New insights into the evolution of TiB whisker and TiC particle during selective laser melting of titanium matrix composites

In-situ TiB, TiC, and (TiB + TiC) reinforced titanium matrix composites were prepared by selective laser melting. We focused on clarifying the evolution mechanism of in-situ TiB whisker and TiC particle. Detailed microstructural characterization and phase diagram analysis revealed that the TiC particles were formed through a dissolution-precipitation mechanism, and the TiB whiskers were predominantly a reaction product. In the hybrid reinforced composite, the reaction product TiB whisker clusters acted as nucleation sites for TiC particles, thereby altering their distribution status. Compressive testing demonstrated that TiB whiskers exhibited a stronger strengthening effect than TiC particles, related to their different spatial distributions. Overall, our findings provide valuable insights into the evolution mechanism of TiB whisker and TiC particle during selective laser melting of titanium matrix composites and have important implications for their design and optimization.