Visn. Nac. Akad. Nauk Ukr. 2018. (6):19-33

G.S. Firstov

Kurdyumov Institute for Metal Physics of the National Academy of Sciences of Ukraine, Kyiv

According to the materials of scientific report at the meeting of the Presidium of NAS of Ukraine, March 21, 2018

An overview of the scientific direction devoted to the study of shape memory functional materials is presented. The special role played by Ukrainian scientists in its founding and development in the world is emphasized. It is noted that shape memory alloys such as nitinol or copper-based alloys cannot be used at elevated temperatures, and so-called high-temperature shape memory alloys have a number of disadvantages, which are mainly related to relaxation processes of internal stresses through plastic deformation and diffusion processes. Medical applications of industrial shape memory alloys are restricted by incomplete biocompatibility. The ways of improvement of alloys with memory of the form through the resistance of forms of degradation, thermal, mechanical, functional fatigue, etc. are analyzed. It is shown that it is the materials with AS / Tmelt not greater than 0.4, with low symmetry of the high-temperature phase, with the essential strengthening are the best for high temperature alloys application. At present, such properties as significant strengthening and slow diffusion are characteristic of the novel structural materials — high-entropy alloys, which by definition have high stability. In the Kurdyumov Institute for Metal Physics for the first time high values of the yield strength twice as high as for nitinol and the possibility of martensitic transformation and corresponding memory behavior was combined in high-entropy intermetallic compounds. It was concluded that new class of functional materials — high entropy shape memory alloys has been created. It will be possible not only to reach a new level of their application in the automotive, aerospace, energy or mining industries, but, most importantly, to deepen their medical application.
Keywords: shape memory functional materials, highly-entropy alloys, martensitic transformations.

Language of article: ukrainian