Improving the tribocorrosion resistance by increasing the impact strength of an iron alloy manufactured by the wire arc additive manufacturing method

The article demonstrates the possibility of increasing the tribocorrosion resistance of sliding friction nodes by increasing the impact strength of the structural material. The concept is an alternative to methods of improving wear resistance by increasing hardness. The study was performed for the iron alloy Fe (0.21 % C, 0.8 % Si, 1.29 % Mn, 1.34 % Cr) in association with an Al₂O₃ ball. The samples were manufactured using Wire Arc Additive Manufacturing (WAAM) technology. This modern welding method is increasingly used to produce prototype machine components. The authors proposed a dedicated heat treatment to enable a significant increase in impact strength. The treatment is a combination of austenitization, martensitic hardening, annealing, and isothermal hardening. Comparative wear tests were conducted on samples with and without heat treatment. The tests were performed on a ball-on-plate model node in a 3.5 % NaCl environment. The alloy samples subjected to dedicated heat treatment showed significantly lower tribocorrosion wear than the untreated base material. No signs of wear were found on the surface of the counter-samples in microscopic observations. In addition, a model of the wear process was formulated to explain the effect of impact strength on the wear rate. The model assumes that the amount of energy supplied by friction and required to detach the deformed material is proportional to the impact strength of the material.