Microstructural Stability of Ti based Composites Fabricated by Spark Plasma Sintering

In our previous study, the effects of TiC heterogeneous nucleation site particles on formability and microstructure of additive manufactured (AMed) Ti-6Al-4V products were studied. It was found that the addition of TiC particles decreased the grain size of primary β phase in AMed Ti-6Al-4V samples, since TiC particles act as heterogeneous nucleation sites. It is also found that the density of AMed Ti-6Al-4V samples could be increased by addition of TiC particles. It is expected that solid-state β-grain growth by the high temperature thermal cycles associated with layer-by-layer manufacturing can be suppressed by the pinning effect of TiC heterogeneous nucleation site particles. In this study, the pinning effect of heterogeneous nucleation site particles on microstructure of Ti at elevated temperatures is studied. For this purpose, Ti-0.3vol%TiC samples fabricated by spark plasma sintering (SPS) are used as the model materials, and microstructure and hardness of the samples heat treated at elevated temperatures are studied