Selective laser melting of TiB2-Ti composite with high content of ceramic phase

An increasing need in customized ceramics and ceramic-metal composites has driven the development of powders feedstock and procedures for utilization of additive manufacturing for production of mechanically reliable composites. However, processing of materials with a high fraction of ceramic particles is still in its infancy. Herein we report on 3D printing of TiB2-TiB-Ti composites from TiB2-Ti powder mixture of high ceramic content (50 wt%TiB2) by an optimized process of selective laser melting. In-situ synthesized from the mixture of commercially pure Ti and TiB2 powders, the composites possess up to 20.4 GPa hardness despite of a relatively high porosity of around 8%. Improvement in hardness is mainly due to hardening effect of both TiB and TiB2 and correlated with an increase in fraction of needle-shaped TiB phase with an increase in laser energy density (LED). Depending on process parameters, an amount of the ceramic phases (needle-shaped TiB and coarse elongated TiB2) can be customized. The laser energy density significantly affects the development of microstructure and size of the ceramic grains as well as the formation of solidification cracks. This study demonstrates the capacity of AM through SLM to produce the composites of high percentage of ceramic phase.