Achieving high performance in (NiTi₂ + TiC)/Ti composites with network architecture via reaction interface design

For the development of discontinuously reinforced titanium matrix composites (DRTMCs), tailoring the reinforcement network distribution has demonstrated significant advantages in alleviating the conflict between strength and ductility. In the present work, network structured titanium matrix composites reinforced with feathery NiTi₂ and TiC nanoparticles were successfully prepared via an in-situ processing strategy. The introduction of C and Ni into the Ti matrix was achieved by electroless nickel plating of graphene nanosheets (GNFs) and a short-time ball milling process. The investigations of microstructure revealed that the 3D network architecture gradually formed with the increase of the reinforcement content, and the in-situ generated feathery NiTi₂ was tightly connected to the TiC nanoparticles and grown into the Ti matrix. However, when the nickel content is too high, the 3D network architecture was replaced by a large number of amorphous areas, thereby deteriorating the performance of the composites. The tensile tests showed that the as-rolled composites can reach a tensile strength of 994 MPa while maintaining an acceptable ductility (~10.5%). The findings highlight the importance of interfacial microstructure design, which is helpful for the development of high-performance titanium matrix composites.