Additive Manufacturing Letters (Dec 2022)
Refined microstructure and ultrahigh mechanical strength of (TiN + TiB)/Ti composites in situ synthesized via laser powder bed fusion
Abstract
Titanium matrix composites reinforced by titanium nitride (TiN) and titanium boride (TiB) were in situ synthesized via laser powder bed fusion (L-PBF) using premixed boron nitride (BN) and titanium powders. The optimal BN content was determined as 0.5 wt%, and a near-full density was achieved with optimized process parameters. The microstructure of the printed composite consisted of α-Ti matrix doped with N, as well as nano-sized TiN and TiB precipitates. The ultimate tensile strength of the printed composite sample was enhanced by ∼85% from ∼590 MPa to ∼1100 MPa as compared with the pure Ti counterpart, whereas the elongation was reduced to ∼3%. This research provides insights into the additive manufacturing of metal composites with near-full density and enhanced mechanical strength.