OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 As can be seen from fig. 6, the corrosion rate has a linear dependence on the magnitude of internal stresses. It should be noted that the maximum change in grain size in this experiment was 20% of the original (table 2). Fig. 7 shows the image of specimen No.3 structure processed in the SIAMS 800 software. Grain boundaries are highlighted in red. Fig. 7. Microstructure of specimen No.3 at 500X magnification with constructed grain boundaries Ta b l e 2 Some parameters of the specimen being investigated Dmin [µm] 2.56 2.82 3.04 2.95 2.87 L, [mm] 0 0.370 0.760 1.130 1.590 Ψ, [%] 0 1.48 3.04 4.52 6.63 Δd, [%] 0 10.07 18.71 15.33 12.09 Dmin is the minimum grain size; L is the specimen elongation; Ψ is the residual deformation of the specimen; Δd is the average change of grain size at material deformation. The maximum change was observed when the material deformed to 3 %, then relaxation processes occurred in the structure and the grain sizes in two directions became equal, which led to a decrease in the average values. The average values of the maximum grain sizes in the longitudinal and transverse directions relative to the external tensile force are used for comparison (fig. 8). This process is also evidenced by the change in longitudinal and transverse grain dimensions expressed in the degree of anisotropy (fig. 9). The degree of anisotropy is defined as the ratio of transverse d2 to the longitudinal d1 grain size. It should be noted that as the strain of the material increases, the dislocation density in the material also increases, the stronger the impact on the metal [24, 25]. The deformation at the initial stage is due to the sliding of a small amount of dislocations present in the material. As the degree of material’s deformation increases, the number of dislocations moving in the
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