Wear Features of Nickel-Based Superalloy ZhS6U and Commercial Pure Titanium During Dry Friction in a Pin-on-Disc Scheme

Extreme working conditions place high demands on material properties. For example, tools for friction stir welding of titanium alloys must be highly wear-resistant, have high strength at high temperatures, and also have high adhesion properties. These requirements complicate the selection of materials for tool manufacturing. One of the possible solutions is heat-resistant nickel superalloys, such as the ZhS6U alloy. However, since these alloys have not been commonly used in friction pairs, they have hardly been studied in the context of friction. This work experimentally investigates the friction and wear characteristics of the nickel alloy ZhS6U and commercial pure titanium under dry friction in a pin-on-disc scheme. The research found that during friction, an oxidized mechanically mixed transfer layer is composed of wear products, and it can reduce the friction coefficient. Only adhesive wear was observed in the selected range of sliding speeds (0.46 m/s–1.84 m/s). It was found that the values of the friction coefficient, the mass loss of the titanium disc, and the width and depth of the friction track correlate with each other—as the speed increases, they first increase to a maximum value and then decrease. Minimal disc wear was observed at a speed of 0.46 m/s. The maximum friction coefficient was 0.79 and was observed at a sliding speed of 0.92 m/s. It was also found that the friction surface area is linearly dependent on the sliding speed, and the wear rate of the pins increases with increasing sliding speed according to an exponential law.