OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 3 2024 When heated to 400 °C in large grains of NixAl1-x, the beginning of the reverse transition of L10 martensite to B2 structure with the secondary phase formation along microtwins is observed. No changes are observed in small grains of the NixAl1-x phase, γ΄-Ni3Al grains and β-NiAl plates. After heating to 600 °C, the shape of the γ’-Ni3Al and NixAl1-x grains approaches equiaxial, which indicates the occurrence of recrystallization processes. The secondary phase is oriented in one direction in NixAl1-x grains. The martensite crystals in large grains are completely transformed into the B2 structure, although it retained its orientation. References 1. Bochenek K., Basista M. Advances in processing of NiAl intermetallic alloys and composites for high temperature aerospace applications. Progress in Aerospace Sciences, 2015, vol. 79, pp. 136–146. DOI: 10.1016/j.paerosci.2015.09.003. 2. Müller M., Enghardt S., Kuczyk M., Riede M., López E., Brueckner F., Marquardt A., Leyens C. Microstructure of NiAl-Ta-Cr in situ alloyed by induction-assisted laser-based directed energy deposition. Materials & Design, 2024, vol. 238, p. 112667. DOI: 10.1016/j.matdes.2024.112667. 3. Zhou L., Mehta A., Cho K., Sohn Y. Composition-dependent interdiffusion coefficient, reduced elastic modulus and hardness in γ-, γ′- and β-phases in the Ni-Al system. Journal of Alloys and Compounds, 2017, vol. 727, pp. 153–162. DOI: 10.1016/j.jallcom.2017.07.256. 4. Darolia R. Ductility and fracture toughness issues related to implementation of NiAl for gas turbine applications. Intermetallics, 2000, vol. 8 (9–11), pp. 1321–1327. DOI: 10.1016/S0966-9795(00)00081-9. Fig. 8. TEM images of coating structure after heating 600 °С: a, b – two-phase area; c, d – prior martensite plates; a, b, c – bright field; d – dark field а b c d
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