Multiscale evolution of lubrication and damage in crankshaft surfaces fabricated by ultrasonic elliptical vibration cutting

Ultrasonic elliptical vibration cutting (UEVC) offers an effective route for generating ordered textures on crankshaft surfaces; however, how these machined textures undergo elastic recovery after material removal, sustain hydrodynamic lubrication, and govern wear-induced subsurface damage remains insufficiently understood. To address this gap, an integrated multiscale framework is established by coupling tool–workpiece kinematics, microtexture formation, hydrodynamic lubrication, and elastic recovery, enabling the evolution of UEVC-generated topography to be traced from a cutting-induced surface feature to an effective load-bearing film geometry and further to wear-induced damage. The framework is examined through comparative machining trials, hydrodynamic lubrication calculations, and lubricated sliding tests, with nanoscratch and EBSD/TEM analyses used to connect the interfacial response with subsurface deformation. The results show that, compared with conventional cutting, UEVC changes the surface-generation mode by suppressing plowing traces, adhesive transfer, and fracture-related defects associated with unstable material removal, producing a more regular ridge-valley texture with improved form accuracy and surface integrity. During lubricated sliding, the periodic ridges, valleys, and vibration-induced scallops provide local lubricant-storage spaces and pressure gradients, promoting lubricant-film redistribution and reducing direct asperity contact. The resulting contact state mitigates localized surface failure and confines the subsurface response to near-surface plastic accommodation, where deformation proceeds mainly through dislocation accumulation, grain refinement, and localized nanocrystallization, with no amorphization or phase transformation observed. These findings provide a mechanistic basis for manufacturing crankshaft surfaces with integrated precision texture generation, stable lubricant-film support, and damage resistance.