OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 1 2025 increasing its hardness and wear resistance. Increasing the dose of N+ from 1017 to 2×1017 does not lead to a change in the phase composition. The studies also showed that after implantation, the size of mosaic blocks (C.S.R.) decreases compared to the initial untreated state. Moreover, the most pronounced decrease is observed in samples after implantation with a dose of 2×1017 ion/cm2 (Table 2). Nitrogen ion implantation introduces significant changes in the structure of cast iron, specifically in its near-surface layer. One of the key changes is an increase in the dislocation density in this layer compared to the initial material, which was not treated. Dislocations, which are defects in the crystal lattice, affect the mechanical properties of materials. Its increased concentration, resulting from ion implantation, leads to an increase in hardness and strength. This is confirmed by observations showing that the highest average dislocation density is found in samples implanted with the highest nitrogen dose – 5×1017 ions/cm2 (Table 3). It is important to note that this dose is considered optimal in this study, as it provides the most effective increase in strength properties without deterioration of other characteristics. Ta b l e 3 Results of X-ray diffraction analysis of samples before and after implantation with N+ ions Cast iron type Radiation power (ion/cm2) Coherent scattering region (D ± ΔD) (cm×10−4) Average dislocation density (ρ ± Δρ) × 109 (cm−2) Phase composition CI 0 (original sample) 2.0 ± 0.12 0.75 ± 0.5 α-Fe 1017 ion/cm2 1.5 ± 0.08 1.3 ± 0.1 α-Fe, Fe 3N, Fe2N 2×1017 ion/cm2 0.9 ± 0.03 3.7 ± 0.6 α-Fe, Fe 3N, Fe2N 5×1017 ion/cm2 0.6 ± 0.03 4.8 ± 0.6 α-Fe, Fe 3N, Fe2N Thus, X-ray diffraction analysis showed that, after implantation with nitrogen ions, an increase in the average dislocation density and a decrease in the size of mosaic blocks occur. Ultimately, these structural changes explain the improvement in surface properties observed in the investigated type of cast iron. Conclusion As a result of the conducted research it is established that nitrogen ion implantation is an effective method for increasing the strength properties of parts made from grey cast iron. 1. According to the results of the work it is shown that the optimal mode of implantation in the conditions of this study is a dose of 5×10¹⁷ ion/cm². At this dose, the maximum increase of microhardness is observed, reaching 24,000 MPa, which significantly exceeds the initial value (2,500 MPa). 2. Ion implantation leads to significant changes in the cast iron microstructure. A diffusion layer about 400 µm thick is formed, in which graphite inclusions are almost completely absent. Fragmentation and disorientation of the pearlite colonies, characteristic of the initial structure of gray cast iron, occur. 3. As a result of nitrogen implantation, the phase composition of the surface layer is changed, and nitrides Fe2N and Fe3N are formed. An increase in the average dislocation density and a decrease in the size of mosaic blocks are observed. Therefore, the application of nitrogen ion implantation with an optimal dose allows obtaining a hardened layer on the surface of cast iron while maintaining the specified dimensions of parts. The obtained results open up opportunities for practical application of ion implantation in industry to improve the durability and reliability of grey cast iron parts used in various fields of engineering. References 1. Martyushev N.V., Kozlov V.N., Qi M., Tynchenko V.S., Kononenko R.V., Konyukhov V.Yu., Valuev D.V. Production of workpieces from martensitic stainless steel using electron-beam surfacing and investigation of cutting forces when milling workpieces. Materials, 2023, vol. 16, p. 4529. DOI: 10.3390/ma16134529.
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