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Ni3Al based alloys in the as-cast state and directionally solidified were used for tests in compression at higher temperatures. The alloys were prepared by vacuum induction melting. Directional solidification was performed by Bridgman method with the vertical arrangement. The mechanical characteristics in compression were determined at the temperatures of 1000 °C and 800 °C with use of the equipment Gleeble 3800. Evolution of deformation of the alloys in the directed and as-cast state has a similar course, yet it is still possible to observe some differences. The directionally solidified alloys show more stable evolution of deformation, whereas the phase Ni-24Al alloys achieve better mechanical properties at higher temperatures. It was found that the yield strength increases up to the temperature of 800 °C. Directionally solidified mono-phase and multi-phase alloys exhibited at testing at the temperature of 1000 °C distinct yield strength, which is not typical for these alloys within the temperature range of 20-800 °C. The yield strengths are similar for all the samples, approximately 530 to 600 MPa at 800 °C. The Ni-22Al alloys are less susceptible to a change of the yield strength with the increasing temperature. The yield strength value does not decrease significantly even at the temperature of 1000 °C.
Keywords: Ni3Al based alloys, directional solidification, Bridgman method, mechanical characteristics, hot compression tests© 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.