Entity

Time filter

Source Type


Padalko A.G.,RAS Institute of Metallurgy | Talanova G.V.,RAS Institute of Metallurgy | Ponomareva E.Yu.,RAS Institute of Metallurgy | Talyat-Kelpsh V.V.,RAS Institute of Metallurgy | And 5 more authors.
Inorganic Materials | Year: 2012

Phase transformations of the 2.7Ni + 97.3Al eutectic alloy have been characterized by differential barothermal analysis (DBA) at temperatures of up to 750°C and pressures of up to -100 MPa. The results demonstrate that the Al matrix of the as-prepared alloy was saturated with micropores. After melting and crystallization in compressed argon, the micropore density increased. As a result of melting and solidification, the fine-grained structure of the as-prepared alloy transformed to a macrocrystalline, dendritic structure. Electron microscopy was used to determine the volume fraction of the intermetallic phase NiAl 3 in the Al matrix. Supersaturated solid solutions of nickel in aluminum decompose at 626°C to give a mixture of Al and NiAl 3. At 100 MPa, the nickel-aluminum solid-solution range extends to 2.7-2.8 at % Ni, and the nickel content at the eutectic point may reach 3.1-3.3 at %. The Al and NiAl 3 in the alloy solidified at 100 MPa had reduced lattice parameters. We determined the microhardness of the Al matrix after DBA. © Pleiades Publishing, Ltd., 2012. Source


Padalko A.G.,RAS Institute of Metallurgy | Ellert O.G.,RAS Kurnakov Institute of General and Inorganic Chemistry | Efimov N.N.,RAS Kurnakov Institute of General and Inorganic Chemistry | Novotortsev V.M.,RAS Kurnakov Institute of General and Inorganic Chemistry | And 5 more authors.
Inorganic Materials | Year: 2013

Phase transformations of the 15Ni-85Al alloy have been studied by differential barothermal analysis at temperatures of up to 900 C and pressures of up to ≅ 100 MPa. We have determined the pressure coefficients of the liquidus and solidus temperatures and the temperatures of solid-state dissolution and precipitation of the intermetallic phase Al3Ni in the Al matrix. Melting and crystallization in compressed argon have been shown to increase the micropore concentration in the material by about one order of magnitude relative to the as-prepared alloy. Crystallization of the alloy at 100 MPa has a significant effect on its microstructure and the particle size and morphology of the intermetallic phase in the aluminum matrix and increases the unit-cell volumes of the Al and Al3Ni. We have compared the magnetic properties of the alloy before and after barothermal analysis. © 2013 Pleiades Publishing, Ltd. Source


Padalko A.G.,RAS Institute of Metallurgy | Dedyaeva E.V.,RAS Institute of Metallurgy | Akopyan T.K.,RAS Institute of Metallurgy | Talanova G.V.,RAS Institute of Metallurgy | And 4 more authors.
Inorganic Materials | Year: 2014

Phase transformations of an Al-12 at % Si alloy have been studied by differential barothermal analysis at temperatures of up to 700°C in argon compressed to 100 MPa. Heating at a rate of 8°C/min under a pressure of 100 MPa has been shown to increase the temperature of the L → (Al) + Si eutectic transformation in the alloy by 4°C. After crystallization of the binary eutectic, the differential thermal analysis cooling curve showed an additional exothermic peak, corresponding to the decomposition of the aluminum-based solid solution (Al) at 547°C and precipitation of silicon particles in the nanometer range. A barothermal scanning cycle reduced numerical porosity characteristics of the alloy, except for the pore number density. The lattice parameter of silicon microparticles in the alloy approaches values in the literature, whereas that of nanoparticles is slightly greater. The lattice parameter of the aluminum remains unchanged during crystallization and cooling in compressed argon. The microhardness of the aluminum matrix of the alloy corresponds to that of pure aluminum. © 2014 Pleiades Publishing, Ltd. Source


Padalko A.G.,RAS Institute of Metallurgy | Ellert O.G.,RAS Kurnakov Institute of General and Inorganic Chemistry | Efimov N.N.,RAS Kurnakov Institute of General and Inorganic Chemistry | Novotortsev V.M.,RAS Kurnakov Institute of General and Inorganic Chemistry | And 5 more authors.
Inorganic Materials | Year: 2013

Phase transformations of the hypereutectic alloy 10Ni-90Al have been studied by differential barothermal analysis at temperatures of up to 900 C and pressures of up to ≅100 MPa. We have determined the pressure coefficients of the liquidus and solidus temperatures and the temperatures of solid-state dissolution and precipitation of the intermetallic phase Al3Ni. At high pressures, the solid-state decomposition of the supersaturated solid solution of nickel in aluminum occurs at 622 C and yields an (Al) + Al 3Ni mixture. We assume that, during cooling of the alloy at high pressure, intermetallic particles form in three steps. Barothermal analysis data have been compared to the canonical t-x phase diagram of the Al-Ni system. As a result of melting and crystallization at high pressure, the microcrystalline structure of the as-prepared alloy transforms to a macrocrystalline, dendritic structure and the micropore concentration increases. X-ray diffraction data indicate an increase in the unit-cell volumes of the Al and Al3Ni in the alloy crystallized at 100MPa. We have studied the magnetic properties of the alloy after barothermal analysis. © 2013 Pleiades Publishing, Ltd. Source

Discover hidden collaborations