Plastic deformation of metals refines the microstructure and increases the strength through work hardening

but this effect of deformation is counterbalanced by dynamic recovery. After large strain

the microstructure typically shows a lamellar morphology

with finely spaced lamellar boundaries connected by triple junctions. Here

we report that mechanically assisted triple junction motion is an important contributor to dynamic recovery

leading to an almost steady state. Triple junction motion replaces two boundaries by one

while maintaining the structural morphology. The observation rationalizes both a decreasing work hardening rate and the approach to a dynamic equilibrium of structural refinement at large strains.