National Research Tomsk State University, Tomsk, Russia
А. N. Monogenov, Senior Researcher of the Laboratory of Superelastic Biointerfaces, Candidate of Physical and Mathematical Sciences, e-mail: monogenov@mail.ru
E. S. Marchenko, Head of the Laboratory for Medical Alloys and Shape Memory Implants at the Siberian Physical-Technical Institute, Candidate of Physical and Mathematical Sciences, Associate Professor, e-mail: 89138641814@mail.ru
О. V. Kokorev, Professor of the Department of Strength and Design, Doctor of Medical Sciences, e-mail: kokorevov@mail.tsu.ru

Cancer Research Institute, a subdivision of the Federal State Budgetary Scientific Institution Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia¹ ; Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia²
V. I. Shtin, Senior Researcher of the Department of Head and Neck Tumors¹, Candidate of Medical Sciences², e-mail: shtinv@mail.ru

Siberian State Medical University, Tomsk, Russia
L. S. Кraevа, Associate Professor of the Department of Neurology and Neurosurgery, Candidate of Medical Sciences, e-mail: kraeva.Is@ssmu.ru

The structure and properties, including biocompatibility of a medical grade alloy based on titanium nickelide alloyed with tungsten, have been studied. The phase composition was determined by X-ray diffraction analysis. Main phases: TiNi; Ti₂Ni; TiNi₃; Ti₃Ni₄; pure W. The elemental composition of the microstructure has been studied. It has been established that tungsten is present in the TiNi alloy in the form of individual particles, the average size of which is 1.5 microns. The alloying of TiNi alloys with tungsten shifts the direct martensitic transformation towards lower temperatures. The value of the accumulated deformation of the multiple shape memory effect (mSME) during cooling decreases from 6.5 to 3% with an increase in the tungsten content from 0 and 0.6% (at.). The temperatures of the beginning – end of the shaping during cooling and the temperatures of the beginning – end of the shaping during heating decrease with an increase in the concentration of tungsten. The value of the mSME of monolithic titanium nickelide-based alloys alloyed to 0.2% (at.) W does not deteriorate and remains at a high level, while the degree of incomplete recovery after the 10^th cooling-heating cycle under load is close to zero, which indicates the high superelastic properties of Ti₅₀Ni_50-xW_x alloys (at x = 0; 0.2; 0.4; 0.6). The practical application of Ti – Ni – W alloys in medicine in relation to physical materials science is promising at concentrations up to 0.2% (at.) W. It was found that tungsten alloying of monolithic titanium nickelide samples improves their biocompatibility in relation to 3T3 cells after 72 hours. The hemolysis test showed that Ti₅₀Ni_50-xW_x alloys (at x = 0; 0.2; 0.4; 0.6) at the indicated alloying concentrations do not have a destructive effect on red blood cells.

V. S. Turskaya and E. A. Kushnarev, the students of Tomsk State University, took part in the work.
The study is carried out under State Сontract No. FSWM-2020-0022.

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