Break through the strength-ductility trade-off dilemma in titanium matrix composites via precipitation assisted interface tailoring and solid solution

Abstract

TiC reinforced Ti matrix composites containing C and Si solid solution elements were successfully synthesized via spark plasma sintering (SPS) using the Ti and SiC as the raw materials. It is found that the C and Si solid solution elements can facilitate the dislocation slip by significant change in their respective critical resolved shear stresses and width of α-Ti and β-Ti. When the SiC addition is up to 0.5 wt% and 1 wt%, the TiC reinforcements were in-situ formed. The microstructure characterizations reveal the orientation relationship between TiC and α-Ti in TiC/Ti composite, which has the robust interfacial bonding. Combined with the effective strengthening mechanisms of C, Si solid solution and TiC with well bonded TiC/Ti interface, the highest ultimate tensile strength (1309 MPa) together with high ductility (5.1 %) can be achieved for 1SiC composite. The improved yield strength of the composites was calculated on the basis of several well-known strengthening mechanisms, such as grain refinement, solid solution, load transfer, thermal mismatch, dislocation strengthening. This strategy not only sheds light on the understanding of the strength-ductility synergy of titanium matrix composites, but also offers an available pathway to design ultra-strong and ductile composites.