Effect of TiB2 Content on Microstructure and Properties of in-situ TiB/Ti6Al4V Composites

Ti6Al4V powder added TiB2 particles with a mass fraction of 0%similar to 5% was melted using selective laser melting to produce the in-situ TiB/ Ti6Al4V composites to study the forming properties, microstructure evolution, and mechanical properties of samples with different TiB2 additions. When the mass fraction of TiB2 added was 1%, the a '- Ti in the microstructure of the sample gradually disappeared, and a dispersedly distributed unit cell like TiB was observed. Further addition of TiB2 caused the strengthening method of the material to evolve from dispersion strengthening to whisker strengthening. Simultaneously, TiB in the grain boundary was enriched to form a dendritic structure and a network structure. The in-situ TiB as a nucleation point can remarkably enhance the hardness and friction performances of the TiB/Ti6Al4V sample under the action of fine grain strengthening, solid solution strengthening, and whisker strengthening. As a result, the microhardness of the sample increased from (336. 8 +/- 6. 64) HV to (498. 07 +/- 12. 56) HV, and the wear mechanism of the sample changed from adhesive wear to abrasive wear. When the mass fraction of TiB2 added was 1%, better wear performance was obtained.