Current-carrying friction induced interfacial degradation and delamination mechanism in AgCu10 alloy

Ag-Cu alloys used in sliding electrical contacts often fail by delamination under current-carrying friction. This study examines the delamination mechanism in AgCu10 by characterizing subsurface microstructural evolution. Results show that gradient subsurface changes and incompatible deformation between the Ag-rich phase and Cu-rich phase, driven by coupled mechanical-electrical-thermal fields, are central to delamination. Near the worn surface, Cu-rich phase transforms into nano-lamellae aligned with the sliding direction, promoting microcrack initiation at Ag/Cu interfaces. Interfacial degradation involves 9R phase formation, lattice distortion, amorphization, and nanoscale recrystallization. These findings reveal the link between subsurface gradients and current-assisted delamination, offering guidance for alloy design.