DOI: 10.22184/1993-8578.2024.17.1.56.70

In the presented article studies were carried out of the influence of multiple martensitic transformations B2-B19’ on the structure and temperatures of transformations in different structural states of the TiNi alloy. It is shown that in coarse-grained, ultrafine-grained and nanocrystalline TiNi alloys, consistent changes occur in the microstructure and temperatures of phase transformations, with an increase in the number of thermal cycles to n=100 with rapid heating and rapid cooling to -196 °C. Transformation temperatures in the ultrafine-grained Ti49.15Ni50.85 state are more resistant to thermal cycling (TC) than in the coarse-grained state. The formation of martensite nanotwins in the nanostructural state after multiple thermal cycles was discovered.