OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 2 2025 a b Fig. 3. Density of deformation microbands (ρdm) and mechanical twins (ρt) as a function of the degree of CRF in Fe-21Mn-6Al-1C steel rod at various distances from the rod center CRF ε = 20 % CRF ε = 40 % CRF ε = 60 % CRF ε = 80 % Center a1 b1 c1 d1 Edge a2 b2 c2 d2 Fig. 4. Orientation maps of austenitic grains and direct pole figures (111) from the center and edge of the rod after CRF with ε = 20% (a1, a2), ε = 40% (b1, b2), ε = 60% (c1, c2), and ε = 80% (d1, d2) the <100>//RA orientation in the center does not exceed 18 %. In this case, the fraction of austenite grains with the <111>//RA orientation in the direction from the center to the edge decreases to 20 %, whereas the fraction of grains with the <100>//RA orientation in the subsurface layer does not exceed 3 %. The distribution of microhardness along the rod diameter depending on the degree of CRF of Fe-21Mn6Al-1C steel is shown in Fig. 5. In the initial state, the uniform distribution of microhardness is observed over the rod cross section. The microhardness of the initial rod is at the level of 230 HV0.2. 20 % CRF causes an increase in the microhardness of the rod periphery to a greater extent compared to the center, which leads to the formation of a gradient of microhardness distribution from the center to the edge of the rod. Subsequent CRF is accompanied by a further increase in the overall level of microhardness. However, after a deformation of 60 %, the pronounced peak of microhardness appears in the core of the rod. At the same time, in the direction from the center to the edge of the rod, the microhardness smoothly decreases, i.e. the microhardness gradient changes its direction from the edge to the center. After 80 % CRF this peak reaches
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