Microstructural refinement and multi-property optimization of TiB2-reinforced tial composites synthesized by spark plasma sintering

TiAl-xTiB 2 (0.5–3.0 wt%) composites were synthesized via spark plasma sintering (SPS) at 1200 °C and 50 MPa to enhance the microstructural integrity and multifunctional performance of TiAl intermetallic. Moderate TiB 2 additions (1.0–1.5 wt%) produced a refined, pore-free matrix through particle-matrix interactions and particle-assisted diffusion, achieving a maximum relative density of 99.2%. Hardness increased from 459 HV (0.5 wt% TiB 2 ) to 488 HV (3.0 wt% TiB 2 ), an improvement attributed to microstructural refinement and dislocation-particle interaction mechanisms. The wear rate decreased significantly from 52.5 × 10 − 5 mm 3 /m (0.5 wt% TiB 2 ) to 11.0 × 10 − 5 mm 3 /m (3.0 wt% TiB 2 ), owing to enhanced hardness, improved load-bearing capability, and the formation of protective mixed tribo-oxide films. Electrochemical tests in NaCl solution revealed the best corrosion resistance occurred at 1.0 wt% TiB 2 with E corr = 0.00 V, I corr = 1.0 × 10 − 6 A/cm 2 , R p = 9.6 × 10 3 Ω.cm 2 , and a corrosion rate of 0.012 mm/yr. Excessive TiB 2 loading (> 2.0 wt%) promoted particle clustering, localized galvanic coupling, and reduced electrochemical stability. Overall, controlled TiB 2 reinforcement (1.0–2.0 wt%) optimally balanced densification, mechanical strength, wear resistance, and corrosion protection, underscoring the potential of SPS-processed TiAl-TiB 2 composites for high-temperature and aerospace structural applications.