Enhanced creep resistance of titanium matrix composites by targeted strengthening of weak phases

High-temperature creep in titanium alloys is governed not only by thermally activated dislocation motion within grains but also by deformation and damage localization at interfaces. Therefore, enhancing creep resistance requires site-specific strengthening of the corresponding weak regions rather than uniform strengthening alone. Here, we reported a Ti55-based titanium matrix composite designed through targeted configuration strengthening, in which multiscale architectures were introduced at prior β grain boundaries, α/β phase boundaries and α grains. The composite consisted of an in-situ TiB network at the prior-β-grain scale, network-distributed (Ti,Zr)₅Si₃ particles along α/β phase boundaries, and dispersed Nd₅Sn₃ particles within α grains. Creep tests showed that the composite achieved a rupture life of 189 h at 650 °C under 200 MPa, representing a 62% improvement over the Ti55 alloy, together with reduced steady-state creep rates. Quasi-in-situ grid tracking, surface-crack and internal-void observations, EBSD-based dislocation analyses and TEM characterization revealed that these multiscale architectures suppressed creep through complementary mechanisms. The TiB network homogenized deformation across prior β grain boundaries and suppressed grain-boundary deformation localization; interfacial (Ti,Zr)₅Si₃ strengthened α/β phase boundaries and delayed interface damage localization; and intragranular Nd₅Sn₃ pinned thermally activated dislocations. During creep, secondary (Ti,Zr)₅Si₃ and dynamically precipitated Ti₃Al further contributed to dislocation pinning. These results establish site-specific configurational strengthening as an effective strategy for improving the creep resistance of titanium matrix composites and provide a quasi-in-situ methodology for decoupling the roles of multiscale strengthening architectures.