Effect of B Content on the Microstructure and Properties of As-cast TC4/B

In this paper, the TC4 titanium matrix composite were fabricated by melting-casting process, the composite was reinforced with different content of B ranging from 0.2wt% to 1.0wt%. The microstructure and mechanical properties of as-cast TC4/B titanium matrix composite were investigated. The results indicate that the elastic modulus increase 15%-30% for TC4/B composite with 0.2wt% to 1.0wt% B. The microstructures of as-cast TC4/B are consisted of lamellar a, grain boundaries beta and the second phase of TiB, and the second phase TiB aggregates at the prior-beta grain boundaries with necklace-like arrangement. The microstructures of TC4/B would refine with the increath of B content. From the analysis of fractographies, it can be found that with the increasing of B content, the fracture model transforms from typical intergranular fracture to mixed fracture.