V. G. Pushin, E. Yu. Muryshev, E. S. Belosludseva, N. N. Kuranova, А. V. Pushin, A. E. Svirid, A. N. Uksusnikov

THE FEATURES OF STRUCTURAL-PHASE TRANSFORMATIONS IN THE 12Kh18N10T STAINLESS STEEL SUBJECTED TO HIGH-FREQUENCY HYDRODYNAMIC EFFECTS UNDER HIGH PRESSURE

For the first time, transmission electron microscopy is applied to the study of stainless steel specimens subjected to prolonged high-frequency (50 MHz) external hydrodynamic effects (EHDE) under high pressure (2-3 GPa) in a device of special design. It is found that, due to EHDE, the solid surface layer of the steel, up to 100 µm thick, undergoes a strain-induced martensitic transformation with the appearance of a finely twinned α- and ɛ-phase crystal structure. In the following intermediate layers located at a depth of 100 to 200 µm, traces of fragmentation with a dislocation and twinned substructure inside the austenite grains are found, which are caused by work hardening of austenite in the process of direct and reverse γ-ɛ-α martensitic transformation. The features of γ-austenite, ɛ- and α-martensite microstructures are studied in detail. It is concluded from the analysis of the obtained and known data that thermo-, baro- and elastic-plastic mechanisms of martensitic transformations take place under multicycle high-frequency external effects. The martensitic transformation must be accompanied by baro- and magnetocaloric exothermal effects, by direct martensitic transformation and, consequently, endothermic effects during reverse transformation.

Acknowledgment: The work was done within state assignment for IMP UB RAS (theme "Structure"), with the support from UB RAS, project 15-9-2-17, and Sole Proprietor Muryshev E. Yu.

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