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Based on the wear analysis of a propeller hub bearing, wear tests are designed under different marine environments to illustrate wear failure mechanisms. The results reveal that the wear failure characteristics of the propeller hub bearing are primarily abrasive wear, accompanied by adhesion and oxidation wears, and plastic deformation. These results agree well with the wear morphologies of the torsional fretting wear tests under starvation lubrication. The wear tests confirm that the wear failure of the propeller hub bearing is owing to the coexistence of multiple wear mechanisms, which is attributed primarily to the superimposed wear behaviors induced by loading, continuous fretting wear, and starvation lubrication in the local contact areas. Hence, the negative effects of interfacial micro-protrusion adhesion and fracture during oil lubrication are difficult to eliminate. Moreover, The uneven radial loads of the contact surfaces of the propeller hub bearing also exhibit a significant influence on the thickness and formation of the oil film at the friction interface. [Display omitted] • Wear failure mechanisms of bearing coated with NAB alloys had been studied. • The designed wear tests were conducted by a self-assemble tribological platform. • Wear failure morphologies of bearing and wear tests results had been discussed. • Physical model at the different wear stages was established. [ABSTRACT FROM AUTHOR]

In this study, NiAl bronze (NAB) alloys are processed using an ultrasonic vibration-assisted milling (UVAM) surface engineering technique. The strengthening mechanisms at different cutting speeds are analysed through well-established models and experiments. The increase in cutting speed produced decrements of 29.5%, 26.6%, and 5.6% in the friction torques, accumulated dissipated energy, and worn surface area, respectively. The microhardness gradually increased by 11%, which helped improve the fretting wear performance. Grain refinement, precipitation, and dislocation strengthening were the main mechanisms. Grain refinement (∆ σ HP) had the greatest contribution to performance, followed by precipitation (∆ σ or) and dislocation (∆ σ d). Nanotwin strengthening was observed at a cutting speed of 150 m/min. Martensite nanotwins may nucleate at the grain boundary and grow toward the grain interior. [Display omitted] • The increase of cutting speed leads to beneficial effects on their fretting behavior including friction torques, accumulated dissipated energy and worn surface area for 29.5%, 26.6% and 5.6%, respectively. • The refinement of the κ phases and the effects of dislocations and stacking faults help increase the hardness and mechanisms were analysed. • The formation of martensite phases in UVAM6000 was attributed to severe plastic deformation and the special 3R martensitic structures of NAB alloys. Specifically, martensite nanotwins may nucleate at the grain boundary and then grew toward the interior of grains. • Grain refinement, precipitate, and dislocation strengthening were the main mechanisms for all samples and its contributions were calculated through well-established models and experiment data. [ABSTRACT FROM AUTHOR]