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The research studies the elastoplastic transition in α-Fe alloy composed of 0.025 wt % of carbon in the temperature range from 296 K to 473 K and deformation velocity from 3.33·10−5 s−1 to 3.33·10−2 s−1. It was found that the lower yield stress increases with an increase of deformation velocity according to the power law. An increase in the test temperature leads to a linear decrease in the velocity sensitivity index and a transition from the stationary kinetics of Chernov-Lüders band propagation to discrete kinetics, when surges in the deformation stress are observed on the yield plateau. On the basis of quantitative estimates, it is shown that the nature of the kinetics of band propagation is controlled by the mobility of impurity insertion atoms. Discrete kinetics occurs at increased temperatures, when high mobility of carbon atoms ensures multiple detachment and pinning of dislocations from impurity centers. Otherwise, the process develops stationary with a constant velocity. The discussion is carried out within the framework of the autowave concept of plastic flow. [ABSTRACT FROM AUTHOR]

The results of acoustic parameter measurements in a deformed material with simultaneous recording of autowave patterns of localized plastic deformation for low-carbon steel 1008 are presented. Specimen deformation affects both the ultrasound velocity increase and the evolution of autowave patterns. The first kink corresponds to the elastic-plastic transition and the formation of switching autowave. The second kink and collapse of the localized deformation autowave correspond to material fracture. [ABSTRACT FROM AUTHOR]

The paper presents the structure and nature of plastic deformation macrolocalization in metastable austenitic-martensitic steel in relation to preliminary thermomechanical processing. Preliminary processing affects the amount of metastable austenite, staging and type of deformation curves, evolution of localized plastic deformation autowaves. It is shown that, during TRIP steel deformation n, one type of autowaves (switching) is changed to another (excitation). The autowave transformation mechanism has been established, in which nucleation sites of switching autowaves are sources of excitation autowaves. [ABSTRACT FROM AUTHOR]

The paper studies the deformation behavior of nitinol in a superelastic state at the macroscopic level. It has been established that both the direct phase transformation B2 → B19' during loading and the reverse phase transformation B19' → B2 during unloading are realized through formation of moving fronts, which are localized plastic deformation switching autowaves. The relationship between autowave propagation velocity during loading and the gripping device speed is investigated. [ABSTRACT FROM AUTHOR]

The deformation of materials with unstable phase structure such as titanium nickelide (nitinol) and steel with transformation induced plasticity (trip-steel) was studied within the framework of the autowave theory. It was established that at the initial stages of deformation a strain induced martensitic phase transformation occurs in both materials, which is realized as switching autowaves of localized plastic deformation. In nitinol it occurs completely, while in TRIP steel the remaining unstable austenite under further deformation expose a transformation similar to the Portevin–Le Chatelier effect with formation of waves of excitation of localized plastic deformation. [ABSTRACT FROM AUTHOR]