Repetitive impact loading strengthens commercial-purity titanium without losing ductility and strain-hardening capacity

Repetitive impact loading was employed to introduce high-density deformation twins in commercial-purity titanium. The yield strength is increased by 38% and the tensile strength by 17%, while the total ductility and strain-hardening capacity are fully preserved. Microstructural observations reveal that pre-existing twin boundaries promote twin boundary migration, secondary twinning, and additional activated slip systems. These deformation mechanisms compensate for the ductility loss associated with high dislocation density and effectively sustain the strain-hardening ability. This work provides a feasible strategy for achieving strength–ductility synergy in hexagonal close packed metals.