Effects of trace TiB and TiC on microstructure and tensile properties of β titanium alloy

In the present work, a β titanium alloy reinforced by trace TiB whiskers and TiC particles was fabricated by common casting and hot-forging. For comparative study, the unreinforced titanium matrix alloy was also fabricated by the same casting and forging process. The microstructure, room temperature, tensile properties and fracture characteristics of the composite and the matrix alloy are presented and discussed. Microstructural analysis of the composite revealed that the reinforcements were uniformly dispersed after forging. The size of the β grains in the composite was refined after solution treatment under the β field. The secondary α lath was also refined during aging heat treatment by the addition of trace boron and carbon. The results of the tensile tests show that the improvement in the strength of the composite can be attributed to the refinement in the grain size and the secondary α lath, while the remarkable reduction in the ductility can be ascribed to the cracking of the reinforcements and the decohesion at the interface between the reinforcements and the matrix.