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Belov N.A.,National Research and Technological University | Alabin A.N.,National Research and Technological University | Matveeva I.A.,UC Rusal
Journal of Alloys and Compounds | Year: 2014

The possibility to use alloys of the Al-Cu-Mn-Zr-Sc system for obtaining rolled sheets directly from cast ingots (without homogenization process) was investigated. The experimental (SEM, TEM, EMPA, and mechanical tests) study and Thermo-Calc software simulation were used for alloy composition optimization. It was shown that optimal structure could be developed in the alloys of the following compositional range: 1-2% Cu, 1-2% Mn, ∼0.2% Zr and ∼0.1% Sc (wt%). Such nearly single-phase structure achieved in the as-cast state provides high ductility of the alloys and allows for up to 87% hot rolling reduction and up to 75% cold rolling reduction without intermediate annealing. Experimental Al-Cu-Mn-Zr-Sc and commercial AA2219 alloys were compared. Tensile tests of 0.5 mm sheets proved the advantage of the experimental alloy. Although the AA2219 alloy can be considerably hardened upon quenching and aging (T6), this hardening effect completely disappears after short-term heating at 300-350 C. On the other hand the experimental alloy was thermally stable due to the formation of polygonized structure, which resulted from large amount of Al 20Cu2Mn3 and Al3(Zr,Sc) (L1 2) dispersoids that effectively pinned down dislocations. No secondary Al2Cu precipitates were detected. Such structure is the most favorable for creep resistance as Mn- and Zr-containing dispersoids have a higher thermal stability than Al2Cu precipitates. Proposed range of compositions can be recommended for the development of new aluminum wrought alloys, which will have two main advantages as compared with commercial alloys of the AA2219 type: (1) high tolerance to heating up to 350 C because of high amount Al3(Zr,Sc) and Al20Cu2Mn dispersoids; (2) energy efficient processing, in particular due to the elimination of homogenization, solution treatment and quenching. © 2013 Elsevier B.V. All rights reserved. Source

Matveeva I.,UC Rusal | Dovzhenko N.,Siberian Federal University | Sidelnikov S.,Siberian Federal University | Trifonenkov L.,RUSAL ETC LLC | And 2 more authors.
TMS Light Metals | Year: 2013

Development of electrical alloys of system aluminium - rare-earth metals and aluminium-zirconium for production of electrotechnical application wire rod. Design of technological line for their manufacturing. The effect of rare-earth and transition metals on the properties of the aluminium alloys containing such metals is analysed. New alloys with different content of zirconium, cerium, and other components featuring enhanced mechanical and electrophysical characteristics have been proposed. New technologies for production of long round-in-section items involving combined processing methods have been developed. The effects of the processing methods on the structure and properties of semi-finished products made of new alloys have been studied and recommendations for the modes of preparing alloys, casting, shaping, and thermal processing have been made for the set of the studied alloys. The method of combined casting and drawing-extrusion is shown to ensure, in laboratory conditions, improved mechanical properties and the required level of electric resistivity. Source

Belov N.A.,Moscow Institute of Steel And Alloys | Alabin A.N.,Moscow Institute of Steel And Alloys | Matveeva I.A.,UC Rusal | Sannikov A.V.,Moscow Institute of Steel And Alloys
TMS Light Metals | Year: 2015

We have calculated liquidus projections in the typical sections of the Al-Ni-Fe-Mn-Si system up to: 9% Ni, 3% Fe, 3% Mn, and 3% Si (%wt). We have identified concentrations of elements enabling primary crystallisation of the Al3Ni, Al9FeNi, Al3Fe, Al6(Fe, Mn), and Al15(Fe, Mn)3Si2 intermetallic phases. We have demonstrated close agreement of the experimental data and calculated data. Primary crystals of two phases - Al9FeNi and Al6(Fe, Mn) will most likely form during casting to metal moulds in the area of nickalyn compositions. Primary crystallisation of the Al3Ni and Al15(Fe, Mn)3Si2 phases is possible only at higher Ni and Si concentrations respectively, while formation of the Al3Fe phase requires slow solidification achieved through casting to expendable moulds. Source

Belov N.A.,National Research and Technological University | Naumova E.A.,Moscow State Technical University | Alabin A.N.,National Research and Technological University | Matveeva I.A.,UC Rusal
Journal of Alloys and Compounds | Year: 2015

Abstract The phase composition, structure and hardening of alloys in the aluminium corner of the Al-Ca-Sc system were studied in the range up to 10% Ca and up to 1% Sc. The experimental study (optical, scanning and transmission electron microscopy with electron-microprobe analysis, differential thermal analysis and hardness measurements) was combined with Thermo-Calc software simulation for the optimization of the alloy composition. It was shown that only phases of the binary systems (Al4Ca N Al3Sc) might be in equilibrium with the aluminium solid solution. It was shown that the (Al)+ Al4Ca eutectic had a much finer structure as compared with the Al-Si eutectic, which suggests a possibility of reaching higher mechanical properties as compared to commercial alloys of the A356 type. The influence of the annealing temperature within the range up to 600 °C on the structure and hardness of the Al-Ca-Sc experimental alloys was studied. It was determined that the maximum hardening corresponded to the annealing at 300 °C, which was due to the precipitation of Al3Sc nanoparticles with their further coarsening. With an example of an Al-7.6% Ca-0.3% Sc model experimental alloy, a principal possibility of manufacturing aluminium casting alloys based on the (Al)+ Al4Ca eutectic was demonstrated. Unlike commercial alloys of the A356 type, the model alloy does not require quenching, as hardening particles are formed in the course of annealing of casting. © 2015 Elsevier B.V. Source

Shtefanyuk Y.,UC Rusal | Mann V.,UC Rusal | Pingin V.,s Engineering and Technology Center | Vinogradov D.,s Engineering and Technology Center | And 4 more authors.
TMS Light Metals | Year: 2015

Primary testing for producing Al-Sc alloy by electrolysis of Sc2O3 dissolved in a cryolite bath containing molten aluminum was performed. A lab-scale cell consisted of graphite anode and aluminum cathode located on the bottom of corundum crucible. A graphite current lead to the aluminum cathode was also served as a stirrer. Molten cryolite NaF-AlF3 or KF-AlF3, or their mixture with cryolite ratio in a range of 1.3-2.3 was used as a solvent for Sc2O3. Electrolysis was carried out in the sodium cryolite with composition similar to conventional electrolyte at 980 °C and in the low-melted sodium and potassium-cryolite-based-electrolytes with cryolite ratio 1.3 and 1.5 at 750, 800 and 850 °C. The cathode current density impact on the composition of producing alloys was studied. The alloy's and electrolyte's composition was analyzed with SEM EDX and ICP methods. A uniform distribution of scandium throughout the Al-Sc alloy matrix for all studied samples was observed. Source

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