be a tool in the treatment of water Polluted [1]. Our contribution consists in using HDL as a means of sorption of dyes which are considered as polluting agents of waters especially for the industry textile. This study considers the removal of the Alizarine Red S (AR) from water on calcined MgAl,ZnAL and MgZnAL-layered double hydroxides. The different LDH was prepared by copreprecipation method. The materials was obtained for molar ratios R =2 for the different LDH. The carbonated layered Calcination of these solids leads to the formation of mixed oxides which have the property of being able to be regenerated by adsorbing new anionic entities. Adsorbents and adsorption products were characterized by physicochemical techniques. The structural characterization of the material was carried out by X-ray diffraction, infrared spectroscopy (FTIR). Dosages of the polluted solutions were monitored by UV-Visible spectrometry.

A novel aluminum based nanocomposite with high strength and good ductility

Energy Technology Data Exchange (ETDEWEB)

Ramezanalizadeh, Hossein, E-mail: hralizadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Emamy, Masoud [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Shokouhimehr, Mohammadreza [School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul (Korea, Republic of)

2015-11-15

Aluminum based nanocomposite containing nano-sized Al{sub 3}Mg{sub 2} reinforcing was fabricated via mechanical milling followed by hot extrusion techniques. For this, Al and Al{sub 3}Mg{sub 2} powders were mixed mechanically and milled at different times (0, 2, 5, 7, 10, 15 and 20 h) to achieve Al–10 wt.% Al{sub 3}Mg{sub 2} composite powders. Hot extrusion of cold pressed powders was done at 400 °C with extrusion ratio of 6:1. Microstructures of the powders and consolidated materials were studied using transmission electron microscopy, scanning electron microscope and X-ray diffraction. Fracture surfaces were also investigated by scanning electron microscopy equipped with EDS analyzer. The results showed that an increase in milling time caused to reduce the grain size unlike the lattice strain of Al matrix. In addition, the fabricated composites exhibited homogeneous distribution and less agglomerations of the n-Al{sub 3}Mg{sub 2} with increasing milling time. The mechanical behavior of these nanocomposites was investigated by hardness and tensile tests, which revealed it has four times the strength of a conventional Al along with good ductility. It was found that the ultimate tensile strength (UTS) and elongation of the nanocomposites were significantly improved with increases in milling time up to 15 h. This improvement was attributed to the grain refinement strengthening and homogeneous distribution of the n-Al{sub 3}Mg{sub 2}. Fracture surfaces showed that the interfacial bonding between Al and Al{sub 3}Mg{sub 2} could be improved with increasing in milling time. Also HRTEM results from interface showed that a metallurgical clean interface and intimate contact between matrix and second phase. By extending the milling process up to 20 h, there was no significant improvement in mechanical behavior of materials, due to the completion of milling process and dynamic and static recovery of composite at higher milling times. - Highlights: • A novel aluminum

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.

Ecotoxicology of aluminum to fish and wildlife

Science.gov (United States)

Sparling, D.W.; Lowe, T.P.; Campbell, P.G.C.; Yokel, Robert A.; Golub, Mari S.

1997-01-01

The toxicity of aluminum has been studied extensively in fish, less so in invertebrates, amphibians, and birds, and not at all in reptiles and free-ranging mammals. For aquatic organisms, Al bioavailability and toxicity are intimately related to ambient pH; changes in ambient acidity may affect Al solubility, dissolved Al speciation, and organism sensitivity to Al. At moderate acidity (pH 5.5 to 7.0), fish and invertebrates may be stressed due to Al adsorption onto gill surfaces and subsequent asphyxiation. At pH 4.5 to 5.5, Al can impair ion regulation and augment the toxicity of H+. At lower pH, elevated Al can temporarily ameliorate the toxic effects of acidity by competing for binding sites with H+. Aluminum toxicity in aquatic environments is further affected by the concentration of ligands such as dissolved organic matter, fluoride, or sulfate, and of other cations such as Ca and Mg which compete for cellular binding sites. Although risk of Al toxicity is often based on a model of free-ion (Al3+) activity, recent evidence suggests that factors determining Al toxicity may be more complex. In general, aquatic invertebrates are less sensitive to Al toxicity and acidity than fish; thus acidified, Al-rich waters may actually reduce predation pressure. Fish may be affected by asphyxiation at moderate acidic conditions or electrolyte imbalances at lower pH. In amphibians, embryos and young larvae are typically more sensitive than older larvae. Early breeding amphibians, which lay eggs in ephemeral ponds and streams subject to spring runoff, are most at risk from Al and acidification; those that breed later in the year in lakes or rivers are least vulnerable. Birds and mammals are most likely exposed through dietary ingestion of soil or Al-contaminated foods. Concentrations > 1000 mg.kg-1 in food may be toxic to young birds and mammals. Clinical signs in these animals are consistent with rickets because Al precipitates with P in the gut. Suggestions for additional

Decarbonization process for carbothermically produced aluminum

Science.gov (United States)

Bruno, Marshall J.; Carkin, Gerald E.; DeYoung, David H.; Dunlap, Sr., Ronald M.

2015-06-30

A method of recovering aluminum is provided. An alloy melt having Al.sub.4C.sub.3 and aluminum is provided. This mixture is cooled and then a sufficient amount of a finely dispersed gas is added to the alloy melt at a temperature of about 700.degree. C. to about 900.degree. C. The aluminum recovered is a decarbonized carbothermically produced aluminum where the step of adding a sufficient amount of the finely dispersed gas effects separation of the aluminum from the Al.sub.4C.sub.3 precipitates by flotation, resulting in two phases with the Al.sub.4C.sub.3 precipitates being the upper layer and the decarbonized aluminum being the lower layer. The aluminum is then recovered from the Al.sub.4C.sub.3 precipitates through decanting.

Investigation of fluorine adsorption on nitrogen doped MgAl_2O_4 surface by first-principles

International Nuclear Information System (INIS)

Lv, Xiaojun; Xu, Zhenming; Li, Jie; Chen, Jiangan; Liu, Qingsheng

2016-01-01

Graphical abstract: First-principles calculations indicate that MgAl_2O_4 surface is fluorine-loving, but hydrophobic. N doped MgAl_2O_4 (100) surface structure shows the highest fluorine adsorption performance and fluorine atom is more preferentially adsorbed on the Mg-Al bridge site. The fluorine adsorption intensity follow this order: N doped MgAl_2O_4 (100) > Al_2O_3 (0001) > MgAl_2O_4 (100) > MgO (100). N doped MgAl_2O_4 is a promising candidate for fluorine removal. - Highlights: • MgAl_2O_4 surface is fluorine-loving, not hydrophilic. • Fluorine preferentially adsorbs on the Mg-Al bridge site. • Adsorption intensity follow this order: N doped MgAl_2O_4 > Al_2O_3 > MgAl_2O_4 > MgO. • Excellent adsorption performance attributes to electron compensation of N atom. • Nitrogen doped MgAl_2O_4 is a promising candidate for fluorine removal. - Abstract: The nature of fluorine adsorption on pure and N doped MgAl_2O_4 surface has been investigated by first-principles calculations based on the density functional theory. Calculated results indicate that MgAl_2O_4 surface is fluorine-loving, not hydrophilic. Nitrogen doped MgAl_2O_4 (100) surface shows the highest fluorine adsorption performance and fluorine atom preferentially adsorbs on the Mg-Al bridge site. The fluorine adsorption intensity follow this order: Nitrogen doped MgAl_2O_4 (100) > Al_2O_3 (0001) > MgAl_2O_4 (100) > MgO (100). In-depth PDOS analysis suggested that 2p orbitals of F atom strongly hybridized with 3s- and 3p-orbitals of Al atom contribute to its high adsorption intensity. According to the analysis of Hirshfeld charge, the excellent fluorine adsorption performance of nitrogen doped MgAl_2O_4 attributes to the electron compensation effect of nitrogen atom and strong electrostatic interactions. All these evidences demonstrate a fact nitrogen doped MgAl_2O_4 is a promising candidate for fluorine removal.

The microstructure and mechanical properties of Mg-3Al-3RE alloys

International Nuclear Information System (INIS)

Tian, X.; Wang, L.M.; Wang, J.L.; Liu, Y.B.; An, J.; Cao, Z.Y.

2008-01-01

The Mg-3Al-3RE alloys (RE, the cerium-rich or the yttrium-rich misch metal) were smelted in a resistance furnace under the protective flux from the Mg-RE master alloys and pure magnesium ingots. The microstructure and mechanical properties of samples prepared by steel mould casting method were investigated. Results show that the main phases of the alloys are α-Mg, Mg 17 Al 12 and Al-RE compounds, and the grain size reduced with the increasing content of the cerium-rich misch metal. Mg-3Al-2Ymm-1Cemm (Ymm, the yttrium-rich misch metal; Cemm, the Cerium-rich misch metal) exhibited the highest mechanical properties, that is UTS = 201 MPa and YS = 75 MPa, and ε = 8.2% at room temperature; UTS = 146 MPa, and YS = 70 MPa, ε = 18.2% at the temperature of 150 deg. C, respectively. Fracture surface analysis revealed that the Mg-3Al-2Ymm-1Cemm alloy has a mixed fracture feature at room temperature but ductile fracture at elevated temperature (150 deg. C)

Reduction of CaO and MgO Slag Components by Al in Liquid Fe

Science.gov (United States)

Mu, Haoyuan; Zhang, Tongsheng; Fruehan, Richard J.; Webler, Bryan A.

2018-05-01

This study documents laboratory-scale observations of reactions between Fe-Al alloys (0.1 to 2 wt pct Al) with slags and refractories. Al in steels is known to reduce oxide components in slag and refractory. With continued development of Al-containing Advanced High-Strength Steel (AHSS) grade, the effects of higher Al must be examined because reduction of components such as CaO and MgO could lead to uncontrolled modification of non-metallic inclusions. This may lead to castability or in-service performance problems. In this work, Fe-Al alloys and CaO-MgO-Al2O3 slags were melted in an MgO crucible and samples were taken at various times up to 60 minutes. Inclusions from these samples were characterized using an automated scanning electron microscope equipped with energy dispersive x-ray analysis (SEM/EDS). Initially Al2O3 inclusions were modified to MgAl2O4, then MgO, then MgO + CaO-Al2O3-MgO liquid inclusions. Modification of the inclusions was faster at higher Al levels. Very little Ca modification was observed except at 2 wt pct Al level. The thermodynamic feasibility of inclusion modification and some of the mass transfer considerations that may have led to the differences in the Mg and Ca modification behavior were discussed.

Karakterisasi Paduan AlMgSi Untuk Kelongsong Bahan Bakar U3Si2/Al Dengan Densitas Uranium 5,2 gU/cm3

Directory of Open Access Journals (Sweden)

Aslina Br. Ginting

2018-03-01

Full Text Available Meningkatnya densitas uranium dari 2,96 gU/cm3 menjadi 5,2 gU/cm3 bahan bakar U3Si2/Al harus diikuti dengan penggunaan kelongsong yang kompatibel. Bahan bakar berdensitas tinggi mempunyai kekerasan yang tinggi, sehingga bila menggunakan paduan AlMg2 sebagai kelongsong dapat menyebabkan terjadi dogbone pada saat perolan. Selain fenomena dogbone, pada saat bahan bakar tersebut digunakan di reaktor dapat terjadi swelling karena meningkatnya hasil fisi maupun burn up. Oleh karena itu, perlu dicari pengganti bahan kelongsong untuk bahan bakar U3Si2/Al densitas tinggi. Pada penelitian ini telah dilakukan karakterisasi paduan AlMgSi sebagai kandidat pengganti kelongsong AlMg2. Karakterisasi yang dilakukan meliputi analisis termal, kekerasan, mikrostruktur dan laju korosi. Analisis termal dilakukan menggunakan DTA (Differential Thermal Analysis dan DSC (Differential Scanning Calorimetry. Analisis kekerasan menggunakan alat uji kekerasan mikro, mikrostruktur menggunakan SEM (Scanning Electron Microscope dan analisis laju korosi dilakukan dengan pemanasan pada temperatur 150 oC selama 77 jam di dalam autoclave. Hasil analisis menunjukkan bahwa kelongsong AlMgSi maupun AlMg2 mempunyai kompatibilitas panas dengan bahan bakar U3Si2/Al cukup stabil hingga temperatur 650 oC. Kelongsong AlMgSi mempunyai kekerasan sebesar 115 HVN dan kelongsong AlMg2 sebesar 70,1 HVN. Sementara itu, analisis mikrostruktur menunjukkan bahwa morfologi ikatan antarmuka (interface bonding kelongsong AlMgSi lebih baik dari kelongsong AlMg2, demikian halnya dengan laju korosi bahwa kelongsong AlMgSi mempunyai laju korosi lebih kecil dibanding kelongsong AlMg2. Hasil karakterisasi termal, kekerasan, mikrostruktur dan laju korosi menunjukkan bahwa PEB U3Si2/Al densitas 5,2 gU/cm3 menggunakan kelongsong AlMgSi lebih baik dibanding PEB U3Si2/Al  densitas 5,2 gU/cm3  menggunakan kelongsong AlMg2. Kata kunci: U3Si2/Al, densitas 5,2 gU/cm3, kelongsong AlMgSi dan AlMg2.

Converting hcp Mg-Al-Zn alloy into bcc Mg-Li-Al-Zn alloy by electrolytic deposition and diffusion of reduced lithium atoms in a molten salt electrolyte LiCl-KCl

International Nuclear Information System (INIS)

Lin, M.C.; Tsai, C.Y.; Uan, J.Y.

2007-01-01

A body-centered cubic (bcc) Mg-12Li-9Al-1Zn (wt.%) alloy was fabricated in air by electrolysis from LiCl-KCl molten salt at 500 deg. C. Electrolytic deposition of Li atoms on cathode (Mg-Al-Zn alloy) and diffusion of the Li atoms formed the bcc Mg-Li-Al-Zn alloy with 12 wt.% Li and only 0.264 wt.% K. Low K concentration in the bcc Mg alloy strip after the electrolysis process resulted from 47% atomic size misfit between K and Mg atoms and low solubility of K in Mg matrix

Low Temperature Mechanical Properties of Scandium-Modified Al-Zn-Mg-Cu Alloys

National Research Council Canada - National Science Library

Senkov, O

2002-01-01

Tensile properties of three wrought alloys, (1) Al-10Zn-3Mg-1.2Cu-0.15Zr, (2) Al-10Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc, and (3) Al-12Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc were studied in T6 and T7 conditions at 298K and 77K...

Study on synthesizing Mg/Al layered double hydroxides at different pHs

Directory of Open Access Journals (Sweden)

E Otgonjargal

2014-12-01

Full Text Available Mg/Al layered double hydroxide (LDH was successfully synthesized at different pHs values. The Mg/AL LDH was well characterized by X-Ray diffraction and Fourier transform infrared analysis. The morphology of the LDH was observed using Scanning electron microscopy with energy dispersive X-ray spectroscopy. The influence of pH values on the morphology of the Mg/Al LDHs were studied. The result showed that the well-synthesized Mg/Al LDHs could be obtained when the pH value was about 10.0 at room temperature.DOI: http://doi.dx.org/10.5564/mjc.v15i0.319 Mongolian Journal of Chemistry 15 (41, 2014, p36-39

Microstructure and mechanical properties of friction stir welded Al/Mg2Si metal matrix cast composite

International Nuclear Information System (INIS)

Nami, H.; Adgi, H.; Sharifitabar, M.; Shamabadi, H.

2011-01-01

In this research, friction stir weldability of 15 wt.% Mg 2 Si particulate aluminum matrix cast composite and effects of tool rotation speed and number of welding passes on microstructure and mechanical properties of the joints were investigated. Microstructural observations were carried out by employing optical and scanning electron microscopy of the cross sections perpendicular to the tool traverse direction. Mechanical properties including microhardness and tensile strength were evaluated in detail. The results showed fragmentation of Mg 2 Si particles and Mg 2 Si needles existing in eutectic structure in stir zone. Also, homogeneous distribution of Mg 2 Si particles was observed in the stir zone as a result of stirring with high plastic strains. Tension test results indicated that tensile strength of the joint had an optimum at 1120 rpm tool rotation speed and decreased with increasing of the number of welding passes. Hardness of the joint increased due to modification of solidification microstructure of the base composite. This research indicates that friction stir welding is a good candidate for joining of 15 wt.% Mg 2 Si aluminum matrix composite castings.

Sputter-deposited Mg-Al-O thin films: linking molecular dynamics simulations to experiments

International Nuclear Information System (INIS)

Georgieva, V; Bogaerts, A; Saraiva, M; Depla, D; Jehanathan, N; Lebelev, O I

2009-01-01

Using a molecular dynamics model the crystallinity of Mg x Al y O z thin films with a variation in the stoichiometry of the thin film is studied at operating conditions similar to the experimental operating conditions of a dual magnetron sputter deposition system. The films are deposited on a crystalline or amorphous substrate. The Mg metal content in the film ranged from 100% (i.e. MgO film) to 0% (i.e. Al 2 O 3 film). The radial distribution function and density of the films are calculated. The results are compared with x-ray diffraction and transmission electron microscopy analyses of experimentally deposited thin films by the dual magnetron reactive sputtering process. Both simulation and experimental results show that the structure of the Mg-Al-O film varies from crystalline to amorphous when the Mg concentration decreases. It seems that the crystalline Mg-Al-O films have a MgO structure with Al atoms in between.

Novel strip-cast Mg/Al clad sheets with excellent tensile and interfacial bonding properties.

Science.gov (United States)

Kim, Jung-Su; Lee, Dong Ho; Jung, Seung-Pill; Lee, Kwang Seok; Kim, Ki Jong; Kim, Hyoung Seop; Lee, Byeong-Joo; Chang, Young Won; Yuh, Junhan; Lee, Sunghak

2016-06-01

In order to broaden industrial applications of Mg alloys, as lightest-weight metal alloys in practical uses, many efforts have been dedicated to manufacture various clad sheets which can complement inherent shortcomings of Mg alloys. Here, we present a new fabrication method of Mg/Al clad sheets by bonding thin Al alloy sheet on to Mg alloy melt during strip casting. In the as-strip-cast Mg/Al clad sheet, homogeneously distributed equi-axed dendrites existed in the Mg alloy side, and two types of thin reaction layers, i.e., γ (Mg17Al12) and β (Mg2Al3) phases, were formed along the Mg/Al interface. After post-treatments (homogenization, warm rolling, and annealing), the interfacial layers were deformed in a sawtooth shape by forming deformation bands in the Mg alloy and interfacial layers, which favorably led to dramatic improvement in tensile and interfacial bonding properties. This work presents new applications to multi-functional lightweight alloy sheets requiring excellent formability, surface quality, and corrosion resistance as well as tensile and interfacial bonding properties.

Acute Toxicity and Accumulation of Iron, Manganese and, Aluminum in Caspian Kutum Fish (Rutilus kutum

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Saeed Zahedi

2014-03-01

Full Text Available Background: Iron, manganese, and aluminum are three abundant metals on earth and their concentrations have increased in aquatic environments as a result of natural and industrial activities. This study was undertaken to report the median acute toxicity (LC50 and accumulation of the sub-lethal concentration (10% 96-h LC50 of iron (Fe, manganese (Mn and aluminum (Al in kutum (Rutilus kutum fingerlings. Methods: For the 96-h LC50, the fish were exposed to concentrations of 105, 111, 117, 123, 129 and 135 mg/l of Fe and 40, 45, 50, 55, 60, and 65 mg/l of Mn and 18, 22, 26, 30, 34 and 38 mg/l of aluminum for 4 days. For sublethal exposure, they were exposed to mediums with concentrations of 12.3, 5.4 and 2.9 for Fe, Mn, and aluminum, respectively. Metal concentrations were determined by atomic absorption spectrophotometry in the gill tissues. Results: Probit analysis showed the 96-h LC50 values of 122.98, 54.39, and 28.89 mg/l for Fe, Mn, and aluminum, respectively. Sub-lethal tests were conducted with nominal concentrations of 12.3, 5.4, and 2.9 mg/l of Fe, Mn, and aluminum for four days, respectively. Significant accumulations were observed in gills for all tested metals as compared to the control groups in short-term exposure (P<0.05. Conclusion: Obtained results clearly show that aluminum is the most toxic metal among tested ones for kutum fingerlings and it has the highest branchial AF value during sub-lethal exposure.

Joining thick section aluminum to steel with suppressed FeAl intermetallic formation via friction stir dovetailing

Energy Technology Data Exchange (ETDEWEB)

Reza-E-Rabby, Md.; Ross, Kenneth; Overman, Nicole R.; Olszta, Matthew J.; McDonnell, Martin; Whalen, Scott A.

2018-04-01

A new solid-phase technique called friction stir dovetailing (FSD) has been developed for joining thick section aluminum to steel. In FSD, mechanical interlocks are formed at the aluminum-steel interface and are reinforced by metallurgical bonds where intermetallic growth has been uniquely suppressed. Lap shear testing shows superior strength and extension at failure compared to popular friction stir approaches where metallurgical bonding is the only joining mechanism. High resolution microscopy revealed the presence of a 40-70 nm interlayer having a composition of 76.4 at% Al, 18.4 at% Fe, and 5.2 at% Si, suggestive of limited FeAl3 intermetallic formation.

Enhanced fluoride adsorption using Al (III) modified calcium hydroxyapatite

International Nuclear Information System (INIS)

Nie, Yulun; Hu, Chun; Kong, Chuipeng

2012-01-01

Highlights: ► Al modified hydroxyapatite possessed a higher defluoridation capacity of 32.57 mg/g. ► Hydroxyl groups on the surface of Al-HAP was the adsorption sites for F − removal. ► Enhanced F − removal over Al-HAP was attributed to the modification with aluminum. - Abstract: Aluminum-modified hydroxyapatite (Al-HAP) was prepared and characterized using XRD and BET analyses. Al-HAP possessed higher defluoridation capacity (DC) of 32.57 mgF − /g than unmodified hydroxyapatite (HAP) which showed a DC of 16.38 mgF − /g. The effect of Al/Ca atomic ratio in Al-HAP, solution pH and co-existing anions was further studied. The results indicated that the adsorption data could be well described by the Langmuir isotherm model and the adsorption kinetic followed the pseudo-second-order model. The pH changes during the adsorption process suggested that the -OH on the surface of Al-HAP was the adsorption sites. The more adsorption sites were formed on Al modified HAP, which possessed abundant surface hydroxyl groups, resulting in higher efficiency of F − removal. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated in order to understand the nature of adsorption process. The results revealed that the adsorption reaction was a spontaneous and endothermic process.

Microstructure and wear properties of laser cladding Ti-Al-Fe-B coatings on AA2024 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Xu Jiang [Laser Processing Research Center, Mechanical Engineering Department, Tsinghua University, Beijing 10084 (China)]. E-mail: xujiang73@sina.com.cn; Liu Wenjin [Laser Processing Research Center, Mechanical Engineering Department, Tsinghua University, Beijing 10084 (China); Kan Yide [Laser Processing Research Center, Mechanical Engineering Department, Tsinghua University, Beijing 10084 (China); Zhong Minlin [Laser Processing Research Center, Mechanical Engineering Department, Tsinghua University, Beijing 10084 (China)

2006-07-01

In order to improve wear resistance of aluminum alloy, the in situ synthesized TiB{sub 2} and Ti{sub 3}B{sub 4} peritectic composite particulate reinforced metal matrix composite formed on the 2024 aluminum alloy by laser cladding with a powder mixture of Fe coated Boron, Ti and Al was successfully achieved using 3 kW CW CO{sub 2} laser. The laser cladding coating present excellent bonding with aluminum alloy substrate. The chemical composition, microstructure and phase structure of the composite clad coating were analyzed by energy dispersive X-ray spectroscopy (EDX), SEM and XRD. The typical microstructure of composite coating is composed of TiB{sub 2}, Ti{sub 3}B{sub 4}, Al{sub 3}Ti, Al{sub 3}Fe and {alpha}-Al. The surface hardness of cladding coating is increased with the amount of added Fe coated B and Ti powder which determines the amount of TiB{sub 2} and Ti{sub 3}B{sub 4} peritectic composite particulate, and obviously higher than that of substrate. The wear tests were carried out using a FALEX-6 type pin-on-disc machine. The test results show that the composite coatings with the in situ synthesized TiB{sub 2} and Ti{sub 3}B{sub 4} peritectic improve wear resistance when compared with the as-received Al substrate.

Microstructure evolution and texture development in thermomechanically processed Mg-Li-Al based alloys

Energy Technology Data Exchange (ETDEWEB)

Kumar, Vinod [Department of Materials Science and Engineering, IIT Kanpur (India); Govind [Vikram Sarabhai Space Center, Trivandrum (India); Shekhar, Rajiv; Balasubramaniam, R. [Department of Materials Science and Engineering, IIT Kanpur (India); Balani, Kantesh, E-mail: kbalani@iitk.ac.in [Department of Materials Science and Engineering, IIT Kanpur (India)

2012-06-15

Highlights: Black-Right-Pointing-Pointer Thermomechanical processing of novel LAT 971 and LATZ 9531 Mg-Al-Li based alloys. Black-Right-Pointing-Pointer Microstructural deviation from the equilibrium phase diagram. Black-Right-Pointing-Pointer Disparity in texture of these alloys after hot-rolling (recrystallization and grain growth). Black-Right-Pointing-Pointer Role of alloying and phase distribution in affecting the texture/interplaner spacing. - Abstract: In the present study, the influence of alloying and thermomechanical processing on the microstructure and texture evolution on the two Mg-Li-Al based alloys, namely Mg-9 wt% Li-7 wt% Al-1 wt% Sn (LAT971) and Mg-9 wt% Li-5 wt% Al-3 wt% Sn-1 wt% Zn (LATZ9531) has been elicited. Novel Mg-Li-Al based alloys were cast (induction melting under protective atmosphere) followed by hot rolling at {approx}573 K with a cumulative reduction of five. A contrary dual phase dendritic microstructure rich in {alpha}-Mg, instead of {beta}-Li phase predicted by equilibrium phase diagram of Mg-Li binary alloy was observed. Preferential presence of Mg-Li-Sn primary precipitates (size 4-10 {mu}m) within {alpha}-Mg phase and Mg-Li-Al secondary precipitates (<3 {mu}m) interspersed in {beta}-Li indicated their degree of dissolution during hot-rolling and homogenization in the dual phase matrix. Presence of Al, Sn and Zn alloying elements in the Mg-Li based alloy has resulted an unusual dual-phase microstructure, change in the lattice parameter, and intriguing texture evolution after hot-rolling of cast LAT 971 and LATZ9531 alloy. Strong texture was absent in the as-cast samples whereas texture development after hot-rolling revealed an increased activity of the non-basal (101{sup Macron }0) slip planes. The quantification of the grain average misorientation (less than 2 Degree-Sign ) using electron backscattered diffraction confirmed the presence of strain free grains in majority of the grains (fraction >0.75) after hot-rolling of Mg-Li-Al

Stimulation of [3H]ouabain binding to rat synaptosomal (Na+ + K+)-ATPase by aluminum

International Nuclear Information System (INIS)

Caspers, M.L.; Dow, M.J.; Kwaiser, T.M.

1991-01-01

The objective of this study was to investigate the effect of aluminum on the (Na + + K + )-ATPase. Synaptosomes were prepared from the cerebral cortices of adult, male Sprague-Dawley rats. The stimulation of [ 3 H]ouabain binding to the high affinity isoform of the (Na + + K + )-ATPase produced by AlCl 3 developed slowly, with a maximum effect observed after a 40 min preincubation. AlCl 3 produced a 26.5% stimulation in [ 3 H]ouabain binding to the synaptosomal (Na + + K + )-ATPase and this stimulation increased to 33.3% at 100 μM. Scatchard analysis of [ 3 H]ouabain binding data in the presence of 100 μM AlCl 3 yielded a B max of 79.4 ± 3.5 pmol/mg protein, significantly elevated from the B max value obtained in the absence of aluminum. The K D values were similar in the presence or absence of aluminum. In summary, aluminum affects the functioning of the synaptosomal (Na + + K + )-ATPase. This may contribute, at least in part, to the disruption of neuronal function associated with disorders where elevated aluminum content in the CNS is noted

BoALMT1, an Al-Induced Malate Transporter in Cabbage, Enhances Aluminum Tolerance in Arabidopsis thaliana

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Lei Zhang

2018-01-01

Full Text Available Aluminum (Al is present in approximately 50% of the arable land worldwide and is regarded as the main limiting factor of crop yield on acidic soil. Al-induced root malate efflux plays an important role in the Al tolerance of plants. Here, the aluminum induced malate transporter BoALMT1 (KF322104 was cloned from cabbage (Brassica oleracea. BoALMT1 showed higher expression in roots than in shoots. The expression of BoALMT1 was specifically induced by Al treatment, but not the trivalent cations lanthanum (La, cadmium (Cd, zinc (Zn, or copper (Cu. Subcellular localization studies were performed in onion epidermal cells and revealed that BoALMT1 was localized at the plasma membrane. Scanning Ion-selective Electrode Technique was used to analyze H+ flux. Xenopus oocytes and Arabidopsis thaliana expressing BoALMT1 excreted more H+ under Al treatment. Overexpressing BoALMT1 in transgenic Arabidopsis resulted in enhanced Al tolerance and increased malate secretion. The results suggested that BoALMT1 functions as an Al-resistant gene and encodes a malate transporter. Expressing BoALMT1 in Xenopus oocytes or A. thaliana indicated that BoALMT1 could increase malate secretion and H+ efflux to resist Al tolerance.

Thermodynamic analysis and experimental study on the oxidation of the Zn-Al-Mg coating baths

Energy Technology Data Exchange (ETDEWEB)

Su, Xuping, E-mail: sxping@cczu.edu.cn [Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, 213164 Jiangsu (China); Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, 213164 Jiangsu (China); Zhou, Jie; Wang, Jianhua; Wu, Changjun; Liu, Ya; Tu, Hao; Peng, Haoping [Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, 213164 Jiangsu (China)

2017-02-28

Highlights: • The surface oxidation products of the Zn-Al-Mg melt were analyzed with XPS. • Certain Al must be added in bath containing Mg to get stable galvanizing melts. • The oxidation products vary with the bath composition. • Oxidation can be predicted in galvanizing by using the calculated phase diagrams. • The thermodynamic analysis can be used to design the practical bath melts. - Abstract: Surface oxidation of molten Zn-6Al baths containing 0.0, 3.0 and 6.0 wt. % Mg were analyzed using X-ray photoelectron spectroscopy. γ-Al{sub 2}O{sub 3} is formed on the surface of the Zn-6Al bath, while MgAl{sub 2}O{sub 4} and MgO occur at 460 °C in the Zn-6Al-3Mg and Zn-6Al-6Mg baths, respectively. Thermodynamic analysis on the oxidation of the Zn-Al-Mg baths was performed. Calculated phase diagrams at 460 °C and 560 °C show good agreements with the experimental results. MgO or MgAl{sub 2}O{sub 4} exists in almost the entire composition range of the calculated oxidation diagrams. According to the calculation, oxidation products depend on the composition and temperature of the baths. The primary and secondary oxidation products of the Zn-Al-Mg baths can be reasonably explained by oxidation phase diagrams. Utilizing these results, the favorable practical bath melts and operating conditions can be designed.

Thermodynamic investigation on the formation of inclusions containing MgAl2O4 spinel during 16Cr-14Ni austenitic stainless steel manufacturing processes

International Nuclear Information System (INIS)

Park, J.H.

2008-01-01

The formation mechanism of the inclusions containing the spinel crystals has been developed based on the experimental results for the equilibrium between the Fe-16%Cr-14%Ni stainless steel melts and the inclusions as well as the compositions of the inclusions in the plant samples. In the laboratory experiments, the molar content of alumina in the inclusions linearly increases with increasing content of aluminum according to the theoretical expectation and the composition of the inclusions could be described as a function of the activity of aluminum and silicon. From the analysis of the plant samples, the content of MgO and Al 2 O 3 in the calcium silicate type inclusions continuously increases as the steel melts transfer from AOD converter to LT processes and thus, the spinel phase could be crystallized and grown in the calcium silicate matrix during cooling through tundish to cast slabs. On the other hand, the manganese silicate type inclusions were observed after tapping molten steel to the ladle, and then the MnO and Cr 2 O 3 (and SiO 2 ) in the inclusions were reduced by silicon and aluminum through LT to CC mold. The fraction of the inclusions containing spinel crystals at cast slabs was null at (Al 2 O 3 ) 2 O 3 ) > 20 mass%

The superconducting gaps of C-substituted and Al-substituted MgB2 single crystals by point-contact spectroscopy

International Nuclear Information System (INIS)

Daghero, D.; Gonnelli, R.S.; Ummarino, G.A.; Calzolari, A.; Dellarocca, Valeria; Stepanov, V.A.; Zhigadlo, N.; Kazakov, S.M.; Karpinski, J.

2005-01-01

We studied the effects of carbon and aluminum substitutions on the gaps of the two-band superconductor MgB 2 by means of point-contact measurements in Mg(B 1-x C x ) 2 and Mg 1-y Al y B 2 single crystals with 0≤x≤0.132 and 0≤y≤0.21. The gap amplitudes, Δ ω and Δ π , were determined by fitting the conductance curves of the point contacts with the standard Blonder-Tinkham-Klapwijk (BTK) model generalized to the two-band case. Whenever possible, their values were confirmed by the independent fit (with a single-band BTK model) of the partial contribution of the two bands to the conductance, separated by means of a suitable magnetic field B*. In C-substituted crystals, the two gaps remain clearly distinct up to x∝0.10, but at x=0.132 we observed for the first time their merging into a single gap Δ≅3 meV with a gap ratio 2Δ=k B T c close to the standard BCS value. In Al-substituted crystals, we found no evidence of this gap merging. Instead, Δ π reaches the value 0.4 meV at y=0.21, where Δ π saturates at about 4 meV. These results are compared with other recent experimental findings in polycrystals and with the predictions of the models for multiband superconductivity. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Effects of aluminum and copper chill on mechanical properties and microstructures of Cu-Zn-Al alloys with sand casting

Science.gov (United States)

Ardhyananta, Hosta; Wibisono, Alvian Toto; Ramadhani, Mavindra; Widyastuti, Farid, Muhammad; Gumilang, Muhammad Shena

2018-04-01

Cu-Zn-Al alloy is one type of brass, which has high strength and high corrosion resistant. It has been applied on ship propellers and marine equipment. In this research, the addition of aluminum (Al) with variation of 1, 2, 3, 4% aluminum to know the effect on mechanical properties and micro structure at casting process using a copper chill and without copper chill. This alloy is melted using furnace in 1100°C without holding. Then, the molten metal is poured into the mold with copper chill and without copper chill. The speciment of Cu-Zn-Al alloy were chracterized by using Optical Emission Spectroscopy (OES), Metallography Test, X-Ray Diffraction (XRD), Hardness Test of Rockwell B and Charpy Impact Test. The result is the addition of aluminum and the use of copper chill on the molds can reduce the grain size, increases the value of hardness and impact.

THE THERMODYNAMIC PROPERTIES OF MELTS OF DOUBLE SYSTEM MgO – Al2O3, MgO – SiO2, MgO – CaF2, Al2O3 – SiO2, Al2O3 – CaF2, SiO2 – CaF2

Directory of Open Access Journals (Sweden)

В. Судавцова

2012-04-01

Full Text Available Methodology of prognostication of thermodynamics properties of melts is presented from the coordinatesof liquidus of diagram of the state in area of equilibria a hard component is solution, on which energies ofmixing of Gibbs are expected in the double border systems of MgO – Al2O3, MgO – SiO2, MgO – CaF2,Al2O3 – SiO2, Al2O3 - CaF2, SiO2 - CaF2. For the areas of equilibrium there is quasibinary connection(MgAl2O4, Mg2SiO4, Al6Si2O13 – a grout at calculations was used equalization of Hauffe-Wagner. Theobtained data comport with literary

Aluminum anode for aluminum-air battery - Part II: Influence of In addition on the electrochemical characteristics of Al-Zn alloy in alkaline solution

Science.gov (United States)

Park, In-Jun; Choi, Seok-Ryul; Kim, Jung-Gu

2017-07-01

Effects of Zn and In additions on the aluminum anode for Al-air battery in alkaline solution are examined by the self-corrosion rate, cell voltage, current-voltage characteristics, anodic polarization, discharge performance and AC impedance measurements. The passivation behavior of Zn-added anode during anodic polarization decreases the discharge performance of Al-air battery. The addition of In to Al-Zn anode reduces the formation of Zn passivation film by repeated adsorption and desorption behavior of In ion onto anode surface. The attenuated Zn passive layer by In ion attack leads to the improvement of discharge performance of Al-air battery.

Newly synthesized MgAl2Ge2: A first-principles comparison with its silicide and carbide counterparts

Science.gov (United States)

Tanveer Karim, A. M. M.; Hadi, M. A.; Alam, M. A.; Parvin, F.; Naqib, S. H.; Islam, A. K. M. A.

2018-06-01

Using plane-wave pseudopotential density functional theory (DFT), the first-principle calculations are performed to investigate the structural aspects, mechanical behaviors and electronic features of the newly synthesized CaAl2Si2-prototype intermetallic compound, MgAl2Ge2 for the first time and the results are compared with those calculated for its silicide and carbide counterparts MgAl2Si2 and MgAl2C2. The calculated lattice constants agree fairly well with their corresponding experimental values. The estimated elastic tensors satisfy the mechanical stability conditions for MgAl2Ge2 along with MgAl2Si2 and MgAl2C2. The level of elastic anisotropy increases following the sequence of X-elements Ge → Si → C. MgAl2Ge2 and MgAl2Si2 are expected to be ductile and damage tolerant, while MgAl2C2 is a brittle one. MgAl2Ge2 and MgAl2Si2 should exhibit better thermal shock resistance and low thermal conductivity and accordingly these can be used as thermal barrier coating (TBC) materials. The Debye temperature of MgAl2Ge2 is lowest among three intermetallic compounds. MgAl2Ge2 and MgAl2Si2 should exhibit metallic conductivity; while the dual characters of weak-metals and semiconductors are expected for MgAl2C2. The values of theoretical Vickers hardness for MgAl2Ge2, MgAl2Si2, and MgAl2C2 are 3.3, 2.7, and 7.7 GPa, respectively, indicating that these three intermetallics are soft and easily machinable.

Divorced Eutectic Solidification of Mg-Al Alloys

Science.gov (United States)

Monas, Alexander; Shchyglo, Oleg; Kim, Se-Jong; Yim, Chang Dong; Höche, Daniel; Steinbach, Ingo

2015-08-01

We present simulations of the nucleation and equiaxed dendritic growth of the primary hexagonal close-packed -Mg phase followed by the nucleation of the -phase in interdendritic regions. A zoomed-in region of a melt channel under eutectic conditions is investigated and compared with experiments. The presented simulations allow prediction of the final properties of an alloy based on process parameters. The obtained results give insight into the solidification processes governing the microstructure formation of Mg-Al alloys, allowing their targeted design for different applications.

Creep behaviour of a casting titanium carbide reinforced AlSi12CuNiMg piston alloy at elevated temperatures; Hochtemperaturkriechverhalten der schmelzmetallurgisch hergestellten dispersionsverstaerkten Kolbenlegierung AlSi12CuNiMg

Energy Technology Data Exchange (ETDEWEB)

Michel, S.; Scholz, A. [Zentrum fuer Konstruktionswerkstoffe, TU Darmstadt (Germany); Tonn, B. [Institut fuer Metallurgie, TU Clausthal (Germany); Zak, H.

2012-03-15

This paper deals with the creep behaviour of the titanium carbide reinforced AlSi12CuNiMg piston alloy at 350 C and its comparison to the conventional AlSi12Cu4Ni2MgTiZr piston alloy. With only 0,02 vol-% TiC reinforcement the creep strength and creep rupture strength of the AlSi12CuNiMg piston alloy are significantly improved and reach the level of the expensive AlSi12Cu4Ni2MgTiZr alloy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Morphologies and growth mechanisms of the eutectic particles in as-cast Al-Mg-Sc alloy; Morphologien und Wachstumsmechanismen eutektischer Partikel in Al-Mg-Sc-Legierung im Gusszustand

Energy Technology Data Exchange (ETDEWEB)

Pan, Dejiang; Zhou, Shi' ang; Li, Heng [Hefei Univ. of Technology (China); Zhang, Zhen; Wu, Yucheng [Laboratories of Nonferrous Metal Material and Processing Engineering of Anhui Province, Hefei (China); Li, Ming [Anhui Jianghuai Automobile Co., Ltd, Hefei (China)

2017-04-15

Primary particles with faceted cubic morphology were produced in as-cast Al-Mg alloy due to the addition of Sc. The cross-section of the particles revealed some eutectic structure composed of multilayer of 'Al{sub 3}Sc + α-Al + Al{sub 3}Sc..'. At the cooling rate of 200 - 300 K/s, Al{sub 3}Sc primary phase nucleated initially on oxides within the melt and developed to a cubic structure with a 'cellular-dendritic' mode of growth. The formation of α-Al structural shells was attributed as a reason for the segregation of Mg-rich lamellar dendrites at later stages. A growth mechanism for multilayer structure was proposed using the results presented.

Effect of Ni on eutectic structural evolution in hypereutectic Al-Mg2Si cast alloys

International Nuclear Information System (INIS)

Li Chong; Wu Yaping; Li Hui; Wu Yuying; Liu Xiangfa

2010-01-01

Research highlights: → By the injection of rod-like NiAl 3 phase in Al-Mg 2 Si alloys, Al-Mg 2 Si binary eutectic structure gradually evolves into Al-Mg 2 Si-NiAl 3 ternary eutectic. → The ternary eutectic presents a unique double rod structure that rod-like NiAl 3 and Mg 2 Si uniformly distribute in Al matrix. → The mechanism of structural evolution was analyzed in terms of the detailed microstructural observations. → The high temperature (350 deg. C) tensile strength of the alloy increases by 23% due to the eutectic structural evolution. - Abstract: The aim of this work is to investigate the eutectic structural evolution of hypereutectic Al-20% Mg 2 Si with Ni addition under a gravity casting process. Three-dimensional morphologies of eutectic phases were observed in detail using field emission scanning electron microscopy, after Al matrix was removed by deep etching or extraction. The results show that Al-Mg 2 Si binary eutectic gradually evolves into Al-Mg 2 Si-NiAl 3 ternary eutectic with the increase of Ni content, and flake-like eutectic Mg 2 Si transforms into rods. The ternary eutectic presents a unique double rod structure that rod-like NiAl 3 and Mg 2 Si uniformly distribute in Al matrix. Further, the high temperature (350 deg. C) tensile strength of the alloy increases by 23% due to the eutectic structure evolution, and the mechanism of structural evolution was discussed and analyzed in terms of the detailed microstructural observations.

Study on effects of powder and flake chemistry and morphology on the properties of Al-Cu-Mg-X-X-X powder metallurgy advanced aluminum alloys

Science.gov (United States)

Meschter, P. J.; Lederich, R. J.; Oneal, J. E.; Pao, P. S.

1985-01-01

The effects of alloy chemistry and particulate morphology on consolidation behavior and consolidated product properties in rapid solidification processed, powder-metallurgical Al-3Li-1.5Cu-1Mg-0.5Co-0.2Zr and Al-4.4Cu-1.5Mg-Fe-Ni-0.2Zr extrusions and forgings were studied. Microstructures and mechanical properties of both alloys are largely unaffected by particulate production method (vacuum atomization, ultrasonic atomization, or twin-roller quenching) and by particulate solidification rates between 1000 and 100,000 K/s. Consolidation processing by canning, cold compaction, degassing, and hot extrusion is sufficient to yield mechanical properties in the non-Li-containing alloy extrusions which are similar to those of 7075-Al, but ductilities and fracture toughnesses are inferior owing to poor interparticle bonding caused by lack of a vacuum-hot-pressing step during consolidation. Mechanical properties of extrusions are superior to those of forgings owing to the stronger textures produced by the more severe hot working during extrusion. The effects on mechanical properties of dispersoid size and volume fraction, substructural refinement, solid solution strengthening by Mg, and precipitate size and distribution are elucidated for both alloy types.

Grain Growth in Nanocrystalline Mg-Al Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kruska, Karen; Rohatgi, Aashish; Vemuri, Venkata Rama Ses; Kovarik, Libor; Moser, Trevor H.; Evans, James E.; Browning, Nigel D.

2017-10-05

An improved understanding of grain growth kinetics in nanocrystalline materials, and in metals and alloys in general, is of continuing interest to the scientific community. In this study, Mg - Al thin films containing ~10 wt.% Al and with 14.5 nm average grain size were produced by magnetron-sputtering and subjected to heat-treatments. The grain growth evolution in the early stages of heat treatment at 423 K (150 °C), 473 K (200 °C) and 573K (300 °C) was observed with transmission electron microscopy and analyzed based upon the classical equation developed by Burke and Turnbull. The grain growth exponent was found to be 7±2 and the activation energy for grain growth was 31.1±13.4 kJ/mol, the latter being significantly lower than in bulk Mg-Al alloys. The observed grain growth kinetics are explained by the Al supersaturation in the matrix and the pinning effects of the rapidly forming beta precipitates and possibly shallow grain boundary grooves. The low activation energy is attributed to the rapid surface diffusion which is dominant in thin film systems.

Environmental hazards of aluminum to plants, invertebrates, fish, and wildlife

Science.gov (United States)

Sparling, D.W.; Lowe, T.P.

1996-01-01

Aluminum is extremely common throughout the world and is innocuous under circumneutral or alkaline conditions. However, in acidic environments, it can be a maJor limiting factor to many plants and aquatic organisms. The greatest concern for toxicity in North America occurs in areas that are affected by wet and dry acid deposition, such as eastern Canada and the northeastern U.S. Acid mine drainage, logging, and water treatment plant effluents containing alum can be other maJor sources of Al. In solution, the metal can combine with several different agents to affect toxicity. In general, Al hydroxides and monomeric Al are the most toxic forms. Dissolved organic carbons, F, PO(3)3- and SO(4)2- ameliorate toxicity by reducing bioavailability. Elevated metal levels in water and soil can cause serious problems for some plants. Algae tend to be both acid- and Al tolerant and, although some species may disappear with reduced pH, overall algae productivity and biomass are seldom affected if pH is above 3.0. Aluminum and acid toxicity tend to be additive to some algae when pH is less than 4.5. Because the metal binds with inorganic P, it may reduce P availability and reduce productivity. Forest die-backs in North America involving red spruce, Fraser fir, balsam fir, loblolly pine, slash pine, and sugar maples have been ascribed to Al toxicity, and extensive areas of European forests have died because of the combination of high soil Al and low pH. Extensive research on crops has produced Al-resistant cultivars and considerable knowledge about mechanisms of and defenses against toxicity. Very low Al levels may benefit some plants, although the metal is not recognized as an essential nutrient. Hyperaccumulator species of plants may concentrate Al to levels that are toxic to herbivores. Toxicity in aquatic invertebrates is also acid dependent. Taxa such as Ephemeroptera, Plecoptera, and Cladocera are sensitive and may perish when Al is less than 1 mg.L-1 whereas dipterans

TEM Nanostructural Study of Al-6Si-3Cu-Mg Melt-Spun Ribbons

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Ismeli Alfonso López

2008-01-01

Full Text Available Three quaternary Al-6Si-3Cu-xMg (x = 0.59, 3.80, and 6.78 wt.% alloys were produced by melt-spun and characterized using X-ray diffractometry (XRD, transmission electron microscopy (TEM, and microhardness techniques. Obtained second phases were Al2Cu( for the alloy with 0.59% Mg and Al5Cu2Mg8Si6 (Q for the alloys with 3.80 and 6.78% Mg. These phases are present as 30–50 nm or as 5–10 nm nanoparticles. Alloying elements content in solid solution increased, mainly for Si and Mg. The high alloying elements content in solid solution and the small -Al cell size for melt-spun alloys leads to microhardness values about 2 times higher than those of ingot counterparts. The microhardness increase for melt-spun alloys with 3.80 and 6.78% Mg depends on Mg content in solid solution.

Centrifugally cast Zn-27Al-xMg-ySi alloys and their in situ (Mg2Si + Si)/ZA27 composites

International Nuclear Information System (INIS)

Wang Qudong; Chen Yongjun; Chen Wenzhou; Wei Yinhong; Zhai Chunquan; Ding Wenjiang

2005-01-01

Effects of composition, mold temperature, rotating rate and modification on microstructure of centrifugally cast Zn-27Al-xMg-ySi alloys have been investigated. In situ composites of Zn-27Al-6.3Mg-3.7Si and Zn-27Al-9.8Mg-5.2Si alloys were fabricated by centrifugal casting using heated permanent mold. These composites consist of three layers: inner layer segregates lots of blocky primary Mg 2 Si and a litter blocky primary Si, middle layer contains without primary Mg 2 Si and primary Si, outer layer contains primary Mg 2 Si and primary Si. The position, quantity and distribution of primary Mg 2 Si and primary Si in the composites are determined jointly by alloy composition, solidification velocity under the effect of centrifugal force and their floating velocity inward. Na salt modifier can refine grain and primary Mg 2 Si and make primary Mg 2 Si distribute more evenly and make primary Si nodular. For centrifugally cast Zn-27Al-3.2Mg-1.8Si alloy, the microstructures of inner layer, middle layer and outer layer are almost similar, single layer materials without primary Mg 2 Si and primary Si are obtained, and their grain sizes increased with the mold temperature increasing

Sulfur-Mediated-Alleviation of Aluminum-Toxicity in Citrus grandis Seedlings

Directory of Open Access Journals (Sweden)

Peng Guo

2017-12-01

Full Text Available Limited data are available on the sulfur (S-mediated-alleviation of aluminum (Al-toxicity in higher plants. Citrus grandis seedlings were irrigated for 18 weeks with 0.5 mM MgSO4 or 0.5 mM MgSO4 + 0.5 mM Na2SO4, and 0 (−Al or 1 mM AlCl3·6H2O (+Al, Al-toxicity. Under Al-toxicity, S decreased the level of Al in leaves; increased the relative water content (RWC of roots and leaves, the contents of phosphorus (P, calcium (Ca and magnesium (Mg per plant, the dry weights (DW of roots and shoots, the ratios of root DW/shoot DW, and the Al-induced secretion of citrate from root; and alleviated the Al-induced inhibition of photosynthesis via mitigating the Al-induced decrease of electron transport capacity resulting from the impaired photosynthetic electron transport chain. In addition to decreasing the Al-stimulated H2O2 production, the S-induced upregulation of both S metabolism-related enzymes and antioxidant enzymes also contributed to the S-mediated-alleviation of oxidative damage in Al-treated roots and leaves. Decreased transport of Al from roots to shoots and relatively little accumulation of Al in leaves, and increased leaf and root RWC and P, Ca, and Mg contents per plant might also play a role in the S-mediated-alleviation of Al-toxicity.

Heavy ion induced damage in MgAl sub 2 O sub 4 , an inert matrix candidate for the transmutation of minor actinides

CERN Document Server

Wiss, T

1999-01-01

Magnesium aluminum spinel (MgAl sub 2 O sub 4) is a material selected as a possible matrix for transmutation of minor actinides by neutron capture or fission in nuclear reactors. To study the radiation stability of this inert matrix, especially against fission product impact, irradiations with heavy energetic ions or clusters have been performed. The high electronic energy losses of the heavy ions in this material led to the formation of visible tracks as evidenced by transmission electron microscopy for 30 MeV C sub 6 sub 0 -Buckminster fullerenes and for ions of energy close to or higher than fission energy ( sup 2 sup 0 sup 9 Bi with 120 MeV and 2.38 GeV energy). The irradiations at high energies showed a pronounced degradation of the spinel. Additionally, MgAl sub 2 O sub 4 exhibited a large swelling for irradiation at high fluences with fission products of fission energy (here I-ions of 72 MeV) and at temperatures <= 500 deg. C. These observations are discussed from the technological point of view in ...

Role of cerium, lanthanum, and strontium additions in an Al-Si-Mg (A356) alloy

Energy Technology Data Exchange (ETDEWEB)

Nabawy, Ahmed M.; Samuel, Agnes M.; Samuel, Fawzy H. [Universite du Quebec, Chicoutimi (Canada). Dept. des Sciences Appliquees; Alkahtani, Saleh A.; Abuhasel, Khaled A. [Salman Bin Abdulaziz Univ., Riyadh (Saudi Arabia). Mechanical Engineering Dept.

2016-05-15

The effects of individual and combined additions of cerium (Ce), lanthanum (La), and strontium (Sr) on the eutectic modification and solidification characteristics of an Al-Si-Mg (A356) aluminum alloy were investigated using optical microscopy and thermal analysis techniques. Addition of Ce, La, and Sr resulted in different depression levels of the eutectic nucleation temperature and eutectic growth undercooling, generating modified eutectic structures exhibiting different levels of modification. Microstructural results showed that the best modification levels using individual additions were achieved by Sr which produced a fine fibrous eutectic structure, followed by La, which produced a refined lamellar structure, with Ce providing the lowest level of modification. On the other hand, a combined addition of Ce and Sr provided the highest modification level, with the production of a very fine fibrous eutectic silicon structure. In general, the addition of Sr helped to further increase the refinement obtained in the alloys containing La or Ce + La additions. In the latter alloy, the main intermetallic phases observed were La(Al,Si){sub 2} and Al{sub 20}(La,Ce)Ti{sub 2}Si. The improved modification levels were found to be proportional to the depression in the eutectic nucleation temperature and the eutectic growth undercooling. A high cooling rate also improved the modification level by at least one level.

Aluminum bioavailability from the approved food additive leavening agent acidic sodium aluminum phosphate, incorporated into a baked good, is lower than from water.

Science.gov (United States)

Yokel, Robert A; Florence, Rebecca L

2006-10-03

There are estimates of oral aluminum (Al) bioavailability from drinking water, but little information on Al bioavailability from foods. Foods contribute approximately 95% and drinking water 1-2% of the typical human's daily Al intake. The objectives were to estimate oral Al bioavailability from a representative food containing the food additive acidic sodium aluminum phosphate (acidic SALP), a leavening agent in baked goods. Rats were acclimated to a special diet that resulted in no stomach contents 14 h after its withdrawal. They were trained to rapidly consume a biscuit containing 1.5% acidic SALP. Oral Al bioavailability was then determined from a biscuit containing 1% or 2% acidic SALP, synthesized to contain (26)Al. The rats received concurrent (27)Al infusion. Blood was repeatedly withdrawn and serum analyzed for (26)Al by accelerator mass spectrometry. Total Al was determined by atomic absorption spectrometry. Oral (26)Al bioavailability was determined from the area under the (26)Al, compared to (27)Al, serum concentrationxtime curves. Oral Al bioavailability (F) from biscuit containing 1% or 2% acidic (26)Al-SALP averaged approximately 0.11% and 0.13%; significantly less than from water, which was previously shown to be approximately 0.3%. The time to maximum serum (26)Al concentration was 4.2 and 6h after consumption of biscuit containing 1% or 2% (26)Al-acidic SALP, respectively, compared to 1-2h following (26)Al in water. These results of oral Al bioavailability from acidic (26)Al-SALP in a biscuit (F approximately 0.1%) and results from (26)Al in water (F approximately 0.3%) x the contributions of food and drinking water to the typical human's daily Al intake ( approximately 5-10mg from food and 0.1mg from water, respectively) suggest food provides approximately 25-fold more Al to systemic circulation, and potential Al body burden, than does drinking water.

Aluminum bioavailability from the approved food additive leavening agent acidic sodium aluminum phosphate, incorporated into a baked good, is lower than from water

International Nuclear Information System (INIS)

Yokel, Robert A.; Florence, Rebecca L.

2006-01-01

There are estimates of oral aluminum (Al) bioavailability from drinking water, but little information on Al bioavailability from foods. Foods contribute ∼95% and drinking water 1-2% of the typical human's daily Al intake. The objectives were to estimate oral Al bioavailability from a representative food containing the food additive acidic sodium aluminum phosphate (acidic SALP), a leavening agent in baked goods. Rats were acclimated to a special diet that resulted in no stomach contents 14 h after its withdrawal. They were trained to rapidly consume a biscuit containing 1.5% acidic SALP. Oral Al bioavailability was then determined from a biscuit containing 1% or 2% acidic SALP, synthesized to contain 26 Al. The rats received concurrent 27 Al infusion. Blood was repeatedly withdrawn and serum analyzed for 26 Al by accelerator mass spectrometry. Total Al was determined by atomic absorption spectrometry. Oral 26 Al bioavailability was determined from the area under the 26 Al, compared to 27 Al, serum concentration x time curves. Oral Al bioavailability (F) from biscuit containing 1% or 2% acidic 26 Al-SALP averaged ∼0.11% and 0.13%; significantly less than from water, which was previously shown to be ∼0.3%. The time to maximum serum 26 Al concentration was 4.2 and 6 h after consumption of biscuit containing 1% or 2% 26 Al-acidic SALP, respectively, compared to 1-2 h following 26 Al in water. These results of oral Al bioavailability from acidic 26 Al-SALP in a biscuit (F ∼ 0.1%) and results from 26 Al in water (F ∼ 0.3%) x the contributions of food and drinking water to the typical human's daily Al intake (∼5-10 mg from food and 0.1 mg from water, respectively) suggest food provides ∼25-fold more Al to systemic circulation, and potential Al body burden, than does drinking water

Effect of Al on Grain Refinement and Mechanical Properties of Mg-3Nd Casting Alloy

Science.gov (United States)

Wang, Lei; Feng, Yicheng; Wang, Liping; Chen, Yanhong; Guo, Erjun

2018-05-01

The effect of Al on the grain refinement and mechanical properties of as-cast Mg-3Nd alloy was investigated systematically by a series of microstructural analysis, solidification analysis and tensile tests. The results show that Al has an obvious refining effect on the as-cast Mg-3Nd alloy. With increasing Al content, the grain size of the as-cast Mg-3Nd alloy decreases firstly, then increases slightly after the Al content reaching 3 wt.%, and the minimum grain size of the Mg-3Nd alloy is 48 ± 4.0 μm. The refining mechanism can be attributed to the formation of Al2Nd particles, which play an important role in the heterogeneous nucleation. The strength and elongation of the Mg-3Nd alloy refined by Al also increase with increasing Al content and slightly decrease when the Al content is more than 3 wt.%, and the strengthening mechanism is attributed to the grain refinement as well as dispersed intermetallic particles. Furthermore, the microstructural thermal stability of the Mg-3Nd-3Al alloy is higher than that of the Mg-3Nd-0.5Zr alloy. Overall, the Mg-3Nd alloy with Al addition is a novel alloy with wide and potential application prospects.

Self-learning kinetic Monte Carlo simulations of Al diffusion in Mg

International Nuclear Information System (INIS)

Nandipati, Giridhar; Govind, Niranjan; Andersen, Amity; Rohatgi, Aashish

2016-01-01

Vacancy-mediated diffusion of an Al atom in the pure Mg matrix is studied using the atomistic, on-lattice self-learning kinetic Monte Carlo (SLKMC) method. Activation barriers for vacancy-Mg and vacancy-Al atom exchange processes are calculated on the fly using the climbing image nudged-elastic-band method and binary Mg–Al modified embedded-atom method interatomic potential. Diffusivities of an Al atom obtained from SLKMC simulations show the same behavior as observed in experimental and theoretical studies available in the literature; that is, an Al atom diffuses faster within the basal plane than along the c-axis. Although the effective activation barriers for an Al atom diffusion from SLKMC simulations are close to experimental and theoretical values, the effective prefactors are lower than those obtained from experiments. We present all the possible vacancy-Mg and vacancy-Al atom exchange processes and their activation barriers identified in SLKMC simulations. A simple mapping scheme to map an HCP lattice onto a simple cubic lattice is described, which enables simulation of the HCP lattice using the on-lattice framework. We also present the pattern recognition scheme which is used in SLKMC simulations to identify the local Al atom configuration around a vacancy. (paper)

Texture development in Al-Mg alloys during high temperature annealing

International Nuclear Information System (INIS)

Saitou, T.; Inagaki, H.

2001-01-01

To clarify the effect of Mg content on annealing textures developed in Al-Mg alloys during high temperature annealing, Al-Mg alloys containing up to 9 wt.% Mg in supersaturated solid solution were cold rolled 95% and isothermally annealed at 450 C. Their textures were investigated with the orientation distribution function analysis. It was found that, in the recrystallization textures observed at complete recrystallization, addition of more than 1 wt.% Mg was sufficient to suppress the development of {100} left angle 001 right angle. With increasing Mg content, {100} left angle 001 right angle decreased remarkably, whereas {100} left angle 013 right angle and {103} left angle 321 right angle increased. Thus, {100} left angle 013 right angle and {103} left angle 321 right angle were found to be the main orientations of the recrystallization textures of Al-Mg alloys annealed at high temperatures. {100} left angle 013 right angle developed most remarkably at 4 wt.% Mg, while {103} left angle 321 right angle showed the maximum development at 7 wt.% Mg. During subsequent grain growth at 450 C, remarkable texture changes were observed only in the alloys containing Mg in the range between 2 and 4 wt.%. In these alloys, {100} left angle 013 right angle developed at the expense of {100} left angle 001 right angle at earlier stages of grain growth, whereas {103} left angle 321 right angle increased independently of these two orientations at later stages of grain growth. Reflecting these texture changes, grain growth occurred in these alloys discontinuously. Such a discontinuous grain growth with large texture changes is expected, if strong textures are already present before grain growth, and if recrystallized grains having similar orientations are distributed by forming large clusters before grain growth. (orig.)

TL and OSL studies of carbon doped magnesium aluminate (MgAl2O4:C)

Science.gov (United States)

Raj, Sanu S.; Mishra, D. R.; Soni, Anuj; Grover, V.; Polymeris, G. S.; Muthe, K. P.; Jha, S. K.; Tyagi, A. K.

2016-10-01

The MgAl2O4:C has been synthesized by using two different methods by electron gun and vacuum assisted melting of MgAl2O4 in presence of graphite. The MgAl2O4:C phosphor thus developed by these two different methods have similar types of the TL/OSL defects with multiple overlapping TL glow peaks from 100 °C to 400 °C. The Computerized Curve De-convolution Analysis (CCDA) has been used to measure TL parameters such as thermal trap depth, frequency factor and order of kinetic associated with charge transfer process in TL phenomenon. The investigated TL/OSL results show that these two methods of incorporating carbon in MgAl2O4 have generated closely resemble the defects of similar types in MgAl2O4:C lattice. However, the MgAl2O4:C synthesized by electron gun shows relatively larger concentration of the TL/OSL defects as compared to MgAl2O4:C synthesized using vacuum assisted melting method. The photo-ionization cross-section (PIC) associated with fastest OSL component of MgAl2O4: C is found to be ∼ 0.5 times than that of fastest OSL component of commercially available dosimetric grade α-Al2O3:C. The MgAl2O4:C thus developed shows good dynamic OSL dose linearity from few mGy to 1 Gy. This work reveals that MgAl2O4:C could be developed as potential tissue equivalent OSL / TL material.

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

High-Throughput Investigation of a Lead-Free AlN-Based Piezoelectric Material, (Mg,Hf)xAl1-xN.

Science.gov (United States)

Nguyen, Hung H; Oguchi, Hiroyuki; Van Minh, Le; Kuwano, Hiroki

2017-06-12

We conducted a high-throughput investigation of the fundamental properties of (Mg,Hf) x Al 1-x N thin films (0 piezoelectric materials. For the high-throughput investigation, we prepared composition-gradient (Mg,Hf) x Al 1-x N films grown on a Si(100) substrate at 600 °C by cosputtering AlN and MgHf targets. To measure the properties of the various compositions at different positions within a single sample, we used characterization techniques with spatial resolution. X-ray diffraction (XRD) with a beam spot diameter of 1.0 mm verified that Mg and Hf had substituted into the Al sites and caused an elongation of the c-axis of AlN from 5.00 Å for x = 0 to 5.11 Å for x = 0.24. In addition, the uniaxial crystal orientation and high crystallinity required for piezoelectric materials to be used as application devices were confirmed. The piezoelectric response microscope indicated that this c-axis elongation increased the piezoelectric coefficient almost linearly from 1.48 pm/V for x = 0 to 5.19 pm/V for x = 0.24. The dielectric constants of (Mg,Hf) x Al 1-x N were investigated using parallel plate capacitor structures with ∼0.07 mm 2 electrodes and showed a slight increase by substitution. These results verified that (Mg,Hf) x Al 1-x N is a promising material for piezoelectric-based application devices, especially for vibrational energy harvesters.

Thermoelectric Properties of Hot-Pressed and PECS-Sintered Magnesium-Doped Copper Aluminum Oxide

Science.gov (United States)

Liu, Chang; Morelli, Donald T.

2011-05-01

Copper aluminum oxide (CuAlO2) is considered as a potential candidate for thermoelectric applications. Partially magnesium-doped CuAlO2 bulk pellets were fabricated using solid-state reactions, hot-pressing, and pulsed electric current sintering (PECS) techniques. X-ray diffraction and scanning electron microscopy were adopted for structural analysis. High-temperature transport property measurements were performed on hot-pressed samples. Electrical conductivity increased with Mg doping before secondary phases became significant, while the Seebeck coefficient displayed the opposite trend. Thermal conductivity was consistently reduced as the Mg concentration increased. Effects of Mg doping, preparation conditions, and future modification on this material's properties are discussed.

Would Aluminum and Nickel Content of Apricot Pose Health Risk to Human?

Directory of Open Access Journals (Sweden)

Gholamhossein DAVARYNEJAD

2012-05-01

Full Text Available Higher demands of food production for human consumption increased uses of fertilizers and other chemicals that arise in a major public problem and heavy-metal pollution. Levels of Aluminum and Nickel which affect mankind health in exact doses, were determined in fresh and dried samples of �Jumbo Cot�, �Tom Cot�, �Gold Strike�, �Gold Bar�, Bergeron�, �Bergarouge�, �Sweet Cot�, �Yellow cot� and �Zebra� apricot cultivars to assess possible health risk of apricot (Prunus armeniaca L. consumption. Highest content of Al and Ni among all cultivars, where 9.71 and 2.14 mg/kg of dehydrated apricot samples. Fresh fruit samples maximally contain 2.9 and 0.425 mg/kg of Aluminum and Nickel respectively. Data analysis showed significant differences between cultivars for Al and Ni. Furthermore, to reveal the health-risk possibility of dried and fresh fruit consumption daily intake of elements and health-risk index were calculated and compared.

Would Aluminum and Nickel Content of Apricot Pose Health Risk to Human?

Directory of Open Access Journals (Sweden)

Gholamhossein DAVARYNEJAD

2012-05-01

Full Text Available Higher demands of food production for human consumption increased uses of fertilizers and other chemicals that arise in a major public problem and heavy-metal pollution. Levels of Aluminum and Nickel which affect mankind health in exact doses, were determined in fresh and dried samples of Jumbo Cot, Tom Cot, Gold Strike, Gold Bar, Bergeron, Bergarouge, Sweet Cot, Yellow cot and Zebra apricot cultivars to assess possible health risk of apricot (Prunus armeniaca L. consumption. Highest content of Al and Ni among all cultivars, where 9.71 and 2.14 mg/kg of dehydrated apricot samples. Fresh fruit samples maximally contain 2.9 and 0.425 mg/kg of Aluminum and Nickel respectively. Data analysis showed significant differences between cultivars for Al and Ni. Furthermore, to reveal the health-risk possibility of dried and fresh fruit consumption daily intake of elements and health-risk index were calculated and compared.

The Effect of Mg Addition and Manufacturing Conditions on the Interfacial Reactions between Al and CNT in Al-CNT Pellets

International Nuclear Information System (INIS)

Lim, Jung-Kyu; Choi, Soon-Yool; Choe, Kyong-Hwan; Cho, Gue-Serb; Kim, Sang-Sub

2013-01-01

In the present study, Al-CNT pellets were investigated to understand the effect of Mg addition and manufacturing conditions on the interfacial reactions between Al and CNTs in Al-CNT pellets. The pellets were heated and held at 700 °C and 800 °C for 2 hours under nitrogen (N_2) atmosphere. To confirm the reactions between Al and CNT in the pellets under different manufacturing conditions, the microstructures were observed by optical microscopy (OM) and field emission scanning electro microscopy (FESEM). And, the composition and reaction phases were analyzed by energy dispersive X-ray spectroscory (EDXS) and X-ray diffractometry (XRD). The presence of oxidation products and Mg on the surface of Al powder in the pellets appeared to prevent the formation of Al_4C_3. But, Al_4C_3 reaction products were increased due to the high temperature of 800 °C, which produced a high amount of reduced aluminium and increased the reaction areas between Al and CNT. The Al-CNT pellets compacted under air atmosphere prohibited the reaction between Al and CNT because of the high amount of oxidation products, such as MgO and MgAl_2O_4.

Fabrication of Spherical AlSi10Mg Powders by Radio Frequency Plasma Spheroidization

Science.gov (United States)

Wang, Linzhi; Liu, Ying; Chang, Sen

2016-05-01

Spherical AlSi10Mg powders were prepared by radio frequency plasma spheroidization from commercial AlSi10Mg powders. The fabrication process parameters and powder characteristics were investigated. Field emission scanning electron microscope, X-ray diffraction, laser particle size analyzer, powder rheometer, and UV/visible/infrared spectrophotometer were used for analyses and measurements of micrographs, phases, granulometric parameters, flowability, and laser absorption properties of the powders, respectively. The results show that the obtained spherical powders exhibit good sphericity, smooth surfaces, favorable dispersity, and excellent fluidity under appropriate feeding rate and flow rate of carrier gas. Further, acicular microstructures of the spherical AlSi10Mg powders are composed of α-Al, Si, and a small amount of Mg2Si phase. In addition, laser absorption values of the spherical AlSi10Mg powders increase obviously compared with raw material, and different spectra have obvious absorption peaks at a wavelength of about 826 nm.

Thermoelectric properties of Al doped Mg{sub 2}Si material

Energy Technology Data Exchange (ETDEWEB)

Kaur, Kulwinder, E-mail: kulwindercmp@gmail.com; Kumar, Ranjan [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Rani, Anita [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Guru Nanak College for Girls, Sri Muktsar Sahib, Punjab (India)

2015-08-28

In the present paper we have calculated thermoelectric properties of Al doped Mg{sub 2}Si material (Mg{sub 2−x}Al{sub x}Si, x=0.06) using Pseudo potential plane wave method based on DFT and Semi classical Boltzmann theory. The calculations showed n-type conduction, indicating that the electrical conduction are due to electron. The electrical conductivity increasing with increasing temperature and the negative value of Seebeck Coefficient also show that the conduction is due to electron. The thermal conductivity was increased slightly by Al doping with increasing temperature due to the much larger contribution of lattice thermal conductivity over electronic thermal conductivity.

Synthesis of high-surface-area spinel-type MgAl2O4 nanoparticles ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 40; Issue 1. Synthesis of high-surface-area spinel-type MgAl 2 O 4 nanoparticles by [Al(sal) 2 (H 2 O) 2 ] 2 [Mg(dipic) 2 ] and [Mg(H 2 O) 6 ][Al(ox) 2 (H 2 O) 2 ] 2 ·5H 2 O: influence of inorganic precursor type. Volume 40 Issue 1 February 2017 pp 45-53 ...

Behavior of aluminum oxide, intermetallics and voids in Cu-Al wire bonds

International Nuclear Information System (INIS)

Xu, H.; Liu, C.; Silberschmidt, V.V.; Pramana, S.S.; White, T.J.; Chen, Z.; Acoff, V.L.

2011-01-01

Nanoscale interfacial evolution in Cu-Al wire bonds during isothermal annealing from 175 deg. C to 250 deg. C was investigated by high resolution transmission electron microscopy (HRTEM). The native aluminum oxide film (∼5 nm thick) of the Al pad migrates towards the Cu ball during annealing. The formation of intermetallic compounds (IMC) is controlled by Cu diffusion, where the kinetics obey a parabolic growth law until complete consumption of the Al pad. The activation energies to initiate crystallization of CuAl 2 and Cu 9 Al 4 are 60.66 kJ mol -1 and 75.61 kJ mol -1 , respectively. During IMC development, Cu 9 Al 4 emerges as a second layer and grows together with the initial CuAl 2 . When Al is completely consumed, CuAl 2 transforms to Cu 9 Al 4 , which is the terminal product. Unlike the excessive void growth in Au-Al bonds, only a few voids nucleate in Cu-Al bonds after long-term annealing at high temperatures (e.g., 250 o C for 25 h), and their diameters are usually in the range of tens of nanometers. This is due to the lower oxidation rate and volumetric shrinkage of Cu-Al IMC compared with Au-Al IMC.

Effect of aluminum treatment on proteomes of radicles of seeds derived from Al-treated tomato plants

Science.gov (United States)

Aluminum (Al) toxicity is a major constraint to plant growth and crop yield in acid soils. Tomato cultivars are especially susceptible to excessive A1 3+ accumulated in the root zone. In this study, tomato plants were grown in a hydroponic culture system supplemented with 50 uM AlK(SO4)2. Seeds harv...

A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys

Directory of Open Access Journals (Sweden)

Liming Liu

2014-05-01

Full Text Available Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research.

A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys

Science.gov (United States)

Liu, Liming; Ren, Daxin; Liu, Fei

2014-01-01

Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC) such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research. PMID:28788646

Casting defects and mechanical properties of high pressure die cast Mg-Zn-Al-RE alloys

Energy Technology Data Exchange (ETDEWEB)

Xiao, Wenlong; Easton, Mark A.; Zhu, Suming; Nie, Jianfeng [CAST Cooperative Research Centre, Department of Materials Engineering Monash University, Melbourne, VIC (Australia); Dargusch, Matthew S. [School of Mechanical and Mining Engineering, University of Queensland, Brisbane, QLD (Australia); Gibson, Mark A. [CSIRO Process Science and Engineering, Melbourne, VIC (Australia); Jia, Shusheng [Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering Jilin University, Changchun (China)

2012-02-15

The die casting defects and tensile properties of high pressure die cast (HPDC) Mg-Zn-Al-RE alloys with various combinations of Zn and Al were studied. The results show that die casting defects in Mg-Zn-Al-RE alloys are affected by the percentage of Zn and Al contents. The hot tearing susceptibility (HTS) of Mg-Zn-Al-RE alloys tends to increase with increasing Zn content up to 6 wt%, while a further increase of Al and/or Zn content reduces the HTS. In tensile tests, the yield strength (YS) is generally improved by increasing Zn or Al content, whereas the tensile strength (TS) and ductility appear to depend largely on the presence of casting defects. Compared with Mg-Zn-Al alloys, the mechanical properties of the Mg-Zn-Al-RE alloy are significantly improved. The Mg-4Zn-4Al-4RE alloy is found to have few casting defects and the optimal tensile properties. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Precipitation kinetics of Al-1.12 Mg{sub 2}Si-0.35 Si and Al-1.07 Mg{sub 2}Si-0.33 Cu alloys

Energy Technology Data Exchange (ETDEWEB)

Gaber, A. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Gaffar, M.A. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt)]. E-mail: mgaafar@aucegypt.edu; Mostafa, M.S. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Zeid, E.F. Abo [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt)

2007-02-21

The kinetics of hardening precipitates of Al-1.12 wt.% Mg{sub 2}Si-0.35 wt.% Si (excess Si) and Al-1.07 wt.% Mg{sub 2}Si-0.33 wt.% Cu (balanced + Cu) alloys have been investigated by means of differential scanning calorimetry and hardness measurements. The excess Si enhances the precipitation kinetics and improves the strength of the material. On the other hand, however addition of Cu assist formation of the Q' phase which positively changed the alloy strength. The high binding energy between vacancies and solute atoms (Si and Mg) enhances the combination of Si, Mg and vacancies to form Si-Mg-vacancy clusters. These clusters act as nucleation sites for GP-zones. The coexistence of the {beta}'- and Q'-precipitates in the balanced + Cu alloy results in a higher peak age hardening compared to the alloy with Si in excess.

Adsorption of Na, Mg, and Al atoms on BN nanotubes

Energy Technology Data Exchange (ETDEWEB)

Beheshtian, Javad [Department of Chemistry, Shahid Rajaee Teacher Training University, P.O. Box: 16875-163, Tehran (Iran, Islamic Republic of); Peyghan, Ali Ahmadi, E-mail: ahmadi.iau@gmail.com [Young Researchers Club, Islamic Azad University, Islamshahr Branch, Tehran (Iran, Islamic Republic of); Bagheri, Zargham [Physics group, Science department, Islamic Azad University, Islamshahr Branch, P.O. Box: 33135-369, Islamshahr, Tehran (Iran, Islamic Republic of)

2012-12-30

Adsorption of three metals (Na, Mg, and Al) on the surface of BN nanotubes (BNNT) has been investigated by using density functional theory. Adsorption energies for Na and Al atoms have been calculated to be about - 0.22 to - 0.61 eV, respectively. Upon the metal adsorption, energy gap between highest occupied and lowest unoccupied orbitals of the tube is dramatically decreased, resulting in enhanced electrical conductivity. However, in the case of Mg atom, the low adsorption energy cannot change electronic property of the tube. The semi-conductive BNNT transform to n-type semiconductor after adsorption of Na atom. The metal adsorption modifies work function of the BNNT and consequently the field-emission current densities of metal-BNNT may be significantly enhanced. - Highlights: Black-Right-Pointing-Pointer Adsorption of Na, Mg, and Al atoms on the BN nanotubes (BNNT) was studied. Black-Right-Pointing-Pointer Adsorption energies for Na and Al atoms are about - 0.22 to - 0.61 eV, respectively. Black-Right-Pointing-Pointer Energy gap of the tube dramatically decreases upon the metals adsorption. Black-Right-Pointing-Pointer Semiconductor BNNT transform to n-type ones upon adsorption of Na and Al atoms. Black-Right-Pointing-Pointer The field-emission current densities of metal-BNNT may be significantly enhanced.

Retardation of surface corrosion of biodegradable magnesium-based materials by aluminum ion implantation

Science.gov (United States)

Wu, Guosong; Xu, Ruizhen; Feng, Kai; Wu, Shuilin; Wu, Zhengwei; Sun, Guangyong; Zheng, Gang; Li, Guangyao; Chu, Paul K.

2012-07-01

Aluminum ion implantation is employed to modify pure Mg as well as AZ31 and AZ91 magnesium alloys and their surface degradation behavior in simulated body fluids is studied. Polarization tests performed in conjunction with scanning electron microscopy (SEM) reveal that the surface corrosion resistance after Al ion implantation is improved appreciably. This enhancement can be attributed to the formation of a gradient surface structure with a gradual transition from an Al-rich oxide layer to Al-rich metal layer. Compared to the high Al-content magnesium alloy (AZ91), a larger reduction in the degradation rate is achieved from pure magnesium and AZ31. Our results reveal that the surface corrosion resistance of Mg alloys with no or low Al content can be improved by Al ion implantation.

Retardation of surface corrosion of biodegradable magnesium-based materials by aluminum ion implantation

International Nuclear Information System (INIS)

Wu Guosong; Xu Ruizhen; Feng Kai; Wu Shuilin; Wu Zhengwei; Sun Guangyong; Zheng Gang; Li Guangyao; Chu, Paul K.

2012-01-01

Aluminum ion implantation is employed to modify pure Mg as well as AZ31 and AZ91 magnesium alloys and their surface degradation behavior in simulated body fluids is studied. Polarization tests performed in conjunction with scanning electron microscopy (SEM) reveal that the surface corrosion resistance after Al ion implantation is improved appreciably. This enhancement can be attributed to the formation of a gradient surface structure with a gradual transition from an Al-rich oxide layer to Al-rich metal layer. Compared to the high Al-content magnesium alloy (AZ91), a larger reduction in the degradation rate is achieved from pure magnesium and AZ31. Our results reveal that the surface corrosion resistance of Mg alloys with no or low Al content can be improved by Al ion implantation.

Aluminum Level in Infants’ Powdered Milk Based Formulae

Directory of Open Access Journals (Sweden)

Ahmed Abdel-Hameid Ahmed

2016-10-01

Full Text Available Aluminum level (Al in infant formula was determined to postulate its public health significance and suggesting recommendations to avoid such contamination. Hence, fifty random samples of infants powdered         milk based formulae were collected from different markets and pharmacies in Assiut Governorate, Egypt. These samples were digested and Al level was detected by using HR-CS (High Resolution Continum Source Atomic Absorption Spectrophotometer and compared with Maximum Permissible Limit (MPL. About 90% of examined infant formula samples containing Al with an average value of 0.145 mg/L and 8% of samples were above the MPL.

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%.

Enhanced Optical Performance of BaMgAl

NARCIS (Netherlands)

Yin, L.J.; Dong, Juntao; Wang, Yinping; Zhang, Bi; Zhou, Zheng Yang; Jian, Xian; Wu, Mengqiang; Xu, Xin; van Ommen, J.R.; Hintzen, H.T.J.M.

2016-01-01

Many strategies have been adopted to improve thermal degradation of phosphors. Because of the stability and high transmittance of graphene, here we report a novel method of carbon coating on BaMgAl₁₀O₁₇:Eu²⁺ (BAM) phosphor particles through chemical vapor

Equilibrium studies of the adsorption of aromatic disulfonates by Mg-Al oxide

Science.gov (United States)

Kameda, Tomohito; Umetsu, Mami; Kumagai, Shogo; Yoshioka, Toshiaki

2018-03-01

The removal of m-benzenedisulfonate (BDS2-) and 2,6-naphthalenedisulfonate (NDS2-) anions by Mg-Al oxide was investigated. Langmuir model best describes the adsorption of both aromatic disulfonate anions, with the maximum amount of uptake higher for BDS2-. Mg-Al oxide reacts easier with the aromatic disulfonate anion with higher charge density, a trend that is the opposite of that observed in aromatic sulfonate anions. After increasing the charge from -1 to -2, the removal of aromatic disulfonates by Mg-Al oxide is controlled by electrostatic interactions, instead of hydrophobic interactions that are dominant for aromatic sulfonate anions.

Role of Cu-Mg-Al mixed oxide catalysts in lignin depolymerization in supercritical ethanol

NARCIS (Netherlands)

Huang, X.; Ceylanpinar, A.; Koranyi, T.I.; Boot, M.D.; Hensen, E.J.M.

2015-01-01

We investigate the role of Cu-Mg-Al mixed oxides in depolymerization of soda lignin in supercritical ethanol. A series of mixed oxides with varying Cu content and (Cu+Mg)/Al ratio were prepared. The optimum catalyst containing 20 wt% Cu and having a (Cu+Mg)/Al ratio of 4 yielded 36 wt% monomers

Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

Energy Technology Data Exchange (ETDEWEB)

Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

2007-08-16

Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

The effect of the aluminum chloride – quercetin complex on Ca(2+,Mg(2+-ATPase activity and contraction dynamic properties of muscle tibialis anterior from Rana temporaria

Directory of Open Access Journals (Sweden)

D. M. Nozdrenko

2015-12-01

Full Text Available Combined effect of aluminum chloride and quercetin solutions on the enzymatic activity and contraction dynamics of muscle fiber bundles of the Rana temporaria m. tibialis anterior was investigated. It was shown that these complexes inhibit muscle contraction. Linear reduction of Ca2+,Mg2+-ATPase activity induced by all of the used concentrations of AlCl3 – quercetin was demonstrated. It was found that complex of quercetin with AlCl3 has a greater inhibitory effect on muscle contraction dynamic and causes greater reduction during all periods of stimulation in comparison to the separate effect of the investigated compounds. All the studied concentrations of AlCl3 and quercetin solutions (AlCl3: 10-4-10-2 M; quercetin: 10-6-10-5 M caused concentration depended contraction strengths and lengths reduction. The decrease in strength and length of muscle contractions was of constant and mostly linear nature within observed timeframe as well as within each periods of contraction. The changes were least pronounced within pretetanic period, but were profound within terminal period of muscle activity. The changes in dynamic contraction properties and Ca2+,Mg2+-ATPase activity of sarcoplasmic reticulum under effect of the investigated compounds was minimal in the beginning of the muscle’s response to stimulus, prior to muscle strength reaching stable contraction level.

Magnesium, Iron and Aluminum in LLNL Air Particulate and Rain Samples with Reference to Magnesium in Industrial Storm Water

Energy Technology Data Exchange (ETDEWEB)

Esser, Bradley K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bibby, Richard K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fish, Craig [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-08-25

Storm water runoff from the Lawrence Livermore National Laboratory’s (LLNL’s) main site and Site 300 periodically exceeds the Discharge Permit Numeric Action Level (NAL) for Magnesium (Mg) under the Industrial General Permit (IGP) Order No. 2014-0057-DWQ. Of particular interest is the source of magnesium in storm water runoff from the site. This special study compares new metals data from air particulate and precipitation samples from the LLNL main site and Site 300 to previous metals data for storm water from the main site and Site 300 and alluvial sediment from the main site to investigate the potential source of elevated Mg in storm water runoff. Data for three metals (Mg, Iron {Fe}, and Aluminum {Al}) were available from all media; data for additional metals, such as Europium (Eu), were available from rain, air particulates, and alluvial sediment. To attribute source, this study compared metals concentration data (for Mg, Al, and Fe) in storm water and rain; metal-metal correlations (Mg with Fe, Mg with Al, Al with Fe, Mg with Eu, Eu with Fe, and Eu with Al) in storm water, rain, air particulates, and sediments; and metal-metal ratios ((Mg/Fe, Mg/Al, Al/Fe, Mg/Eu, Eu/Fe, and Eu/Al) in storm water, rain, air particulates and sediments. The results presented in this study are consistent with a simple conceptual model where the source of Mg in storm water runoff is air particulate matter that has dry-deposited on impervious surfaces and subsequently entrained in runoff during precipitation events. Such a conceptual model is consistent with 1) higher concentrations of metals in storm water runoff than in precipitation, 2) the strong correlation of Mg with Aluminum (Al) and Iron (Fe) in both storm water and air particulates, and 3) the similarity in metal mass ratios between storm water and air particulates in contrast to the dissimilarity of metal mass ratios between storm water and precipitation or alluvial sediment. The strong correlation of Mg with Fe and Al

Aluminum-based water treatment residual use in a constructed wetland for capturing urban runoff phosphorus: Column study

Science.gov (United States)

Aluminum-based water treatment residuals (Al-WTR) have a strong affinity to sorb phosphorus. In a proof-of-concept greenhouse column study, Al-WTR was surface-applied at 0, 62, 124, and 248 Mg/ha to 15 cm of soil on top of 46 cm of sand; Al-WTR rates were estimated to capture 0, 10, 20, and 40 year...

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.

Preparation and Properties of Mg-Cu-Y-Al bulk Amorphous Alloys

DEFF Research Database (Denmark)

Pryds, Nini; Eldrup, Morten Mostgaard; Ohnuma, M.

2000-01-01

Bulk amorphous (Mg(1-gamma)Al(gamma))(60)CU(30)Y(10) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper wedge mould. The temperature vs, time was recorded during the cooling and solidification process of the melt and compared with a spacial and tempo......Bulk amorphous (Mg(1-gamma)Al(gamma))(60)CU(30)Y(10) alloys were prepared using a relatively simple technique of rapid cooling of the melt in a copper wedge mould. The temperature vs, time was recorded during the cooling and solidification process of the melt and compared with a spacial...... temperatures in specimens containing a few percent Al. The alloy with no Al crystallises apparently without the formation of nanoparticles. The critical cooling rate for the formation of an amorphous Mg(60)CU(30)Y(10) specimen was determined experimentally by a combination of DSC data and temperature vs, time...

Defect reduction in seeded aluminum nitride crystal growth

Science.gov (United States)

Bondokov, Robert T.; Schowalter, Leo J.; Morgan, Kenneth; Slack, Glen A; Rao, Shailaja P.; Gibb, Shawn Robert

2017-09-26

Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density.ltoreq.100 cm.sup.-2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

Fabrication of hierarchical core-shell polydopamine@MgAl-LDHs composites for the efficient enrichment of radionuclides

Energy Technology Data Exchange (ETDEWEB)

Zhu, Kairuo [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy Sciences, P.O. Box 1126, Hefei, 230031 (China); Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123 (China); Lu, Songhua; Gao, Yang; Zhang, Rui; Tan, Xiaoli [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy Sciences, P.O. Box 1126, Hefei, 230031 (China); Chen, Changlun, E-mail: clchen@ipp.ac.cn [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy Sciences, P.O. Box 1126, Hefei, 230031 (China); Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123 (China); AAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2017-02-28

Highlights: • Novel hierarchical core/shell structured PDA@MgAl-LDHs were prepared. • PDA@MgAl-LDHs exhibited higher sorption ability for U(VI) and Eu(III). • PDA@MgAl-LDHs were promising materials for the enrichment of radionuclides. - Abstract: Novel hierarchical core/shell structured polydopamine@MgAl-layered double hydroxides (PDA@MgAl-LDHs) composites involving MgAl-layered double hydroxide shells and PDA cores were fabricated thought one-pot coprecipitation assembly and methodically characterized by X-ray diffraction, Fourier transformed infrared spectroscopy, scanning/transmission electron microscopy, selected area electron diffraction, elemental mapping, thermogravimetric analysis and X-ray photoelectron spectroscopy technologies. U(VI) and Eu(III) sorption experiments showed that the PDA@MgAl-LDHs exhibited higher sorption ability with a maximum sorption capacity of 142.86 and 76.02 mg/g at 298 K and pH 4.5, respectively. More importantly, according to XPS analyses, U(VI) and Eu(III) were sorbed on PDA@MgAl-LDHs via oxygen-containing functional groups, and the chemical affinity of U(VI) by oxygen-containing functional groups is higher than that of Eu(III). These observations show great expectations in the enrichment of radionuclides from aquatic environments by PDA@MgAl-LDHs.

Improved mechanical proprieties of “magnesium based composites” with titanium–aluminum hybrids

Directory of Open Access Journals (Sweden)