  We investigate elastic-plastic adhesive wear via a continuum variational
phase-field approach. The model seamlessly captures the transition from
perfectly brittle, over quasi-brittle to elastic-plastic wear regimes, as the
ductility of the contacting material increases. Simulation results highlight
the existence of a critical condition that morphological features and material
ductility need to satisfy for the adhesive junction to detach a wear debris. We
propose a new criterion to discriminate between non-critical and critical
asperity contacts, where the former produce negligible wear while the latter
lead to significant debris formation.
