OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 1 2023 Fig. 13. Images of the wear surfaces of C65500 bronze specimens, printed according to 1 (a), 3 (b) and 7 (c) EBAM modes, annealed specimen (d), deformed and annealed specimen (e) a b c d e the marks of bronze adhered to balls’ surface are observed. This is due to the adhesive wear mechanism in the considered steel-bronze friction pair. The thickness of these adhesion transferred layers does not exceed 1.5 μm, which was established from measurement of a three-dimensional surface profile using laser scanning microscopy. The surface of wear tracks of bronze specimens (Fig. 15), printed with the addition of aluminum filament, significantly differs from those of the tracks on the surface of as-printed bronze specimens C65500 (Fig. 13). There are no traces of plastic deformation of the material at the periphery of the tracks; there is also no surface oxidation in the form of dark spots. At the same time, on the periphery of the tracks there are areas with material pushed aside as a result of deformation. The surface of the balls (Fig. 16) is covered with a layer of adhesion-transferred bronze, which is significant both in area and in thickness. The thickness of the adhered material is uneven over the entire area and reaches 5–12 µm. This indicates a stronger adhesive interaction between the materials of the friction pair. The experimental data obtained indicate that in the case of dry reciprocating sliding of the specimens, the CoF fluctuations were revealed, which are unavoidable with the use this experimental scheme and the combined adhesive-oxidative wear mechanism.
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