Breaking the strength-ductility trade-off in graphene/pure-Ti composites fabricated via selective laser melting

Enhancing the strength and ductility of commercially pure titanium (CP-Ti) holds significant promise for aerospace automotive and other industries, but overcoming the inherent trade-off between these properties remains a major challenge. This study investigates the effect of graphene addition on the mechanical properties, and strengthening-toughening mechanisms of CP-Ti by selective laser melting (SLM). The 0.3 wt% graphene-reinforced titanium composite demonstrates an exceptional strength-ductility synergy, achieving a yield strength of 708 MPa and tensile strength of 809 MPa – representing approximately 100% enhancement over pure CP-Ti – while maintaining remarkable elongation (38.9%). Therein, graphene significantly modify the as-deposited microstructure of CP-Ti, suppressing thermal stress-induced microcracks, promoting martensitic transformation and in-situ TiC formation. Furthermore, in-situ synchrotron X-ray diffraction reveals that graphene and TiC maintain high load-bearing capacity during deformation. Graphene inhibits matrix dislocation slip through interface coupling, while TiC contributes by providing a high elastic modulus and stable deformation resistance. This study clarifies the synergistic strengthening effects of graphene and TiC, offering new insights for optimizing the strength-ductility balance in titanium composites.