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The paper deals with the characterization of the structure and phase composition of selected types of nickel alloys. Castings were prepared by vacuum induction melting and centrifugal casting. Samples of Ni-Al-Mo based alloys with various contents of molybdenum were directionally solidified by Bridgman method in corundum tubes with specified apex angle. Rate of solidification was 50 and 20 mm/h. The samples were used for structural analysis in longitudinal and transverse direction. The structure is significantly influenced by the process of directional solidification. Microstructural characterization of materials was performed with use of scanning electron microscope. Distribution of individual elements in phases was captured on linear analysis. These alloys do not exhibit significant chemical heterogeneity. The samples are composed of a phases Ni3Al and (Ni) with various contents of molybdenum. The existence of a separate phase (Mo) was not confirmed. Determined values of microhardness show the dependence on molybdenum content and rate of directional solidification.
Keywords: Ni-Al based alloys, molybdenum, directional solidification, Bridgman method, 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.