Evaluation of the Physical, Mechanical, Tribological, Electrochemical, and Oxidation Resistance Behaviour of Spark Plasma Sintering-Synthesized Ceramic-Reinforced Ti6Al4V-Based Composites

Abstract Lightweight materials like Ti6Al4V are ideal for faster aircraft engines with higher thrust-to-mass ratios and lower fuel consumption. However, a high thrust-to-weight ratio elevates engine operating temperatures above service limits, which is detrimental to both mechanical and oxidation resistance. This study reports the synthesis of Ti6Al4V-based composites through spark plasma sintering, incorporating 5 wt.% of hexagonal boron nitride ( h -BN), titanium nitride (TiN), and aluminium nitride (AlN) nanoparticles. The synthesized composites were evaluated for microstructure, phase composition, density, microhardness, tribological properties, electrochemical behaviour, and oxidation resistance. The composites exhibit a decrease in effective density as compared to unreinforced Ti6Al4V (4.42 g/cm 3 ), with measured values of 4.12 g/cm 3 (5 h -BN/Ti6Al4V), 4.32 g/cm 3 (5TiN/Ti6Al4V), and 4.13 g/cm 3 (5AlN/Ti6Al4V), corresponding to relative densities of 97.40%, 97.63%, and 95.14%. The microhardness of unreinforced Ti6Al4V increased from 331.79 to 740.43 HV following reinforcement. Specifically, 5 h -BN/Ti6Al4V demonstrated a performance enhancement of nearly 123%, while 5TiN/Ti6Al4V and 5AlN/Ti6Al4V showed increases of 48% and approximately 52%. The unreinforced alloy demonstrates a higher mean coefficient of friction (COF) as compared to reinforced composites. 5AlN/Ti6Al4V exhibits the highest mean COF values among the composites, followed by 5TiN/Ti6Al4V, and subsequently, 5 h -BN/Ti6Al4V. Each composite exhibits a reduced specific wear rate compared with the unreinforced alloy, which can be attributed to its enhanced microhardness. 5TiN/Ti6Al4V exhibited optimal electrochemical characteristics, with a polarization resistance of 4291.6 Ω and a comparatively low corrosion rate of 0.037641 mm/year. Furthermore, 5TiN/Ti6Al4V exhibits markedly improved oxidation resistance, as indicated by its minimal weight gain of 2.06% compared to its counterparts. The synthesis of composites with enhanced performance is anticipated to expand Ti6Al4V alloy's aerospace applications and help develop more sustainable aerospace technologies.