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1–10 of about 18200 matches for aluminum OR al
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Phase Equilibria of the Ternary Al-Cu-Ni System and Interfacial Reactions of Related Systems at 800°C (20072541)
Metallurgical & Materials Transactions A P199-209
A series of Al-Cu-Mi alloys of various compositions were made and annealed at 800°C. The equilibrium phases were studied by metallography, X-ray diffraction (XRD) analysis, and electron probe microanalysis. The isothermal section of the ternary Al-Cu-Ni system at 800°C was then determined based on these experimental results and the available phase relationship knowledge of the three constituent binary systems. No ternary compound was found. All three phases, AlNi3, AlNi and Al3Ni2 have very high ternary solubility, especially the AlNi phase, which almost reaches the binary Al-Cu side. However, no continuous solid solution was formed between the AlNi phase and any of the binary AlCu phases. Interfacial reactions of Al/Ni, Al/Cu, Al-Cu/Ni and Al-Ni/Cu at 800°C were investigated by using reaction couple techniques. The results showed that Al2Ni and Al2Ni2 phases were formed in the Al/Ni couples; â-AlCu4, ã1-Al4Cu3 phases were formed in the Al-Cu couples. As for the results in the Al-2 at. Pct Ni/Cu, Al-5 at. Pct Ni/Cu and Al-2 at. Pct Cu/Ni, Al-4.5 at. Pct Cu/Ni, and Al-6 at. Pct. Cu/Ni were similar to those in the binary Al/Cu and Al/Ni couples, respectively. A different reaction path was found in the Al-7.5 at. Pct Cu/Ni couples, and an AlNi solid solution layer was formed instead of the Al3Ni and Al3Ni2 phases.

Evaporation Behavior of Aluminum during the Cold Crucible Induction Skull Melting of Titanium Aluminum Alloys (20072281)
Metallurgical and Materials Transactions B V31B P837-844
Taking the Ti-Al binary alloy as an example, this article studied the evaporation behavior of Al during the cold crucible induction skull melting (ISM) process of titanium alloys. A formula was deduced to predict the activity of Al in molten Ti-Al binary system. The calculated activity of Al negatively deviates from an ideal solution. A model was established to judge the evaporation controlling mode and, on this basis, several conclusions were obtained. (1) The evaporation controlling mode of Al in molten Ti-Al transfers from the evaporation reaction controlling mode to the double controlling mode (diffusion and evaporation reaction) with increasing melt temperature (Tm) and/or Al content (XAl) and/or decreasing pressure (P) in the melting chamber. (2) The expression P = Pcrit (Pcrit ˜ 0.44 Pe(Al)) is a criterion used to judge whether the evaporation is in the state of free evaporation. (3) The term Pimpe (Pimpe = (3.5 to 4) Pe(Al) is a critical value which impedes the evaporation loss. Almost all of common used ternary additions could enhance the activity of Al in molten Ti-Al and, accordingly, aggravate the evaporation of Al, except for Zr. The enhancing sequence is Y, Ni, Nb, Mn, V, Fe, Cr, Mo, Cu, Si, W, Mg, B and Sn. The Al evaporation mass-transfer losses, measured from the melting experiments of several titanium aluminum alloys, were in reasonable agreement with the calculated results.

PHASE EQUILBRIA OF THE TERNARY AL-CU-NI SYSTEM AND INTERFACIAL REACTIONS OF RELATED SYSTEMS AT 800 C (20061620)
Metallurgical and Materials Transactions A, V 34A-No.2, P 199 - 209 (11 p) 2003
A series of Al-Cu-Ni alloys of various compositions were made and annealed at 800 C. The equilibrium phases were studied by metallography, X-ray diffraction (XRD) analysis, and electron probe microanalysis. The isothermal section of the ternary Al-Cu-Ni system at 800 C was then determined based on these experimental results and the available phase relationship knowledge of the three constituent binary systems. No ternary compound was found. All three phases, AlNi3, AlNi, and Al3Ni2, have very high ternary solubility, especially the AlNi phase, which almost reached the binary Al-Cu side. However, no continuous solid solution was formed between the AlNi phase and any of the binary Al-Cu phases. Interfacial reactions of Al/Ni, Al/Cu, Al-Cu/Ni, and Al-Ni/Cu at 800 C were investigated by using reaction couple techniques. The results showed that Al3Ni and Al3Ni2 phases were formed in the Al/Ni couples; B-AlCu4, y1-Al4Cu9, and E2-Al2Cu3 phases were formed in the Al/Cu couples. As for the results in the Al-2 at. pct Ni/Cu, Al-5 at. Pct Ni/Cu, and Al-2 at. pct Cu/Ni, Al-4.5 at. pct Cu/Ni, and Al-6 at. pct Cu/Ni were similar to those in the binary Al/Cu and Al/Ni couples, respectively. A different reaction path was found in the Al-7.5 at. pct Cu/Ni couples, and an AlNi solid solution layer was formed instead of the Al3Ni and Al3Ni2 phases.

Thermodynamic Modeling and Experimental Investigation of the Magnesium-Aluminum-Strontium-Calcium System (20082840)
Proceedings of the Third International Conference on Light Metals Technology Sept 24-26 2007 Quebec, Canada P53-57
The phase equilibria and thermodynamic properties of the Mg-Al-Sr-Ca system were analyzed in this work and a thermodynamic description of the system was obtained using a computerized optimization procedure. The available thermodynamic and phase diagram data were critically assessed for all the binary and ternary sub-systems. Optimized thermodynamic properties of the binary systems were then used to construct a database and calculate the ternary phase diagrams. The phase equilibria in the Mg-Al-Sr and Mg-Al-Ca systems were investigated experimentally by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and quantitative electron probe micro-analysis (EPMA). A new ternary solid solution, MgxAl4xSr, was observed in the Mg-Al-Sr system, which is due to the substitution of Al by Mg atoms in the Al4Sr compound. Maximum solubilities of 21.3 at.% Al in Mg17Sr2 and 11.4 at.% Al in Mg were observed. It was also noticed that Mg38Sr9 dissolved 12.5 at.% Al, In the Mg-Al-Ca ternary system, one of the invariant transformation, predicted by thermodynamic modeling, was verified experimentally and found to occur at 512°C with composition close to 10.8 at.% Ca, 79.5 at.% Mg ad 9.7 at.% Al. Large solid solubility of Al in Mg2Ca was observed. The Mg-Ca-Sr and Al-Ca-Sr phase diagrams were also calculated from the established database for the Mg-Al-Ca-Sr system.

DIE SOLDERING: MECHANISM OF THE INTERFACE REACTION BETWEEN MOLTEN ALUMINUM ALLOY AND TOOL STEEL (20061656)
Metallurgical and Materials Transactions B, V 33B-No.3, P 465 - 479 (12 p) 2002
Die soldering is the result when molten aluminum sticks to the surface of the die material and remains there after the ejection of the part; it results in considerable economic and production losses in the casting industry, and is a major quality detractor. In order to alleviate or mitigate die soldering, one must have a thorough understanding of the mechanism by which the aluminum sticks to the die material. A key question is whether the die soldering reaction is diffusion controlled or interface controlled. A set of diffusion couple experiments between molten aluminum alloy and the ferrous die was carried out. The results of the diffusion couple experiments showed that soldering is a diffusional process. When aluminum comes in contact with the ferrous die material, the iron and the aluminum atoms diffuse into each other resulting in the formation of a series of intermetallic phases over the die material. Initially iron and aluminum react with each other to form binary iron-aluminum intermetallic phases. Subsequently, these phases react with the molten aluminum to further form ternary iron-aluminum-silicon intermetallic phases. Iron and aluminum have a great affinity for each other and the root cause of die soldering is the high reaction kinetics, which exists between iron and aluminum. Once the initial binary and ternary intermetallic phase layers are formed over the die material, the aluminum sticks to the die due to the abnormally low thermal conductivity of the intermetallic phases, and due to favorable interface energies between the intermetallic layers and aluminum. The experimental details, the results of the interface reactions, and the analysis leading to the establishment of the mechanism giving rise to die soldering are reviewed discussed.

Development of Alcoa Aluminum Foam Products (20082874)
Proceedings of the Third International Conference on Light Metals Technology Sept 24-26 2007 Quebec, Canada P217-222
Aluminum foams have achieved only a fraction of market acceptance enjoyed by polymeric foams, even though aluminum foams offer the potential of superior service performance and improved environmental sustainability. This presentation describes a new light weight aluminum foam product developed at Alcoa Technical Center to capture this potential. Through the controlled decomposition of carbonate powders within molten aluminum, a stable, foamable suspension is created that resists both coalescence and drainage. A novel processing method provides for the economical production of wide panels of self-stabilized aluminum foam. The physical and mechanical properties of these fined celled aluminum foams are related to their cellular structure and the properties of these fined celled aluminum foams are related to their cellular structure and the properties of the aluminum alloy matrix from attractive combination of performance attributes, such as low density, high rigidity, high energy absorption and fire resistance, and contributes to Alcoa’s sustainability goals of energy efficiency and recycling through high aluminum scrap tolerance. A range of product applications incorporating Alcoa Aluminum Foam, n both monolithic form as well as a core material in laminate structure, is currently being studied for service in the building, construction and transportation markets. Performance of Alcoa Aluminum Foam products under different service conditions will be discussed.

NITROGEN SOLUBILITY AND ALUMINUM NITRIDE PRECIPITATION IN LIQUID IRON ALLOYS CONTAINING NICKEL AND ALUMINUM (19790947)
Metallurgical Transactions B (September 1979), p. 409-412, 4 pages
The solubility of nitrogen in liquid iron-base Fe-Ni-Al alloys has been measured up to the solubility limit for formation of aluminum nitride using the Sieverts' method. Measurements were conducted over the temperature range from 1843 to 2023 K and aluminum concentration range from 1.5 to 3.0 wt pct Al. The effect of nickel additions was determined at 2, 5 and 10 wt pct Ni. The solubility product of aluminum nitride increases with increasing aluminum content and increasing temperature. The effect of nickel additions show little effect on the solubility products of aluminum nitride in higher aluminum alloys. However, nickel decreases the solubility products of aluminum nitride in lower aluminum content alloys.

Nucleation of Solid Aluminum on Inclusion Particles Injected into Al-Si-Fe Alloys (20082771)
Metallurgical and Materials Transactions A V35A P3233-3250
Systematic inoculation experiments were carried out to study the influence of various inclusions on the nucleation of the á-Al phase in Al-Si-Fe alloys at different cooling rates. The results showed that in dilute alloys, containing les than 1.5 pct Si + Fe, almost all the inclusion types have high percentages of occurrence within the á-Al phase, indicating that nucleation can be promoted on the surface of such inclusions. In a hypoeutectic Al-Si alloy containing 6.3 pct Si, the inclusion particles of MgO, TiB2, TiC, á-Al2O3, and SiC become mostly inactive nucleants and are pushed to the interdendritic regions because of the dominating poisoning effect of Si. The current results were used successfully to explain the efficiency differences between the commercial grain refiners in the hypoeutectic Al-Si alloys. Silicon is observed to preferentially segregate to the liquid-Al/inclusion interfaces so as to lower the free energy of such interfaces. A theoretical analysis of the poisoning effect of Si showed that Si segregation to the liquid/nucleant interface alters the interfacial energy balance so that the catalytic efficiency of the nucleant particles is dramatically reduced. Careful analysis showed that the poisoning effect of Si in the hypoeutectic alloy is overcome when the nucleant particles have active surface characteristics, as represented by the high catalytic potencies of ã-Al2O3, CaO and Al4C3 particles in nucleating the á-Al phase of the hypoeutectic Al-Si alloy. Although some inclusions have comparable or higher occurrence levels than TiB2 in the á-Al phase, they cannot be used as efficient nucleants because of either their poor wettability with liquid aluminum or their chemical reactivity, which can change the alloy chemistry.

Measurement and Removal of Hydrogen in Aluminum Alloys (19980642)
American Foundrymen’s Society Special Report, 1998
Aluminum alloy cleanliness, which has been in the limelight during the last two decades, remains one of the aluminum casting industry’s primary concerns. When applied to aluminum alloys, the term cleanliness refers to minimal levels of the following contaminants: 1) dissolved hydrogen, 2) alkaline elements, such as Na, Li and Ca, and 3) inclusions. Extensive research ahs contributed greatly to our fundamental understanding of these contaminants. As a result, many companies routinely follow procedures for removing inclusions, and the removal of hydrogen and alkaline elements has become an indispensable melt treatment procedure. However, with ever-increasing demand for improved alloy properties, requirements for alloy cleanliness are becoming more and more stringent, leading greater number of foundries to pay closer attention to this parameter. The U.S. Department of Energy through the Cast Metals Coalition (CM C) is funding a major research project on aluminum alloy cleanliness which is being conducted by the Aluminum Casting Research Laboratory (ACRL) at Worcester Polytechnic Institute (WPI). As part of this project, a critical review of various aspects of aluminum alloy cleanliness has been conducted. The present contribution is a survey of the research on the measurement and removal of hydrogen from aluminum alloy melts. In this survey, more attention is paid to the technical aspects of hydrogen in aluminum alloys (which are related to the production practice), than to a theoretical analysis of mathematical description of the mechanisms involved. The information presented in four chapters: (1) A brief summary of hydrogen introduction into aluminum alloys, and porosity formation and its effects on casting quality. (2) A comprehensive review of measurement of hydrogen solubility in aluminum and aluminum alloys. (3) A review of the various methods of determining the hydrogen content of aluminum and aluminum alloys. (4) A comprehensive review of the technology of hydrogen removal from aluminum alloys melts.

DEOXIDATION EQUILIBRIUM OF ALUMINUM AND SILICON IN THE LIQUIDIRON-NICKEL ALLOYS (20050623)
ISIJ International V 45 N 1 P 8 – 11, 2005
Thermodynamic analysis and experiments showed the deoxidation ability of aluminum in the iron-nickel melts to be lower than that in pure iron and nickel. With an increase in the nickel content, the deoxidation ability of aluminum decreases to about 50% Mi and then it rises. In pure nickel, the deoxidation ability of aluminum is almost equal to that in pure iron. On one hand, this can be explained by an increase in the bond strength of aluminum with this melt when the nickel content rises and, on the other hand, by a decrease in that of oxygen. Curves of the oxygen solubility pass through the minimum whose location is independent of the nickel content in melt. The minimum oxygen concentrations are reached at —0.2% Al: the further additions of aluminum result in a rise in the oxygen concentration. Experimental and calculated results are in good agreement. Complex deoxidation of Fe-40%Ni with aluminum and silicon has been experimentally studied. The formation of solutions and chemical compounds between oxides of these elements promotes the participation of silicon in the deoxidation. The lower oxygen concentrations are reached after the combined deoxidation in comparison with the aluminum deoxidation. However, when the aluminum content rises in the melt at the same silicon concentration, this difference decreases: at a certain aluminum concentration, its deoxidation power becomes equal to that of complex action of aluminum and silicon. This occurs due to an increase in the content of aluminum oxide in slag. When the slag is saturated with aluminum oxide, silicon does not take part in the deoxidation.

1–10 of about 18200 matches for aluminum OR al
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