from the conferences organized by TANGER Ltd.
A preparation of alloys based on the Ni3Al intermetallic compound alloyed with molybdenum by classical castings methods, such as an induction melting, is limited by a high melting point of molybdenum (2623 °C). Decreasing of the melting point on the value of 1417 °C was reached by a preparation of the Ni-15Mo (wt.%) master alloy by plasma metallurgy. The master alloy was used as an input material for a preparation of the Ni-7Al-14Mo (wt.%) alloy by an induction melting with a centrifugal casting. Castings of the Ni-7Al-14Mo alloy were directionally solidified in a resistance furnace working on the Bridgman method principle at the rates of 20 and 50 mm/h and the constant thermal gradient of 75 °C/cm. All experimental alloys were examined by a chemical and structural analysis. A matrix of the master alloy was homogeneous without precipitates and formed by the MoNi8 phase. Matrixes of the casting and directionally solidified rods of the Ni-7Al-14Mo alloy consisted of the Ni3Al phase and the solid solution of aluminum in nickel, mutually arranged as a mesh. There were small precipitates rich in molybdenum situated along grain boundaries. A structure of the casting and the directionally solidified rods was polycrystalline, but the grains of the directionally solidified rods were oriented in a growth direction of solid-liquid interface.
Keywords: Ni-7Al-14Mo alloy, Ni-15Mo alloy, plasma metallurgy, directional solidification, microstructure© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.