OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 3 2025 Fig. 2. X-ray diffraction (XRD) patterns of Cu-Al-Si-Mn bronze samples a b c d forging (Sample 2, Figs. 2, c, d). The intensity of the reflections from this phase increased after multidirectional forging, presumably due to the formation of γ2-Cu9Al4 during plastic deformation within the CuAl system. It is known that γ2-Cu9Al4 is formed during mechanical alloying and friction stir processing and decomposes into its components when heated above 180 °C [22]. Therefore, either intermediate annealing before rolling or complete annealing at 400 °C can completely eliminate this phase. In addition, reflections of the β-Cu3Al phase are observed, which are found in samples of the as-printed bronze (Sample 1, Figs. 2, c, d), samples after multi-directional forging (Sample 2, Figs. 2, c, d), and heattreated samples after multi-directional forging (Sample 4, Figs. 2, c, d). One of the key factors affecting the phase composition of samples after SPD is the mechanism of deformation-induced dissolution of intermetallic phases [23]. As a result of SPD, particles of secondary phases dissolve, are fragmented, and refined under the influence of high stresses and a dislocation density close to the theoretical limit [24]. The possibility of precipitation of finely dispersed intermetallic particles is also not excluded, which is also a consequence of SPD and leads to additional strengthening of the alloy. The modification of the material’s structure through severe plastic deformation (SPD), followed by subsequent heat treatment, resulted in changes to the mechanical properties of the bronze, in comparison to the as-printed condition. The conducted investigations clearly demonstrate that the sequential application of SPD methods — namely, multi-directional forging and rolling — causes a substantial increase in the tensile strength of the bronze compared to the initial state obtained by the electron beam additive manufacturing method (Fig. 3, a). In particular, the use of multi-directional forging provided a significant strength increase of 179 MPa, while the rolling process led to an even more pronounced enhancement of mechanical properties, increasing the tensile strength by 515 MPa.
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