Microstructural aspects of in-situ TiB reinforced Ti-6Al-4V composite processed by spark plasma sintering

Titanium-matrix composites have important and wide applications in the transport and aerospace industries. The current research was focused on powder metallurgy processing of in-situ reinforced titanium-matrix composite with TiB whiskers. The Ti-6Al-4V alloy and B4C additive powders were used as raw materials. Two different consolidation techniques, namely press-and-sintering and spark plasma sintering, were selected. It was observed that in-situ TiB whiskers were formed during sintering in both methods. The changes in size, aspect ratio and distribution of in-situ whiskers in different composite samples were monitored. The effect of spark plasma sintering temperature on the synthesis of in-situ whiskers was also investigated. Based on the microstructural observations (optical microscopy and scanning electron microscopy) and the energy dispersive spectroscopy analysis, it was concluded that increasing the spark plasma sintering temperature from 900 to 1100 degrees C would lead to the complete formation of in-situ TiB whiskers and reduced porosity content.