Materials, Methods & Technologies, Volume 15, 2021

Rezumat: In the rough and semi-pure processing of metal alloys, as well as in additive technologies, surface defects are often observed - the appearance of scratches, creases, recesses, incisions, pores, ridges, protruding particles, and other unevenness, undesirable spiral or concentric relief, traces of cutting edges of the tool and high roughness on the treated surface. In this work, the possibilities for improving the surface characteristics of materials such as steels, invar and titanium alloys with typical surface defects through reaction electrospark deposition (ESD) are investigated. A study of the conditions for the local formation of reactive phases and reduction of surface roughness during the electrospark modification was performed. Layering electrodes of low-melting Al-Si alloys were used. Their choice was made on the assumption that a liquid melt is formed in the process of ESD. It is expected that it will fill the recesses, pores and scratches and interact with the chemical elements contained in the substrate. The results of the studies of the change in the roughness, thickness and microstructural characteristics of the modified surfaces depending on the energy of the pulses and their influence on the wear resistance at friction are presented. A double effect has been achieved - a significant improvement in both the surface characteristics and the wear resistance of the modified surfaces. It was found that the improvement of surface quality and wear resistance was achieved as a result of partially burning the protrusions, filling the depressions with low melting electrode alloy and local synthesis of wear-resistant surface structures and phases obtained by the chemical interaction of the melt with the substrate. The energy parameters of the electric discharges, the process parameters, and the ESD conditions, suitable for the realization of the above phenomena, have been determined and optimized.