Study on Ultrasonic Rolling Enhancement of TC4 and Its Tribological Characteristics Under Seawater Lubrication

To enhance the abrasion resistance of TC4 titanium alloy and meet the demand for wear-resistant and corrosion-resistant friction pair materials for water-hydraulic components of marine equipment, the tribological properties of the material subsequent to ultrasonic rolling extrusion surface strengthening under seawater-lubricated conditions were investigated. The process of ultrasonic rolling machining was simulated and analyzed by the finite element method. The influence of process parameters on surface residual stress and surface roughness of TC4 was studied, and the appropriate range of process parameters was determined. The effects of key process parameters such as rolling times, static pressure, amplitude, and rotational speed on the surface properties of TC4 were investigated by the single-factor test method. Based on the response surface methodology, a prediction model of surface hardness and roughness of TC4 was constructed, and the process parameters were optimized and analyzed. The friction coefficient, wear amount, and wear rate of TC4 and CFRPEEK under seawater lubrication before and after strengthening were studied by wear tests. The wear morphologies of the specimens prior to and subsequent to strengthening were analyzed, and the friction and wear mechanisms were explored in depth. The results indicate that ultrasonic rolling extrusion surface strengthening process facilitates grain refinement in the surface layer of TC4, enhances surface hardness, and optimizes surface roughness, thereby improving its wear resistance. This is of guiding significance to the design and use of hydraulic components in seawater and has a promoting effect on the development of marine equipment.