Achieving superior creep properties in high-temperature titanium alloys via heterostructure and multiscale precipitates

Titanium alloys for high-temperature applications require superior creep resistance for fabricating high-performance structural components. Here, we design a hetero-structured Ti60 alloy decorated with multiscale precipitates. It is characterized by lamellar α phase with submicron and nanosizes, and multiscale silicides, achieved via a rapid heating and aging (RHA) process. At 600 °C/300 MPa, this hetero-structured Ti60 alloy demonstrates a significantly reduced steady-state creep rate from 4.65 × 10 −6 s −1 to 1.22 × 10 −6 s −1 , and an extension in creep rupture life from 33.8 h to 105.8 h, successfully enhancing damage tolerance in a fully lamellar microstructure. The dense heterointerfaces and multiscale silicides cooperatively impede dislocation slip and grain boundary sliding, which improves high-temperature creep resistance. Moreover, the heterogeneous microstructure facilitates improved strain partitioning and develops deformation compatibility to effectively delocalize strain concentration, while the multiscale silicides with proper volume fraction minimize particle-induced stress concentration. Furthermore, the multiscale silicides with controlled grain boundary precipitation behavior suppress brittle-like creep fracture. This work provides a new pathway to optimize creep performance in titanium alloys for high-temperature applications.