| Abstrakt: |
A review of the published data concerning the structural features of TRIP/TWIP steels, the relationship thereof to mechanical properties, and the relationship between strength parameters under static and cyclic loading is presented. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is represented by stacking fault energy, the level of which is decisive in the formation of austenite twins and/or in the formation of strain martensite. By choosing the chemical composition, one can set the level of stacking fault energy corresponding to the required mechanical characteristics. In the case of cyclic loading, an important role is played by the strain rate and the maximum load in the course of testing. So, at a high loading rate and a load approaching the yield strength under tension, the intensity of twinning processes and the rate of formation of martensite increases. It has been shown that one of the relevant ways to further improving the structural and functional properties of TRIP and TWIP steels consists in developing composite materials based on them. At present, surface modification and coating application, especially by means ion-vacuum methods, can be considered the most promising direction for making such composites. [ABSTRACT FROM AUTHOR] |
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