Microstructure evolution of in-situ synthesised (TiB + TiC) particulate reinforced titanium matrix composites casting

Abstract

This research article focuses on the microstructure evolution and crystallisation sequence of particulate-reinforced titanium matrix composites (TMCs) prepared through the investment casting process. Boron carbide (B4C) was added to the titanium melts using vacuum induction melting, resulting in an in-situ reaction, 5Ti + B4C = 4TiB + TiC, that produced 5, 10 and 20 vol.-% (TiB + TiC) reinforcements. The results showed that the size and distribution of the in-situ reinforcements varied with the B4C size and content. Additionally, the presence of carbon element in graphite crucible affected the crystallisation sequence of TiB and TiC, leading to different morphologies and sizes. The study also investigated the interaction between the TMCs and mould materials, demonstrating the feasibility of achieving alpha-case controlled TMC castings.