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1571 |
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A combined process: cold spraying of heterogeneous coatings followed with their high energy treatment
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Oleg Solonenko / Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Russia Vladimir Kosarev/ Khristianovich Institute of Theoretical and Applied Mechanics, SB RAS, Russia Alexey Golovin/ Khristianovich Institute of Theoretical and Applied Mechanics, SB RAS, Russia Vladimir Neronov/ Khristianovich Institute of Theoretical and Applied Mechanics, SB RAS, Russia Mikhail Korchagin/ Institute of Solid State Chemistry and Mechanochemistry, SB RAS, Russia Vladimir Poluboyarov/ Institute of Solid State Chemistry and Mechanochemistry, SB RAS, Russia |
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Presently, the self-propagating high-temperature synthesis (SHS) has found wide use in the production of compacts and powder materials, and also in the fabrication of end products. Yet, a disadvantageous feature of the standard SHS process, which can be overcome in part by running the synthesis reaction under pressure, is that it fails to provide the possibility of obtaining high-density materials and products. It is therefore of interest to develop a combined process which would allow one to apply a two-component Ni-Al coating with prescribed stoichiometric composition by cold spraying of a nickel-aluminum powder mixture followed by self-propagating high-temperature synthesis of a target intermetallide (Ni3Al or NiAl) by treating the surface layer of the cold sprayed coating with a highly-concentrated energy flux (argon plasma jet). Preparation methods for nickel-aluminum powder mixtures (in particular, mechanochemical activation) intended for cold spraying process are discussed. Computational experiments were performed to substantiate the choice of stationary, traveling and pulsed energy sources for subsequent initiation of SHS in the heterogeneous layer deposited onto a steel substrate. A model was developed to predict the local phase state of the material synthesized in the coating; this model involves the state diagram of the Ni-Al system. The characteristics of sprayed coatings were examined. The developed approach is shown to offer much potential in practical applications. |