Mechanical property and microstructure of in-situ TiB/Ti64 composites via adding oxygen scavenger CaB6

Powder metallurgy in-situ TiB/Ti6Al4V composites with good mechanical properties are fabricated by vacuum sintering using high-oxygen HDH Ti6Al4V and CaB6 powders. CaB6 can not only be used as a boron source, but also synthesize Ca-Ti-O ternary compounds with solid solution oxygen in titanium matrix. Therefore, it has a purification effect on oxygen scavenging, and the relative density of TiB/Ti6Al4V composites can exceed 99%. The interface between titanium matrix and TiB is semi-coherent. Good interfacial adhesion, high density, and reduced oxygen content make the composite material exhibit higher ductility. Although the equivalent oxygen content for Ti6Al4V-0.1CaB6 composite material is about 0.57 wt%, the elongation still reaches 9.5%, which is 57.4% higher than that of CaB6-free sample. Besides, the ultimate tensile strength reaches 1015.6 MPa, and the yield strength is 932.0 MPa.