Achieving high strength and ductility in multiscale (TiC+(TiZr)₅Si₃)/TA15 composites via spark plasma sintering and hot rolling

A (TiC + (TiZr)₅Si₃)/TA15 composite was successfully fabricated using polycarbosilane (PCS) and TA15 alloy as starting materials via spark plasma sintering followed by hot rolling. This processing route resulted in simultaneous enhancements in both strength and ductility. The present study systematically investigates the microstructural evolution and mechanical performance of the composite before and after hot rolling. Compared with the as-sintered condition, the hot-rolled composite exhibits significant grain refinement and the development of a pronounced T-type texture in the α-Ti matrix. Mechanical testing reveals that the hot-rolled composite with 1 wt% PCS achieves a yield strength (YS) of 1334 MPa, an ultimate tensile strength (UTS) of 1422 MPa, and a total elongation of 17.2 %. Increasing the PCS content to 2 wt% leads to further improvements in YS and UTS, reaching 1456 MPa and 1542 MPa, respectively, albeit with a reduction in ductility to 2.3 %. At 600 °C, the tensile strengths of the hot-rolled composites with 1 wt% and 2 wt% PCS reach 929 MPa and 1037 MPa, respectively, demonstrating excellent high-temperature mechanical performance. Further analysis indicates that grain boundary strengthening, dislocation strengthening, and texture strengthening are the primary contributors to the enhanced strength of the as-rolled composites. Meanwhile, the improved ductility is primarily attributed to grain refinement, enhanced matrix connectivity, and the activation of multiple slip systems during tensile deformation.