Ultrahigh strength and ductile titanium composites enabled by nanoscale reinforcement and heterostructure engineering

Overcoming the strength–ductility trade-off remains a central challenge for titanium matrix composites, because ceramic reinforcements often induce severe interfacial stress concentration and premature cracking. Here, we develop a hierarchical heterostructure in Ti–6.5Al–2Zr–1Mo–1 V through in-situ reaction and subsequent hot extrusion, consisting of nanoscale TiB reinforcements, primary α, β phase and secondary α. The pronounced hetero-deformation-induced strengthening and activation of ⟨c + a⟩ dislocations enable the composite to achieve 1351 MPa tensile strength and 15.9% elongation, representing increases of 40.1% and 26.2% over the matrix alloy, respectively. This strategy offers a scalable route for designing high-performance titanium composites.Highlightsαp, β, autocatalytic αs and in-situ-formed nanoscale TiB jointly constitute the HHS composite.The HHS delivers 1351 MPa tensile strength and 15.9% elongation.Multiple deformation mechanisms collectively sustain the work-hardening capacity.TiB-assisted strain accommodation alleviates local stress concentration.