Laser metal deposition of TiB/Ti6Al4V composites with first-scale network microstructure

This study investigated the effect of in-situ alloying of Ti6Al4V and TiB 2 during laser metal deposition for microstructure, hardness and tensile properties enhancement. It was found that the addition of TiB 2 at powder feed rates of range 0.1–0.3 rpm resulted in the formation of TiB whiskers with columnar and equiaxed network morphologies, in a lamella α + β matrix. By increasing TiB 2 at 0.4–0.5 rpm, a complete dissolution of the equiaxed and columnar network morphologies were achieved. The dissolution led to a random distribution of formed TiB whiskers, resulting in enhanced hardness and ultimate tensile strength (UTS), with the 0.5 rpm giving the highest hardness and UTS values of 511 ± 13 HV and 1745 MPa, respectively.