High-strength Ti-BN composites with core-shell structured matrix and network-woven structured TiB nanowires
(1. School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072, Australia;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: A novel architectural Ti composite composed of network-woven structured TiB nanowires in a core-shell structured Ti matrix was fabricated to improve the strength of Ti matrix composites (TMCs), where the shell consists of rich N solute atoms while the core is deficient of N solute atoms through spark plasma sintering of powder mixtures of Ti powder and BN nano-powder. The phase composition, morphology, element distribution, and mechanical properties of prepared samples were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), electron probe microanalyzer (EPMA), and electronic universal material testing machine. The results indicate that the TMCs with designed architectures have been successfully achieved, and the as-prepared Ti-2BN (wt.%) composite exhibits an ultimate compressive strength of ~1.8 GPa with a strain-to-fracture of ~9%, while the Ti-1BN (wt.%) attains an ultimate compressive strength of ~1.6 GPa and a strain-to-fracture of ~20%. Moreover, the roles of the hybrid reinforcement structures in strengthening the Ti composites were discussed.
Key words: titanium matrix composites; TiB nanowires; nitrogen; network-woven structure; core-shell structure