OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 2 2025 analysis, the misorientation between adjacent regions separated by microbands is negligible (<2°). With an increase in the CRF reduction to 40 %, mechanical twins appear (Fig. 2, b1 and b2). Microdiffraction and EBSD analysis indicated that the mechanical twins are located in the {111} planes and are misoriented by approximately 60° relative to the parent austenite (Σ3 boundary). In this case, parallel primary mechanical twins of one plane set meet in the center of the rod (Fig. 2, b1), and packets of parallel mechanical twins are formed at the edge of the rod (Fig. 2, b2). A further increase in the CRF reduction to 60 % is accompanied by the development of mechanical twinning in secondary systems in the center of the rod (Fig. 2, c1). Towards the edge of the rod, a pronounced lamellar structure is observed to form, resulting frommechanical twinning on a single system (Fig. 2, c2). In addition, shear bands are formed across the twin lamellas (Fig. 2, c2). After 80 % CRF, an increase in the number of twins in the center of the rod is detected (Fig. 2, d1). In turn, at the edge of the rod, the structure is fragmented due to the formation of shear bands in the original lamellar microstructure (Fig. 2, d2). CRF ε = 20 % CRF ε = 40 % CRF ε = 60 % CRF ε = 80 % Center a1 b1 c1 d1 Edge a2 b2 c2 d2 Fig. 2. Fine structure of the Fe-21Mn-6Al-1Csteel after CRF with ε = 20% (a1, a2), ε = 40% (b1, b2), ε = 60% (c1, c2), and ε = 80% (d1, d2) in the center and at the edge of the rod The results of the quantitative analysis of the density of deformation microbands (ρdm) and mechanical twins (ρt) after CRF with different degrees are shown in Fig. 3. The results indicate that CRF leads to an increase in the density of deformation microbands, beginning at 20 % deformation (Fig. 3, a), and mechanical twins, beginning at 40 % deformation (Fig. 3, b). It should be noted that after 60 % CRF, the density of crystal structure defects in both cases is higher in the rod center than that at the rod edge. 80 % CRF causes, on the one hand, a further increase in the density of both deformation microbands and mechanical twins in the center. On the other hand, a decrease in the density of these defects occurs at the edge, apparently due to fragmentation of the microstructure during the formation of shear bands. After 80 % CRF, the average size of the elements of the fragmented structure at the edge of the rods of the studied steels is 200‑250 nm, and in the center ‑ 300‑350 nm (Fig. 2, d1 and d2). The maps of the distribution of austenite crystal orientations and the direct pole figures of the center and edge of the rod after CRF with different reductions are shown in Fig. 4. The direct pole figures of the rod center demonstrate a pronounced axial two-component texture <111>//rod axis (RA) and <100>//RA (Fig. 4, a1-d1), which in the subsurface layer is replaced by the simple shear texture B/B ̅(Fig. 4, a2-d2). It is worth noting that increasing the CRF reduction enhances the intensity of these texture patterns on the corresponding pole figures. A further increase in the CRF reduction to 80 % in the center of the rod develops the sharp axial texture <111>//RA (Fig. 4, a1-d1), while the fraction of austenite grains with such an orientation reaches 70 %. At the same time, after 80 % CRF, the volume fraction of austenite grains with
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