A mesoscopic model of dissolution/disintegration of nanocrystalline metals via vacancy diffusion along grain boundaries

► Surface vacancy supersaturation results in the growth of subsurface pores. ► Polycrystal disintegrates by grain detachment once the pores reach the surface. ► Pore growth by surface and grain boundary diffusion is analyzed. ► The proposed mechanism can operate at room temperature in nanocrystalline Cu and Fe.