Influence of Si3N4 on Ti-6Al-4V via spark plasma sintering: Microstructure, corrosion and thermal stability

Highlights: • The Ti-6Al-4V-xSi₃N₄ composites were fabricated by spark plasma sintering technique at 1000°C. • Tubular mixing of Ti-6Al-4V with micron-sized Si₃N₄ powder resulted in fine dispersion within the titanium matrix. • Spark plasma sintered Ti-6Al-4V reinforced with Si₃N₄ particulates shows high hardness and corrosion-resistance properties. • The composites fabricated with 10 wt. %Si₃N₄ exhibits dense microstructures and excellent properties. The objective of this research was to study the influence Si₃N₄ on Ti-6Al-4V via spark plasma sintering process. The experiments were performed at a temperature of 1000 °C with a holding time of 6 min under a pressure of 50Mpa.Ti-6Al-4V powder was admixed with different weight proportions of Si₃N₄ powder. Sintered composite samples were produced from the mixture and the influence of Si₃N₄ on the microstructure; mechanical and thermal properties of the composites were investigated. Scanning electron microscope (SEM-EDS) was used to study the bulk morphology of the sintered composites. The phases present in the fabricated sintered composites were observed by energy dispersive X-ray diffraction spectrometer (XRD). Microhardness was investigated by the means of high impact diamond Durascan micros hardness tester. Electrochemical behavior of the sintered samples was measured by potentiodynamic polarization method. The thermal performances of the sintered composites were explored by a Thermal gravimetric analyser (TGA). The experimental results revealed that the microstructure, corrosion resistance and thermal stability properties of the material were improved by the addition of Si₃N₄. The effect of Si₃N₄ on the performance characteristics of Ti6AI4V alloy was seen to be compactable and useful in aerospace application.