Federal State Budgetary Educational Institution of Higher Education “Pacific National University”, Khabarovsk, Russia:

E. H. Ri, Dr. Eng., Prof., Head of the Department of Foundry Engineering and Metal Technology, e-mail: erikri999@mail.ru
Hosen Ri, Dr. Eng., Prof., e-mail: opirus@bk.ru
K. V. Doroshenko, Post-graduate Student of the Department of Foundry and Metal Technology, e-mail: rbhbkk1212@yandex.ru
E. V. Kim, Senior Lecturer of the Department of Foundry Engineering and Metal Technology, e-mail: jenya_1992g@mail.ru

The paper is devoted to revealing the regularities of the influence of titanium (0.91, 2.42, 3.19, 3.39, 4.32 and 8.81 wt.%) on structure formation, nature of element distribution and microhardness of structural components in Al – Ni – Ti alloys by aluminothermy during SHS metallurgy. As the initial composition of the charge were selected the following materials in fractional parts: Al:NiO₂:CaF₂:NaNO₃:TiO₂ = 10:10:12:6:X, where X = 1.5, 4.5, 5.0, 7.0, 10.0. The structural components in Al – Ni – Ti alloys have been identified by electron microscopy and X-ray spectral analysis of elements. In the alloys with 0.91–4.32 wt.% Ti the following phases crystallize: β'-phase (solid solution of Ni in the nickel aluminide AlNi) Al₃Ni₂, Al₃Ti, Al3Ni and α-solid solution of Ni and Ti in aluminum. In an alloy with 8.81 wt.% Ti the β'-phase turns into a titanium-doped nickel aluminide Al(NiTi) (composition in at.%: 50.53 Al; 1.47 Ti; 48.0 Ni). The increase of titanium content in Al – Ni – Ti alloys increases the solubility of Ni in the β'-phase and at titanium concentration in the alloy 8.81 wt.% in the aluminide Al(NiTi) up to 48 at.% Ni is dissolved compared to the solubility of nickel (38 at.%) in the alloy with 0.91 wt.% Ti. Increasing the nickel content in the above phases contributes to their microhardness from 13 GPa to 14.8 GPa at 8.81 wt.% Ti. Increasing the titanium content in Al – Ni – Ti alloys to 4.32 wt.% increases the solubility of nickel in the nickel aluminide Al₃Ni, with a higher concentration of titanium (8.81 wt.%) in the nickel aluminide with titanium Al(NiTi) dissolves up to 48.53 at.% Ni, while in the alloy with 0.91 wt.% Ti – only about 1.0 at.% Ni. At the same time, the Al and Ti content in titanium aluminide Al₃Ti decreases and its microhardness increases. It was not possible to determine the microhardness of Al(NiTi) aluminide because of the formation of a porous structure. In nickel aluminide Al₃Ni, an increase in titanium content leads to an increase in nickel concentration to 4.32 wt.% Ti followed by a slight increase to 8.81 wt.% Ti. Despite increasing the nickel content and decreasing the aluminum concentration, the microhardness of the nickel aluminide decreases. Apparently, this circumstance is caused by the formation of a porous structure in this phase.

The research was carried out at the Center for Collective Use “Applied Materials Science” of the Federal State Budgetary Educational Institution of Higher Education “TOGU” with the financial support of the Ministry of Science and Education of the Russian Federation within the framework of research work No state reg. of the state task AAAA-A20-120021490002-1.

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