OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 7 No. 2 2025 Similarly, to the gradual change in the feed rate of materials, the value of heat input also gradually changed along the height of the specimen (Fig. 6), unlike the change in heat input values depending on the layer when manufacturing bimetallic specimens with a sharp interface (Fig. 4). The heat input value when depositing layers of copper M1 does not exceed 0.27 kJ/mm. The heat input value when depositing layers of stainless steel AISI 321 is similar for both the manufacturing of bimetallic specimens with a smooth boundary of the AISI 321 –M1 system and the AISI 321-Cu-9 Al-2 Mn system: in the first case, the value varies within 0.36‑ 0.23 kJ/mm, in the second case it varies within 0.38‑0.28 kJ/mm, which is 1.5 times less than the heat input value when depositing steel layers during the manufacture of a bimetallic specimen of the AISI 321 - Cu-9 Al-2 Mn system. The heat input value when depositing layers of copper alloy Cu-9 Al-2 Mn during the manufacture of a bimetallic specimen of the AISI 321 - Cu-9 Al-2 Mn system does not exceed 0.23 kJ/mm, which is less than the heat input value for the 0.09 C-2 Mn-Si-Cu-9 Al-2 Mn system. The heat input value during the manufacture of a bimetallic specimen of the AISI 321-Cu-9 Al-2 Mn system does not exceed 0.37 kJ/mm. a b c Fig. 6. Variation of heat input values as a function of layer during EBAM of a bimetallic sample with a smooth interface between dissimilar materials: а – 0.12 C-18 Cr-9 Ni-Ti and M1; b – 0.12 C-18 Cr-9 Ni-Ti and Cu-9 Al-2 Mn; c – 0.09 C-2 Mn-Si and Cu-9 Al-2 Mn When forming a heterogeneous structure in a bimetallic specimen, the printing strategy was changed depending on the percentage ratio of the volume of dissimilar alloy wires fed. In the case of a larger volume of copper wire fed in relation to the iron wire fed, only the first material was continuously fed while the second material was fed in droplets, discretely. Discrete wire feeding involves portioned delivery of material to the melting zone. This method allows precise control of the volume of material fed and reduces thermal overloads, which is especially important when working with materials sensitive to thermal deformations. However, this approach requires high precision synchronization between the movement of the electron beam and wire feeding, which complicates process control. From the perspective of electron scattering theory, discrete wire feeding is characterized by local exposure of the electron beam to the material. Nevertheless, there is a risk of uneven heat distribution, which can cause defects such as local overheating or insufficient melting. To minimize these effects, it is necessary to carefully calculate electron beam parameters, such as energy, focusing, and pulse duration, taking into account the properties of the material. In the case of equal or smaller volume of copper wire fed in relation to the iron wire fed, simultaneous continuous feeding of wires into the melt pool was performed – continuous printing strategy (Fig. 7). Continuous wire feeding provides constant delivery of material to the melting zone, which contributes to more uniform heat distribution and reduces the risk of defects such as pores or cracks. However, continuous feeding requires precise control of wire feed rate and electron beam power to avoid overheating or insufficient melting. The difference in printing strategy is based on the strong differences in melting temperature and thermal conductivity of the materials used. When manufacturing bimetallic specimens with a smooth interface, it was found that the amount of material fed into the melt pool directly depends on the wire feed rate. To form
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