Influence of spark plasma sintering on microstructure and corrosion behaviour of Ti-6Al-4V alloy reinforced with micron-sized Si3N4 powder

Abstract

Ti-6Al-4V-Si3N4 composites were effectively fabricated by spark plasma sintering (SPS) technique. The addition of Si3N4 on Ti-6Al-4V was varied from 5% to 15% (wt fraction). The effect of Si3N4 addition on the densification, microstructure, and microhardness and corrosion behaviour of Ti-6Al-4V was investigated. An increase in microhardness value was recorded from 325.46 HV0.1 to 585.73 HV0.1. X-ray diffraction (XRD) analysis showed that the intensity of diffraction peaks of Si3N4 phase in the composites increased. The sintered Ti-6Al-4V reinforced with Si3N4 compacts revealed the non-existence of intermediate phases, such as TiSi2 (titanium silicide) which was expected. SEM analysis of the spark plasma sintered composites revealed α and β phase microstructures in Ti-6Al-4V with uniform distribution of Si3N4 particulates in the matrix. The corrosion resistance property of the material was improved by the addition of Si3N4 from 0.986629 mm/year to 0.030547 mm/year. Keywords: Spark plasma sintering, Si3N4, Ti-6Al-4V, Microstructure, Corrosion