OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 3 2025 Bronzes containing aluminum, silicon, and manganese are considered strain-hardening alloys. Applying severe plastic deformation (SPD) methods is a practical approach to intentionally modify their structuralphase state and, thereby, their mechanical properties. These methods encompass: forging, rolling, equalchannel angular pressing, high-pressure torsion, and surface plastic deformation [19, 20]. Currently, the impact of SPD on the structural, mechanical, and tribological characteristics of the Cu-AlSi-Mn bronze system, a material with considerable potential for industrial use, remains unexplored. This is particularly the case for materials fabricated via additive manufacturing techniques. In light of the foregoing review, the inherent promise of the material, and the identified deficiencies in existing studies, the objective of this research was established: to explore the correlations between the diverse structural states and the properties of the Cu-Al-Si-Mn copper alloy. To realize this objective, the following experimental tasks were undertaken: – to characterize the structure and phase composition of samples in the as-printed condition and following the application of intense plastic deformation techniques; – to evaluate mechanical properties, specifically tensile strength and microhardness, for samples exhibiting various structural states; – to analyze the tribological behavior of the samples; – to examine the morphology of the wear track surfaces. Methods To investigate the influence of structural states on the properties of Cu-Al-Si-Mn bronze, samples in the form of prismatic blocks (20×20×40 mm³) were fabricated using electron beam additive manufacturing. Printing was performed by simultaneously feeding two wires: Cu-3 Si-1 Mn (BrKMts 3-1) and commercially pure aluminum, in a ratio of 90 % bronze to 10 % aluminum [21]. The chemical composition of the samples was 93.8 wt.% Cu, 2.5 wt.% Al, 2.8 wt.% Si, 0.9 wt.% Mn. The printed blocks were subjected to severe plastic deformation (SPD) by means of multi-directional forging and rolling. In addition, the samples were also subjected to low-temperature heat treatment after SPD. The designations of the investigated samples and the processing parameters are listed in Table. Designation of samples and methods for forming their structure Sample designation Method of forming a structural state 1 Electron beam additive manufacturing 2 Multi-axial forging along three geometric axes until 40% plastic deformation is achieved in each direction 3 Rolling after multi-axial forging until 50% plastic deformation is achieved 4 Low-temperature annealing (30 min. at 400°C) after multi-axial forging with rapid cooling in water 5 Low-temperature annealing (30 min. at 400°C) after rolling with rapid cooling in water Flat tension test specimens were cut from the obtained samples using an electrical discharge machine for mechanical testing on a Testsystem UTS-110M testing machine. The tensile speed was 1 mm/min. Samples in the form of plates were additionally cut for conducting X-ray diffraction analysis on a Shimadzu XRD-7000 diffractometer. Microhardness measurements were performed using a Tochline-TBM microhardness tester with a load of 100 N. The fine structure of the samples was investigated by transmission electron microscopy on a JEOL JEM-2100 microscope. Tribological tests were conducted at a fixed sliding speed of 0.1 m/s and a normal load of 20 N under dry sliding friction conditions using a pin-on-disk scheme. Disks were cut from bronzes with different structural states. Counterbodies were made of ball-bearing steel (1 C-1.5 Cr). Tescan MIRA 3 LMU and Olympus OLS-4100 microscopes were used to investigate the surface condition of the samples after friction
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